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International Geology Review

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Arc magmatic evolution and the construction ofcontinental crust at the Central American VolcanicArc system

Scott A Whattam amp Robert J Stern

To cite this article Scott A Whattam amp Robert J Stern (2015) Arc magmatic evolution and theconstruction of continental crust at the Central American Volcanic Arc system InternationalGeology Review DOI 1010800020681420151103668

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Arc magmatic evolution and the construction of continental crust at the CentralAmerican Volcanic Arc systemScott A Whattama and Robert J Sternb

aDepartment of Earth and Environmental Sciences Korea University Seoul Republic of Korea bGeosciences Department University of Texasat Dallas Richardson TX 75083-0688 USA

ABSTRACTWhether or not magmatic arcs evolve compositionally with time and the processes responsibleremain controversial Resolution of this question requires the reconstruction of arc geochemicalevolution at the level of a discrete arc system Here we address this problem using the well-studied Central American Volcanic Arc System (CAVAS) as an example Geochemical and isotopicdata were compiled for 1031 samples of lavas and intrusive rocks from the ~1100 km-longsegment of oceanic CAVAS (Panama Costa Rica Nicaragua) built on thickened oceanic crustover its 75 million year lifespan We used available age constraints to subdivide this data set intosix magmatic phases 75ndash39 Ma (Phase I or PI) 35ndash16 Ma (PII) 16ndash6 Ma (PIII) 6ndash3 Ma (PIV)59ndash001 Ma (PVa arc alkaline and PVb adakitic) and 26ndash0 Ma (PVI Quaternary to modernmagmatism predominantly ≪ 1 Ma) To correct for magmatic fractionation selected major andtrace element abundances were linearly regressed to 55 wt SiO2 The most striking observationis the overall evolution of the CAVAS to more incompatible element enriched and ultimatelycontinental-like compositions with time although magmatic evolution took on a more regionalcharacter in the youngest rocks with magmatic rocks of Nicaragua becoming increasinglydistinguishable from those of Costa Rica and Panama with time Models entailing progressivearc magmatic enrichment are generally supported by the CAVAS record Progressive enrichmentof the oceanic CAVAS with time reflects changes in mantle wedge composition and decreasedmelting due to arc crust thickening which was kick-started by the involvement of enriched plumemantle in the formation of the CAVAS Progressive crustal thickening and associated changes inthe sub-arc thermal regime resulted in decreasing degrees of partial melting over time whichallowed for progressive enrichment of the CAVAS and ultimately the production of continental-like crust in Panama and Costa Rica by ~16ndash10 Ma

ARTICLE HISTORYReceived 30 September 2015Accepted 1 October 2015

KEYWORDSVolcanic arc subductioncontinental crust tectonicsCentral America CaribbeanGalapagos Plume

1 Introduction

Subduction zone magmatism results primarily from thedehydration of subducted oceanic crust and sedimentmelting and the subsequent transfer of these liquids tothe overlying mantle wedge where partial meltingoccurs (White and Patchett 1984 McCulloch andGamble 1991 Plank and Langmuir 1993 Hawkesworthet al 1993a 1993b Pearce and Peate 1995 Ishikawaand Tera 1997 Kimura et al 2014) The diagnostic che-mical signatures of subduction zone magmatisminclude (1) abundant felsic rocks (2) a tendency tominimize Fe-enrichment during magmatic fractionation(3) elevated abundances of large ion lithophile elements(LILEs) relative to the light rare earth elements (LREEs)and (4) depletion of high field strength elements(HFSEs) (eg Arculus 1994) (see Table 1 for a list of themost common abbreviations and acronyms used here

and their definitions) These characteristics are largelydue to the fluid-mediated nature of convergent marginmagmatism and to the fact that in contrast to igneousactivity at mid-ocean ridges and hotspots arc magmaticactivity stays in the same place relative to the under-lying crust for tens of millions of years

Study of arc igneous rocks must also consider the roleof the underlying crust because this crust can beinvolved in magmagenesis obscuring the geochemicaland isotopic signature of mantle-derived magmas Thickgranitic continental crust favours the establishment ofMASH (melting assimilation storage and homogeniza-tion Hildreth and Moorbath 1988) zones with massiveinvolvement of especially the lower crust in the resultantmagmas Intra-oceanic arc (IOA) systems (see review ofStern 2010 and references therein) ndash where the crust isthinner more mafic and more refractory ndash are sites

CONTACT Scott A Whattam whattamkoreaackrSupplemental data for this article can be accessed at [httpdxdoi1010800020681420151103668]

INTERNATIONAL GEOLOGY REVIEW 2015httpdxdoiorg1010800020681420151103668

copy 2015 Taylor amp Francis

where contributions from the crust of the overridingplate are minimized IOAs are thus preferred for inferringsubduction-related magmatic processes IOAs representthe most important sites of juvenile mantle-derivedcontinental crust formation and arcndashcontinent collisionand the subsequent accretion of arc-related terranes isbelieved to be key for the growth of continental crust(Taylor and McLennan 1985 Rudnick 1995 Rudnick andFountain 1995) Approximately 85ndash95 of the mass ofcontinental crust is estimated to have formed at mag-matic arcs above subduction zones (Rudnick 1995 Barthet al 2000)

It has been recognized since the earliest discussions ofPlate Tectonics that convergent margin magmatismshows strong spatial controls which are a function ofslab depth ie from the production of depleted tholeiitesabove shallow subduction zones to the generation ofenriched alkali basalts over deep subduction zones(Kuno 1966 Dickinson and Hatherton 1967 Sugimura1968 Gill 1970 Ringwood 1974) More recent studiesdemonstrated fundamental relations between subduc-tion zone chemical systematics and variations in themantle wedge melting regime (Plank and Langmuir1988) and chemical variability as a function of slab orwedge processes (Turner and Langmuir 2015) It is lesscertain whether or not arc magmas evolve composition-ally with time Some early (Jakeš and White 1969 1972Jakeš and Gill 1970) and more recent (Jolly et al 1998a1998b 2001 duBray and John 2011 Zernack et al 2012Gazel et al 2015) studies of the chemical evolution of

magmatic arcs argued for evolution from early low-Ktholeiitic magmas to later incompatible element-enriched high-K calc-alkaline and shoshonitic magma-tism Jakeš and White (1972) suggested that the mostimportant chemotemporal (chemical changes with time)trends exhibited by magmatic arcs include a switch fromthe eruption of early tholeiites followed by later calc-alkaline and finally shoshonitic magmas progressiveenrichments in K and other fluid-mobile LILE elementssuch as Rb Ba and Sr and other large cations (Th U Pb)and LREE increases in K2ONa2O ratios and decreases iniron enrichment and KRb ratios Arculus and Johnson(1978) challenged this interpretation by pointing outseveral exceptions including a decrease in incompatibleelements with time for the Cascades and Lesser AntillesIn a similar vein recent studies of stratigraphically con-strained tephra in IODP cores indicate that the composi-tion of Izu-Bonin-Mariana arc magmas has changed verylittle over the past ~40 Ma (Lee et al 1995 Bryant et al2003 Straub 2003 Straub et al 2015)

Resolving the controversy as to why some convergentmargin magmatic systems evolve with time whereasothers do not is important for understanding convergentmargin processes and how continents form The first stepis to reconstruct the magmatic history of the arc thesecond step is to understand what this tells us about theprocesses controlling magma evolution which couldreflect variations in slab contributions mantle contribu-tions crustal contributions local tectonics or all four Ourchemotemporal study of the Central American VolcanicArc system (CAVAS) is restricted to the ~75ndash0 Ma arcsegment constructed upon oceanic crust in NicaraguaCosta Rica and Panama we do not consider the part ofthe arc in El Salvador and Guatemala which may be builton the continental crust of the Chortis Block Our studiedtime interval is identical to that of the study of Gazel et al(2015) which also documents the physical and chemicalevolution of the arc in Panama and Costa Rica The studyof Gazel et al (2015) differs spatially from ours as theirsdoes not encompass Nicaragua or the Late CretaceousGolfito Complex of southernmost Costa Rica Moreoverthe study of Gazel et al (2015) does not include keygeochemical data from the studies of Lissinna (2005) andBuchs et al (2010) which provide important constraintson the geochemical composition of earliest arc magmaserupted in Panama and southernmost Costa RicaNevertheless our results mostly support their conclusions

Although a number of studies have documentedthe chemical variability in CAVAS magmas (egPatino et al 2000 Plank et al 2002 Hoernle et al2008 Heydolph et al 2012) all of these deal withmagmatic activity which spans a maximum of ~30 mil-lion years duration (30 Ma to the present) some of

Table 1 Abbreviations and definitions of commonly used terms(Whattam and Stern 2015)Abbreviationacronym Definition

BAB Back arc basinBCC Bulk continental crustCAVAS Central American Volcanic Arc systemCLIP Caribbean Large Igneous Province (an OP)GAA Greater Antilles ArcHFSE High-field strength element (eg Nb Zr Ti)HREE Heavy REEIBM IzundashBoninndashMariana (a convergent margin in the

western Pacific)IOA Intra-oceanic arc (or magmatic arc)IODP International Oceanic Drilling Program (now

International Ocean Discovery Program)LILE Large ion lithophile element (eg Rb Ba)LREE Light REEMASH Melting assimilation storage and homogenizationMORB Mid-ocean ridge basalt (pure asthenospheric melt)OIB Ocean island basalt (tholeiitic and alkalic basalts of

within-plate oceanic volcanoes)OPB Oceanic plateau basalt (plume basalt)PI PII PVI (Temporal) Phase I Phase II Phase VIREE Rare earth elementTHI Tholeiitic index tholeiitic suites have THI gt 1 calc-

alkaline suites have THI lt 1VAB Volcanic arc basalt (subduction-modified basalt)

2 S A WHATTAM AND R J STERN

these (eg Heydolph et al 2012) encompass onlyNicaragua and segments of the CAVAS to the west ofNicaragua constructed upon continental crust Otherstudies have dealt with longer-duration studies ofCAVAS evolution but only of Panama (Wegner et al2011) To date no studies have explicitly consideredthe chemotemporal evolution of the entire segment ofthe CAVAS constructed on oceanic crust in PanamaCosta Rica and Nicaragua Here we present the firstsynergistic chemotemporal treatment of the CAVASfrom establishment by ~75 Ma to the present Wefirst demonstrate that many of the chemotemporaltrends outlined by Jakeš and White (1972) hold truefor the oceanic CAVAS system between 75 and 16 Ma(sometimes between 75 and 6 Ma) and show how thisis reflected in trace element and isotope systematicsSecond we explain CAVAS chemotemporal evolutionin terms of varying degrees and modes of melting thenature and relative lsquodepletednessrsquo of the source rela-tive contributions of fluids and sediments subductedseamount and mantle plume contributions and therole of major tectonic tectonomagmatic and oceano-graphic events over the course of CAVAS evolutionOur goal is to understand what the CAVAS teachesabout arc magmatic evolution This compilation thusserves two purposes it represents a report on CAVASarc evolution and it illustrates the challenges facingany effort to capture the long-term magmatic evolu-tion of convergent plate margin igneous activity

2 Synopsis of CAVAS magmatic historydistribution in space and time

The modern CAVAS volcanic front stretches ~1100 kmalong the western margin of the Caribbean plate fromCosta Rica through Nicaragua El Salvador andGuatemala to the GuatemalandashMexico border at thesouthern margin of the North American plate (Figure 1)CAVAS also extended into Panama but this part of thearc shut down within the last few millions of yearsUnequivocal CAVAS magmatic activity began ~75 Ma(Buchs et al 2010) (however see also Whattam andStern 2015) when the Farallon Plate (now the CocosPlate) began to subduct beneath thickened CaribbeanLarge Igneous Province (CLIP) oceanic plateau (eg Hauffet al 2000b and references therein Whattam and Stern2015) Today the CAVAS reflects the eastward subduc-tion of the Cocos plate at ~70ndash85 mmyear beneath thewestern edge of the Caribbean plate (Carr et al 2003)

The oldest CAVAS sequences (Phase I PI) are bestexposed in the 73ndash39 Ma SonandashAzuero Arc of westernPanama and the 70ndash39 Ma ChagresndashBayano Arc ofeastern Panama (Figure 2) The Golfito Complex was

originally interpreted as a CLIP segment (Hauff et al2000b) but more recently as a 75ndash66 Ma arc segment(Buchs et al 2010) an interpretation that we followhere on the basis of geochemical considerations(Section 4 see also Whattam and Stern 2015)Oligocene and early Miocene igneous rocks are bestexposed in Costa Rica western Nicaragua and iso-lated regions in Panama (Figure 2) Middle and lateMiocene arc sequences are broadly exposed west ofthe Canal Zone in central Panama whereas lateMiocenendashPliocene CAVAS sequences are best exposedin Costa Rica (Figure 2) Quaternary bimodal lavas andadakitic intrusions are concentrated in SE Costa Ricaand western Panama and behind the volcanic front inNW Costa Rica (Figure 2) A detailed treatment of thechemotemporal evolution of the CAVAS over its75 Ma history is provided in the Supplementary data

Venezuela

Yucatan

Hispaniola

Jamaica

o 80 Wo 90 Wo 100 W o 70 W o 60 W

o 20 N

Colombia

GAA system

ean LIbb Pi r a C

system

COCOSPLATE

CARIBBEANPLATE

Curacao

SOUTH AMERICANPLATE

NORTHAMERICANPLATE

400 kmo10 N

Virgin Islands

NAZCA PLATE

Fig 1b

aGalapagos

Islands

CARIBBEANPLATE

100 km

HONDURAS

NICARAGUA

Central Chortis TerraneenarreT sitrohC nretsaE

Nicaragua Rise

Siuna Terrane

southern Chortis Terrane

oceanic basement (of the SCT amp Siuna Terrane)

~ COBB

o 14 N

o 87 W

sseHtnempracse

Figure 1 (a) Present-day tectonic configuration of the Circum-Caribbean region (modified from Meschede and Frisch 1998)Abbreviations CR Costa Rica LAA Lesser Antilles Arc GAAGreater Antilles Arc NIC Nicaragua PAN Panama (b) Sketchof Middle America showing the distribution of Chortis Blockterranes and the Siuna Terrane of Nicaragua El Salvador andHonduras (modified from Rogers et al 2007b) AbbreviationsCOBB Continentalndashoceanic basement boundary ES El SalvadorGUAT Guatemala MFZ Motagua Fault Zone

INTERNATIONAL GEOLOGY REVIEW 3

(see httpdxdoi org1010800020681420151103668)

3 Geochemical geochronological and isotopedata set compilation manipulation andsources

Detailed methods are provided in the Supplementarydata Below we summarize our methodology for datacompilation manipulation and filtering

Central America is a collage of several terranes con-tinental in the north (Chortis Block) and oceanic (CLIP)in the south (Figure 2) (eg Mann et al 2007) To avoidbiasing our reconstruction of magmatic evolutionbecause of the interaction of arc magmas with pre-existing continental crust we limited our investigationto the ~1100 km-long portion of the CAVAS constructedon oceanic crust in Nicaragua Costa Rica and PanamaWe note here that the exact nature (continental vsoceanic) of segments of the basement of Nicaraguaand the contact between continental and oceanic

Canal Basin

CARIBBEAN PLATE

PANAMA

Caribbean Large Igneous Province(CLIP)

Chortis Block

COSTA RICA

UNT PRO

EBGolfito

SonaCIAzuero

10deg N

12deg N

08deg N

Chagres-Bayano

Cord de Tal

250 km

Cord n a Pde

86deg W 82deg W84deg W 80deg W

CB Arc

Sona-Azuero Arc

GF Arc

SP ArcTD

AG Arc

NC HD amp TG

CY Arc

Distribution of CAVAS samples used (this study)

PI (75-39 n = 139)

PIV (6-3 n = 19)

PII (35-16 n = 67)PII ALIPIII (16-6 n = 122)

PV (59-002)PVa arc alks (n = 15)PVb adakites (n = 86)PVI (26-0 n = 583)

Phase interval (Ma)arc basement of apparent

189-85 Ma CLIP plateau affinityaccreted Cretaceous- oceanic

1seamounts and plateausNeogene arc (ie undifferentiated

1 2magmatism spanning PII-PVI)3CR-PAN mafic adakites

3CR-PAN alkali basalts3rear arc alkali basalts

Other relevant subduction-relatedfeatures amp materialsNICARAGUA

~SCT (SW)Siuna Terrane (NE) boundary

Figure 2 Detail of the study area (boxed region in Figure 1) showing the distribution of PI to PVI (75ndash0 Ma) magmatism in PanamaCosta Rica and Nicaragua as bracketed by this study Note that the present-day CAVAS volcanic front trends to the northwest fromnorthwest Nicaragua through Honduras El Salvador and Guatemala to the southwest margin of the North American Plate as shownin Figure 1 An approximate boundary between the Southern Chortis Terrane (SCT) to the southwest and the Siuna Terrane to thenortheast is shown for southern Nicaragua (see text and Rogers et al 2007a 2007b) Distribution of PIndashPIV magmatism in Panama isbased on the studies of Lissinna (2005) Buchs et al (2010) Wegner et al (2011) Rooney et al (2010) Farris et al (2011) Monteset al (2012a 2012b) and Whattam et al (2012 and references therein) Distribution of PIndashPIV magmatism in Costa Rica is based onthe studies of MacMillan et al (2004) Gazel et al (2005 2009) and Buchs et al (2010) Distribution of PIIndashPIV magmatism inNicaragua is based on the studies of Ehrenborg (1996) Elming et al (2001) Plank et al (2002) and Saginor et al (2011) Distributionof PV magmatism in Panama and Costa Rica is based on the studies of Defant et al (1991a 1991b 1992) Drummond et al (1995)MacMillan et al (2004) and Lissinna (2005) see also Gazel et al (2009 and references therein) Distribution and extent of theNeogene arc (ie light green-blue shade that encompasses our PIIndashIV magmatism) are from Elming et al (2001) and Buchs et al(2010) Phases IndashV magmatic products shown as circles as opposed to larger shaded regions indicate either a smaller extent ofmagmatism or situations in which in the extent of magmatic products is uncertain In the case of Phase IV magmatism each redcircle represents a discrete Quaternary (26ndash0 Ma) volcano (locations and distribution taken from Mann et al 2007) Distribution ofthe Seamount Province to the immediate west of the Cocos Ridge is from Gazel et al (2009) and location and distribution of adakitelocalities are as shown in Wegner et al (2011) Abbreviations of localities discrete volcanoes and oceanic features BDT Bocas delToro BH Bahia Pina Cord de Pan Cordillera de Panama Cord de Tal Cordillera de Talamanca CI Coiba Island EB El Baru (volcano)EV El Valle (volcano) LY La Yeguada (volcano) MJ Maje MN Managua PC Panama City PI Pearl Islands PQ Petaquilla PROVProvince SJ San Jose Abbreviations of arcs and arc-related units and formations AG Aguacate C-B Chagres-Bayano CY Coyol DMDominical (unit) GF Golfito LC Fm La Cruz Formation PR Paso Real S-A Sona-Azuero SP Sarapiqui TD Trinidad TM FmTamarindo Formation TR Talamanca Range Abbreviations of units interpreted as CLIP oceanic plateau HD Herradura NC NicoyaComplex TG Tortugal Abbreviations (legend) ALI adakitic-like intrusives (Whattam et al 2012) CLIP Caribbean Large IgneousProvince (oceanic plateau) Superscripts 1 Buchs et al (2010) 2 Elming et al (2001) 3 Hoernle et al (2008)

basement units are controversial and we use the inter-pretations of Venable (1994) and Rogers et al (2007a2007b) for westernmost Nicaragua These workers con-clude that both the Siuna Terrane of western Nicaraguaand the westernmost Chortis Block (southern ChortisTerrane SCT Figure 1b) comprise Early Cretaceous vol-canic arc fragments constructed on oceanic basementthat accreted to the eastern Chortis Terrane and theCentral Chortis Block respectively in the EarlyCretaceous (eg see Table 2 of Rogers et al 2007b seealso Baumgartner et al 2008) CAVAS samples fromNicaragua used in our study (Ehrenborg 1996 Elminget al 2001 Plank et al 2002 Gazel et al 2011 Saginoret al 2011) are limited to those from northwesternsouthwestern and eastern Nicaragua which comprisethe Siuna Terrane and the SCT (Figure 2) and hence arethe ones interpreted as having been constructed uponan oceanic basement We do not consider CAVAS sam-ples from the north of the Siuna Terrane in Nicaraguaor the ones from El Salvador and Guatemala which maybe underlain by Palaeozoic and older continental crustof the Chortis Block Conversely there is little dispute asto the nature of the basement beneath Panama andCosta Rica which is universally considered as a CLIPoceanic plateau (eg Hauff et al 2000a 2000b)

We compiled all relevant geochemical geochrono-logical and isotopic data available in the literature forCAVAS samples from Panama Costa Rica andNicaragua Collective (ie Panama plus Costa RicaPanama plus Costa Rica plus Nicaragua or Costa Ricaplus Nicaragua) linearly regressed data (see Section33 below) for each temporal phase is provided inTable 2 Supplementary Table S1 provides anexpanded version of Table 2 at the level of specificregion Raw geochemical data and the sources forthese data are provided in Supplementary Table S2Sources for the isotope data sets are provided in thecaption for relevant figures in Section 5 and also inSupplementary Table S3 We amassed 1031 pertinentsamples with a full set of major element chemistryanalyses but with varying completeness of trace ele-ment and isotopic data Both volcanic (n = 922) andplutonic (n = 109) samples are included (In caseswhere it was not specified whether the sample wasvolcanic or plutonic we assume these to be volcanicin our calculation of relative abundance of eachSamples described as basaltic dikes are considered asplutonic) As it is difficult to determine where themagmatic front was over the 75 million year lifespanof the CAVAS we have not distinguished betweenmagmas emplaced at the magmatic front from thoseemplaced behind the magmatic front except forQuaternary lavas We do not think this significantly Table2

Selected

andtraceelem

entdata

VASlavasandintrusives

ofPIPIIPIIIPIVPV

oftheseph

discrim

inated

byregion

linearly

regressedto

PhaseI

PhaseII

PhaseIII

PhaseIV

PhaseVa

PhaseVb

PhaseVI

SE(PAN

SE(arc

SE(adak)

SE(CR+

Agerang

a)75ndash39

35ndash16

16ndash6

6ndash3

590ndash001

420ndash015

26ndash0

Meanage(M

plusmn18

255plusmn95

11plusmn5

45plusmn15

3plusmn3

22plusmn20

13plusmn13

samples)

oxides

FeOt M

TholeiiticIndex1

K 2ONa 2O

Traceelem

ents55

Sr25844

140052

Ti505240

550899

551525

468245

933173

517084

484556

tinued)

Table2

tinued) Ph

PhaseII

PhaseIII

PhaseIV

PhaseVa

PhaseVb

PhaseVI

SE(PAN

SE(arc

SE(adak)

SE(CR+

Zr6844

K502137

840251

1206677

1573212

133153

1606374

1647473

922040

Ba24111

Ce1470

sumREE2

V26967

ofsomelinearly

regressedvalues

indicate

increasing

values

ofthelistedincompatib

lemajor

andtraceelem

entsandratio

increase

theprevious

phasePIdata

arealso

ldtext

forvisualaidSee

lementary

formetho

linearregression

reviationsN

tanalyzed

tapplicableN

tcalculablewhere

totaln

umberof

FeO40andor

FeO80was

lt1Superscripts12

ΣREEareto

indicate

errorsfortheseareSTD(fo

entandelem

entratio

certaintiesarestandard

errorSEo

fthemean)

Notes(1)

Thistablerepresentsacond

ensedversionof

lementary

Table1which

provides

thesameregresseddata

inadditio

region

specificregresseddata

(ieregresseddata

provided

atthelevelo

fregionndash

PanamaCo

staRicaetc)

(2)Thedata

inthistablearerepresentedas

largelight

lsquoxrsquosin

ourvario

usgeochemicalplotsThecoloured

lsrepresentdistinct

region

sandthedata

fortheseareprovided

inSupp

lementaryTable1(see

Note1above)(3)FeO40andFeO80arebasedon

non-no

rmalized

dances

ofFeOtandMgO

References

atasetsareprovided

inSection32(5)R

awdata

values

calculated

areprovided

lementary

TableS2

biases the data as there is no evidence to suggestlsquobehind arcrsquo activity prior to Quaternary time

31 Temporal subdivisions

Based on radiometric and biostratigraphic agesreported in the literature we temporally subdivideCAVAS magmatism into six phases at 75ndash39 Ma (PhaseI PI Panama Costa Rica) 35ndash16 Ma (PII Panama CostaRica Nicaragua) 16ndash6 Ma (PIII Panama Costa RicaNicaragua) 6ndash3 Ma (PIV Costa Rica Nicaragua) 59ndash002 Ma (PVa arc alkaline in Costa Rica and westernPanama and PVb adakites in Panama and Costa Rica)and 26ndash0 Ma (PVI the Quaternary and modern volcanicfront Costa Rica Nicaragua) (Figure 2) Further detailson age bracketing are provided in the Supplementarydata We are unsatisfied with the coarse temporal reso-lution in PI (75ndash39 Ma) PII (35ndash16 Ma) and PIII (16ndash6 Ma) one positive outcome of this study would be tostimulate future integrated geochronologic studies ofCAVAS PI II and III Geochemical analyses were com-piled for lavas and intrusives of the aforementionedtemporal phases PI (n = 139) PII (n = 67) PIII(n = 122) PIV (n = 19) PV (PVa n = 15 PVb n = 86)and PVI (n = 583) (Table 2 provides mean data linearlyregressed to 55 wt SiO2 see Section 33 below) Weinclude chemical data only for those samples that areconfidently assigned to a particular formation and thusage range

32 Geochemical data set compilations

Details of geochemical data set compilations employedincluding references are provided in the Supplementarydata

33 Geochemical data manipulation

It would be optimal to correct all data to primitivebasalt with Mg = 65 but the paucity of these sam-ples makes this impractical To compare the compiledsuites of geochemical data selected major and traceelement abundances were linearly regressed to55 wt SiO2 (Table 2) This composition lies nearthe mafic end of our sample suite for which SiO2

contents range from 45 to 78 wt (Figure S1Figures 3 and 4) and close to the mean SiO2 contentof 558 wt Although SiO2 content can vary as afunction of melt generation mechanisms and pres-sures associated with crystal fractionation the vastmajority of samples have 60 or less wt SiO2 withmean compositions of each temporal phase rangingfrom ~51 to 59 wt Furthermore the existence of

large ranges in MgO at a given SiO2 content eg PIlavas and intrusives that range from ~38 to 75 wtMgO at 55 wt SiO2 further justifies our normaliza-tion to silica The regressed oxide and trace elementconcentrations are expressed as X55 where X repre-sents the linearly regressed oxide or trace elementThis parameter must be interpreted thoughtfullygiven the processes that could contribute to CAVASlava compositional diversity We discuss the implica-tions of interpreting the chemotemporal trends ofregressed elemental abundances in Section 61

SiO2 wt

basalt

dacite

trachy-basalt

59-0 Ma

45 55 65 7550 60 70 80

75-16 Ma2

basalt

dacite

rhyolite

trachy-basalt

trachy-dacite

enilaklabus

16-3 Ma

TR-TIS

andesite

enilakla

basalticandesite

andesite

basandesite

trachy-andesite

Region

CR NIC

Va Vb VIPhase

Region

III IVPhase

basaltic trachy-andesite

Region

IPhase

Figure 3 Total alkali-silica (TAS) (Le Bas et al 1986) classifica-tion of (a) PI and PII (75ndash39 Ma 35ndash16 Ma) (b) PIII and PIV (16ndash6 Ma 6ndash3 Ma) and (c) PV and PVI (59ndash002 Ma 26ndash0 Ma) lavasand intrusives Abbreviations in (b) BDT Bocas del Toro TR-TISTalamanca Range-Talamancas Intrusive Suite (see Figure 2 forlocations) See Table 2 for the number of samples of each phaseplotted here and in subsequent plots References for all phaseshere and in succeeding figures are provided in theSupplementary data

In all but one case the data sets employed providenon-normalized major element compositions in thesecases we have filtered the data such that only samplesthat yield major element concentrations that sum to97ndash102 wt (excluding volatiles) are used in an iden-tical manner to the CentAm Database (Jordan et al2012) In the one case where data adjusted to sum to100 is presented (Plank et al 2002) we filtered thedata such that only those with lt3 loss on ignitionwere used (46 of 48 samples) An exception to the97ndash102 wt rule is our use of three Phase IV (6ndash3 Ma)Nicaraguan samples (CO-Nic-6 CO-Nic-17 C51 Saginoret al 2011) which have sums between 9642 and9675 wt As there is only one Phase IV Nicaraguansample (C-06-Nic-3) with 97ndash102 wt oxides we alsouse these three other samples Samples with trace ele-ment data only were not used because these could notbe normalized to 55 wt SiO2 Geochemical data fromthe modern volcanic front in the CentAm Database issubjected to various other filters (see Jordan et al 2012at httpwwwearthchemorggrl) In our geochemicalplots oxides are shown in wt and sums are recalcu-lated to 100 anhydrous Trace element concentrationsare expressed in ppm

4 Results

41 Chemotemporal trends

A major concern is whether or not it is useful to treatthe chemotemporal evolution of an arc as a whole orsubdivide it further To address this concern we con-sider both collective CAVAS chemotemporal trends(changes in magma chemistry with time irrespective ofgeographic location) and region-specific chemotem-poral trends We emphasize that some chemotemporaltrends particularly for PI magmatism which was thelongest of all phases (~36 million years) must reflectan aggregate of shorter episodes and trends thatrequire more radiometric ages to be resolved For exam-ple PI magmatism appears to have begun at about75 Ma in western Panama in the SonandashAzuero Arc andeasternmost Costa Rica in the Golfito Arc Magmatismcontinued until about 39 Ma in the SonandashAzuero Arc(according to Lissinna 2005) but the lifespan of theGolfito Arc was much shorter terminating by ~66 Ma(see Buchs et al 2010 and references therein) SimilarlyChagresndashBayano magmatism in eastern Panama did notbegin until about 70 Ma and ended at about the sametime (39 Ma) (Wegner et al 2011) as the SonandashAzueroArc Thus PI magmatism reflects complex aggregationsof trends characteristic of three chemically and tempo-rally discrete arc segments For this reason we have

40 45 50 55 60 65 70 75 80

SiO2 wt

basaltgabbro

b-ag-d

anddior

dacite amp rhyolitegranodior amp gran

tholeiitic and calc-alkaline series

shoshonite series

TR-TIS

calc-alk

med-K calc-alk

shoshonite

low-K thol

16-3 Ma

59-0 Ma

high-K

calc-alk

high- K cal c-alk

low-K thol

PI (75-39)PII (35-16)PIII (16-6)PIV (6-3)PVI (26-0)

061101145189111

009051045018045

2K O R2 55Phase interval (Ma)

Region

III IVPhase

Region

I IIPhase

Region

CR NIC

Va Vb VIPhase

75-16 Ma

aM61-53IIP

aM9-375IP

aM6-61IIIP

aM3-6VIP

Figure 4 SiO2 versus K2O plot (Peccerillo and Taylor 1976) of (a)PI and PII (75ndash39 Ma 35ndash16 Ma) (b) PIII and PIV (16ndash6 Ma6ndash3 Ma) and (c) PV and PVI (59ndash002 Ma 26ndash0 Ma) lavas andintrusives In (d) the lines represent best-fit linear trend lines ofcollective data (ie all geographic regions within a given phase)of phases I II III IV and VI The relatively low R2 values of PIdata are likely the result of element mobility and alteration andin general for all phases because the data is collective eglinearly regressed best-fit lines for discrete regions generallyyield much higher R2 values (see Supplementary Figure S1)Abbreviations in top box basgabb basalt gabbro b-a g-abasaltic- and gabbroic-andesite anddior andesite dioritegrandior and gran granodiorite granite

parsed PI data in some instances into these discrete arcsegments

42 Synopsis of major element chemical evolution

Below we summarize the main features identified fromour compilations to delineate CAVAS major elementevolution (Figures 3ndash6) We provide a more detailedtreatment of major element chemotemporal evolutionin the Supplementary data

CAVAS evolved from an early primitive mafic con-struct to an increasingly fractionated and enriched arcup until the end of PIII (Nicaragua) or PIV (Costa Rica)(Figures 3ndash6) Mean SiO2 increased only slightly over the

first three stages for Panama from 563 58 and584 wt whereas it dropped from 523 to 514 wtbetween PI and PII for Costa Rica before climbing to59 wt during PIII (Nicaragua mean SiO2 remained thesame during PII (555 wt) and PIII (551 wt)) (FigureS1) The first three phases span ~75 to 6 Ma or ~92 ofthe CAVAS history The overall trend towards increas-ingly fractionated magmas reversed in the last 6 Ma asthe arc erupted more mafic lavas during PIV with amean of 514 wt SiO2 (Costa Rica and Nicaraguarecord mean SiO2 of 51 and 53 wt respectively)CAVAS erupted increasingly enriched lavas over thefirst ~69 million years of its history from low-K lavasduring PI to medium-K lava during PII to high-K lavas

75-16 Ma

med-Fe

16-3 Ma

SiO wt 2

40 45 50 55 60 65 70 75 80

low-Fe

med-Fe

kla-clac

high-Fe

59-0 Ma

Fe-enrichment

Na O+K O2 2 MgO

increasing arc maturity (from 1-4)

12100806

Tholeiitic Index

calc-alk thol

high-Fe

Region

III IVPhase

Region

I IIPhase

Region

CR NIC

VaPhase

Figure 5 (a) Subalkaline affinity discrimination diagram on the basis of SiO2 versus FeOtMgO (Miyashiro 1974) superimposed with

the high- medium- and low-Fe subdivisions of Arculus (2003) of lavas and intrusives of (from bottom to top) PI and PII PIII and PIVand PV and PVI magamatism Two PI PAN one PIII NIC one PVa and two PVI CR with high silica plot outside the plot with FeOtMgOgt 8) (b) Subalkaline affinity discrimination diagram on the basis of total alkalis-FeOt-MgO (AFM Irvine and Baragar 1971)superimposed with the trends of increasing arc maturity (from 1 to 4 as labelled in the top plot) from Brown (1982) of (frombottom to top) PI and PII PIII and PIV and PVa and PVI lavas and intrusives Arc maturity trends are from the following arc systems1 Tonga-Marianas South Sandwich 2 Aleutians-Lesser Antilles 3 New Zealand Mexico Japan and 4 Cascades northern Chile NewGuinea (c) Tholeiitic index (Fe40Fe80 where Fe40 and Fe80 represent the average FeO

t of lavas and intrusives with 3ndash5 and 7ndash9 wt MgO respectively) (Zimmer et al 2010) versus time of phases in which THI was calculable (see Supplementary data) The light greylsquoXrsquos represent mean THI of both or all regions for a particular (temporal) phase

during PIII (Figure 4) During the late Miocene (PIV) theCAVAS began to erupt less-enriched magmas earlier inNicaragua than in Costa Rica and PIV through PVI wascharacterized by medium-K calc-alkaline magmatism Aplot of tholeiitic index (THI Zimmer et al 2010 seeSupplementary data for further details of THI) demon-strates that the overall enrichment of the CAVAS wasaccompanied by a trend from early tholeiitic and calc-alkaline affinities to stronger calc-alkaline affinities apartfrom PIII Nicaragua which exhibits a weakly tholeiiticaffinity (Figure 5c)

Collectively the CAVAS evolved over its 75 millionyear lifespan from an initial low-K tholeiitic to a weaklycalc-alkaline system in its infancy during PI (75ndash39 Ma)to a medium-K calc-alkaline system in PII (35ndash16 Ma) toa high-K calc-alkaline system during PIII (16ndash6 Ma) Afternormal arc magmatism ended in Panama by 6 Ma mag-matic activity was dominated by the production ofadakites and arc alkaline basalts in Panama and CostaRica and a return to medium-K calc-alkaline igneousactivity in Costa Rica and Nicaragua thereafter PVIlavas in particular returned to greater iron enrichment

IBMVAB

Time (Ma)70 60 50 40 30 20 10 0

PVa micro = 06955

Region

CR NIC

I II IVIII Va Vb VIPhase

PANCRNICall

Figure 6 Concentrations of (a) TiO2 (b) P2O5 and (c) K2O and the ratios of (d) K2ONa2O of magmatic products of PI (75ndash39 Ma) PII(35ndash16 Ma) PIII (16ndash6 Ma) PIV (6ndash3 Ma) PV (59ndash002 Ma) and PVI (26ndash0 Ma) and phases further discriminated into regions linearlyregressed to 55 wt SiO2 versus time MORB and OIB values are from Sun and McDonough (1989) and mean IzundashBoninndashMarianavolcanic arc basalt (IBMVAB) data is calculated from data as compiled by Jordan et al (2012 N = 517) In (a) and (b) the upper limit(mean plus standard error of the mean SE) of TiO2 of PVa arc alkalic basalts is 168 and the linearly regressed P2O5 of the PVa arcalkalic basalts is 069 plusmn 004 (SE) Note also that in (a) the TiO2 of PII PAN and CR overlap and in (bndashd) P2O5 K2O and K2ONa2Oalmost completely overlap in PII PAN CR and NIC thereby making symbol discrimination difficult The light grey lsquoXrsquos here and insubsequent plots represent the mean of both or all three regions of a particular phase In most instances the vertical uncertainty (SEof the mean of regressed compositions) is smaller than the symbol size To avoid clutter the horizontal SE (age) is shown for phasesonly (ie this is not shown for regional within-phase data)

CAVAS lavas show similar increases in other incompati-ble major elements in addition to potassium between PIand PIII especially P2O5 and K2ONa2O for Costa Ricaand Panama but less so for K2O and K2ONa2O forNicaragua between PII and PIII (Figure 7) A clear diver-gence between Costa Rica and Nicaragua is seen duringPIV (6ndash3 Ma) whereas Costa Rica continues to moreenriched P2O5 K2O and K2ONa2O and Nicaraguanmagmas decrease to lower concentrations (Figures 6bndash6d) The behaviour of TiO2 is more complex because it isincompatible until magnetite precipitates Apart fromNicaragua exhibiting anomalously high TiO2 relative toPanama and Costa Rica other normalized major incom-patible element concentrations of Panama Costa Ricaand Nicaragua were nearly identical during PIII

43 Trace element chemical evolution

431 Incompatible element trendsMean abundances of all LILEs Th U Pb Zr LREEsLREEsHREEs and ΣREEs (normalized to 55 wt SiO2)increase between PI (75ndash39 Ma) and PIII (16ndash6 Ma) andusually until 3 Ma (PIV 6ndash3 Ma) with a maximumexhibited by PVb adakites before decreasing slightly inQuaternary lavas (PIV 26ndash0 Ma) (Figures 7 and 8Table 2) For example Ba55 rises from PI (~240 ppm)to PII (~470 ppm) PIII (~770 ppm) and PIV (~880 ppm)before reaching a maximum in PVa arc alkalic basalts(~900 ppm) and PVb adakites (~980 ppm) subse-quently PVI arc basalts record a Ba55 of 640 ppm inter-mediate to that of PII and PIII (Figure 7b Table 2) Theremaining fluid-mobile LILEs (Rb Sr Figures 7a and 7c)and K demonstrate similar trends Trends for LILEs couldpartially reflect greenschist-facies alteration-derivedmobility (eg K Rb Ba) and the effects of plagioclasefractionation (Sr) however the fact that alteration-resis-tant incompatible element concentrations also increasewith time suggests that the trends mostly reflect anoverall progressive enrichment of incompatible ele-ments in CAVAS magmas

Regressed Th U Pb and Zr concentrations showevolutionary trends that are similar to those of theLILEs with progressive increases between PI and PIV(Th55 U55) (Figures 7d and 7e) or PI and PIII (Pb55Zr55) (Figures 7f and 7g) with a maximum reached inthe PVa adakites or PVb arc alkali lavas in the caseof U55

LREE55 (La55-Nd55) (Ce55 shown only in Figure 8a)LREE55 fractionations (La55Sm55 La55Yb55) (Figures 8band 8c) and ΣREE55 (Figure 8d) collectively increasesimilarly from PI to PIV with a maximum exhibited bythe PVa adakites followed by a drop back to approxi-mately PIV abundances during PVI

The aforementioned trends with time are summar-ized in collective and region-specific chondrite-normal-ized REE and N-MORB-normalized plots on Figures 9and 10 respectively The most striking feature of the

MORBIBMVAB

MORBIBM

OIBBCC

IBMVAB

OIBBCC

IBMVAB

BCC (11)

Time (Ma)

IBMVAB

OIB (280)BCC

70 60 50 40 30 20 10 0

CR PIV micro = 28255

CR PIV micro = 5855

Region

CR NIC

OPB (grey lined)

Figure 7 Concentrations of (a) Rb (b) Ba (c) Sr (d) Th (e) U (f)Pb and (g) Zr of magmatic products of PI PII PIII PIV PV andPVI linearly regressed to 55 wt SiO2 versus time Referencesfor MORB OIB and mean IBM (arc basalt) and other relevantdetails are given in the caption for Figure 8 and the value forbulk continental crust (BCC) is from Rudnick and Gao (2003)Mean oceanic plateau basalt (OPB thick grey line) is calculatedfrom data of references provided in the SupplementaryDocument

collective plots is the progressive enrichments in line-arly regressed LREEs (La-Nd) LREE fractionations (LaSmLaYb) ΣREE and all but the least incompatible ele-ments (Figures 9a and 8c) as also demonstrated inFigures 6ndash8 Compositions of the CAVAS ultimatelybecame lsquocontinental-likersquo by PIII or certainly by PIV (6ndash3 Ma) (Figures 9 and 9d) The plots in Figure 9 alsodemonstrate that the progression to bulk continentalcrust (BCC) compositions was gradual and not sudden

It is important to note however that when data areparsed into discrete regions although Panama andCosta Rica usually follow progressive enrichments withtime as described above Nicaragua does not as is read-ily apparent in Figure 10 For example concentrations ofTh U and Zr decrease between PII and PIII Nicaraguawhereas Pb remains unchanged during this interval incontrast to Costa Rica and Panama which (apart from Uwhich remains unchanged in Costa Rica between PI andPII) show increases in these elements between PI andPIII (Figure 7) Similarly when parsed into region LREEsLREE fractionations and ΣREE deviate from overalltrends suggesting progressive enrichment For exam-ple only Ce55 and ΣREEs exhibit higher concentrationswith time in both Costa Rica and Panama between PI

and PIII LREE fractionations generally stay the sameduring this interval apart from PII Panama which exhi-bits anomalously high LaSm (Figure 8) Only slightlyincreased LREE fractionations and ΣREEs are shown byNicaragua between PII and PIII before moderate tosignificant drops in Ce LREE fractionations and ΣREEsare recorded during PIV In contrast Ce LREE fractiona-tions and ΣREEs show significant positive spikes duringPIV in Costa Rica before dropping to values similar toNicaragua during PVI and Costa Rica and Panama dur-ing PIII

Similarly when PI-IV and PVI data are parsed byregion and chondrite-normalized REEs and N-MORB-normalized incompatible plots are considered(Figure 10) a number of salient features are evident(1) Regressed mean chondrite-normalized REEs andN-MORB-normalized trace element patterns of allthree PI arc segments (Golfito Complex Sona-Azueroand Chagres-Bayano) fall within the range of composi-tions of 98ndash82 Ma western Costa Rica units interpretedas CLIP (Figures 10a and 10b) This demonstrates simi-lar sources for PI arc segments and the CLIP (as verifiedby Pb and Nd isotopes Section 4) (2) The similarity ofthe Golfito N-MORB-normalized incompatible elementsignature with that of the Sona-Azuero and Chagres-Bayano segments and its prominent negative Nbanomaly coupled with LILE enrichment (Figures 10aand 10b) clearly favour its interpretation as an arcsegment (Buchs et al 2010) as opposed to a plateausegment (Hauff et al 2000b) (3) Apart from minorexceptions the chondrite-normalized REEs andN-MORB-normalized patterns of PII Panama CostaRica and Nicaragua are remarkably similar (Figures10c and 10d) This suggests that magmas for all threearc segments were likely derived from similar sourcesduring PII (4) BCC-like compositions are achieved inPanama and Costa Rica arguably during PIII (16ndash6 Ma)and certainly by PIV (Figures 10endash10h) (5) Nicaraguachemotemporal evolution began to diverge from CostaRica and Panama during PIII (Figures 10e and 10f)Whereas Costa Rica and Panama PIII lavas becamemore enriched than PII Nicaragua PIII lavas changedlittle from PII compositions (6) Chemotemporal diver-gence between Costa Rica and Nicaragua is mostobvious in PIV when Costa Rica again continued tomore enriched compositions and Nicaragua again didnot (Figures 10g and 10h) (7) N-MORB-normalizedincompatible element patterns of PVI (26ndash0 Ma)Costa Rica and Nicaragua are similar (Figures S2i j)PVI thus marks the lsquoresettingrsquo of production of magmaswith more depleted compositions similar to those gen-erated during PIII or even earlier

BCC OIB (199 ppm)

IBMVAB

IBMVAB20

Time (Ma)

070 60 50 40 30 20 10 0

OPB (grey lined)

Region

CR NIC

Figure 8 Concentrations and ratios of (a) Ce (b) LaSm (c) LaYb and (d) ƩREEs of magmatic products of PI PII PIII PIV PVand PVI linearly regressed to 55 wt SiO2 versus time

The REE and N-MORB-normalized plots discriminatedby region and discrete PI arc units (Figure 10) showsubtle intra-phase differences not listed above Forexample Figures 10a and b illustrate that the68ndash39 Ma ChagresndashBayano Arc lavas of easternPanama more closely resemble average IzundashBoninndashMariana (IBM) volcanic arc basalt (VAB) than do lavasfrom the ~75ndash39 Ma Sona-Azuero and 75ndash66 Ma Golfitosegments Despite this and other minor region-specificdifferences the regressed incompatible trace elementdata demonstrate that CAVAS magmas were initiallygenerated from a depleted mantle source which wasalso strongly influenced by plume contributions (seebelow) The CAVAS changed little over the first half ofits lifespan (during PI 75ndash39 Ma) segments in PanamaCosta Rica and Nicaragua were all similar during PII (35ndash16 Ma) but magma compositions diverged thereafter

432 Trends in magma enrichmentdepletion andsubduction additionsArc magmatic evolution can reflect changing slab con-tributions mantle wedge compositions degrees of

mantle melting degrees of crustal melting or a combi-nation of these processes Incompatible element ratiosthat gauge source fertility such as ZrY and NbYb areuseful for elucidating source evolution ie changes inthe degree of partial melting or fertility of the sourceZr55Y55 (Figure 11a) and Nb55Yb55 (Figure 11c) bothincrease with time between PI and the end of PIV inmagmatic rocks of Panama and Costa Rica Whenparsed into region however increases in both ZrYand NbYb between PI and PII Costa Rica are slightand the collective shift to higher NbYb during PII isdue to Panama which exhibits anomalously high NbYb(~3) The most significant shifts to higher ZrY and NbYb occurred between PIII and PIV in Costa Rica As thereis no evidence of the presence of garnet in the source ofany CAVAS igneous rocks except for PV adakites and arcalkali basalts higher ZrY and NbYb probably representeither a shift to more enriched sources or lesser degreesof partial melting conversely as these ratios decrease inNicaragua between PII and PIII this suggests eithershifts to higher degrees of partial melting or tappingof a more depleted source or both

Cs Ba U K Ce Pr P Zr Eu Dy YbRb Th Nb La Pb Sr Nd Sm Ti Y Lu

PVbadaks

PVa arc alks

La LaCe CePr PrNd NdSm SmEu EuGd GdTb TbDy DyHo HoEr ErTm TmYb YbLu Lu

PV (59-002 Ma) (inset) Bulk Continental Crust

(602 wt SiO )2

mean Izu-Bonin Marianamean Volcanic Arc basalt

PI PIV

Phase interval (Ma)

PI (75-39) PII (35-16)PIII (16-6)

PIV (6-3)PVI (26-0)

Figure 9 (a c) Chondrite-normalized REEs and (b d) N-MORB-normalized incompatible element plots of incompatible and REEconcentrations of collective (a b) PI PII PIII PIV PV and PVI magmatic products linearly regressed to 55 wt SiO2 and (c d) PI andPIV from (a) and (b) versus Bulk Continental Crust (BCC 602 wt SiO2 Rudnick and Gao 2003) and mean IzundashBoninndashMarianavolcanic arc basalt composition (as compiled by Jordan et al 2012 where mean IBM VAB is based on the number of samples with afull suite of REE) References for these tectonomagmatic suites are the same in succeeding figures Chondrite and N-MORBabundances are from Nakamura (1974) and Sun and McDonough (1989) respectively

CAVAS PI La55Sm55 and La55Yb55 are similar to OPBin PI by PII both ratios meet or exceed those of IBMVAB although the more LREE-enriched nature ofPanama PII lavas is apparent (Figure 8) Similarly

Zr55Y55 of PII Panama is equivalent to that of meanOPB whereas PII Costa Rica and Nicaragua are slightlyless enriched with values intermediate to that of MORBand OPB (Figure 11a) Apart from the PVa alkalic

Golfito Arc (CR n = 8) Sona-Azuero Arc (PAN n = 57) Chagres-Bayano Arc (PAN n = 68) all (PAN+CR n = 139)

PII 35-16 Ma

PIII 16-6 Ma

PIV 6-3 Ma

PVI 26-0 Ma

PAN (ALI+non-ALI n = 35 ) PAN (ALI n = 13) CR (n = 15) NIC (n = 17) all (PAN+CR+NIC n = 67) Phase I (all)

PAN (n = 54) CR (n = 38) NIC (n = 31) all (PAN+CR+NIC n = 123) Phase I (all) Phase II (all)

La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Bulk Continental Crust (BCC 602 wt SiO )2

mean Izu-Bonin Marianamean Volcanic Arc basalt (n = 177)

98-82 Ma western Costa Rica igneous units interpreted as CLIP (N = 37)

PI 75-39 Ma

CR (n = 15) NIC (n = 4) all (CR+NIC n = 19) Phase I (all) Phase II (all) Phase III (all)

CR (n = 405) NIC (n = 178) all (CR+NIC n = 573) PI (all) PII (all) PIII (all) PIV (all)

Figure 10 (a c e g i) Chondrite-normalized REE and (b d f h j) N-MORB-normalized incompatible plots of incompatible and REEconcentrations (a b) PI (c d) PII (e f) PIII (g h) PIV and (i j) PVI magmatic products of Panama Costa Rica and Nicaragua parsedinto regions and in (a) distinct arc segments In (a b) the 98ndash82 Ma western Costa Rica units interpreted as CLIP comprise the NicoyaComplex (Sinton et al 1997 Hauff et al 2000b) and the Herradura and Tortugal complexes (tholeiitic basalts and diabases onlyn = number of samples with a complete suite of REE analyses Hauff et al 2000b) In (c d) ALI represents PII ~32ndash19 Ma adakitic-likeintrusives (Whattam et al 2012) that formed subsequent to the shutdown of PI and via partial melting of mafic arc substrate (seetext) Chondrite and N-MORB abundances are from Nakamura (1974) and Sun and McDonough (1989) respectively

basalts and PVb adakites which have higher regressedZrY than BCC (~7) and even ocean island basalt (OIB)(97) in the case of the adakites (Zr55Y55 of 102)CAVAS Zr55Y55 is much less than BCC Neverthelessit is evident that both Panama and Costa Rica evolvedtowards BCC-like compositions during PIII with Zr55Y55intermediate to OPB and BCC whereas Nicaragua Zr55Y55 decreased slightly in PIII A similar trend is seen inZr55Nb55 and Nb55Yb55 which reflect source deple-tion andor the degree of partial melting Overall thesetrends demonstrate a shift to strong enrichmentbeneath Costa Rica but only slight enrichments inPanama and Nicaragua between 35 and 16 MaDuring PIV dramatic changes are recorded with diver-gence between Costa Rica and Nicaragua Whereas PIVCosta Rica records low BCC-like concentrations of Zr55Nb55 (16) akin to the PVb adakites (18) PIV Nicaraguaalternatively records by far the highest Zr55Nb55 ofany phase or region (61) An identical pattern is seenin Nb55Yb55 with PIV Costa Rica magmas recording thehighest ratios (5) and Nicaragua the lowest ratios(042) This further demonstrates a dramatic composi-tional divergence between 6 and 3 Ma igneous rocks in

Costa Rica and Nicaragua the possible causes of whichare discussed in Section 633

Also plotted on Figure 11 (d) is La55Nb55 whichgauges the lsquodepthrsquo of the negative Nb anomaly and is~1 or less for magmas formed away from subductionzones eg LaNb of OIB and MORB are 08 and 11respectively (Figure11d) Collectively La55Nb55 varieslittle from PI to PIII (21ndash26) but jumps to higher valuesin PIV Costa Rica (41) similar to the PVb adakites (42)and Nicaragua (54) before falling back to values similarto PIndashPIII in PVI Costa Rica and Nicaragua (22 collec-tively) (Figure 11d Table 2) PVa alkali basalts record avery low OIB-like La55Nb55 of 08

Ratios of specific fluid-mobile element to HSFE (SrNd PbCe UTh BaLa BaTh BaNb and ThNb) areuseful for inferring changes in subducted slab contribu-tions and are plotted on Figure 12 to illustrate how thisinfluence on the CAVAS source has changed over timeThese plots generally show increases between PIndashPIIIand PIndashPIV but when considered on the basis of dis-crete region it is apparent that there is little change inPanama and Costa Rica and the most significantchanges are in Nicaragua which generally show largejumps in these ratios between PII and PIV or PII and PIIISr55Nd55 collectively increases from PI (011 339 258)to PII (026 545 311) to PIII (031 774 332) to PIV(041 933 378) and is the only ratio that also increaseswhen parsed into regions (Figure 12a) CAVAS UTh inPanama and Costa Rica scatters with no hint of a trendand is broadly higher than mean IBM VAB even in PI(Figure 12c) However Pb55Ce55 increases from PI (010)to PII (013) to PIII (014) before dropping to a value(008) lower than that of PI during PVI (Figure12b) andenrichment is dominated by Nicaragua with muchhigher PbCe than Panama and Costa Rica during PII-PI CAVAS Pb55Ce55 never reaches as high a mean asIBM VAB (Figure 12b) but by PIII Nicaragua PbCe isidentical to that of mean IBM VAB and by PIV it isidentical to BCC

Fluid-mobile Ba and melt-mobile Th are good tracersof total and shallow subducted slab inputs especiallywhen compared with La and Nb (Pearce and Peate1995) Ba55La55 Ba55Th55 Ba55Nb55 and Th55Nb55versus time are also plotted in Figure 12 Variations inBaTh in the CAVAS have been interpreted as reflectingdifferences in the amount or composition of sedimentsover time (Patino et al 2000) BaTh in general reflectsshallow additions of subduction-related fluids to themantle source (Pearce et al 2005) (Figure 12e) CAVASBa55Th55 increases from PI (280) to PII (326) to PIII (355)before subsequently dropping to values near those ofIBM VAB during PIV PV and PVI (Figure 12e Table 2)However and similar to other slab contributions

OIB (97)

IBMVAB

OIB (222)

OIB BCC

OPB (grey lined)

IBM (19)

MORBIBMVABc

PVb micro = 10255

NIC PIV micro = 60655

PVa micro = 28655

PVb micro = 6855

Region

CR NIC

IBMVAB (771)

70 60 50 40 30 20 10 0

Figure 11 Ratios of (a) ZrY (b) ZrNb (c) NbYb and (d) LaNbof magmatic products of PI PII PIII PIV PV and PVI linearlyregressed to 55 wt SiO2 In (a) the Zr55Y55 of PVb adakitesplots outside of the plot 1023 plusmn 033 and in (c) the PVa arcalkalic basalts and PVb adakites plot outside the plot with Nb55Y55 of 2856 plusmn 244 and 679 plusmn 050 respectively

discussed above this collective progression in BaTh(and BaLa) is the influence of Nicaragua (Figures 12dand 12e) For example BaTh remains essentially thesame in Panama (~200ndash300) during PIndashPIII and inCosta Rica although BaTh increases slightly betweenPI and PII (from ~425ndash450) this ratio drops suddenly inPIII to a value (~250) similar to that of Panama (BaNb)and deep (ThNb) subduction additions (Elliot et al1997 Pearce et al 2005) (Figures 12f and 12g) showno increases between PI and PII and only slightincreases in PIII before jumping to high values in PIVWhereas PIV BaNb is unchanged from PIII in Costa RicaBaNb jumps to an extremely high value in PIV inNicaragua (702) ThNb is much higher in both PIVCosta Rica and Nicaragua than in PIII Costa Rica andNicaragua Similar to other trends described above PVIBaNb and ThNb drop similar to or slightly less thanthose of PI-PIII PVa arc alkalic basalts show low OIB-likeBa55Nb55 and Th55Nb55 and the PVb adakites show BaNb similar to PIII and ThNb similar to PIV The signifi-cance in the difference in trends displayed by BaThversus BaNb and ThNb is explored in Section 6

5 Radiogenic isotope trends

We compiled available data for radiogenic isotopes SrNd and Pb We do not emphasize Sr isotopic composi-tions as these are vulnerable to alteration As Nd and Pbisotopes are much less affected by alteration and recordthe most obvious trends in CAVAS isotopes source evo-lution (Figures 13ndash15) we restrict our discussion here tothese isotopes but provide details of Sr isotopes in theSupplementary data There are no Hf isotope data forpre-PVI CAVAS sequences but these should start toappear as LA-ICP-MS zircon geochronology of theregion advances Sources for the compiled isotopedata sets are listed in the captions for Figures 13ndash15

51 Pb isotopes

Raw isotope data (Sr Nd Pb) (and the sources for thesedata in addition to being provided in the captions ofFigures 13ndash15) is provided in Supplementary Table S3We show the initial 206Pb204Pb versus 208Pb204Pb plotsof PIndashPVI in Figure 13 Similar to other isotope plotspresented (Figures 14 and 15 Supplementary FigureS4) we compare the composition of PI lavas and intru-sives with those of the 98ndash82 Ma western Costa Ricaigneous units (at Nicoya Herradura and Tortugal seeFigure 2 for locations) (Sinton et al 1997 Hauff et al

IBMVAB

b 55 g

deep subduction additions

IBMVAB

300350

IBMVAB

total subduction additions

NIC PIV micro = 702

OPB (grey line)

shallow subduction additions

IBMVAB10

Time (Ma)70 60 50 40 30 20 10 0

IBMVAB

MORB BCC

IBMVAB

OPB (grey lined)

MORBamp OIB

IBMVAB

IBMVABMORB

09CR micro = 111

Region

CR NIC

Figure 12 Ratios of (a) SrNd (b) PbCe (c) UTh (d) BaLa (e)BaTh (f) BaNb and (g) ThNb of magmatic products of PI PIIPIII PIV PV and PVI linearly regressed to 55 wt SiO2 versustime

2000a 2000b) interpreted by most as CLIP oceanicplateau fragments or as (hybrid) plume- and arc-relatedunits generated soon after subduction initiation at the

CAVAS via melting of a mixed plume- and subduction-modified source (Whattam and Stern 2015) We do thisparticularly as trace element chemistry of PI magmas

central southern amp SE Costa Rica BVF amp VF alkaline (pale yellow)

PVa amp PVb59-001 Ma

Region

Va VbPhase

PVI26-0 Ma

CR NIC

SW NIC

NE CR central CR

NW NIC

Miocene Nicaragua

Miocene Costa Rica

PII-PIV35-3 Ma

Region

II III IVPhase

19-6 Ma

75-39 M

NIC Miocene

CR MioceneCR 75-66 Ma

CR 35-16 Ma

CR 16-6 Ma

CR 6-3 Ma

CR NIC

GP at 28-0 Ma (from d)

98-82 Ma CLIP(from a white)

Cocos Plate sediments

subducting

SP (NGD)

subducting CCR (C

CocosNazca Plate

PI 75-39 Ma

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

206 204Pb Pb

Galapagos Islands (ie GP) at 28-0 Ma

Region

PII Costa Rica (from b light blue)

PII amp PIII Panama(from b light green)

CBA (eastern(Panama light pink)

SAA (central Panama light yellow)

200 185

CR NW NIC NW SW

Region Phase VI

central

eastern

PAN SAA CBA

Region Phase I

98-82 Ma CLIP 80-60 Ma accreted OIB

other western CR igneous units

Figure 13 206Pb204Pb versus 208Pb206Pb isotope data for (a) PI (75ndash39 Ma) CAVAS magmatic products of Panama and Costa Rica versuslavas from 98ndash82 Ma western Costa Rica igneous units that include Nicoya Herradura and Tortugal (Sinton et al 1997 Hauff et al2000a 2000b) (locations are shown on Figure 2) which are interpreted by most as CLIP or lsquoplume- and arc-relatedrsquo (PAR by Whattamand Stern 2015 see text) 80ndash60 Ma accreted OIB in western Costa Rica (Hauff et al 2000b) and 28 Ma lavas of the Galapagos Islands(ie Galapagos Plume GP White et al 1998) and CAVAS magmatic products of (b) PIIndashPIV (35ndash3 Ma) (c) PVa (arc alkaline basalts 590ndash001 Ma) and PVb (adakites 420ndash015 Ma) and (d) PVI (26ndash0 Ma) in Panama Costa Rica and Nicaragua In (a) the PI Sona-Azuero Arc(SAA) samples from central Panama are discriminated from all others from the Chagres-Bayano Arc in eastern Panama to highlight thecompositional differences Also in (a) two accreted OIB samples from Osa (OSA6 and OSA16 Hauff et al 2000b) exhibit very low208Pb204Pb of 37946 and 38025 and plot of the diagram Note that in (d) as the PVI samples from northwest Nicaragua might havebeen constructed on continental as opposed to oceanic basement (see Section 1) these have been discriminated (open triangles) fromsamples of southwest Nicaragua constructed on oceanic basement Moreover for visual clarity to see clearer the compositionaldifferences between central versus northwest Costa Rica during PVI samples from Central Costa Rica (pink squares) are discriminatedfrom those of northwest Costa Rica Geographical segmentation of PVI magmatism in Costa Rica and Nicaragua (eg central Costa RicaNW Nicaragua) is based on the geographical segmentations of Hoernle et al (2008 their Figure 1) an exception is our use of lsquoeasternNicaraguarsquo which comprises samples from the eastern margin of Nicaragua between ~123 to 126deg N and ndash837 to 840deg E (eg CukraHill Pearl Lagoon from Gazel et al 2011) Isotope data from the CAVAS are from Gazel et al (2009 PIIndashPIV Costa Rica) Gazel et al (2011PIV PVa PVb PVI Costa Rica) Hoernle et al (2008 PVa PVb Panama PVa southern and central Costa Rica BVF PVb southern CostaRica PVI NW central and southern Costa Rica VF PVI southwest and northwest Nicaragua and the Miocene Costa Rica and MioceneNicaragua fields) Wegner et al (2011) (PIndashPIII PVb Panama) the GEOROC data base at httpgeorocmpchainzgwdgdegeoroc (PVICosta Rica and Nicaragua only dated samples that yield ages of Quaternary are plotted) and the CentAm Database version 102 athttpwwwearthchemorggrldatabases (PVI Costa Rica and Nicaragua as compiled by Jordan et al 2012) Fields for the subductingCocos and Coiba ridges (CCR or Central Galapagos Domain CGD) Seamount Province (SP or Northern Galapagos Domain NGD) andCocosNazca Plate are from Hoernle et al (2000) and Werner et al (2003) (as presented in Hoernle et al 2008) The compositions of(subducting) Cocos sediments are from Feigenson et al (2004) and the depleted mantle (DM) composition is from Werner et al (2003see Gazel et al 2009 for details) The boundaries of the stippled field with horizontal lines represent mixing lines that connect the threecompositional end-members (DM depleted mantle SP and CCR Cocos and Coiba ridges) required to explain the isotopic variations In(a) and (b) the numbers beside some PI PII and PIII Panama samples represent ages in Ma (from Wegner et al 2011) The boxes inset in(b) and (d) represent the summaries of temporal isotopic changes without the symbols (the box in (b) represents the summary of (a)and (b) and the box in (d) represents the summary of (d) only) Abbreviations BVF behind volcanic front CCR Cocos-Coiba ridges CGDCentral Galapagos Domain NGD Northern Galapagos Domain SP Seamount Province VF volcanic front

exhibits a clear affinity for 98ndash82 Ma units interpreted asCLIP (see Section 4 main text)

Based on isotope and radiometric data amassed forthe ~73ndash69 Ma Sona-Azuero (based on the radiometricage data of Wegner et al 2011 only) ~70ndash39 MaChagresndashBayano and the ~20ndash7 Ma Cordilleran arc

complexes of Panama (which encompass PIndashPIII of thisstudy) and comparison of their Pb isotope compositionswith those of CLIP (from data of Kerr et al 1997 2002Hauff et al 2000a) Wegner et al (2011) demonstrated (1)an overlap in initial 206PbPb204 versus initial 208Pb204Pbof the older arc systems with the CLIP and (2) a shift to

central

CR NIC

051280

051285

051290

051295

051300

051305

051310

051275

051280

051285

051290

051295

051300

051305

051310

051315

subductin g

Seamount Province

Region

Va VbPhase

051275

PVI26-0 Ma

d051275

051280

051285

051290

051295

051300

051305

051310

subducting Cocos amp Coiba ridges

PII- PIV35-3 Ma

CCR (CGD)

CocosNazca Plate

107142 86

Cocos Plate sediments (05124-05127)

H26-6 Ma CRVF

CR PANDM

CR 75-66 Ma

CR 6-3 MaCR 35-6 Ma

SP see (c)

98-82 Ma CLIP (from a)

344 217 201324

all regions of Costa Rica BVF amp VF alkaline

Region

II III IVPhase

206 204Pb Pb

051275

051280

051285

051290

051295

051300

051305

051310

aGP at 90 Ma

GP at 28 Ma (from d)

GP at 60 Ma

499-448

Region

PI 75-39 Ma

SAA(central Panama(yellow)

543400

170 200

CBA (eastern Panama light pink)

CR NW NIC NW SW eastern

Region Phase VI

central

PAN SAA CBA

Region Phase I

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

Figure 14 206Pb204Pb versus 143Nd144Nd isotope data for (a) PI (75ndash39 Ma) CAVAS magmatic products of Panama and Costa Ricaversus 98ndash82 Ma western Costa Rica units which include Nicoya Herradura and Tortugal (Sinton et al 1997 Hauff et al 2000b) andwhich are interpreted by most as CLIP or as plume- and arc-related units generated soon after subduction initiation at the CAVAS(Whattam and Stern 2015) 80ndash60 Ma accreted oceanic island basalt (OIB) units in western Costa Rica that comprise the Burica Osa andBurica units (Hauff et al 2000b see also Hoernle et al 2002 Hoernle and Hauff 2007 Buchs et al 2009 2011) and the Galapagos Plume(GP) at 90 Ma 60 Ma (fields at 90 and 60 Ma from Hauff et al 2000a) and 28 Ma (ie the Galapagos Islands White et al 1998) andCAVAS magmatic products of (b) PIIndashIV (35ndash3 Ma) (c) PVa (arc alkaline basalts 590ndash001 Ma) and PVb (adakites 420ndash015 Ma) and (d)PVI (26ndash0 Ma) in Panama Costa Rica and Nicaragua In (a) the PI Sona-Azuero Arc (SAA) samples from central Panama aredifferentiated from the Chagres-Bayano Arc in eastern Panama to highlight the compositional differences BUR and TAP stand forBurica (an accreted OIB unit in western Costa Rica) and Tortugal alkali picrites repectively In (a) and (b) the numbers beside some PIPII and PIII Panama samples represent ages in Ma (from Wegner et al 2011) In (b) the 26ndash6 Ma CRVF field demarcates samples fromthe southern Costa Rica Miocene volcanic front (superscript lsquoHrsquo for Hoernle et al 2008) The boxes inset of (b) and (d) representsummaries of temporal isotopic changes without the symbols (the box in (b) represents the summary of (a) and (b) and the box in (d)represents the summary of (d) only) In (d) the geographical segmentation of PVI magmatism in Costa Rica and Nicaragua (eg centralCosta Rica northwest Nicaragua) is based on the geographical segmentations of Hoernle et al (2008 their Figure 1) an exception is ouruse of lsquoeastern Nicaraguarsquo which comprise samples from the eastern margin of Nicaragua between ~123 to 126deg N and ndash837 to 840degE (eg Cukra Hill Pearl Lagoon from Gazel et al 2011) Isotope data from the CAVAS are from Gazel et al (2009 PIIndashPIV Costa Rica)Gazel et al (2011 PIV PVa PVb PVI Costa Rica) Hoernle et al (2008 PVa PVb Panama PVa southern and central Costa Rica BVF PVbsouthern Costa Rica PVI NW central and southern Costa Rica VF PVI southwest and northwest Nicaragua and the Miocene Costa Ricaand Miocene Nicaragua fields) Wegner et al (2011) (PIndashPIII PVb Panama) the GEOROC data base at httpgeorocmpchainzgwdgdegeoroc (PVI Costa Rica and Nicaragua only dated samples that yield ages of Quaternary are plotted) and the CentAm Databaseversion 102 at httpwwwearthchemorggrldatabases (PVI Costa Rica and Nicaragua as compiled by Jordan et al 2012) Fields forthe subducting Cocos and Coiba ridges (CCR or Central Galapagos Domain CGD) Seamount Province (SP or Northern GalapagosDomain NGD) and CocosNazca Plate are from Hoernle et al (2000) and Werner et al (2003) (as presented in Hoernle et al 2008) Thecompositions of (subducting) Cocos sediments are from Feigenson et al (2004) and the depleted mantle (DM) composition is fromWerner et al (2003 see Gazel et al 2009 for details) Other abbreviations not defined above CBA Chagres-Bayano Arc CCR CocosndashCoiba ridges CGD Central Galapagos Domain NGD Northern Galapagos Domain SAA SonandashAzuero Arc

more radiogenic Pb (higher 206Pb204Pb and 208Pb204Pb)with time This plateau-like affinity of the oldest arcsamples (Figure 13a) is not surprising as plume emplace-ment was likely the catalyst for the initiation of theCAVAS (plume-induced subduction initiation or PISIWhattam and Stern 2015) and hence early subductiontapped a strongly plume-modified mantle source InitialPb isotopic compositions evolve with time during PII toPIV but show increasingly distinctive regional variationswith Nicaragua always being less radiogenic than CostaRicandashPanama Similar to the trend to enriched sourceswith time explained above Hoernle et al (2008) andGazel et al (2009 2011) demonstrated a similar trend inCosta Rica after 6 Ma which is location dependent(Feigenson et al 2004 Goss and Kay 2006 Hoernleet al 2008 Gazel et al 2009 2011) (Figures 13c and13d) For example whereas northwest PVI Costa Ricalavas plot similarly to older PIV Costa Rica magmas (com-pare Figures 13b and 13d) with relatively low206Pb204Pb (~186ndash191) and 208Pb204Pb (~382ndash388)PVI lavas from central and northeast Costa Rica exhibithigher 206Pb204Pb (~190ndash193) and 208Pb204Pb (~387ndash391) with the most enriched samples overlapping thecompositional field defined by the subducting SeamountProvince (Figure 13d see location of province onFigure 2) This along-arc isotopic provinciality is one ofthe main pieces of evidence given that subducted sea-mounts modified the Costa Rica mantle source after 6 Ma

(Hoernle et al 2008 Gazel et al 2009 2011) These work-ers also demonstrated the low 206Pb204Pb and208Pb204Pb nature of Nicaragua arc magmas the com-positions of which have changed little from the Miocene(eg compare Figures 13b and 13d)

Figure 13a also shows the 40Ar39Ar ages ofPanamanian arc samples (Wegner et al 2011) whichfurther underscores the compositional similarities of PIarc samples with those of 98ndash82 Ma western Costa RicaCLIP sequences (Sinton et al 1997 Hauff et al 2000a2000b) However Figure 13 also demonstrates thatsamples from the 73ndash69 Ma SonandashAzuero Arc(Wegner et al 2011) of central Panama and the ~75ndash66 Ma Golfito Arc (Hauff et al 2000a 2000b Buchset al 2010) of easternmost Costa Rica are markedlyless radiogenic than lavas of the CLIP and lavas of theyounger (~70ndash39 Ma) ChagresndashBayano Arc (Wegneret al 2011) of eastern Panama (at 772ndash799deg W)Wegner et al (2011) noted that the SonandashAzuero Arcwas less radiogenic with respect to Pb isotopes thanthe Chagres-Bayano Arc but did not correlate thisobservation with data from lavas of the GolfitoComplex or other arc-related complexes in Costa Ricaand Nicaragua Whereas the two samples from theSona-Azuero Arc (723 and 675 Ma) exhibit206Pb204Pb of 1853ndash1865 and 208Pb204Pb of 3811ndash3841 similar to that of the Golfito Arc with 206Pb204Pband 208Pb204Pb of 1857ndash1877 and 3820ndash3833 (Hauff

051280

051285

051290

051295

051300

051305

051310

051315

051275

Time (Ma)7090 80100 60 50 40 30 20 10 0

PIIIPIV

PVIPICLIP

age of accreted

central CR

SW NICNW

NICeastern

Galapagos Islands (ie GP) at 28-0 Ma (grey bar)

onset of collision of Cocos Ridge with CAVAS trench98-82 Ma CLIP

80-60 Ma accreted OIB

OIB in western CR

Burica(N = 5)

PAN SAA CBA

Region Phase I PII PIII PIV PVa PVb PVI

CR GA NIC eastern

central NW NW SW

Figure 15 Initial 143Nd144Nd versus time for CAVAS magmatic products of PIndashPVI in Panama Costa Rica and Nicaragua Largesymbols represent undated samples and are plotted at the mean age of the associated unit small symbols represent dated samplesColour code schemes with their age brackets (age uncertainties) and encompassed units from left to right are as follows light grey98ndash82 Ma western Costa Rica igneous units interpreted as CLIP light purple PI (75ndash39 Ma) light blue PII (35ndash16 Ma) light greenPIII (16ndash6 Ma) PIV (6ndash3 Ma) light yellow and PVI (26ndash0 Ma) light pink The 80ndash60 Ma accreted OIB field is demarcated by theregion between the two solid grey vertical lines and the PV (PVa arc alkalics and PVb adakites 59ndash015 Ma) field is demarcated bythe region between the two dotted vertical lines For Costa Rica and Nicaragua PVI samples locations were plotted with coordinatesprovided in each relevant paper based on the way Hoernle et al (2008 Figure 1) subdivided Costa Rica into northwest central andsouthwest and Nicaragua into southwest and northwest In most cases the vertical error (compositional uncertainty) is smaller thanthe symbol size and is not plotted References for data sets are as given in the Figure 18 caption

et al 2000b) respectively the oldest Chagres-BayanoArc sample (685 Ma) exhibits 206Pb204Pb of 1882 and208Pb204Pb of 3842 lavas of the entire suite ofChagres-Bayano Arc samples display a range in206Pb204Pb of 1875ndash1907 and 208Pb204Pb of 3833ndash3885 which encompasses the composition of the old-est sample and which are higher than those of theGolfito and SonandashAzuero arcs The fact that ChagresndashBayano Arc samples are typically more radiogenic thansimilarly aged SonandashAzuero and Golfito Arc lavas andthat some relatively old ChagresndashBayano Arc samplesexhibit relatively very high 206Pb204Pb and 208Pb204Pb(eg a 659 Ma sample with 206Pb204Pb and208Pb204Pb of 1907 and 3883 respectively) suggestnot a temporal evolution with time but rather a loca-tion-dependent trend at least in Panama for reasonsthat are uncertain sources to the west were clearly lessradiogenic with respect to Pb than sources to the eastduring PI (Figure 13a) and remained so during PII andPIII (see below)

This observation of an apparent lack of radiogenicenrichment of Pb with time in Panama is largely sup-ported by the fact that PII and PIII (36ndash6 Ma) Panamasamples plot almost entirely within the range of PIPanama with 206Pb204Pb of 1879ndash1912 and208Pb204Pb of 3855ndash3892 however the broad EndashWdistribution of these samples from the PanamandashCostaRica border in the west to the Panama Canal near thewesternmost border of the ChagresndashBayano Arc in theeast makes it difficult to ascertain whether the PII andPIII sources were spatially associated with those of theSonandashAzuero Arc or the ChagresndashBayano Arc Perusal ofFigure 2 of Wegner et al (2011) suggests that themajority of samples with isotope data (those with cor-responding radiometric age data) are from regions tothe immediate north and west of the Sona and Azueropeninsulas in the Cordillera de Panama (see also ourFigure 2) Hence based on this spatial distribution itmay then be reasonable to assume a temporal shift tomore radiogenic Pb assuming a Sona-Azuero proximalsource for PII and PIII magmas in Panama

During PII in Costa Rica 206Pb204Pb (1855ndash1869) didnot rise from PI values (1857ndash1877) but 208Pb204Pb(3819ndash3845) ranged to higher concentrations (than PIwith 208Pb204Pb 3820ndash3833) Similarly throughout PIII206Pb204Pb (1860ndash1880) changed little from initial PIvalues but 208Pb204Pb (3820ndash3848) continued to rise orat least range to higher values A dramatic change tounequivocally more radiogenic Pb compositions began inPIV (6ndash3Ma) in Costa Rica with 206Pb204Pb and 208Pb204Pbreaching values (1886ndash1912 and 3854ndash3886 respectively)similar to (a) Panama during PIII and (b) NW Costa Ricaduring PVI (26ndash0 Ma see below)

The data for Pb isotopes discussed above demon-strates that while sources for Panama and Costa Ricalavas could be argued as distinct (from each other)throughout PIndashPIII overall the sources can be consid-ered as relatively similar throughout PIndashPIV Apart fromthe relatively slight increases in 208Pb204Pb between PIand PIII Costa Rica magmas remained essentiallyunchanged with respect to Pb isotope compositionbetween 75 and 6 Ma Similarly Panama magmasrecorded only slight increases in 206Pb204Pb and208Pb204Pb in PII and PIII relative to PI in Panama butshowed elevated values relative to Costa Rica until theend of PIII (16ndash6 Ma) It is not until PIV (6ndash3 Ma) that thesource of Costa Rica magmas lsquocatch uprsquo to the moreradiogenic Pb isotope compositions of PII and PIII mag-mas in Panama (Figure 13b) with 206Pb204Pb of 1886ndash1912 and 208Pb204Pb of 3854ndash3886 which fall (almost)completely within the range of PII and PIII Panamamagmas (206Pb204Pb of 1879ndash1912 and 208Pb204Pbof 3855ndash3892)

Several studies have focused on the isotopic natureand evolution of post 6 Ma lavas of the CAVAS (egFeigenson et al 2004 Goss and Kay 2006 Hoernle et al2008 Gazel et al 2009 2011) A major finding of theseaforementioned studies was the location- (along the vol-canic arc) dependent isotopic composition of Quaternaryto present lavas Although PVI Costa Rica magmas spanthe entire gamut of 206Pb204Pb and 208Pb204Pb compo-sitions exhibited by older (PIndashPVI) lavas (Figure 13d) andextend to even more radiogenic compositions their loca-tion in 206Pb204Pb versus 208Pb204Pb space is conditionalupon their geographic location along the volcanic arcWhereas Costa Rica lavas from NW Costa Rica exhibit awide range of Pb isotopes extending from relativelyunradiogenic compositions (eg with 206Pb204Pb of~3826 and 208Pb204Pb of ~1863) to moderately radio-genic compositions (with 206Pb204Pb of ~3884 and208Pb204Pb of ~1910) similar to maximum values exhib-ited by older PI (Chagres-Bayano Arc)ndashPIII Panama mag-mas and PIIndashPIV Costa Rica magmas (eg compareFigures 13a and 13b with d) PVI Nicaraguan magmasare unradiogenic and uniquely range to very depletedcompositions akin to N-MORB (Figure S5d) In contrastmagmas from NE and Central Costa Rica exhibit muchhigher 206Pb204Pb and 208Pb204Pb of ~3876ndash3910 and1908ndash1929 respectively Similarly the PV arc alkalicbasalts and adakites exhibit a similar highly radiogenicnature (with respect to Pb) as lavas from central and NECosta Rica (Figure 13d)

Feigenson et al (2004) demonstrated the exception-ally unradiogenic nature of local marine sediments (withrespect to Pb) and concluded that the high radiogenicnature of central Costa Rica magmas did not require a

subducted component (addition) Various enrichmentmodels for central Costa Rica were proffered byFeigenson et al (2004) but favoured the ones entailingeither the melting of enriched veined mantle or the re-melting of Galapagos Plume-influenced mantle In con-trast more recent models to explain enrichment includeforearc erosion (Goss and Kay 2006) and SeamountProvincendashsubduction interaction (Hoernle et al 2008Gazel et al 2009 2011) Models are scrutinized inSection 6

52 Nd isotopes

In contrast to Pb isotopes (206Pb204Pb and 208Pb204Pb)which are clearly less radiogenic in Golfito and Sona-Azuero compared with units interpreted as CLIP andthe ChagresndashBayano Arc (Figure 13) the 143Nd144Ndvalues of all PI arc segments fall within the range ofunits interpreted as CLIP (Figures 14 and 15) PI lavasare strikingly similar to those of 98ndash82 Ma western CostaRica units interpreted as CLIP in terms of 143Nd144Nd(Figures 14a and 15) only alkali basalts of the TortugalComplex exhibit contrasting (lower) 143Nd144Nd(0512740ndash0512798) (Hauff et al 2000b) (Figure 14a) Interms of Nd isotopes PI arc lavas in the west (ie Golfitoand SonandashAzuero) are similar to those in the east(ChagresndashBayano) (Figures 14a and 15) In detail theGolfito Complex records significantly higher 143Nd144Nd(0512922ndash0512959) than the SonandashAzuero Arc(0512864ndash00512866)

Plots of 206Pb204Pb versus 143Nd144Nd and143Nd144Nd versus time (Figures 14 and 15) also showa temporal trend to more radiogenic Nd relative to Pbas magma sources beneath both Costa Rica andPanama start to differentiate from CLIP-like143Nd144Nd during PII by becoming more radiogenic(Figure 15) Whereas the oldest radiometrically datedSona-Azuero and ChagresndashBayano samples (723ndash659 Ma) (Wegner et al 2011) exhibit the lowest143Nd144Nd and plot along the lower cusp of the com-positional field defined by the Galapagos plume at90 Ma all younger radiometrically dated PI Panamasamples from ChagresndashBayano with ages of 659ndash449 Ma display higher 143Nd144Nd and plot near thelower cusp of the Galapagos plume compositional fieldat 60 Ma (Figures 14a and b) Furthermore PII (35ndash16 Ma) samples from both Panama and Costa Ricarecord higher 143Nd144Nd than PI products but plotwithin the field of the Galapagos Plume at 60 Ma(Figure 14b) PIII lavas return to slightly lower143Nd144Nd than older PII These data demonstrate aswitch to less radiogenic Nd which was accompaniedby more radiogenic Pb (higher 206Pb204Pb and

208Pb204Pb Figure 13) beginning in PIII and reachinga pre-26 Ma peak in PIV Costa Rica

The PVa arc alkalic basalts and PVb adakites con-tinue the isotopic shift to lower 143Nd144Nd (Figures14c) and higher 206Pb204Pb and 208Pb204Pb and over-lap the fields of Cocos-Coiba Ridges and SeamountProvince fields Similarly the PVI lavas from centralCosta Rica (with 143Nd144Nd of 0512918ndash0512979)(Figures 14d and 15) which range to the lowest143Nd144Nd also overlap the CocosndashCoiba Ridgesand Seamount Province fields Analogous to the situa-tion with Pb isotopes where PVI northwest Costa Ricalavas formed from depleted sources relative to thoseof PVI central and northeast Costa Rica by virtue ofexhibiting lower 206Pb204Pb and 208Pb204Pb the PVInorthwest Costa Rica lavas have more radiogenic Ndthan PVI lavas in central and NE Costa Rica with143Nd144Nd of 0512922ndash0513040 Also similar to thesituation with Pb isotope compositions which chan-ged little in Nicaragua between the Miocene and pre-sent there is little change in this interval in Nd isotopecompositions (Figure 14d) An exception is three PVI(26ndash0 Ma) behind the volcanic front alkalic basalts (asdescribed in the Georoc dataset where these sampleswere listed) in eastern Nicaragua and within theCaribbean Sea (~123degN838degW) which plot similarlyin the 206Pb204Pb versus 143Nd144Nd space as PIIIPanama and PIV Costa Rica with ~ 1887ndash1990206Pb204Pb and 0512999ndash0515303 143Nd144Nd Theremaining (NW and SW) Nicaragua samples plot clo-sest to depleted MORB with high 143Nd144Nd(~051299ndash051311) and low 206PbPb204 (Figure 14d)

6 Discussion

The general evolution of the CAVAS towards moreenriched compositions suggests that one or more ofthe several processes became increasingly importantwith time a greater depth of melting so that garnetplayed a role an increase in sediment fluid and meltadditions an increase in plume or OIB contributions tothe mantle source a decrease in the degrees of partialmelting in the mantle wedge changes in the thermalstructure of the slab or wedge or a combination of twoor more of these processes A noteworthy feature is thatincompatible trace element enrichment is accompaniedby isotopic evolution to more depleted sources (higher143Nd144Nd lower 206Pb204Pb) with time (Figure 14)This anti-correlation may reflect that the asthenosphericmantle flowing into the mantle wedge changed withtime from enriched (plume-like) during PI to moredepleted (more MORB-like) in Neogene Strong along-arc isotopic gradients are found in Quaternary lavas

with MORB-like sources for Nicaragua and plume-likesources for Costa Rica

We explain below why and how a dual processentailing a first-order mechanism of progressivelydecreasing degrees of partial melting as a result of arccrustal thickening and associated changes in the mantlethermal structure possibly coupled with subducted sea-mounts and participation of more depleted mantlerepresents the one most likely responsible for incompa-tible enrichment in the CAVAS

Below we first discuss how to interpret CAVAS che-motemporal trends Next we examine the chemotem-poral record to determine whether the roles of crustinteraction and tectonics were important in controllingCAVAS magmagenetic evolution Finally on the basis ofour observations and interpretations of CAVAS chemo-temporal evolution we discuss the larger challenge ofdetermining why some arc magmatic systems evolvewith time whereas others do not

61 How to interpret CAVAS X55 chemotemporaltrends

Lavas erupted from long-lived arc systems ndash like theCAVAS ndash are likely to reflect more complex magmaevolution processes than those erupted from the othertwo major magmagenetic systems of divergent platemargins (mid-ocean ridges) and hotspots particularlythose on fast-moving oceanic plates Such complex-ities include ponding of mantle-derived mafic melts inthe crust where fractionation to form intermediate andfelsic melts can occur Such ponding will heat the crustand cause melting to generate felsic melts and themixing of mafic and felsic melts can generate inter-mediate melts (eg Stamatelopoulou-Seymour et al1990) Thinner mafic oceanic crust like that of CLIP isless likely to re-melt than thicker continental crust buthow much crustal melting occurs in each case isunclear in both cases there is likely to be more melt-ing with time as the lower crust is warmed by thepassage and ponding of magma but this dependson magma flux (Annen et al 2006) The role of thecrustal filter must be kept in mind when interpretingCAVAS chemotemporal evolution

Mantle processes must also be considered wheninterpreting CAVAS chemotemporal trends If the man-tle source of basalt magmas evolves compositionallythe resultant complex magmatic evolution can be diffi-cult to interpret as summarized in Figure 16 If the mostimportant process is fractional crystallization compari-son of X55 allows different mantle influxes of basalt tobe compared at similar stages of evolution In this casendash and assuming that similar degrees of mantle wedge

melting occurred to generate all CAVAS basalts ndash differ-ences in X55 largely reflect the variations in mantleenrichment presumably due to the addition of subduc-tion components On the other hand if crustal meltingto form felsic melts and the resultant hybridization isthe most important controlling compositional diversitythen the compositional spectrum is more difficult tointerpret As magmas with 55 wt SiO2 are more akinto the ones recording mantle input (~50 wt SiO2) asopposed to crustal input (~70 wt SiO2) abundancesnormalized to 55 wt SiO2 (X55) emphasize mantleinput

62 Role of the crust

Below we use two approaches to evaluate the extent towhich CAVAS chemotemporal trends could reflect

50 700

Mantle melting

Basalt

Rhyolite

Andesite

Basalt

CLIP crust

FC generatesintermediate ampfelsic melts nocrustal melting

Lower crust meltinggenerates felsic melts mixing generates intermediate melts

SiO wt 2

K55(t3)

K55(t2)

K55(t1)

K55(t3)

K55(t2)

K55(t1)

fractio

nation

mix ing

crustal melt

mantle source enrichment

Figure 16 Illustration of how element concentrations regressedto 55 wt SiO2 (X55) can be interpreted using potassium (K55)as an example (a) Mantle source is enriched with time andmelts to generate progressively more enriched basalts frommost depleted (t1) to most enriched (t3) Mantle-generatedbasalts traverse the crust quickly and do not heat the crustsufficiently to melt it No differentiated magmas are producedand it is easy to infer progressive mantle enrichment (b)Progressively enriched mantle output (basalt) experiences frac-tional crystallization to form andesite and rhyolite Regressionof compositions to K55 allows mantle evolution to be clearlyidentified (c) Progressively enriched mantle output heats theCLIP lower crust causing it to melt and generate felsic liquids(rhyolite) These mix with basaltic magmas to generate ande-sites Regression to K55 allows most of the progressive mantleenrichment to be identified

crustal interactions trends in K2O and other incompati-ble elements versus SiO2 and Nd isotopic data

621 Incompatible elements versus SiO2 trendsOne perspective on the issue of crustal interaction canbe gleaned from plots showing best-fit lines throughincompatible elements versus SiO2 (eg K2O vs SiO2Figure 4d see also Supplementary Figure S2) Mixingof mantle-derived basalts with crustal melt is likely todefine magmatic trends that converge on the crustalmelt as shown in Figure 16c CAVAS magmatic trendsdo not converge on a likely crustal melt compositionand instead show increasing slopes with enrichmentmore consistent with magmatic differentiation from dif-ferent mafic parents The slope of the PIV trend is theonly exception and it could be that the lower slope forthis sequence reflects the mixing between the maficmelts of enriched mantle and the crustal melt

A lack of crustal interaction is also readily apparenton various incompatible elements versus SiO2 plotswhen considering the best line of fit through the data(not shown) For example when considering PI Ba RbTh U and Nb versus SiO2 the low R2 values (007 00101 01 and 003 respectively) demonstrate that crustalinteraction was not a major factor in magmagenesis

622 Nd isotopesThe Nd isotopic data also record no evidence ofincreased crustal participation with time CAVAS mag-mas have very CLIP-like compositions during PI but thesource region evolved to more depleted compositionwith time as shown by higher 143Nd144Nd (Figure 15)This isotopic evolution is most easily explained by theparticipation of more depleted mantle with time per-haps by the replacement of the original GalapagosCLIPplume-like mantle by a more depleted normalasthenosphere

We conclude that CAVAS chemotemporal evolutiondoes not reflect increased crustal interactions with timea conclusion also reached by Gazel et al (2015) InsteadCAVAS chemotemporal variations mostly reflect thefractionation of mantle-derived mafic magmas In thiscase the approach we outlined in Section 61 capturesmantle source variations similar to what is shown inFigure 16b

63 Role of local tectonic events

It is important to determine the extent to which long-term arc magmatic evolution is affected by regionaltectonic events such as changing slab configurationsand upper plate extension Several major tectonicevents occurred in and around CAVAS during its lifetime

(Supplementary Figure S4) some of which had specificmagmatic expressions for the CAVAS Such localizedtectonic events and their magmatic responses providefew insights into the larger question of overall mag-matic evolution but the extent to which these haveaffected magma compositions provides fundamentalinsights into what are the key controls on arc magma-genesis in the CAVAS provided it is possible to removethis lsquotectonic noisersquo from the lsquotruersquo magmatic signals Itis thus important to identify these so we can disentan-gle which aspects of the CAVAS record are source evo-lution signal and which are local tectonic noise

Three outstanding aspects of CAVAS magmatic evo-lution that reflect local tectonics are (1) the divergencein compositions between Costa Rica plus Panama versusNicaragua which began between PIII (16ndash6 Ma) andpeaked during PIV (6ndash3 Ma) (2) the production of PVadakites and arc alkaline magmas in Panama and CostaRica after 6 Ma and (3) the lsquoresettingrsquo of the CAVASsource back to more depleted compositions after 3 Mawhich apart from Nicaragua erupting moderately moremafic lavas than Costa Rica are otherwise broadly simi-lar in terms of incompatible trace element systematicsin both regions These three issues are addressedfurther below

631 Neogene NicaraguandashCosta Rica compositionaldivergenceAccording to our present data set CAVAS magma che-mistries in each region appear to have been similarbefore beginning to diverge during PIII (16ndash6 Ma) anddramatically diverging during PIV (6ndash3 Ma) (eg Figures6ndash12) Whereas Costa Rica PIV lavas continued anenrichment trend relative to PIII compositions PIVNicaragua lavas reverted to derivation from a moredepleted mantle source that was more modified byslab contributions (eg Figures 11 and 12) These dis-similarities are especially clear for PIV Costa Rica lavaswhich exhibit strong LREE fractionations (La55Sm55 andLa55Yb55) in contrast to the only slightly enriched nat-ure of PIV Nicaragua lavas (Figure 8 Table 2) Otherdifferences apparent on the N-MORB normalized plot(Figure 10j) are the lower Th (and higher UTh) andhigher BaTh BaLa and NbLa of PIV Nicaraguan lavasrelative to Costa Rican PIV lavas which partly reflect thegreater sediment additions and in the case of elevatedUTh in Nicaragua lavas a change in composition of thesubducted sediments (Plank et al 2002)

What was the cause of compositional divergencebetween Costa Rica and Nicaragua CAVAS beginning~16ndash6 Ma There are several factors related to eitherchanges in what the subducted slab was doing (steeperslab dip) what was coming off the subducted slab

(change in fluid andor melt compositions due to chan-ging sediment composition the onset of OIB seamountsubduction beneath central Costa Rica or higher fluidflux) or what the upper plate was doing (changes inmantle wedge composition and upper plate extension)These possibilities are further described next

With respect to changes in subducted sediment com-positions the U and Ba enrichment in Nicaraguan mag-mas has been explained as reflecting a lsquocarbonate crashrsquo~10 Ma (event 7 Figure S4) when dominantly carbonatesedimentation on the Cocos Plate was replaced byhemipelagic ooze sedimentation as the result of theshallowing of the carbonate compensation depth by~800 m this occurred because the Panama ridge cutoff deep water flowing westwards out of the Caribbean(Plank et al 2002) Subduction erosion of forearcigneous units and trench sediments and the additionof changed sediment components to the mantle source(Goss and Kay 2006) have been posited as an alternativeto seamount subduction to explain enrichmentHowever Hoernle et al (2008) note that the isotopiccomposition of forearc units does not match those ofthe Seamount Province in contrast to post-6 Maenriched lavas in (mostly central) Costa Rica which areisotopically similar to the Seamount Province Moreoverwe showed in Section 4 that enrichment increaseddramatically over a short interval in PIV (6ndash3 Ma)which suggests a rapid short-lived enrichment processthat contrasts with that expected from forearc erosionwhich should be modest and prolonged

The subduction of Cocos Plate seamounts and theirmetasomatic interaction with the mantle sourcebeneath central Costa Rica (event 9 Figure S4) havebeen proposed to explain the distinctive enrichmentsrecorded by PVa alkaline basalts and PVb adakites (egHoernle et al 2008 Gazel et al 2009 2011) as commen-cing about the same time (10ndash8 Ma) as the arrival of theCocos Ridge and the carbonate crash However inspec-tion of Figure 13 (206Pb204Pb vs 208Pb204Pb) andFigure 14 (206Pb204Pb vs 143Nd144Nd) shows that Pband Nd isotopic compositions similar to that of thesubducting Seamount Province occurred as early as20 Ma in Panama (blue circle with age of 192 Ma)Two other PII (16ndash6 Ma) samples from Panama alsoplot within the subducting Seamount Province field interms of both Pb isotopes (206Pb204Pb and 208Pb204Pb)and Nd isotopes (Wegner et al 2011) If seamount sub-duction was important for enrichment this might havestarted much earlier than 8ndash10 Ma Seamount subduc-tion thus may explain the presence of OIB-like signa-tures in ~6 Ma and younger central Costa Rica CAVASsequences (Reagan and Gill 1989 Hoernle et al 2008Gazel et al 2009 2011 2015) however our regressed

data suggests that BaLa has always been lower in CostaRica than in Nicaragua (Ba55La55 of 14ndash31 in Costa Ricawhich peaked in PIII and 61ndash130 in Nicaragua whichpeaked in PIV Table 2) Similarly Plank et al (2002)established that high BaLa (gt70) in the Nicaragua vol-canic front is a long-lived feature Irrespective of thecause of lower BaLa in Costa Rica it has been operatingover the entire CAVAS lifetime although the discre-pancy is the largest during PIV If BaLa is indeed relatedto the subduction and interaction of hotspot tracks thelong-lived nature of the signal suggests that plumendashsubduction interactions began with initial oceanic islandaccretion and subduction ~60 Ma (eg Hoernle et al2002 Hoernle and Hauff 2007 Buchs et al 2009 2011see also Gazel et al 2015) or even earlier (see Whattamand Stern 2015)

The inferred higher degrees of partial melting inNicaragua versus Costa Rica (Saginor et al 2013) areascribed to the steeper slab dip beneath Nicaraguaversus Costa Rica (Syracuse et al 2008) This resulted inslab-derived fluids being released across a smaller widthof the arc beneath Nicaragua which enhanced melting(Carr et al 1990) Melting beneath Nicaragua was furtherenhanced by extension (see below) Furthermore theslab beneath Nicaragua is more serpentinized (~10ndash20extending some 20ndash28 km beneath the slab surface)than that beneath Costa Rica (Syracuse et al 2008 VanAvendonk et al 2011 see also Heydolph et al 2012)thus more fluid might have been released into theasthenospheric mantle wedge beneath Nicaragua rela-tive to Costa Rica Greater fluid flux would cause moremelting beneath Nicaragua than Costa Rica and wouldalso deliver different subduction-related metasomaticcomponents We do not know when these three differ-ences ndash slab dip upper plate extension and subductionof more serpentinized slab ndash between Nicaragua andCosta Rica convergent margins first appeared but oneor more of them starting ~16ndash6 Ma could explain theobserved compositional divergence

A possible cause of compositional divergencebetween Costa Rica and Nicaragua lava compositionswas the formation of the Nicaragua depression whichbegan during PII at about 23 Ma and continues untiltoday (Funk et al 2009) Extension thinned the litho-sphere and lengthened the melting columns beneathNicaragua allowing for higher degrees of meltingwhich was further aided by the enhanced water fluxfrom a more steeply dipping moderately serpentinizedslab Plank and Langmuir (1988) showed how the heightof the mantle column available for melting beneath arcsis a function of arc crust thickness If melting beginsbeneath arcs at similar depths then the column ofmantle that undergoes decompression melting is

shorter beneath the thicker arc crust Hence the longermantle column for arcs built on rifted crust will lead tohigher degrees of partial melting However Turner andLangmuir (2015) concluded that the length of the melt-ing column cannot be the determining factor in con-trolling the extent of partial melting and that rather athicker arc edifice would depress isotherms deeper (seealso Karlstrom et al 2014) Hence if the lithospherebeneath Nicaragua was thinner than that beneathCosta Rica as a result of forming the Nicaragua depres-sion a taller melting column accompanied by steeperdipping slab and more water flux and the migrationupwards of hotter isotherms (Turner and Langmuir2015) would be expected to lead to higher degrees ofpartial melting beneath Nicaragua relative to Costa Rica

632 Production of PV adakites and arc alkalinemagmas in Panama and Costa Rica after 6 MaSubduction terminated beneath Costa Rica and Panamasoon after 8 Ma as the result of collision and attemptedsubduction of the Cocos Ridge beneath Central America(Abratis and Woumlrner 2001) this was followed soon afterby the production of adakites and arc-alkaline basalts Ithas long been recognized that the end of subductionmay be marked by the eruption of alkaline basalts (egJakeš and White 1969) and sometimes a bimodal arcalkaline basalt and adakite association accompanies thesubduction of a hot slab (eg Kimura et al 2014) Theformation of alkaline-adakite bimodal magmatic asso-ciations have been explained by varying percentages ofsediments and altered crust comprising the slab differ-ing fractions of slab flux and differing PndashT conditions ofmantle melting (eg Martin et al 2005) Gazel et al(2009 2011) suggest that Costa Rica adakites mayform as a result of seamount subduction but this isnot a common explanation for adakites Neverthelessin the case of the CAVAS the isotope evidence providesstrong support for seamount subduction and interac-tion with mantle sources (Gazel et al 2011) Accordingto the model of Gazel et al (2011) for instance post-6 Ma alkali basalt and adakite formation in westernPanama and Costa Rica was related to terminal subduc-tion slab break-off and subsequent asthenosphericupwelling In either case the eruption of adakites andalkali basalts during CAVAS PV reflects local tectonicsrelated to subduction termination and does not revealmuch about the overall CAVAS magmatic evolution

633 lsquoResettingrsquo of the CAVAS source back to moredepleted compositions after 3 MaPVI marks the resetting of CAVAS magma compositionsto compositions similar to more depleted compositionssuch as those of PIndashPIII What was responsible for this

apparent reversal of magmatic evolution As La and Nbhave similar low Kd values (eg ~005 and 0005 inbasalt clinoproxene GERM data base) and ZrNb canbe fractionated only by extremely low degrees of partialmelting (F lt 05 Sun and McDonough 1989) thehigher LaNb of PIV Nicaragua relative to Costa Rica ismore likely to reflect greater additions of La relative toNb from the subducted slab consistent with other indi-cators as discussed previously However the higher ZrNb and the much lower NbYb of Nicaragua PIV mag-mas relative to Costa Rica demonstrate either the higherdegrees of partial melting or the tapping of a moredepleted source or both (Pearce and Peate 1995)

We suggest that the higher degrees of partial melt-ing in Nicaragua which began about 20 Ma coincidentwith the initial formation of the Nicaragua depressionwas the result of associated lithosphere thinning andchanges in the mantle thermal structure As lithosphericthickening would displace colder isotherms deeperresulting in a lower degree of partial melting litho-spheric thinning would have an opposite effect iethe displacement of hotter isotherms upwards resultingin a higher degree of partial melting (Turner andLangmuir 2015) It may be that lithospheric thinningpropagated eastwards to beneath Costa Rica by thetime the lsquomodern-dayrsquo CAVAS began to erupt at26 Ma Alternatively along-arc trench-parallel mantleflow may be partly responsible for the recent changes inmagma compositions (Hoernle et al 2008)

64 Long-term chemotemporal evolution of theCAVAS

There is strong evidence that despite significant effectsdue to regional tectonic changes the CAVAS systemevolved chemically over its 75 million year historyfrom depleted to enriched magmas In this section wefirst consider what processes were responsible the evo-lution of CAVAS towards continental crust composi-tions the role of mantle plumes in arc evolution andfinally present a synthesis and model for this evolution

641 Causes of progressive CAVAS magmaenrichmentIn Section 62 we showed that increasing crustal inter-action was probably not responsible for source enrich-ment over time and we conclude that the long-termenrichments reflect systematic changes in magmasources andor magmagenetic processes with timeSuch systematic changes could include the participationof progressively more enriched mantle progressivelygreater slab contributions or progressively lowerdegrees of melting Our conclusions thus echo those

of Turner and Langmuir (2015) who concluded that twodistinct explanations could account for the global varia-tions in arc magma compositions different extents ofmantle wedge melting due to differing (mantle) thermalstructures or varying contributions from the subductedslab We can track mantle evolution with ZrY(Figure 11a) and NbYb (Figure 11c) both of whichincrease with mantle enrichment but can also vary asa function of the degree of partial melting (or if garnetis involved which except for PV adakites and arc alka-line basalts does not seem to be the case for CAVAS)ZrY increases over the CAVAS lifespan suggestingeither that the mantle feeding the early CAVAS wasmore depleted than that feeding it now or that thedegree of partial melting has decreased over time NbYb ratios diverge strongly with higher values for CostaRica and Panama (indicating mantle source enrichmentor lesser melting) and lower values for Nicaragua (indi-cating mantle source depletion or higher melting) Thetrace element evidence of progressive enrichment con-trasts with the isotopic evidence that more depletedmantle was involved however isotopic compositionsreflect time-integrated parentdaughter ratios and areinsensitive to recent changes in source composition Weconclude from the trace element and isotopic data thatthe CAVAS mantle source changed significantly over the75 Ma life of CAVAS becoming somewhat enriched withtime at least for Costa Rica and Panama

Another possible explanation is that the subductioninput has increased with time or that its nature haschanged Subduction input can be subdivided intothose elements that are mobile in hydrous fluids (RbBa Sr U Pb LREEs) and those that are only trans-ported by melts (Zr Th Nb HREEs) Absolute concen-trations of linearly regressed fluid-mobile traceelements K2O Rb Ba Sr U and Pb increase over thelife of the arc (Figures 6ndash8) although chemotemporalevolution is more complex when the CAVAS is subdi-vided into regions Part of the subduction input can beisolated by focusing on the ratios of fluid-mobile tofluid-immobile incompatible trace elements which aregenerally acknowledged to reflect the transfer of fluid-mobile elements from the subducted slab to the man-tle wedge The only such ratio that increases with timein Panama and Costa Rica between PI and PIII is SrNdUTh increases between PI and PII only and PbCeremains more or less constant through time(Figure 12) Nonetheless the patterns of some ofthese ratios suggest that part of the explanation forthe long-term source enrichment of CAVAS magmasmight reflect subduction-related metasomatismSubduction-related progressive enrichment of theCAVAS source could reflect either instantaneous or

cumulative processes In the first case increased effi-cacy of fluid transfer from slab to mantle would beresponsible for increasing the fluid-mobile to fluid-immobile incompatible element ratios fluid-mobileelements released from the slab would immediatelyaffect melt compositions but would have no long-term effect on the mantle wedge composition In thesecond case the cumulate effect of fluids releasedfrom the subducted slab would metasomatically enrichthe mantle source in LILEs over time As we see noreason as to why subduction processes should moreefficiently release fluid-mobile elements with time weprefer the second explanation that the cumulate effectof fluids released from the slab metasomaticallyenriched the mantle source over time and concludethat the residence time of circulating asthenosphere inthe mantle wedge is long relative to subduction-related enrichment processes We note that theobserved anti-correlation of trace element enrichmentand especially Nd isotopic evidence for the increas-ingly depleted mantle source region may reflect thatthe asthenospheric mantle source flowing into themantle wedge changed with time from enriched(plume-like) during PI to more depleted (more MORB-like) in Neogene especially for Nicaragua lavas

A change in mantle or slab thermal structure (Turnerand Langmuir 2015) may represent alternative mechan-isms for varying slab-mantle fluxes over time In parti-cular the driving of cold isotherms to progressivelydeeper depths associated with arc edifice thickeningcould displace mantle melting to higher pressures andlower temperatures and hence lower degrees of melt-ing This change in mantle thermal structure could thusresult in more enriched magmas than those generatedbeneath a relatively thinner lithosphere We expand onthis idea in Section 644

642 Continental crust formation at the CAVASIt is generally agreed that continental crust todaymostly forms above subduction zones Despite difficul-ties in resolving the differences between the maficLREE-depleted nature of igneous rocks generated atIOCs versus those of more siliceous LREE-enriched con-tinental arcs and their roles in continental crustal gen-esis (Kay 1985 Ellam and Hawkesworth 1988) theaccretion of arc-related terranes due to collision is con-sidered to have been fundamental in the growth anddevelopment of continental crust throughout at leastthe Phanerozoic time (Taylor and McLennan 1985Rudnick 1995 Rudnick and Fountain 1995)

Based on ~03ndash6 Ma silicic ignimbrites from the CostaRica volcanic front Vogel et al (2004) suggest thatcontinental crust formed there as the result of the

addition of silicic magmas to the subduction-modifiedoceanic plateau crust possibly aided by the founderingof maficultramafic residues and cumulates from thebase of the crust Vogel et al (2004) suggested thatthe origin of these silicic magmas was the result ofreprocessing initially juvenile mantle-derived subduc-tion-related magmas that ponded in the crust similar tothe process proposed for converting basaltic crust tocontinental crust in Costa Rica by Pichler and Weyl(1975) Although this might have been important latein the evolution of the CAVAS in Costa Rica this doesnot explain the general enrichment in the CAVAS thatbegan during PIII (35ndash16 Ma) As shown in Figure 10continental crust-like compositions were achieved inthe CAVAS by at least 6 Ma Furthermore the transfor-mation from mafic to continental-like compositionsstarted much earlier (by ~35 Ma) and was gradual

Gazel et al (2015) concluded that partial melting ofenriched subducting Galapagos hotspot tracks pro-duced young andesitic continental crust beginning at~ 10 Ma as recorded in the Central American LandBridge (CALB Panama and Costa Rica) geochemicalevolution As shown in Figure 9 collective compositionsof Costa Rica plus Nicaragua are nearly identical to thecontinental crust at 6ndash3 Ma although when parsed intoregion it is evident that whereas Costa Rica was clearlycontinental-like Nicaragua was not during this interval(Figure 10) Thus our data mostly agrees with those ofGazel et al (2015) in the timing of when continental-likecompositions appeared but differs in (1) the rate atwhich this continental crust composition was reachedand (2) the cause of enrichment We stress that conti-nental-like compositions did not suddenly appear at10 Ma but rather that the enrichment was gradualover CAVAS history from PII (35ndash16 Ma) to the presentin Panama and Costa Rica as shown in Section 4 andsummarized in Figure 9 As Galapagos hotspot tracksappear to have been only subducted beneath CostaRica beginning about 10 Ma (Gazel et al 2015 andreferences therein) enrichment during PII cannot onlybe the result of hotspot track subduction and the asso-ciated mantle metasomatism

Moreover the if the tenets of the model of Gazelet al (2015) represent an overarching process necessaryfor enrichment in other enriched arcs (eg thePhilippines) this then requires the serendipitous addi-tion and interaction of hotspot-tracks (at other enrichedarc systems) Alternatively with our model all that isrequired is the thickening of the arc edifice and achange in the associated sub-arc mantle wedge thermalstructure Enrichment at the CAVAS and perhaps

enriched arcs in general would be further intensifiedby the lack of backarc formation behind the arc afeature of which characterizes for example theenriched Greater Antilles Arc (GAA) system Enrichmentat the well-documented GAA (Jolly et al 1998a 1998b2001) was not sudden but gradual over tens of millionsof years similar to that of the CAVAS It seems morereasonable to us that an overarching cause of enrich-ment would be common in different arc systems asopposed to unique in each arc We conclude that gra-dual enrichment with time demonstrated by the CAVASis the result of gradual thickening of the arc substrateand a change in the wedge thermal structure whichallowed for the driving of isotherms downwards tohigher pressures and colder temperatures and hencelesser degrees of partial melting (Turner and Langmuir2015)

643 Role of mantle plumes in the generation ofcontinental crustThe role of enriched mantle sources in the generation ofcontinental crust has long been proposed (egHawkesworth and Kemp 2006 and references therein)Primarily via isotopic evidence we showed the contri-butions of the Galapagos Plume to CAVAS magmatismwhich has been noted by others (eg Wegner et al2011 for Panama Whattam and Stern 2015 referencestherein for various regions around the periphery andcentre of the Caribbean Plate) A model of plume-induced subduction initiation (PISI) around the CLIPthe plume head of the Galapagos Plume to initiatethe CAVAS (Whattam and Stern 2015 see also Geryaet al 2015) explains its isotopic and trace elementsimilarity during PI with the Galapagos Plume and OPBin general however it is evident that plume-like mantlecontributions occurred all throughout the lifespan ofthe CAVAS and continue to this day (see Whattam andStern 2015 and references therein) Although emplace-ment of the CLIP oceanic plateau and continual feedingof plume magmatism would have provided a head-starton enrichment via the production of an anomalouslythick arc substrate enrichment cannot be solely attrib-uted to plume contributions The reason for this is thatwhereas the isotopic affinities of CAVAS products keptpace with that of the Galapagos Plume the trace ele-ment chemistry subsequently changed to moreenriched compositions (than the Galapagos Plume iethe CLIP) after 35 Ma This also rules out enrichment asthe result of OIB subduction accompanying accretionafter 60 Ma

644 Chemotemporal evolution of the CAVASsynthesis and modelBased on the results and interpretations of this studywe provide a graphical representation of the chemo-temporal evolution of the CAVAS from arc establish-ment to the present day in Figure 17 PI at 75ndash39 Mamarked the establishment of the CAVAS magmatic arcand the production of arc tholeiites Subsequentthickening of the sub-arc lithosphere during PII (35ndash16 Ma) and PIII (16ndash6 Ma) drove the isotherms deeperwith the consequent displacement of melting tohigher pressures and lower temperatures to formincreasingly enriched magmas This process continuedin Costa Rica during PIV (6ndash3 Ma) however extensionof the sub-arc lithosphere beneath Nicaragua begin-ning in the early Miocene resulted instead in theupward displacement of hotter isotherms beneathNicaragua This in addition to the more steeply dip-ping and serpentinized nature of the slab beneathNicaragua compared with Costa Rica gave rise tomore melting and the production of more depletedmagmas Subsequent to the termination of subduc-tion beneath Panama and southeast Costa Rica duringPhase V (59ndash002 Ma) subsequent slab melting andpartial melting of upwelling asthenosphere resulted inthe production of adakites and arc alkalic basaltsrespectively Enrichment after 6 Ma in central andnortheast Costa Rica was likely accentuated by sea-mountndashsubduction interaction as proposed by othersHowever we propose that continued extensionwhich first began beneath Nicaragua circa 20 Mawith the initial formation of the Nicaragua depressionpropagated eastwards to beneath (both Nicaraguaand) Costa Rica during PVI (26ndash0 Ma (Figure 17)This resulted in attenuation of the sub-arc lithosphereresulting in the driving of hotter isotherms upwardsmore melting and the formation of depleted magmassimilar in composition to those of PIndashPIII

7 Conclusions

Seven important conclusions about the geochemicalevolution of the CAVAS are drawn from this study

(1) Early CAVAS volcanism (PI 75ndash39 Ma) was char-acterized by low-K tholeiitic to weakly calc-alka-line activity with compositions that are broadlysimilar to the depleted sediment-poor lavas ofthe IBM arc system There was an apparent WndashEand possibly older to younger transition fromMORB-like magmatism in the 73ndash39 Ma SonandashAzuero Arc to the 70ndash39 Ma ChagresndashBayano Arc

(2) Elevated concentrations of some incompatibleelements and element ratios however are higherthan those of the IBM and similar in many casesto mean OPB This and the fact that early andlater magmas kept pace with the isotopic evolu-tion of the Galapagos Plumes demonstrate sig-nificant plumendashsubduction interactions thatoccurred throughout the CAVAS lifespan

(3) The most striking feature of CAVAS geochem-ical evolution was the progression in incompa-tible-element enrichment with time after35 Ma The composition of mean linearlyregressed PII (35ndash16 Ma) lavas and intrusivesof both Panama and Costa Rica and the collec-tive composition of PIV (6ndash3 Ma Costa Rica plusNicaragua) magmas closely resemble that ofBCC The best explanation for CAVAS enrich-ment is decreasing degrees of partial meltingwith time as the result of crustal thickening andchanges to the sub-arc mantle thermal struc-ture (progressive downwards displacement ofisotherms) accompanied by cumulative metaso-matic enrichment of the mantle wedge abovethe subducting Cocos Plate

(4) A fundamental compositional divergence isrecorded in PVI Nicaraguan and Costa Rican mag-mas manifest in elevated UTh and BaLa and amuch more depleted source beneath Nicaraguawhich is likely the result of higher degrees ofmantle melting The elevated UTh has beenascribed to the post-10 Ma carbonate crashwhich changed the subducting Cocos Plate sedi-ments from U-poor carbonates to U-rich hemipe-lagic muds whereas the lower BaLa in Costa Ricahas been interpreted as the result of OIB sea-mountndashsubduction interactions The higherdegree of partial melting beneath Nicaraguamay be the result of steeper slab dip and upperplate extension resulting in changes to the sub-arc mantle thermal regime (displacement of theisotherms upwards) accompanying the formationof the Nicaragua depression the combinedeffects of which resulted in higher degrees ofmelting The higher degree of melting is alsolikely related to the more serpentinized natureof the Nicaraguan slab

(5) Chemotemporal enrichments of CAVAS and otherarcs partly reflect whether or not an arc system isassociated with a backarc basin Arcs associatedwith backarc basins are fed by a more depletedmantle and have taller melt columns unrifted arclithosphere in contrast thickens with time

resulting in progressively lower degrees of melt-ing and more enriched lava compositionsOpening of a backarc basin essentially reverses

arc magmatic evolution Early Galapagos Plumecontributions in forming the CAVAS mantlewedge kick-started CAVAS enrichment

Cocos Plate

Phase I (75-39 Ma)development of magmatic arc contributions from Galapagos Plume result in construction of anomalously thick arc substrate eruption of arctholeiites

Phase II (35-16 Ma)thickening of lithosphere beneath magmatic arc results in shorter melt column - displacement of isotherms downwards - less melting - more enriched magmas extension beneath Nicaragua (not shown)begins around 23 Ma and results in extension of melt column - displacement of hot isotherms upwards - more melting beneath Nicaragua relative to Costa Rica beginning in PIII

Phase III (16-6 Ma)continued thickening of lithosphere beneath Costa Rica results in even shorter melt column - continualdisplacement of isotherms downwards - even less melting and even more enriched magmas continuedextension beneath Nicaragua however results in incipient divergence in source compositions beneath Nicaragua vs Costa Rica to more depleted and enriched beneath the former and latter respectively

Phase IV (6-3 Ma) Costa Ricacontinued thickening of lithosphere beneath magmatic arc results in even shorter melt column - continualdisplacement of isotherms even further downwards -even less melting - even more enriched magmassubduction of Seamount Province seamountsaccentuates enrichment

Phase IV (6-3 Ma) Nicaraguacontinued extension thins lithosphere lengthensmelt column - displacement of isotherms upwards -more melting - more depleted magmas

Phase V (59-002 Ma)termination of subduction beneath Panama and SE Costa Rica leads to slab melting (adakite formation) and alkalic basalt formation

Phase VI (26-0 Ma)continued extension beneath Nicaragua and NW Costa Rica lengthens melt column - displacement of isotherms upwards - more melting - more depleted magmas

Farallon Plate

Seamount Province

alkalic basalts

slab tear

adakitesasthenosphere flow

Figure 17 Graphical representation of the chemotemporal evolution of the CAVAS between magmatic arc establishment and thepresent day based on Turner and Langmuir (2015) and Plank and Langmuir (1988) (see text for details) Note that the green linesbeneath the CAVAS arc edifice in Costa Rica and Panama between PII (35ndash16 Ma) and PIV (6ndash3 Ma) represent gradual lithosphericthickening which resulted in the progressive displacement of isotherms downwards lower degrees of partial melting and thegeneration of increasing enriched magmas An opposite mechanism of lithospheric attenuationextension occurred beneathNicaragua beginning ~23 Ma concomitant with the commencement of Nicaragua depression formation resulting in the displace-ment of isotherms upwards higher degrees of melting and the production of more depleted magmas By 3 Ma extension beneathNicaragua had propagated to the SW beneath Costa Rica resulting in the resetting to the production of more depleted magmacompositions similar to those produced between PI and PIII

(6) Models calling for the chemical evolution of mag-matic arcs from depleted to enriched with time(ie early arc evolution studies) are generally sup-ported by the study of the CAVAS systemTectonic events can complicate simple modelsfor arc evolution and even the reversal of long-term chemotemporal enrichment trends

(7) Future studies are needed to improve coarsetemporal resolution in especially PI (75ndash39 Ma)PII (35ndash16 Ma) and PIII (16ndash6 Ma) More inte-grated geochronologic studies of especiallyCAVAS PI II and III are required

Acknowledgements

We greatly appreciate the detailed and constructive com-ments of four anonymous reviewers which led to a greatlyrevised ndash and we believe improved ndash manuscript

Disclosure statement

No potential conflict of interest was reported by the authors

Funding

SAW acknowledges financial support from the Smithsonian(Washington) and the Smithsonian Tropical ResearchInstitute (Panama) during his 1 year tenure at the latter duringthe period 2009ndash2010

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Annen C Blundy JD and Sparks RSJ 2006 Genesis ofintermediate and Silicic Magmas in deep crustal hotzones Journal of Petrology v 47 p 505ndash539 doi101093petrologyegi084

Arculus RJ 1994 Aspects of magma genesis in arcs Lithos v33 p 189ndash208 doi1010160024-4937(94)90060-4

Arculus RJ 2003 Use and abuse of the terms calcalkaline andcalcalkalic Journal of Petrology v 44 p 929ndash935doi101093petrology445929

Arculus RJ and Johnson RW 1978 Criticism of generalisedmodels for the magmatic evolution of arc-trench systemsEarth and Planetary Science Letters v 39 p 118ndash126doi1010160012-821X(78)90148-6

Barth MG McDonough WF and Rudnick RL 2000Tracking the budget of Nb and Ta in the continental crustChemical Geology v 165 p 197ndash213 doi101016S0009-2541(99)00173-4

Baumgartner PO Flores K Bandini AN Girault F and CruzD 2008 Upper Triassic to Cretaceous radiolaria fromNicaragua and northern Costa Rica ndash The Mesquito compo-site oceanic terrane Ophioliti v 33 p 1ndash19

Brown GC 1982 Calc-alkaline intrusive rocks Their diversityevolution and relation to volcanic arcs in Thorpe RS edOrogenic andesites and related rocks London Wiley p437ndash461

Bryant CJ Arculus RJ and Eggins SM 2003 The geochem-ical evolution of the Izu-Bonin Arc System A perspectivefrom tephras recovered by deep-sea drilling GeochemistryGeophysics Geosystems v 4 doi1010292002GC000427

Buchs DM Arculus RJ Baumgartner PO Baumgartner-Mora C and Ulianov A 2010 Late Cretaceous arc devel-opment on the SW margin of the Caribbean Plate Insightsfrom the Golfito Costa Rica and Azuero Panama com-plexes Geochemistry Geophysics Geosystems v 11doi1010292009GC002901

Buchs DM Arculus RJ Baumgartner PO and Ulianov A2011 Oceanic intraplate volcanoes exposed Example fromseamounts accreted in Panama Geology v 39 p 335ndash338doi101130G317031

Buchs DM Baumgartner PO Baumgartner-Mora CBandini AN Jackett S-J Diserens M-O and Stucki J2009 Late Cretaceous to Miocene seamount accretion andmeacutelange formation in the Osa and Burica Peninsulas (south-ern Costa Rica) Episodic growth of a convergent margin inJames K et al eds The origin and evolution of theCaribbean Plate Geological Society of London SpecialPublication 328 p 411ndash456

Carr MJ Feigenson MD and Bennett EA 1990Incompatible element and isotopic evidence for tectoniccontrol of source mixing and melt extraction along theCentral American arc Contributions to Mineralogy andPetrology v 105 p 369ndash380 doi101007BF00286825

Carr MJ Feigenson MD Patino LC and Walker JA 2003Volcanism and geochemistry in Central America Progressand problems in Eiler J ed Inside the Subduction FactoryGeophysical Monograph Series 138 p 153ndash174

Defant MJ Clark LF Stewart RH Drummond MS DeBoer JZ Maury RC Bellon H Jackson TE andRestrepo JF 1991a Andesite and dacite genesis via con-trasting processes The geology and geochemistry of ElValle Volcano Panama Contributions to Mineralogy andPetrology v 106 p 309ndash324 doi101007BF00324560

Defant MJ Jackson TE Drummond MS De Boer JZBellon H Feigenson MD Maury RC and Stewart RH1992 The geochemistry of young volcanism throughoutwestern Panama and southeastern Costa Rica An overviewJournal of the Geological Society of London v 149 p 569ndash579 doi101144gsjgs14940569

Defant MJ Richerson PM De Boer JZ Stewart RH MauryRC Bellon H Drummond MS Feigenson MD andJackson TE 1991b Dacite Genesis via both Slab Meltingand Differentiation Petrogenesis of La Yeguada VolcanicComplex Panama Journal of Petrology v 32 p 1101ndash1142 doi101093petrology3261101

Dickinson WR and Hatherton T 1967 Andesitic volcanismand seismicity around the Pacific Science v 157 p 801ndash803 doi101126science1573790801

Drummond MS Bordelon M De Boer JZ Defant MJBellon H and Feigenson MD 1995 Igneous petrogenesisand tectonic setting of plutonic and volcanic rocks of theCordillera de Talamanca Costa Rica-Panama CentralAmerican arc American Journal of Science v 295 p 875ndash919 doi102475ajs2957875

Du Bray EA and John DA 2011 Petrologic tectonic andmetallogenic evolution of the Ancestral Cascades magmaticarc Washington Oregon and northern CaliforniaGeosphere v 7 p 1102ndash1133 doi101130GES006691

Ehrenborg J 1996 A new stratigraphy for the Tertiary volca-nic rocks of the Nicaraguan highland Geological Society ofAmerica Bulletin v 108 p 830ndash842 doi1011300016-7606(1996)108lt0830ANSFTTgt23CO2

Ellam RM and Hawkesworth CJ 1988 Is average continentalcrust generated at subduction zones Geology v 16 p 314ndash317 doi1011300091-7613(1988)016lt0314IACCGAgt23CO2

Elliot T Plank T Zindler A White W and Bourdon B 1997Element transport from slab to volcanic front at the Marianaarc Journal of Geophysical Research v 102 p 14991ndash15019 doi10102997JB00788

Elming S-A Layer P and Ubieta K 2001 A palaeomagneticstudy and age determinations of Tertiary rocks inNicaragua Central America Geophysical JournalInternational v 147 p 294ndash309 doi101046j0956-540x200101526x

Farris DW Jaramillo C Bayona G Restrepo-Moreno SAMontes C Cardona A Mora A Speakman RJ GlascockMD and Valencia V 2011 Fracturing of the Panamanianisthmus during initial collision with South AmericaGeology v 39 p 1007ndash1010 doi101130G322371

Feigenson MD Carr MJ Maharaj SV Julianao S andBolge LL 2004 Lead isotope composition of centralAmerican volcanoes Influence of the Galapagos plumeGeochemistry Geophysics Geosystems v 5 no 6Q06001 doi1010292003GC000621

Funk J Mann P McIntosh K and Stephens J 2009Cenozoic tectonics of the Nicaraguan depressionNicaragua and Median trough El Salvador based on seis-mic-reflection profiling and remote-sensing dataGeological Society of America Bulletin v 121 p 1491ndash1521 doi101130B264281

Gazel E Alvarado GE Obando J and Alfaro A 2005Evolucioacuten magmaacutetica del arco de Sarapiquiacute Costa RicaReviews of the Geology of Central America v 32 p 13ndash31

Gazel E Carr MJ Hoernle K Feigenson MD Hauff FSzymanski D and Van Den Bogaard P 2009 TheGalapagos-OIB signature in southern Central AmericaMantle re-fertilization by arc-hotspot interactionGeochemistry Geophysics Geosystems Q02S11doi1010292008GC002246

Gazel E Hayes JL Hoernle K Kelemen P Everson EHolbrook WS Hauff F Van Den Bogaard P Vance EAChu S Calvert AJ Carr MJ and Yogodzinski GM 2015Continental Crust generated in oceanic arcs NatureGeosciences v 8 p 321ndash327 doi101038ngeo2392

Gazel E Hoernle K Carr MJ Herzberg C Saginor I VanDen Bogaard P Hauff F Feigenson M and Swisher C III2011 Plume-subduction interaction in southern CentralAmerica Mantle upwelling and slab melting Lithos v121 p 117ndash134 doi101016jlithos201010008

Gerya T Stern RJ Baes M Sobolev S and Whattam SA2015 Plume-induced subduction initiation triggered platetectonics on Earth Nature (in press)

Gill JB 1970 Geochemistry of Viti Levu Fiji and its evolutionas an island arc Contributions to Mineralogy and Petrologyv 27 p 179ndash203 doi101007BF00385777

Goss AR and Kay SM 2006 Steep REE patterns andenriched Pb isotopes in Central American arc magmasEvidence for forearc erosion Geochemistry GeophysicsGeosystems v 7 no 5 Q05016 doi1010292005GC001163

Hauff F Hoernle K Tilton G Graham DW and Kerr AC2000a Large volume recycling of oceanic lithosphere overshort time scales Geochemical constraints from theCaribbean large Igneous Province Earth and PlanetaryScience Letters v 174 p 247ndash263 doi101016S0012-821X(99)00272-1

Hauff F Hoernle K Van Den Bogaard P Alvarado G andGarbe-Schoumlnberg D 2000b Age and geochemistry ofbasaltic complexes in western Costa Rica Contributions tothe geotectonic evolution of Central AmericaGeochemistry Geophysics Geosystems v 1 Paper no1999GC000020 doi1010291999GC000020

Hawkesworth CJ Gallagher K Hergt JM and McDermottF 1993a Mantle and slab contributions in arc-magmasAnnual Review of Earth and Planetary Sciences v 21 p175ndash204 doi101146annurevea21050193001135

Hawkesworth CJ Gallagher K Hergt JM and McDermottF 1993b Trace element fractionation processes in thegeneration of island arc basalts Philosophical Transactionsof the Royal Society A Mathematical Physical andEngineering Sciences v 342 p 179ndash191 doi101098rsta19930013

Hawkesworth CJ and Kemp AIS 2006 Evolution of thecontinental crust Nature v 443 p 811ndash817 doi101038nature05191

Heydolph K Hoernle K Hauff F Bogaard PVD PortnyaginM Bindeman I and Garbe-Schoumlnberg D 2012 Along andacross arc geochemical variations in NW Central AmericaEvidence for involvement of lithospheric pyroxeniteGeochimica Et Cosmochimica Acta v 84 p 459ndash491doi101016jgca201201035

Hildreth WE and Moorbath S 1988 Crustal contributions toarc magmatism in the Andes of central Chile Contributionsto Mineralogy and Petrology v 98 p 455ndash489 doi101007BF00372365

Hoernle K Abt DL Fischer KM Nichols H Hauff F AbersGA Van Den Bogaard P Heydolph K Alvarado G ProttiM and Strauch W 2008 Arc-parallel flow in the mantlewedge beneath Costa Rica and Nicaragua Nature v 451 p1094ndash1097 doi101038nature06550

Hoernle K and Hauff F 2007 Oceanic igneous complexes inBundschuh J and Alvarado G eds Central America geol-ogy resources hazards Volume 1 London Taylor amp Francisp 523ndash548

Hoernle K Van Den Bogaard P Werner R Lissinna B HauffF Alvarado G and Garbe-Schoumlnberg D 2002 Missinghistory (16ndash71 Ma) of the Galaacutepagos hotspot Implicationsfor the tectonic and biological evolution of the AmericasGeology v 30 p 795ndash798 doi1011300091-7613(2002)030lt0795MHMOTGgt20CO2

Hoernle KA Werner R Phipps Morgan J Garbe-SchoumlnbergD Bryce J and Mrazek J 2000 Existence ofcomplex spatial zonation in the Galaacutepagos plumeGeology v 28 p 435ndash438 doi1011300091-7613(2000)28lt435EOCSZIgt20CO2

Irvine TN and Baragar WRA 1971 A Guide to the ChemicalClassification of the Common Volcanic Rocks Canadian

Journal of Earth Sciences v 8 p 523ndash548 doi101139e71-055

Ishikawa T and Tera F 1997 Source composition and dis-tribution of the fluid in the Kurile mantle wedgeConstraints from across- arc variations of BNb and B iso-topes Earth and Planetary Science Letters v 152 p 123ndash138 doi101016S0012-821X(97)00144-1

Jakeš P and White AJR 1969 Structure of the Melanesianarcs and correlation with distribution of magma typesTectonophysics v 8 p 223ndash236 doi1010160040-1951(69)90099-7

Jakeš P and White AJR 1972 Major and trace elementabundances in volcanic rocks of orogenic areas GeologicalSociety of America Bulletin v 83 p 29ndash40 doi1011300016-7606(1972)83[29MATEAI]20CO2

Jakeš P and Gill JB 1970 Rare earth elements and theisland arc tholeiitic series Earth and Planetary ScienceLetters v 9 p 17ndash28 doi1010160012-821X(70)90018-X

Jolly WT Lidiak EG Dickin AP and Wu T-W 1998bGeochemical diversity of Mesozoic island arc tectonicblocks eastern Puerto Rico in Lidiak EG and Larue DKeds Tectonics and geochemistry of the NortheastCaribbean Volume 322 Geological Society of AmericaSpecial Paper p 67ndash98

Jolly WT Lidiak EG Dickin AP and Wu T-W 2001 SecularGeochemistry of Central Puerto Rican Island Arc LavasConstraints on Mesozoic Tectonism in the Eastern GreaterAntilles Journal of Petrology v 42 p 2197ndash2214doi101093petrology42122197

Jolly WT Lidiak EG Schelleckens HS and Santos S 1998aVolcanism tectonics and stratigraphic relations in PuertoRico in Lidiak EG and Larue DK eds Tectonics andgeochemistry of the Northeast Caribbean Volume 322Geological Society of America Special Paper p 1ndash34

Jordan EK Lieu W Stern RJ Carr MJ Gill JB andLehnert K 2012 Geochemical data library for Quaternarylavas from the magmatic front of the Central American andIzu-Bonin-Mariana arcs Explanation to accompany excelworkbook ldquoCentAm and IBM geochem databaserdquo version102 located at httpwwwearthchemorggrl

Karlstrom L Lee C-TA and Manga M 2014 The role ofmagmatically driven lithospheric thickening on arc frontmigration Geochemistry Geophysics Geosystems v 15 p2655ndash2675 doi1010022014GC005355

Kay RW 1985 Island arc processes relevant to crustal andmantle evolution Tectonophysics v 112 p 1ndash15doi1010160040-1951(85)90169-6

Kerr AC Marriner GF Tarney J Nivia A Saunders ADThirlwall MF and Sinton CW 1997 Cretaceous basalticterranes in Western Columbia Elemental chronological andSr-Nd isotopic constraints on Petrogenesis Journal ofPetrology v 38 p 677ndash702 doi101093petroj386677

Kerr AC Tarney J Kempton PD Spadea P Nivia AMarriner GF and Duncan RA 2002 Pervasive mantleplume head heterogeneity Evidence from the lateCretaceous Caribbean-Colombian oceanic plateau Journalof Geophysical Research v 107 doi1010292001JB000790

Kimura JI Gill JB Kunikiyo T Osaka I Shimoshioiri YKatakuse M Kakubuchi S Nagao T Furuyama KKamei A Kawabata H Nakajima J Van Keken PE andStern RJ 2014 Diverse magmatic effects of subducting ahot slab in SW Japan Results from forward modeling

Geochemistry Geophysics Geosystems v 15 p 691ndash739doi1010022013GC005132

Kuno H 1966 Lateral variation of basalt magma type acrosscontinental margins and island arcs BulletinVolcanologique v 29 p 195ndash222 doi101007BF02597153

Le Bas MJ Le Maitre RW Streckeisen A and Zanettin B1986 A chemical classification of volcanic rocks based onthe total alkali-Silica diagram Journal of Petrology v 27 p745ndash750 doi101093petrology273745

Lee JM Stern RJ and Bloomer SH 1995 Forty millionyears of magmatic evolution in the Mariana arc The tephraglass record Journal of Geophysical Research v 100 no B9p 17671ndash17687 doi10102995JB01685

Lissinna BA 2005 Profile though the Central AmericanLandbridge in western Panama 115 Ma interplay betweenthe Galaacutepagos Hotspot and the Central AmericanSubduction Zone [PhD thesis] Kiel Germany Christian-Albrechts University 102 pp

MacMillan I Gans PB and Alvarado G 2004 MiddleMiocene to present plate tectonic history of the southernCentral American volcanic arc Tectonophysics v 392 p325ndash348 doi101016jtecto200404014

Mann P Rogers R and Gahagan L 2007 Overview of platetectonic history and its unresolved tectonic problems inBundschuh J and Alvarado G eds Central AmericaGeology Resources and Hazards Volume 1 Leiden TheNetherlands Taylor and FrancisBalkema p 201ndash237

Martin H Smithies RH Rapp R Moyen J-F and ChampionD 2005 An overview of adakite tonalitendashtrondhjemitendashgranodiorite (TTG) and sanukitoid Relationships andsome implications for crustal evolution Lithos v 79 p 1ndash24 doi101016jlithos200404048

McCulloch MT and Gamble JA 1991 Geochemical andgeodynamical constraints on subduction zone magmatismEarth and Planetary Science Letters v 102 p 358ndash374doi1010160012-821X(91)90029-H

Meschede M and Frisch W 1998 A plate-tectonic model forthe Mesozoic and early Cenozoic history of the CaribbeanPlate Tectonophysics v 296 p 269ndash291 doi101016S0040-1951(98)00157-7

Miyashiro A 1974 Volcanic rock series in island arcs andactive continental margins American Journal of Science v274 p 321ndash355 doi102475ajs2744321

Montes C Bayona GA Cardona A Buchs DM Silva CAMoroacuten SE Hoyos N Ramiacuterez DA Jaramillo CA andValencia V 2012a Arc-continent collision and orocline for-mation Closing of the Central American seaway Journal ofGeophysical Research v 117 p B04105 doi1010292011JB008959

Montes C Cardona A McFadden R Moron SE Silva CARestrepo-Moreno S Ramirez DA Hoyos N Wilson JFarris D Bayona GA Jaramillo CA Valencia V BryanJ and Flores JA 2012b Evidence for middle Eocene andyounger land emergence in central Panama Implicationsfor Isthmus closure Geological Society of America Bulletinv 124 p 780ndash799 doi101130B305281

Nakamura N 1974 Determination of REE Ba Fe Mg Na andK in carbonaceous and ordinary chondrites Geochimica EtCosmochimica Acta v 38 p 757ndash775 doi1010160016-7037(74)90149-5

Patino LC Carr MJ and Feigenenson MD 2000 Localand regional variations in Central American arc lavas

controlled by variations in subducted sediment inputContributions to Mineralogy and Petrology v 138 p265ndash283

Pearce JA and Peate DW 1995 Tectonic implications of thecomposition of volcanic arc magmas Annual Review ofEarth and Planetary Sciences v 23 p 251ndash285doi101146annurevea23050195001343

Pearce JA Stern RJ Bloomer SH and Fryer P 2005Geochemical mapping of the Mariana arc-basin systemImplications for the nature and distribution of subductioncomponents Geochemistry Geophysics Geosystems v 67doi1010292004GC000895

Peccerillo A and Taylor SR 1976 Geochemistry of eocenecalc-alkaline volcanic rocks from the Kastamonu areaNorthern Turkey Contributions to Mineralogy andPetrology v 58 p 63ndash81 doi101007BF00384745

Pichler H and Weyl R 1975 Magmatism and crustal evolu-tion in Costa Rica (Central America) Geol Rundsch v 64 p457ndash475 doi101007BF01820678

Plank T Balzer V and Carr MJ 2002 Nicaraguanvolcanoes record paleoceanographic changes accompanyingclosure of the Panama gateway Geology v 30 p 1087ndash1090doi1011300091-7613(2002)030lt1087NVRPCAgt20CO2

Plank T and Langmuir CH 1988 An evaluation of the globalvariations in the major element chemistry of arc basaltsEarth and Planetary Science Letters v 90 p 349ndash370doi1010160012-821X(88)90135-5

Plank T and Langmuir CH 1993 Tracing trace elementsfrom sediment input to volcanic output at subductionzones Nature v 362 p 739ndash743 doi101038362739a0

Reagan MK and Gill JB 1989 Coexisting calcalkaline andhigh-niobium basalts from Turrialba Volcano Costa RicaImplications for residual titanates in arc magma sourcesJournal of Geophysical Research v 94 p 4619ndash4633doi101029JB094iB04p04619

Ringwood AE 1974 The petrological evolution of island arcsystems Twenty-seventh William Smith Lecture Journal ofthe Geological Society of London v 130 p 183ndash204doi101144gsjgs13030183

Rogers RD Mann P and Emmet PA 2007b Tectonic ter-ranes of the Chortis Block based on integration of regionalaeromagnetic and geologic data in Mann P ed Geologicand tectonic development of the Caribbean plate in north-ern Central America The Geological Society of AmericaSpecial Paper 428 doi10113020072428(04)

Rogers RD Mann P Emmet PA and Venable ME 2007aColon fold belt of Honduras Evidence for Late Cretaceouscollision between the continental Chortis block and intra-oceanic Caribbean arc in Mann P ed Geologic and tec-tonic development of the Caribbean plate in northernCentral America Volume 428 The Geological Society ofAmerica Special Paper doi10113020072428(06)

Rooney TO Franceschi P and Hall CM 2010 Water-satu-rated magmas in the Panama Canal region A precursor toadakite-like magma generation Contributions toMineralogy and Petrology doi101007s00410-010-0537-8

Rudnick RL 1995 Making continental crust Nature v 378 p571ndash578 doi101038378571a0

Rudnick RL and Fountain DM 1995 Nature and composi-tion of the continental crust A lower crustal perspectiveReviews of Geophysics v 33 p 267ndash309 doi10102995RG01302

Rudnick RL and Gao S 2003 Composition of the continen-tal crust in Rudnick RL Holland HD and Turekian KKeds Treatise on Geochemistry Volume 3 Oxford Elsevierp 1ndash64

Saginor I Gazel E Carr MJ Swisher C III and Turrin B2011 New PliocenendashPleistocene 40Ar39Ar ages fill in tem-poral gaps in the Nicaraguan volcanic record Journal ofVolcanology and Geothermal Research v 202 p 143ndash152doi101016jjvolgeores201102002

Saginor I Gazel E Condie C and Carr MJ 2013 Evolutionof geochemical variations along the Central American vol-canic front Geochemistry Geophysics Geosystems v 14 p4504ndash4522 doi101002ggge20259

Stamatelopoulou-Seymour K Vlassopoulos D Pearce THand Rice C 1990 The record of magma chamber processesin plagioclase phenocrysts at Thera Volcano AegeanVolcanic Arc Greece Contributions to Mineralogy andPetrology v 104 no 1 p 73ndash84 doi101007BF00310647

Stern RJ 2010 The anatomy and ontogeny of modern intra-oceanic arc systems in Kusky TM Zhai M-G and Xiao Weds The evolving continents Understanding processes ofcontinental growth Geological Society of London SpecialPublication 338 p 7ndash34

Straub SM 2003 The evolution of the Izu-Bonin-Marianavolcanic arcs (NW Pacific) in terms of major elementsGeochemistry Geophysics Geosystems v 4 p 1018doi1010292002GC000357

Straub SM Woodhead JD and Arculus RJ 2015 Temporalevolution of the Mariana Arc Mantle wedge and subductedslab controls revealed with a tephra perspective Journal ofPetrology v 56 p 409ndash439 doi101093petrologyegv005

Sugimura A 1968 Spatial relations of basaltic magmas inisland arcs in Hess HH and Poldervaart A eds BasaltsThe Poldervaart treatise on rocks of basaltic compositionNew York Wiley p 537ndash572

Sun SS and McDonough WF 1989 Chemical and isotopicsystematics of oceanic basalts Implications for mantle com-position and processes in Saunders AD and Norry MJeds Magmatism in the Ocean Basins Geological Society ofLondon Special Publication 42 p 313ndash345

Syracuse EM Abers GA Fischer K MacKenzie L RychertC Protti M Gonzaacutelez V and Strauch W 2008 Seismictomography and earthquake locations in the Nicaraguanand Costa Rican upper mantle Geochemistry GeophysicsGeosystems v 9 no 7 p Q07S08 doi1010292008GC001963

Taylor SR and McLennan SM 1985 The continental crustIts composition and evolution Oxford Blackwell Scientific

Turner SJ and Langmuir CH 2015 What processes controlthe chemical compositions of arc front stratovolcanoesGeochemistry Geophysics Geosystems v 16 p 1865ndash1893 doi1010022014GC005633

Van Avendonk HJ Holbrook WS Lizarralde D and DenyerP 2011 Structure and serpentinization of the subductingCocos plate offshore Nicaragua and Costa RicaGeochemistry Geophysics Geosystems v 12 doi1010292011GC003592

Venable M 1994 A geological tectonic and metallogenicevaluation of the Siuna terrrane (Nicaragua) [PhD disserta-tion] Tucson AZ University of Arizona 154 p

Vogel TA Patino LC Alvarado GE and Gans PB 2004Silicic ignimbrites within the Costa Rican volcanic front

Evidence for the formation of continental crust Earth andPlanetary Science Letters v 226 p 149ndash159 doi101016jepsl200407013

Wegner W Worner G Harmon RS and Jicha BR 2011Magmatic history and evolution of the Central American landbridge in Panama since Cretaceous times Geological Society ofAmerica Bulletin v 123 p 703ndash724 doi101130B301091

Werner R Hoernle K Barckhausen U and Hauff F 2003Geodynamic evolution of the Galapagos hot spot system(Central East Pacific) over the past 20 my Constraints frommorphology geochemistry and magnetic anomaliesGeochemistry Geophysics Geosysttems v 4 doi1010292003GC000576

Whattam SA Montes C McFadden RR Cardona ARamirez D and Valencia V 2012 Age and origin of ear-liest adakitic-like magmatism in Panama Implications forthe tectonic evolution of the Panamanian magmatic arcsystem Lithos v 142-143 p 226ndash244 doi101016jlithos201202017

Whattam SA and Stern RJ 2015 Late Cretaceous plume-induced subduction initiation along the southern margin ofthe Caribbean and NW South America The first documen-ted example with implications for the onset of plate tec-tonics Gondwana Research v 27 p 38ndash63 httpdxdoiorg101016jgr201407011

White WM McBirney AR and Duncan RA 1998 Petrologyand geochemistry of the Galapagos Islands Portrait of apathological mantle plume Journal of GeophysicalResearch v 98 no B11 p 19533ndash19563

White WM and Patchett J 1984 HfNdSr isotopes andincompatible element abundances in island arcsImplications for magma origins and crust-mantle evolutionEarth and Planetary Science Letters v 67 p 167ndash185doi1010160012-821X(84)90112-2

Woumlrner G Harmon RS and Wegner W 2009 Backbone ofthe Americas in Kay SM Ramos VA and Dickinson Weds Shallow subduction plateau uplift and ridge and ter-rane collision Geological Society of America Memoir 204 p183ndash196

Zernack AV Price RC Smith IEM Cronin SJ and StewartRB 2012 Temporal evolution of a high-K andesitic mag-matic system Taranaki Volcano New Zealand Journalof Petrology v 53 p 325ndash363 doi101093petrologyegr064

Zimmer MM Plank T Hauri EH Yogodzinski GM StellingP Larsen J Singer B Jicha B Mandeville C and Nye CJ 2010 The role of water in generating the calc-alkalinetrend New volatile data for Aleutian magmas and a newtholeiitic index Journal of Petrology v 51 p 2411ndash2444doi101093petrologyegq062

Abstract

1 Introduction

2 Synopsis of CAVAS magmatic history distribution in space and time

3 Geochemical geochronological and isotope data set compilation manipulation and sources




4 Results




431 Incompatible element trends

432 Trends in magma enrichmentdepletion and subduction additions


51 Pb isotopes

52 Nd isotopes

6 Discussion

61 How to interpret CAVAS X55 chemotemporal trends


621 Incompatible elements versus SiO2 trends

622 Nd isotopes


631 Neogene NicaraguandashCosta Rica compositional divergence

632 Production of PV adakites and arc alkaline magmas in Panama and Costa Rica after 6euroMa

633 lsquoResettingrsquo of the CAVAS source back to more depleted compositions after 3euroMa

64 Long-term chemotemporal evolution of the CAVAS

641 Causes of progressive CAVAS magma enrichment

642 Continental crust formation at the CAVAS

643 Role of mantle plumes in the generation of continental crust

644 Chemotemporal evolution of the CAVAS synthesis and model

7 Conclusions

Acknowledgements


Funding

References

Arc magmatic evolution and the construction of continental crust at the CentralAmerican Volcanic Arc systemScott A Whattama and Robert J Sternb

aDepartment of Earth and Environmental Sciences Korea University Seoul Republic of Korea bGeosciences Department University of Texasat Dallas Richardson TX 75083-0688 USA

ABSTRACTWhether or not magmatic arcs evolve compositionally with time and the processes responsibleremain controversial Resolution of this question requires the reconstruction of arc geochemicalevolution at the level of a discrete arc system Here we address this problem using the well-studied Central American Volcanic Arc System (CAVAS) as an example Geochemical and isotopicdata were compiled for 1031 samples of lavas and intrusive rocks from the ~1100 km-longsegment of oceanic CAVAS (Panama Costa Rica Nicaragua) built on thickened oceanic crustover its 75 million year lifespan We used available age constraints to subdivide this data set intosix magmatic phases 75ndash39 Ma (Phase I or PI) 35ndash16 Ma (PII) 16ndash6 Ma (PIII) 6ndash3 Ma (PIV)59ndash001 Ma (PVa arc alkaline and PVb adakitic) and 26ndash0 Ma (PVI Quaternary to modernmagmatism predominantly ≪ 1 Ma) To correct for magmatic fractionation selected major andtrace element abundances were linearly regressed to 55 wt SiO2 The most striking observationis the overall evolution of the CAVAS to more incompatible element enriched and ultimatelycontinental-like compositions with time although magmatic evolution took on a more regionalcharacter in the youngest rocks with magmatic rocks of Nicaragua becoming increasinglydistinguishable from those of Costa Rica and Panama with time Models entailing progressivearc magmatic enrichment are generally supported by the CAVAS record Progressive enrichmentof the oceanic CAVAS with time reflects changes in mantle wedge composition and decreasedmelting due to arc crust thickening which was kick-started by the involvement of enriched plumemantle in the formation of the CAVAS Progressive crustal thickening and associated changes inthe sub-arc thermal regime resulted in decreasing degrees of partial melting over time whichallowed for progressive enrichment of the CAVAS and ultimately the production of continental-like crust in Panama and Costa Rica by ~16ndash10 Ma

ARTICLE HISTORYReceived 30 September 2015Accepted 1 October 2015

KEYWORDSVolcanic arc subductioncontinental crust tectonicsCentral America CaribbeanGalapagos Plume

1 Introduction

Subduction zone magmatism results primarily from thedehydration of subducted oceanic crust and sedimentmelting and the subsequent transfer of these liquids tothe overlying mantle wedge where partial meltingoccurs (White and Patchett 1984 McCulloch andGamble 1991 Plank and Langmuir 1993 Hawkesworthet al 1993a 1993b Pearce and Peate 1995 Ishikawaand Tera 1997 Kimura et al 2014) The diagnostic che-mical signatures of subduction zone magmatisminclude (1) abundant felsic rocks (2) a tendency tominimize Fe-enrichment during magmatic fractionation(3) elevated abundances of large ion lithophile elements(LILEs) relative to the light rare earth elements (LREEs)and (4) depletion of high field strength elements(HFSEs) (eg Arculus 1994) (see Table 1 for a list of themost common abbreviations and acronyms used here

and their definitions) These characteristics are largelydue to the fluid-mediated nature of convergent marginmagmatism and to the fact that in contrast to igneousactivity at mid-ocean ridges and hotspots arc magmaticactivity stays in the same place relative to the under-lying crust for tens of millions of years

Study of arc igneous rocks must also consider the roleof the underlying crust because this crust can beinvolved in magmagenesis obscuring the geochemicaland isotopic signature of mantle-derived magmas Thickgranitic continental crust favours the establishment ofMASH (melting assimilation storage and homogeniza-tion Hildreth and Moorbath 1988) zones with massiveinvolvement of especially the lower crust in the resultantmagmas Intra-oceanic arc (IOA) systems (see review ofStern 2010 and references therein) ndash where the crust isthinner more mafic and more refractory ndash are sites

CONTACT Scott A Whattam whattamkoreaackrSupplemental data for this article can be accessed at [httpdxdoi1010800020681420151103668]

INTERNATIONAL GEOLOGY REVIEW 2015httpdxdoiorg1010800020681420151103668

copy 2015 Taylor amp Francis

Venezuela

Yucatan

Hispaniola

Jamaica

o 80 Wo 90 Wo 100 W o 70 W o 60 W

o 20 N

Colombia

GAA system

ean LIbb Pi r a C

system

COCOSPLATE

CARIBBEANPLATE

Curacao

SOUTH AMERICANPLATE

NORTHAMERICANPLATE

400 kmo10 N

Virgin Islands

NAZCA PLATE

Fig 1b

aGalapagos

Islands

CARIBBEANPLATE

100 km

HONDURAS

NICARAGUA

Nicaragua Rise

Siuna Terrane

~ COBB

o 14 N

o 87 W

sseHtnempracse

Canal Basin

CARIBBEAN PLATE

PANAMA

Chortis Block

COSTA RICA

UNT PRO

EBGolfito

SonaCIAzuero

10deg N

12deg N

08deg N

Chagres-Bayano

Cord de Tal

250 km

Cord n a Pde

CB Arc

Sona-Azuero Arc

GF Arc

SP ArcTD

AG Arc

NC HD amp TG

CY Arc

PI (75-39 n = 139)

PIV (6-3 n = 19)

Selected

andtraceelem

entdata

ofPIPIIPIIIPIVPV

oftheseph

discrim

inated

byregion

linearly

regressedto

PhaseI

PhaseII

PhaseIII

PhaseIV

PhaseVa

PhaseVb

PhaseVI

SE(PAN

SE(arc

SE(adak)

SE(CR+

Agerang

a)75ndash39

35ndash16

16ndash6

6ndash3

590ndash001

420ndash015

26ndash0

Meanage(M

plusmn18

255plusmn95

11plusmn5

45plusmn15

3plusmn3

22plusmn20

13plusmn13

samples)

oxides

FeOt M

TholeiiticIndex1

K 2ONa 2O

Traceelem

ents55

Sr25844

140052

Ti505240

550899

551525

468245

933173

517084

484556

tinued)

Table2

tinued) Ph

PhaseII

PhaseIII

PhaseIV

PhaseVa

PhaseVb

PhaseVI

SE(PAN

SE(arc

SE(adak)

SE(CR+

Zr6844

K502137

840251

1206677

1573212

133153

1606374

1647473

922040

Ba24111

Ce1470

sumREE2

V26967

ofsomelinearly

regressedvalues

indicate

increasing

values

lemajor

andtraceelem

entsandratio

increase

theprevious

phasePIdata

arealso

ldtext

forvisualaidSee

lementary

formetho

linearregression

reviationsN

tanalyzed

tapplicableN

tcalculablewhere

totaln

umberof

FeO40andor

FeO80was

lt1Superscripts12

ΣREEareto

indicate

entandelem

entratio

errorSEo

fthemean)

Notes(1)

ensedversionof

lementary

Table1which

provides

inadditio

region

(ieregresseddata

provided

atthelevelo

fregionndash

PanamaCo

staRicaetc)

(2)Thedata

largelight

lsquoxrsquosin

ourvario

lsrepresentdistinct

region

sandthedata

fortheseareprovided

inSupp

lementaryTable1(see

non-no

rmalized

dances

ofFeOtandMgO

References

atasetsareprovided

inSection32(5)R

awdata

values

calculated

areprovided

lementary

TableS2

SiO2 wt

basalt

dacite

trachy-basalt

59-0 Ma

45 55 65 7550 60 70 80

75-16 Ma2

basalt

dacite

rhyolite

trachy-basalt

trachy-dacite

enilaklabus

16-3 Ma

TR-TIS

andesite

enilakla

basalticandesite

andesite

basandesite

trachy-andesite

Region

CR NIC

Va Vb VIPhase

Region

III IVPhase

Region

IPhase

4 Results

40 45 50 55 60 65 70 75 80

SiO2 wt

basaltgabbro

b-ag-d

anddior

shoshonite series

TR-TIS

calc-alk

med-K calc-alk

shoshonite

low-K thol

16-3 Ma

59-0 Ma

high-K

calc-alk

high- K cal c-alk

low-K thol

061101145189111

009051045018045

Region

III IVPhase

Region

I IIPhase

Region

CR NIC

Va Vb VIPhase

75-16 Ma

aM61-53IIP

aM9-375IP

aM6-61IIIP

aM3-6VIP

75-16 Ma

med-Fe

16-3 Ma

SiO wt 2

40 45 50 55 60 65 70 75 80

low-Fe

med-Fe

kla-clac

high-Fe

59-0 Ma

Fe-enrichment

Na O+K O2 2 MgO

12100806

Tholeiitic Index

calc-alk thol

high-Fe

Region

III IVPhase

Region

I IIPhase

Region

CR NIC

VaPhase

IBMVAB

Time (Ma)70 60 50 40 30 20 10 0

PVa micro = 06955

Region

CR NIC

PANCRNICall

MORBIBMVAB

MORBIBM

OIBBCC

IBMVAB

OIBBCC

IBMVAB

BCC (11)

Time (Ma)

IBMVAB

OIB (280)BCC

70 60 50 40 30 20 10 0

CR PIV micro = 5855

Region

CR NIC

OPB (grey lined)

BCC OIB (199 ppm)

IBMVAB

IBMVAB20

Time (Ma)

070 60 50 40 30 20 10 0

OPB (grey lined)

Region

CR NIC

PVbadaks

PVa arc alks

(602 wt SiO )2

PI PIV

Phase interval (Ma)

PI (75-39) PII (35-16)PIII (16-6)

PIV (6-3)PVI (26-0)

PII 35-16 Ma

PIII 16-6 Ma

PIV 6-3 Ma

PVI 26-0 Ma

PI 75-39 Ma

OIB (97)

IBMVAB

OIB (222)

OIB BCC

OPB (grey lined)

IBM (19)

MORBIBMVABc

PVb micro = 10255

PVa micro = 28655

PVb micro = 6855

Region

CR NIC

IBMVAB (771)

70 60 50 40 30 20 10 0

51 Pb isotopes

IBMVAB

b 55 g

IBMVAB

300350

IBMVAB

NIC PIV micro = 702

OPB (grey line)

IBMVAB10

Time (Ma)70 60 50 40 30 20 10 0

IBMVAB

MORB BCC

IBMVAB

OPB (grey lined)

MORBamp OIB

IBMVAB

IBMVABMORB

09CR micro = 111

Region

CR NIC

Region

Va VbPhase

PVI26-0 Ma

CR NIC

SW NIC

NE CR central CR

NW NIC

Miocene Nicaragua

Miocene Costa Rica

PII-PIV35-3 Ma

Region

II III IVPhase

19-6 Ma

75-39 M

NIC Miocene

CR 35-16 Ma

CR 16-6 Ma

CR 6-3 Ma

CR NIC

subducting

SP (NGD)

subducting CCR (C

CocosNazca Plate

PI 75-39 Ma

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

206 204Pb Pb

Region

200 185

CR NW NIC NW SW

Region Phase VI

central

eastern

PAN SAA CBA

Region Phase I

central

CR NIC

051280

051285

051290

051295

051300

051305

051310

051275

051280

051285

051290

051295

051300

051305

051310

051315

subductin g

Seamount Province

Region

Va VbPhase

051275

PVI26-0 Ma

d051275

051280

051285

051290

051295

051300

051305

051310

PII- PIV35-3 Ma

CCR (CGD)

CocosNazca Plate

107142 86

H26-6 Ma CRVF

CR PANDM

CR 75-66 Ma

CR 6-3 MaCR 35-6 Ma

SP see (c)

344 217 201324

Region

II III IVPhase

206 204Pb Pb

051275

051280

051285

051290

051295

051300

051305

051310

aGP at 90 Ma

GP at 60 Ma

499-448

Region

PI 75-39 Ma

543400

170 200

Region Phase VI

central

PAN SAA CBA

Region Phase I

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

051280

051285

051290

051295

051300

051305

051310

051315

051275

Time (Ma)7090 80100 60 50 40 30 20 10 0

PIIIPIV

PVIPICLIP

age of accreted

central CR

SW NICNW

NICeastern

OIB in western CR

Burica(N = 5)

PAN SAA CBA

CR GA NIC eastern

central NW NW SW

52 Nd isotopes

6 Discussion

50 700

Mantle melting

Basalt

Rhyolite

Andesite

Basalt

CLIP crust

SiO wt 2

K55(t3)

K55(t2)

K55(t1)

K55(t3)

K55(t2)

K55(t1)

fractio

nation

mix ing

crustal melt

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

Venezuela

Yucatan

Hispaniola

Jamaica

o 80 Wo 90 Wo 100 W o 70 W o 60 W

o 20 N

Colombia

GAA system

ean LIbb Pi r a C

system

COCOSPLATE

CARIBBEANPLATE

Curacao

SOUTH AMERICANPLATE

NORTHAMERICANPLATE

400 kmo10 N

Virgin Islands

NAZCA PLATE

Fig 1b

aGalapagos

Islands

CARIBBEANPLATE

100 km

HONDURAS

NICARAGUA

Nicaragua Rise

Siuna Terrane

~ COBB

o 14 N

o 87 W

sseHtnempracse

Canal Basin

CARIBBEAN PLATE

PANAMA

Chortis Block

COSTA RICA

UNT PRO

EBGolfito

SonaCIAzuero

10deg N

12deg N

08deg N

Chagres-Bayano

Cord de Tal

250 km

Cord n a Pde

CB Arc

Sona-Azuero Arc

GF Arc

SP ArcTD

AG Arc

NC HD amp TG

CY Arc

PI (75-39 n = 139)

PIV (6-3 n = 19)

Selected

andtraceelem

entdata

ofPIPIIPIIIPIVPV

oftheseph

discrim

inated

byregion

linearly

regressedto

PhaseI

PhaseII

PhaseIII

PhaseIV

PhaseVa

PhaseVb

PhaseVI

SE(PAN

SE(arc

SE(adak)

SE(CR+

Agerang

a)75ndash39

35ndash16

16ndash6

6ndash3

590ndash001

420ndash015

26ndash0

Meanage(M

plusmn18

255plusmn95

11plusmn5

45plusmn15

3plusmn3

22plusmn20

13plusmn13

samples)

oxides

FeOt M

TholeiiticIndex1

K 2ONa 2O

Traceelem

ents55

Sr25844

140052

Ti505240

550899

551525

468245

933173

517084

484556

tinued)

Table2

tinued) Ph

PhaseII

PhaseIII

PhaseIV

PhaseVa

PhaseVb

PhaseVI

SE(PAN

SE(arc

SE(adak)

SE(CR+

Zr6844

K502137

840251

1206677

1573212

133153

1606374

1647473

922040

Ba24111

Ce1470

sumREE2

V26967

ofsomelinearly

regressedvalues

indicate

increasing

values

lemajor

andtraceelem

entsandratio

increase

theprevious

phasePIdata

arealso

ldtext

forvisualaidSee

lementary

formetho

linearregression

reviationsN

tanalyzed

tapplicableN

tcalculablewhere

totaln

umberof

FeO40andor

FeO80was

lt1Superscripts12

ΣREEareto

indicate

entandelem

entratio

errorSEo

fthemean)

Notes(1)

ensedversionof

lementary

Table1which

provides

inadditio

region

(ieregresseddata

provided

atthelevelo

fregionndash

PanamaCo

staRicaetc)

(2)Thedata

largelight

lsquoxrsquosin

ourvario

lsrepresentdistinct

region

sandthedata

fortheseareprovided

inSupp

lementaryTable1(see

non-no

rmalized

dances

ofFeOtandMgO

References

atasetsareprovided

inSection32(5)R

awdata

values

calculated

areprovided

lementary

TableS2

SiO2 wt

basalt

dacite

trachy-basalt

59-0 Ma

45 55 65 7550 60 70 80

75-16 Ma2

basalt

dacite

rhyolite

trachy-basalt

trachy-dacite

enilaklabus

16-3 Ma

TR-TIS

andesite

enilakla

basalticandesite

andesite

basandesite

trachy-andesite

Region

CR NIC

Va Vb VIPhase

Region

III IVPhase

Region

IPhase

4 Results

40 45 50 55 60 65 70 75 80

SiO2 wt

basaltgabbro

b-ag-d

anddior

shoshonite series

TR-TIS

calc-alk

med-K calc-alk

shoshonite

low-K thol

16-3 Ma

59-0 Ma

high-K

calc-alk

high- K cal c-alk

low-K thol

061101145189111

009051045018045

Region

III IVPhase

Region

I IIPhase

Region

CR NIC

Va Vb VIPhase

75-16 Ma

aM61-53IIP

aM9-375IP

aM6-61IIIP

aM3-6VIP

75-16 Ma

med-Fe

16-3 Ma

SiO wt 2

40 45 50 55 60 65 70 75 80

low-Fe

med-Fe

kla-clac

high-Fe

59-0 Ma

Fe-enrichment

Na O+K O2 2 MgO

12100806

Tholeiitic Index

calc-alk thol

high-Fe

Region

III IVPhase

Region

I IIPhase

Region

CR NIC

VaPhase

IBMVAB

Time (Ma)70 60 50 40 30 20 10 0

PVa micro = 06955

Region

CR NIC

PANCRNICall

MORBIBMVAB

MORBIBM

OIBBCC

IBMVAB

OIBBCC

IBMVAB

BCC (11)

Time (Ma)

IBMVAB

OIB (280)BCC

70 60 50 40 30 20 10 0

CR PIV micro = 5855

Region

CR NIC

OPB (grey lined)

BCC OIB (199 ppm)

IBMVAB

IBMVAB20

Time (Ma)

070 60 50 40 30 20 10 0

OPB (grey lined)

Region

CR NIC

PVbadaks

PVa arc alks

(602 wt SiO )2

PI PIV

Phase interval (Ma)

PI (75-39) PII (35-16)PIII (16-6)

PIV (6-3)PVI (26-0)

PII 35-16 Ma

PIII 16-6 Ma

PIV 6-3 Ma

PVI 26-0 Ma

PI 75-39 Ma

OIB (97)

IBMVAB

OIB (222)

OIB BCC

OPB (grey lined)

IBM (19)

MORBIBMVABc

PVb micro = 10255

PVa micro = 28655

PVb micro = 6855

Region

CR NIC

IBMVAB (771)

70 60 50 40 30 20 10 0

51 Pb isotopes

IBMVAB

b 55 g

IBMVAB

300350

IBMVAB

NIC PIV micro = 702

OPB (grey line)

IBMVAB10

Time (Ma)70 60 50 40 30 20 10 0

IBMVAB

MORB BCC

IBMVAB

OPB (grey lined)

MORBamp OIB

IBMVAB

IBMVABMORB

09CR micro = 111

Region

CR NIC

Region

Va VbPhase

PVI26-0 Ma

CR NIC

SW NIC

NE CR central CR

NW NIC

Miocene Nicaragua

Miocene Costa Rica

PII-PIV35-3 Ma

Region

II III IVPhase

19-6 Ma

75-39 M

NIC Miocene

CR 35-16 Ma

CR 16-6 Ma

CR 6-3 Ma

CR NIC

subducting

SP (NGD)

subducting CCR (C

CocosNazca Plate

PI 75-39 Ma

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

206 204Pb Pb

Region

200 185

CR NW NIC NW SW

Region Phase VI

central

eastern

PAN SAA CBA

Region Phase I

central

CR NIC

051280

051285

051290

051295

051300

051305

051310

051275

051280

051285

051290

051295

051300

051305

051310

051315

subductin g

Seamount Province

Region

Va VbPhase

051275

PVI26-0 Ma

d051275

051280

051285

051290

051295

051300

051305

051310

PII- PIV35-3 Ma

CCR (CGD)

CocosNazca Plate

107142 86

H26-6 Ma CRVF

CR PANDM

CR 75-66 Ma

CR 6-3 MaCR 35-6 Ma

SP see (c)

344 217 201324

Region

II III IVPhase

206 204Pb Pb

051275

051280

051285

051290

051295

051300

051305

051310

aGP at 90 Ma

GP at 60 Ma

499-448

Region

PI 75-39 Ma

543400

170 200

Region Phase VI

central

PAN SAA CBA

Region Phase I

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

051280

051285

051290

051295

051300

051305

051310

051315

051275

Time (Ma)7090 80100 60 50 40 30 20 10 0

PIIIPIV

PVIPICLIP

age of accreted

central CR

SW NICNW

NICeastern

OIB in western CR

Burica(N = 5)

PAN SAA CBA

CR GA NIC eastern

central NW NW SW

52 Nd isotopes

6 Discussion

50 700

Mantle melting

Basalt

Rhyolite

Andesite

Basalt

CLIP crust

SiO wt 2

K55(t3)

K55(t2)

K55(t1)

K55(t3)

K55(t2)

K55(t1)

fractio

nation

mix ing

crustal melt

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

Venezuela

Yucatan

Hispaniola

Jamaica

o 80 Wo 90 Wo 100 W o 70 W o 60 W

o 20 N

Colombia

GAA system

ean LIbb Pi r a C

system

COCOSPLATE

CARIBBEANPLATE

Curacao

SOUTH AMERICANPLATE

NORTHAMERICANPLATE

400 kmo10 N

Virgin Islands

NAZCA PLATE

Fig 1b

aGalapagos

Islands

CARIBBEANPLATE

100 km

HONDURAS

NICARAGUA

Nicaragua Rise

Siuna Terrane

~ COBB

o 14 N

o 87 W

sseHtnempracse

Canal Basin

CARIBBEAN PLATE

PANAMA

Chortis Block

COSTA RICA

UNT PRO

EBGolfito

SonaCIAzuero

10deg N

12deg N

08deg N

Chagres-Bayano

Cord de Tal

250 km

Cord n a Pde

CB Arc

Sona-Azuero Arc

GF Arc

SP ArcTD

AG Arc

NC HD amp TG

CY Arc

PI (75-39 n = 139)

PIV (6-3 n = 19)

Selected

andtraceelem

entdata

ofPIPIIPIIIPIVPV

oftheseph

discrim

inated

byregion

linearly

regressedto

PhaseI

PhaseII

PhaseIII

PhaseIV

PhaseVa

PhaseVb

PhaseVI

SE(PAN

SE(arc

SE(adak)

SE(CR+

Agerang

a)75ndash39

35ndash16

16ndash6

6ndash3

590ndash001

420ndash015

26ndash0

Meanage(M

plusmn18

255plusmn95

11plusmn5

45plusmn15

3plusmn3

22plusmn20

13plusmn13

samples)

oxides

FeOt M

TholeiiticIndex1

K 2ONa 2O

Traceelem

ents55

Sr25844

140052

Ti505240

550899

551525

468245

933173

517084

484556

tinued)

Table2

tinued) Ph

PhaseII

PhaseIII

PhaseIV

PhaseVa

PhaseVb

PhaseVI

SE(PAN

SE(arc

SE(adak)

SE(CR+

Zr6844

K502137

840251

1206677

1573212

133153

1606374

1647473

922040

Ba24111

Ce1470

sumREE2

V26967

ofsomelinearly

regressedvalues

indicate

increasing

values

lemajor

andtraceelem

entsandratio

increase

theprevious

phasePIdata

arealso

ldtext

forvisualaidSee

lementary

formetho

linearregression

reviationsN

tanalyzed

tapplicableN

tcalculablewhere

totaln

umberof

FeO40andor

FeO80was

lt1Superscripts12

ΣREEareto

indicate

entandelem

entratio

errorSEo

fthemean)

Notes(1)

ensedversionof

lementary

Table1which

provides

inadditio

region

(ieregresseddata

provided

atthelevelo

fregionndash

PanamaCo

staRicaetc)

(2)Thedata

largelight

lsquoxrsquosin

ourvario

lsrepresentdistinct

region

sandthedata

fortheseareprovided

inSupp

lementaryTable1(see

non-no

rmalized

dances

ofFeOtandMgO

References

atasetsareprovided

inSection32(5)R

awdata

values

calculated

areprovided

lementary

TableS2

SiO2 wt

basalt

dacite

trachy-basalt

59-0 Ma

45 55 65 7550 60 70 80

75-16 Ma2

basalt

dacite

rhyolite

trachy-basalt

trachy-dacite

enilaklabus

16-3 Ma

TR-TIS

andesite

enilakla

basalticandesite

andesite

basandesite

trachy-andesite

Region

CR NIC

Va Vb VIPhase

Region

III IVPhase

Region

IPhase

4 Results

40 45 50 55 60 65 70 75 80

SiO2 wt

basaltgabbro

b-ag-d

anddior

shoshonite series

TR-TIS

calc-alk

med-K calc-alk

shoshonite

low-K thol

16-3 Ma

59-0 Ma

high-K

calc-alk

high- K cal c-alk

low-K thol

061101145189111

009051045018045

Region

III IVPhase

Region

I IIPhase

Region

CR NIC

Va Vb VIPhase

75-16 Ma

aM61-53IIP

aM9-375IP

aM6-61IIIP

aM3-6VIP

75-16 Ma

med-Fe

16-3 Ma

SiO wt 2

40 45 50 55 60 65 70 75 80

low-Fe

med-Fe

kla-clac

high-Fe

59-0 Ma

Fe-enrichment

Na O+K O2 2 MgO

12100806

Tholeiitic Index

calc-alk thol

high-Fe

Region

III IVPhase

Region

I IIPhase

Region

CR NIC

VaPhase

IBMVAB

Time (Ma)70 60 50 40 30 20 10 0

PVa micro = 06955

Region

CR NIC

PANCRNICall

MORBIBMVAB

MORBIBM

OIBBCC

IBMVAB

OIBBCC

IBMVAB

BCC (11)

Time (Ma)

IBMVAB

OIB (280)BCC

70 60 50 40 30 20 10 0

CR PIV micro = 5855

Region

CR NIC

OPB (grey lined)

BCC OIB (199 ppm)

IBMVAB

IBMVAB20

Time (Ma)

070 60 50 40 30 20 10 0

OPB (grey lined)

Region

CR NIC

PVbadaks

PVa arc alks

(602 wt SiO )2

PI PIV

Phase interval (Ma)

PI (75-39) PII (35-16)PIII (16-6)

PIV (6-3)PVI (26-0)

PII 35-16 Ma

PIII 16-6 Ma

PIV 6-3 Ma

PVI 26-0 Ma

PI 75-39 Ma

OIB (97)

IBMVAB

OIB (222)

OIB BCC

OPB (grey lined)

IBM (19)

MORBIBMVABc

PVb micro = 10255

PVa micro = 28655

PVb micro = 6855

Region

CR NIC

IBMVAB (771)

70 60 50 40 30 20 10 0

51 Pb isotopes

IBMVAB

b 55 g

IBMVAB

300350

IBMVAB

NIC PIV micro = 702

OPB (grey line)

IBMVAB10

Time (Ma)70 60 50 40 30 20 10 0

IBMVAB

MORB BCC

IBMVAB

OPB (grey lined)

MORBamp OIB

IBMVAB

IBMVABMORB

09CR micro = 111

Region

CR NIC

Region

Va VbPhase

PVI26-0 Ma

CR NIC

SW NIC

NE CR central CR

NW NIC

Miocene Nicaragua

Miocene Costa Rica

PII-PIV35-3 Ma

Region

II III IVPhase

19-6 Ma

75-39 M

NIC Miocene

CR 35-16 Ma

CR 16-6 Ma

CR 6-3 Ma

CR NIC

subducting

SP (NGD)

subducting CCR (C

CocosNazca Plate

PI 75-39 Ma

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

206 204Pb Pb

Region

200 185

CR NW NIC NW SW

Region Phase VI

central

eastern

PAN SAA CBA

Region Phase I

central

CR NIC

051280

051285

051290

051295

051300

051305

051310

051275

051280

051285

051290

051295

051300

051305

051310

051315

subductin g

Seamount Province

Region

Va VbPhase

051275

PVI26-0 Ma

d051275

051280

051285

051290

051295

051300

051305

051310

PII- PIV35-3 Ma

CCR (CGD)

CocosNazca Plate

107142 86

H26-6 Ma CRVF

CR PANDM

CR 75-66 Ma

CR 6-3 MaCR 35-6 Ma

SP see (c)

344 217 201324

Region

II III IVPhase

206 204Pb Pb

051275

051280

051285

051290

051295

051300

051305

051310

aGP at 90 Ma

GP at 60 Ma

499-448

Region

PI 75-39 Ma

543400

170 200

Region Phase VI

central

PAN SAA CBA

Region Phase I

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

051280

051285

051290

051295

051300

051305

051310

051315

051275

Time (Ma)7090 80100 60 50 40 30 20 10 0

PIIIPIV

PVIPICLIP

age of accreted

central CR

SW NICNW

NICeastern

OIB in western CR

Burica(N = 5)

PAN SAA CBA

CR GA NIC eastern

central NW NW SW

52 Nd isotopes

6 Discussion

50 700

Mantle melting

Basalt

Rhyolite

Andesite

Basalt

CLIP crust

SiO wt 2

K55(t3)

K55(t2)

K55(t1)

K55(t3)

K55(t2)

K55(t1)

fractio

nation

mix ing

crustal melt

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

Canal Basin

CARIBBEAN PLATE

PANAMA

Chortis Block

COSTA RICA

UNT PRO

EBGolfito

SonaCIAzuero

10deg N

12deg N

08deg N

Chagres-Bayano

Cord de Tal

250 km

Cord n a Pde

CB Arc

Sona-Azuero Arc

GF Arc

SP ArcTD

AG Arc

NC HD amp TG

CY Arc

PI (75-39 n = 139)

PIV (6-3 n = 19)

Selected

andtraceelem

entdata

ofPIPIIPIIIPIVPV

oftheseph

discrim

inated

byregion

linearly

regressedto

PhaseI

PhaseII

PhaseIII

PhaseIV

PhaseVa

PhaseVb

PhaseVI

SE(PAN

SE(arc

SE(adak)

SE(CR+

Agerang

a)75ndash39

35ndash16

16ndash6

6ndash3

590ndash001

420ndash015

26ndash0

Meanage(M

plusmn18

255plusmn95

11plusmn5

45plusmn15

3plusmn3

22plusmn20

13plusmn13

samples)

oxides

FeOt M

TholeiiticIndex1

K 2ONa 2O

Traceelem

ents55

Sr25844

140052

Ti505240

550899

551525

468245

933173

517084

484556

tinued)

Table2

tinued) Ph

PhaseII

PhaseIII

PhaseIV

PhaseVa

PhaseVb

PhaseVI

SE(PAN

SE(arc

SE(adak)

SE(CR+

Zr6844

K502137

840251

1206677

1573212

133153

1606374

1647473

922040

Ba24111

Ce1470

sumREE2

V26967

ofsomelinearly

regressedvalues

indicate

increasing

values

lemajor

andtraceelem

entsandratio

increase

theprevious

phasePIdata

arealso

ldtext

forvisualaidSee

lementary

formetho

linearregression

reviationsN

tanalyzed

tapplicableN

tcalculablewhere

totaln

umberof

FeO40andor

FeO80was

lt1Superscripts12

ΣREEareto

indicate

entandelem

entratio

errorSEo

fthemean)

Notes(1)

ensedversionof

lementary

Table1which

provides

inadditio

region

(ieregresseddata

provided

atthelevelo

fregionndash

PanamaCo

staRicaetc)

(2)Thedata

largelight

lsquoxrsquosin

ourvario

lsrepresentdistinct

region

sandthedata

fortheseareprovided

inSupp

lementaryTable1(see

non-no

rmalized

dances

ofFeOtandMgO

References

atasetsareprovided

inSection32(5)R

awdata

values

calculated

areprovided

lementary

TableS2

SiO2 wt

basalt

dacite

trachy-basalt

59-0 Ma

45 55 65 7550 60 70 80

75-16 Ma2

basalt

dacite

rhyolite

trachy-basalt

trachy-dacite

enilaklabus

16-3 Ma

TR-TIS

andesite

enilakla

basalticandesite

andesite

basandesite

trachy-andesite

Region

CR NIC

Va Vb VIPhase

Region

III IVPhase

Region

IPhase

4 Results

40 45 50 55 60 65 70 75 80

SiO2 wt

basaltgabbro

b-ag-d

anddior

shoshonite series

TR-TIS

calc-alk

med-K calc-alk

shoshonite

low-K thol

16-3 Ma

59-0 Ma

high-K

calc-alk

high- K cal c-alk

low-K thol

061101145189111

009051045018045

Region

III IVPhase

Region

I IIPhase

Region

CR NIC

Va Vb VIPhase

75-16 Ma

aM61-53IIP

aM9-375IP

aM6-61IIIP

aM3-6VIP

75-16 Ma

med-Fe

16-3 Ma

SiO wt 2

40 45 50 55 60 65 70 75 80

low-Fe

med-Fe

kla-clac

high-Fe

59-0 Ma

Fe-enrichment

Na O+K O2 2 MgO

12100806

Tholeiitic Index

calc-alk thol

high-Fe

Region

III IVPhase

Region

I IIPhase

Region

CR NIC

VaPhase

IBMVAB

Time (Ma)70 60 50 40 30 20 10 0

PVa micro = 06955

Region

CR NIC

PANCRNICall

MORBIBMVAB

MORBIBM

OIBBCC

IBMVAB

OIBBCC

IBMVAB

BCC (11)

Time (Ma)

IBMVAB

OIB (280)BCC

70 60 50 40 30 20 10 0

CR PIV micro = 5855

Region

CR NIC

OPB (grey lined)

BCC OIB (199 ppm)

IBMVAB

IBMVAB20

Time (Ma)

070 60 50 40 30 20 10 0

OPB (grey lined)

Region

CR NIC

PVbadaks

PVa arc alks

(602 wt SiO )2

PI PIV

Phase interval (Ma)

PI (75-39) PII (35-16)PIII (16-6)

PIV (6-3)PVI (26-0)

PII 35-16 Ma

PIII 16-6 Ma

PIV 6-3 Ma

PVI 26-0 Ma

PI 75-39 Ma

OIB (97)

IBMVAB

OIB (222)

OIB BCC

OPB (grey lined)

IBM (19)

MORBIBMVABc

PVb micro = 10255

PVa micro = 28655

PVb micro = 6855

Region

CR NIC

IBMVAB (771)

70 60 50 40 30 20 10 0

51 Pb isotopes

IBMVAB

b 55 g

IBMVAB

300350

IBMVAB

NIC PIV micro = 702

OPB (grey line)

IBMVAB10

Time (Ma)70 60 50 40 30 20 10 0

IBMVAB

MORB BCC

IBMVAB

OPB (grey lined)

MORBamp OIB

IBMVAB

IBMVABMORB

09CR micro = 111

Region

CR NIC

Region

Va VbPhase

PVI26-0 Ma

CR NIC

SW NIC

NE CR central CR

NW NIC

Miocene Nicaragua

Miocene Costa Rica

PII-PIV35-3 Ma

Region

II III IVPhase

19-6 Ma

75-39 M

NIC Miocene

CR 35-16 Ma

CR 16-6 Ma

CR 6-3 Ma

CR NIC

subducting

SP (NGD)

subducting CCR (C

CocosNazca Plate

PI 75-39 Ma

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

206 204Pb Pb

Region

200 185

CR NW NIC NW SW

Region Phase VI

central

eastern

PAN SAA CBA

Region Phase I

central

CR NIC

051280

051285

051290

051295

051300

051305

051310

051275

051280

051285

051290

051295

051300

051305

051310

051315

subductin g

Seamount Province

Region

Va VbPhase

051275

PVI26-0 Ma

d051275

051280

051285

051290

051295

051300

051305

051310

PII- PIV35-3 Ma

CCR (CGD)

CocosNazca Plate

107142 86

H26-6 Ma CRVF

CR PANDM

CR 75-66 Ma

CR 6-3 MaCR 35-6 Ma

SP see (c)

344 217 201324

Region

II III IVPhase

206 204Pb Pb

051275

051280

051285

051290

051295

051300

051305

051310

aGP at 90 Ma

GP at 60 Ma

499-448

Region

PI 75-39 Ma

543400

170 200

Region Phase VI

central

PAN SAA CBA

Region Phase I

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

051280

051285

051290

051295

051300

051305

051310

051315

051275

Time (Ma)7090 80100 60 50 40 30 20 10 0

PIIIPIV

PVIPICLIP

age of accreted

central CR

SW NICNW

NICeastern

OIB in western CR

Burica(N = 5)

PAN SAA CBA

CR GA NIC eastern

central NW NW SW

52 Nd isotopes

6 Discussion

50 700

Mantle melting

Basalt

Rhyolite

Andesite

Basalt

CLIP crust

SiO wt 2

K55(t3)

K55(t2)

K55(t1)

K55(t3)

K55(t2)

K55(t1)

fractio

nation

mix ing

crustal melt

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

Selected

andtraceelem

entdata

ofPIPIIPIIIPIVPV

oftheseph

discrim

inated

byregion

linearly

regressedto

PhaseI

PhaseII

PhaseIII

PhaseIV

PhaseVa

PhaseVb

PhaseVI

SE(PAN

SE(arc

SE(adak)

SE(CR+

Agerang

a)75ndash39

35ndash16

16ndash6

6ndash3

590ndash001

420ndash015

26ndash0

Meanage(M

plusmn18

255plusmn95

11plusmn5

45plusmn15

3plusmn3

22plusmn20

13plusmn13

samples)

oxides

FeOt M

TholeiiticIndex1

K 2ONa 2O

Traceelem

ents55

Sr25844

140052

Ti505240

550899

551525

468245

933173

517084

484556

tinued)

Table2

tinued) Ph

PhaseII

PhaseIII

PhaseIV

PhaseVa

PhaseVb

PhaseVI

SE(PAN

SE(arc

SE(adak)

SE(CR+

Zr6844

K502137

840251

1206677

1573212

133153

1606374

1647473

922040

Ba24111

Ce1470

sumREE2

V26967

ofsomelinearly

regressedvalues

indicate

increasing

values

lemajor

andtraceelem

entsandratio

increase

theprevious

phasePIdata

arealso

ldtext

forvisualaidSee

lementary

formetho

linearregression

reviationsN

tanalyzed

tapplicableN

tcalculablewhere

totaln

umberof

FeO40andor

FeO80was

lt1Superscripts12

ΣREEareto

indicate

entandelem

entratio

errorSEo

fthemean)

Notes(1)

ensedversionof

lementary

Table1which

provides

inadditio

region

(ieregresseddata

provided

atthelevelo

fregionndash

PanamaCo

staRicaetc)

(2)Thedata

largelight

lsquoxrsquosin

ourvario

lsrepresentdistinct

region

sandthedata

fortheseareprovided

inSupp

lementaryTable1(see

non-no

rmalized

dances

ofFeOtandMgO

References

atasetsareprovided

inSection32(5)R

awdata

values

calculated

areprovided

lementary

TableS2

SiO2 wt

basalt

dacite

trachy-basalt

59-0 Ma

45 55 65 7550 60 70 80

75-16 Ma2

basalt

dacite

rhyolite

trachy-basalt

trachy-dacite

enilaklabus

16-3 Ma

TR-TIS

andesite

enilakla

basalticandesite

andesite

basandesite

trachy-andesite

Region

CR NIC

Va Vb VIPhase

Region

III IVPhase

Region

IPhase

4 Results

40 45 50 55 60 65 70 75 80

SiO2 wt

basaltgabbro

b-ag-d

anddior

shoshonite series

TR-TIS

calc-alk

med-K calc-alk

shoshonite

low-K thol

16-3 Ma

59-0 Ma

high-K

calc-alk

high- K cal c-alk

low-K thol

061101145189111

009051045018045

Region

III IVPhase

Region

I IIPhase

Region

CR NIC

Va Vb VIPhase

75-16 Ma

aM61-53IIP

aM9-375IP

aM6-61IIIP

aM3-6VIP

75-16 Ma

med-Fe

16-3 Ma

SiO wt 2

40 45 50 55 60 65 70 75 80

low-Fe

med-Fe

kla-clac

high-Fe

59-0 Ma

Fe-enrichment

Na O+K O2 2 MgO

12100806

Tholeiitic Index

calc-alk thol

high-Fe

Region

III IVPhase

Region

I IIPhase

Region

CR NIC

VaPhase

IBMVAB

Time (Ma)70 60 50 40 30 20 10 0

PVa micro = 06955

Region

CR NIC

PANCRNICall

MORBIBMVAB

MORBIBM

OIBBCC

IBMVAB

OIBBCC

IBMVAB

BCC (11)

Time (Ma)

IBMVAB

OIB (280)BCC

70 60 50 40 30 20 10 0

CR PIV micro = 5855

Region

CR NIC

OPB (grey lined)

BCC OIB (199 ppm)

IBMVAB

IBMVAB20

Time (Ma)

070 60 50 40 30 20 10 0

OPB (grey lined)

Region

CR NIC

PVbadaks

PVa arc alks

(602 wt SiO )2

PI PIV

Phase interval (Ma)

PI (75-39) PII (35-16)PIII (16-6)

PIV (6-3)PVI (26-0)

PII 35-16 Ma

PIII 16-6 Ma

PIV 6-3 Ma

PVI 26-0 Ma

PI 75-39 Ma

OIB (97)

IBMVAB

OIB (222)

OIB BCC

OPB (grey lined)

IBM (19)

MORBIBMVABc

PVb micro = 10255

PVa micro = 28655

PVb micro = 6855

Region

CR NIC

IBMVAB (771)

70 60 50 40 30 20 10 0

51 Pb isotopes

IBMVAB

b 55 g

IBMVAB

300350

IBMVAB

NIC PIV micro = 702

OPB (grey line)

IBMVAB10

Time (Ma)70 60 50 40 30 20 10 0

IBMVAB

MORB BCC

IBMVAB

OPB (grey lined)

MORBamp OIB

IBMVAB

IBMVABMORB

09CR micro = 111

Region

CR NIC

Region

Va VbPhase

PVI26-0 Ma

CR NIC

SW NIC

NE CR central CR

NW NIC

Miocene Nicaragua

Miocene Costa Rica

PII-PIV35-3 Ma

Region

II III IVPhase

19-6 Ma

75-39 M

NIC Miocene

CR 35-16 Ma

CR 16-6 Ma

CR 6-3 Ma

CR NIC

subducting

SP (NGD)

subducting CCR (C

CocosNazca Plate

PI 75-39 Ma

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

206 204Pb Pb

Region

200 185

CR NW NIC NW SW

Region Phase VI

central

eastern

PAN SAA CBA

Region Phase I

central

CR NIC

051280

051285

051290

051295

051300

051305

051310

051275

051280

051285

051290

051295

051300

051305

051310

051315

subductin g

Seamount Province

Region

Va VbPhase

051275

PVI26-0 Ma

d051275

051280

051285

051290

051295

051300

051305

051310

PII- PIV35-3 Ma

CCR (CGD)

CocosNazca Plate

107142 86

H26-6 Ma CRVF

CR PANDM

CR 75-66 Ma

CR 6-3 MaCR 35-6 Ma

SP see (c)

344 217 201324

Region

II III IVPhase

206 204Pb Pb

051275

051280

051285

051290

051295

051300

051305

051310

aGP at 90 Ma

GP at 60 Ma

499-448

Region

PI 75-39 Ma

543400

170 200

Region Phase VI

central

PAN SAA CBA

Region Phase I

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

051280

051285

051290

051295

051300

051305

051310

051315

051275

Time (Ma)7090 80100 60 50 40 30 20 10 0

PIIIPIV

PVIPICLIP

age of accreted

central CR

SW NICNW

NICeastern

OIB in western CR

Burica(N = 5)

PAN SAA CBA

CR GA NIC eastern

central NW NW SW

52 Nd isotopes

6 Discussion

50 700

Mantle melting

Basalt

Rhyolite

Andesite

Basalt

CLIP crust

SiO wt 2

K55(t3)

K55(t2)

K55(t1)

K55(t3)

K55(t2)

K55(t1)

fractio

nation

mix ing

crustal melt

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

Table2

tinued) Ph

PhaseII

PhaseIII

PhaseIV

PhaseVa

PhaseVb

PhaseVI

SE(PAN

SE(arc

SE(adak)

SE(CR+

Zr6844

K502137

840251

1206677

1573212

133153

1606374

1647473

922040

Ba24111

Ce1470

sumREE2

V26967

ofsomelinearly

regressedvalues

indicate

increasing

values

lemajor

andtraceelem

entsandratio

increase

theprevious

phasePIdata

arealso

ldtext

forvisualaidSee

lementary

formetho

linearregression

reviationsN

tanalyzed

tapplicableN

tcalculablewhere

totaln

umberof

FeO40andor

FeO80was

lt1Superscripts12

ΣREEareto

indicate

entandelem

entratio

errorSEo

fthemean)

Notes(1)

ensedversionof

lementary

Table1which

provides

inadditio

region

(ieregresseddata

provided

atthelevelo

fregionndash

PanamaCo

staRicaetc)

(2)Thedata

largelight

lsquoxrsquosin

ourvario

lsrepresentdistinct

region

sandthedata

fortheseareprovided

inSupp

lementaryTable1(see

non-no

rmalized

dances

ofFeOtandMgO

References

atasetsareprovided

inSection32(5)R

awdata

values

calculated

areprovided

lementary

TableS2

SiO2 wt

basalt

dacite

trachy-basalt

59-0 Ma

45 55 65 7550 60 70 80

75-16 Ma2

basalt

dacite

rhyolite

trachy-basalt

trachy-dacite

enilaklabus

16-3 Ma

TR-TIS

andesite

enilakla

basalticandesite

andesite

basandesite

trachy-andesite

Region

CR NIC

Va Vb VIPhase

Region

III IVPhase

Region

IPhase

4 Results

40 45 50 55 60 65 70 75 80

SiO2 wt

basaltgabbro

b-ag-d

anddior

shoshonite series

TR-TIS

calc-alk

med-K calc-alk

shoshonite

low-K thol

16-3 Ma

59-0 Ma

high-K

calc-alk

high- K cal c-alk

low-K thol

061101145189111

009051045018045

Region

III IVPhase

Region

I IIPhase

Region

CR NIC

Va Vb VIPhase

75-16 Ma

aM61-53IIP

aM9-375IP

aM6-61IIIP

aM3-6VIP

75-16 Ma

med-Fe

16-3 Ma

SiO wt 2

40 45 50 55 60 65 70 75 80

low-Fe

med-Fe

kla-clac

high-Fe

59-0 Ma

Fe-enrichment

Na O+K O2 2 MgO

12100806

Tholeiitic Index

calc-alk thol

high-Fe

Region

III IVPhase

Region

I IIPhase

Region

CR NIC

VaPhase

IBMVAB

Time (Ma)70 60 50 40 30 20 10 0

PVa micro = 06955

Region

CR NIC

PANCRNICall

MORBIBMVAB

MORBIBM

OIBBCC

IBMVAB

OIBBCC

IBMVAB

BCC (11)

Time (Ma)

IBMVAB

OIB (280)BCC

70 60 50 40 30 20 10 0

CR PIV micro = 5855

Region

CR NIC

OPB (grey lined)

BCC OIB (199 ppm)

IBMVAB

IBMVAB20

Time (Ma)

070 60 50 40 30 20 10 0

OPB (grey lined)

Region

CR NIC

PVbadaks

PVa arc alks

(602 wt SiO )2

PI PIV

Phase interval (Ma)

PI (75-39) PII (35-16)PIII (16-6)

PIV (6-3)PVI (26-0)

PII 35-16 Ma

PIII 16-6 Ma

PIV 6-3 Ma

PVI 26-0 Ma

PI 75-39 Ma

OIB (97)

IBMVAB

OIB (222)

OIB BCC

OPB (grey lined)

IBM (19)

MORBIBMVABc

PVb micro = 10255

PVa micro = 28655

PVb micro = 6855

Region

CR NIC

IBMVAB (771)

70 60 50 40 30 20 10 0

51 Pb isotopes

IBMVAB

b 55 g

IBMVAB

300350

IBMVAB

NIC PIV micro = 702

OPB (grey line)

IBMVAB10

Time (Ma)70 60 50 40 30 20 10 0

IBMVAB

MORB BCC

IBMVAB

OPB (grey lined)

MORBamp OIB

IBMVAB

IBMVABMORB

09CR micro = 111

Region

CR NIC

Region

Va VbPhase

PVI26-0 Ma

CR NIC

SW NIC

NE CR central CR

NW NIC

Miocene Nicaragua

Miocene Costa Rica

PII-PIV35-3 Ma

Region

II III IVPhase

19-6 Ma

75-39 M

NIC Miocene

CR 35-16 Ma

CR 16-6 Ma

CR 6-3 Ma

CR NIC

subducting

SP (NGD)

subducting CCR (C

CocosNazca Plate

PI 75-39 Ma

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

206 204Pb Pb

Region

200 185

CR NW NIC NW SW

Region Phase VI

central

eastern

PAN SAA CBA

Region Phase I

central

CR NIC

051280

051285

051290

051295

051300

051305

051310

051275

051280

051285

051290

051295

051300

051305

051310

051315

subductin g

Seamount Province

Region

Va VbPhase

051275

PVI26-0 Ma

d051275

051280

051285

051290

051295

051300

051305

051310

PII- PIV35-3 Ma

CCR (CGD)

CocosNazca Plate

107142 86

H26-6 Ma CRVF

CR PANDM

CR 75-66 Ma

CR 6-3 MaCR 35-6 Ma

SP see (c)

344 217 201324

Region

II III IVPhase

206 204Pb Pb

051275

051280

051285

051290

051295

051300

051305

051310

aGP at 90 Ma

GP at 60 Ma

499-448

Region

PI 75-39 Ma

543400

170 200

Region Phase VI

central

PAN SAA CBA

Region Phase I

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

051280

051285

051290

051295

051300

051305

051310

051315

051275

Time (Ma)7090 80100 60 50 40 30 20 10 0

PIIIPIV

PVIPICLIP

age of accreted

central CR

SW NICNW

NICeastern

OIB in western CR

Burica(N = 5)

PAN SAA CBA

CR GA NIC eastern

central NW NW SW

52 Nd isotopes

6 Discussion

50 700

Mantle melting

Basalt

Rhyolite

Andesite

Basalt

CLIP crust

SiO wt 2

K55(t3)

K55(t2)

K55(t1)

K55(t3)

K55(t2)

K55(t1)

fractio

nation

mix ing

crustal melt

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

SiO2 wt

basalt

dacite

trachy-basalt

59-0 Ma

45 55 65 7550 60 70 80

75-16 Ma2

basalt

dacite

rhyolite

trachy-basalt

trachy-dacite

enilaklabus

16-3 Ma

TR-TIS

andesite

enilakla

basalticandesite

andesite

basandesite

trachy-andesite

Region

CR NIC

Va Vb VIPhase

Region

III IVPhase

Region

IPhase

4 Results

40 45 50 55 60 65 70 75 80

SiO2 wt

basaltgabbro

b-ag-d

anddior

shoshonite series

TR-TIS

calc-alk

med-K calc-alk

shoshonite

low-K thol

16-3 Ma

59-0 Ma

high-K

calc-alk

high- K cal c-alk

low-K thol

061101145189111

009051045018045

Region

III IVPhase

Region

I IIPhase

Region

CR NIC

Va Vb VIPhase

75-16 Ma

aM61-53IIP

aM9-375IP

aM6-61IIIP

aM3-6VIP

75-16 Ma

med-Fe

16-3 Ma

SiO wt 2

40 45 50 55 60 65 70 75 80

low-Fe

med-Fe

kla-clac

high-Fe

59-0 Ma

Fe-enrichment

Na O+K O2 2 MgO

12100806

Tholeiitic Index

calc-alk thol

high-Fe

Region

III IVPhase

Region

I IIPhase

Region

CR NIC

VaPhase

IBMVAB

Time (Ma)70 60 50 40 30 20 10 0

PVa micro = 06955

Region

CR NIC

PANCRNICall

MORBIBMVAB

MORBIBM

OIBBCC

IBMVAB

OIBBCC

IBMVAB

BCC (11)

Time (Ma)

IBMVAB

OIB (280)BCC

70 60 50 40 30 20 10 0

CR PIV micro = 5855

Region

CR NIC

OPB (grey lined)

BCC OIB (199 ppm)

IBMVAB

IBMVAB20

Time (Ma)

070 60 50 40 30 20 10 0

OPB (grey lined)

Region

CR NIC

PVbadaks

PVa arc alks

(602 wt SiO )2

PI PIV

Phase interval (Ma)

PI (75-39) PII (35-16)PIII (16-6)

PIV (6-3)PVI (26-0)

PII 35-16 Ma

PIII 16-6 Ma

PIV 6-3 Ma

PVI 26-0 Ma

PI 75-39 Ma

OIB (97)

IBMVAB

OIB (222)

OIB BCC

OPB (grey lined)

IBM (19)

MORBIBMVABc

PVb micro = 10255

PVa micro = 28655

PVb micro = 6855

Region

CR NIC

IBMVAB (771)

70 60 50 40 30 20 10 0

51 Pb isotopes

IBMVAB

b 55 g

IBMVAB

300350

IBMVAB

NIC PIV micro = 702

OPB (grey line)

IBMVAB10

Time (Ma)70 60 50 40 30 20 10 0

IBMVAB

MORB BCC

IBMVAB

OPB (grey lined)

MORBamp OIB

IBMVAB

IBMVABMORB

09CR micro = 111

Region

CR NIC

Region

Va VbPhase

PVI26-0 Ma

CR NIC

SW NIC

NE CR central CR

NW NIC

Miocene Nicaragua

Miocene Costa Rica

PII-PIV35-3 Ma

Region

II III IVPhase

19-6 Ma

75-39 M

NIC Miocene

CR 35-16 Ma

CR 16-6 Ma

CR 6-3 Ma

CR NIC

subducting

SP (NGD)

subducting CCR (C

CocosNazca Plate

PI 75-39 Ma

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

206 204Pb Pb

Region

200 185

CR NW NIC NW SW

Region Phase VI

central

eastern

PAN SAA CBA

Region Phase I

central

CR NIC

051280

051285

051290

051295

051300

051305

051310

051275

051280

051285

051290

051295

051300

051305

051310

051315

subductin g

Seamount Province

Region

Va VbPhase

051275

PVI26-0 Ma

d051275

051280

051285

051290

051295

051300

051305

051310

PII- PIV35-3 Ma

CCR (CGD)

CocosNazca Plate

107142 86

H26-6 Ma CRVF

CR PANDM

CR 75-66 Ma

CR 6-3 MaCR 35-6 Ma

SP see (c)

344 217 201324

Region

II III IVPhase

206 204Pb Pb

051275

051280

051285

051290

051295

051300

051305

051310

aGP at 90 Ma

GP at 60 Ma

499-448

Region

PI 75-39 Ma

543400

170 200

Region Phase VI

central

PAN SAA CBA

Region Phase I

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

051280

051285

051290

051295

051300

051305

051310

051315

051275

Time (Ma)7090 80100 60 50 40 30 20 10 0

PIIIPIV

PVIPICLIP

age of accreted

central CR

SW NICNW

NICeastern

OIB in western CR

Burica(N = 5)

PAN SAA CBA

CR GA NIC eastern

central NW NW SW

52 Nd isotopes

6 Discussion

50 700

Mantle melting

Basalt

Rhyolite

Andesite

Basalt

CLIP crust

SiO wt 2

K55(t3)

K55(t2)

K55(t1)

K55(t3)

K55(t2)

K55(t1)

fractio

nation

mix ing

crustal melt

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

4 Results

40 45 50 55 60 65 70 75 80

SiO2 wt

basaltgabbro

b-ag-d

anddior

shoshonite series

TR-TIS

calc-alk

med-K calc-alk

shoshonite

low-K thol

16-3 Ma

59-0 Ma

high-K

calc-alk

high- K cal c-alk

low-K thol

061101145189111

009051045018045

Region

III IVPhase

Region

I IIPhase

Region

CR NIC

Va Vb VIPhase

75-16 Ma

aM61-53IIP

aM9-375IP

aM6-61IIIP

aM3-6VIP

75-16 Ma

med-Fe

16-3 Ma

SiO wt 2

40 45 50 55 60 65 70 75 80

low-Fe

med-Fe

kla-clac

high-Fe

59-0 Ma

Fe-enrichment

Na O+K O2 2 MgO

12100806

Tholeiitic Index

calc-alk thol

high-Fe

Region

III IVPhase

Region

I IIPhase

Region

CR NIC

VaPhase

IBMVAB

Time (Ma)70 60 50 40 30 20 10 0

PVa micro = 06955

Region

CR NIC

PANCRNICall

MORBIBMVAB

MORBIBM

OIBBCC

IBMVAB

OIBBCC

IBMVAB

BCC (11)

Time (Ma)

IBMVAB

OIB (280)BCC

70 60 50 40 30 20 10 0

CR PIV micro = 5855

Region

CR NIC

OPB (grey lined)

BCC OIB (199 ppm)

IBMVAB

IBMVAB20

Time (Ma)

070 60 50 40 30 20 10 0

OPB (grey lined)

Region

CR NIC

PVbadaks

PVa arc alks

(602 wt SiO )2

PI PIV

Phase interval (Ma)

PI (75-39) PII (35-16)PIII (16-6)

PIV (6-3)PVI (26-0)

PII 35-16 Ma

PIII 16-6 Ma

PIV 6-3 Ma

PVI 26-0 Ma

PI 75-39 Ma

OIB (97)

IBMVAB

OIB (222)

OIB BCC

OPB (grey lined)

IBM (19)

MORBIBMVABc

PVb micro = 10255

PVa micro = 28655

PVb micro = 6855

Region

CR NIC

IBMVAB (771)

70 60 50 40 30 20 10 0

51 Pb isotopes

IBMVAB

b 55 g

IBMVAB

300350

IBMVAB

NIC PIV micro = 702

OPB (grey line)

IBMVAB10

Time (Ma)70 60 50 40 30 20 10 0

IBMVAB

MORB BCC

IBMVAB

OPB (grey lined)

MORBamp OIB

IBMVAB

IBMVABMORB

09CR micro = 111

Region

CR NIC

Region

Va VbPhase

PVI26-0 Ma

CR NIC

SW NIC

NE CR central CR

NW NIC

Miocene Nicaragua

Miocene Costa Rica

PII-PIV35-3 Ma

Region

II III IVPhase

19-6 Ma

75-39 M

NIC Miocene

CR 35-16 Ma

CR 16-6 Ma

CR 6-3 Ma

CR NIC

subducting

SP (NGD)

subducting CCR (C

CocosNazca Plate

PI 75-39 Ma

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

206 204Pb Pb

Region

200 185

CR NW NIC NW SW

Region Phase VI

central

eastern

PAN SAA CBA

Region Phase I

central

CR NIC

051280

051285

051290

051295

051300

051305

051310

051275

051280

051285

051290

051295

051300

051305

051310

051315

subductin g

Seamount Province

Region

Va VbPhase

051275

PVI26-0 Ma

d051275

051280

051285

051290

051295

051300

051305

051310

PII- PIV35-3 Ma

CCR (CGD)

CocosNazca Plate

107142 86

H26-6 Ma CRVF

CR PANDM

CR 75-66 Ma

CR 6-3 MaCR 35-6 Ma

SP see (c)

344 217 201324

Region

II III IVPhase

206 204Pb Pb

051275

051280

051285

051290

051295

051300

051305

051310

aGP at 90 Ma

GP at 60 Ma

499-448

Region

PI 75-39 Ma

543400

170 200

Region Phase VI

central

PAN SAA CBA

Region Phase I

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

051280

051285

051290

051295

051300

051305

051310

051315

051275

Time (Ma)7090 80100 60 50 40 30 20 10 0

PIIIPIV

PVIPICLIP

age of accreted

central CR

SW NICNW

NICeastern

OIB in western CR

Burica(N = 5)

PAN SAA CBA

CR GA NIC eastern

central NW NW SW

52 Nd isotopes

6 Discussion

50 700

Mantle melting

Basalt

Rhyolite

Andesite

Basalt

CLIP crust

SiO wt 2

K55(t3)

K55(t2)

K55(t1)

K55(t3)

K55(t2)

K55(t1)

fractio

nation

mix ing

crustal melt

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

75-16 Ma

med-Fe

16-3 Ma

SiO wt 2

40 45 50 55 60 65 70 75 80

low-Fe

med-Fe

kla-clac

high-Fe

59-0 Ma

Fe-enrichment

Na O+K O2 2 MgO

12100806

Tholeiitic Index

calc-alk thol

high-Fe

Region

III IVPhase

Region

I IIPhase

Region

CR NIC

VaPhase

IBMVAB

Time (Ma)70 60 50 40 30 20 10 0

PVa micro = 06955

Region

CR NIC

PANCRNICall

MORBIBMVAB

MORBIBM

OIBBCC

IBMVAB

OIBBCC

IBMVAB

BCC (11)

Time (Ma)

IBMVAB

OIB (280)BCC

70 60 50 40 30 20 10 0

CR PIV micro = 5855

Region

CR NIC

OPB (grey lined)

BCC OIB (199 ppm)

IBMVAB

IBMVAB20

Time (Ma)

070 60 50 40 30 20 10 0

OPB (grey lined)

Region

CR NIC

PVbadaks

PVa arc alks

(602 wt SiO )2

PI PIV

Phase interval (Ma)

PI (75-39) PII (35-16)PIII (16-6)

PIV (6-3)PVI (26-0)

PII 35-16 Ma

PIII 16-6 Ma

PIV 6-3 Ma

PVI 26-0 Ma

PI 75-39 Ma

OIB (97)

IBMVAB

OIB (222)

OIB BCC

OPB (grey lined)

IBM (19)

MORBIBMVABc

PVb micro = 10255

PVa micro = 28655

PVb micro = 6855

Region

CR NIC

IBMVAB (771)

70 60 50 40 30 20 10 0

51 Pb isotopes

IBMVAB

b 55 g

IBMVAB

300350

IBMVAB

NIC PIV micro = 702

OPB (grey line)

IBMVAB10

Time (Ma)70 60 50 40 30 20 10 0

IBMVAB

MORB BCC

IBMVAB

OPB (grey lined)

MORBamp OIB

IBMVAB

IBMVABMORB

09CR micro = 111

Region

CR NIC

Region

Va VbPhase

PVI26-0 Ma

CR NIC

SW NIC

NE CR central CR

NW NIC

Miocene Nicaragua

Miocene Costa Rica

PII-PIV35-3 Ma

Region

II III IVPhase

19-6 Ma

75-39 M

NIC Miocene

CR 35-16 Ma

CR 16-6 Ma

CR 6-3 Ma

CR NIC

subducting

SP (NGD)

subducting CCR (C

CocosNazca Plate

PI 75-39 Ma

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

206 204Pb Pb

Region

200 185

CR NW NIC NW SW

Region Phase VI

central

eastern

PAN SAA CBA

Region Phase I

central

CR NIC

051280

051285

051290

051295

051300

051305

051310

051275

051280

051285

051290

051295

051300

051305

051310

051315

subductin g

Seamount Province

Region

Va VbPhase

051275

PVI26-0 Ma

d051275

051280

051285

051290

051295

051300

051305

051310

PII- PIV35-3 Ma

CCR (CGD)

CocosNazca Plate

107142 86

H26-6 Ma CRVF

CR PANDM

CR 75-66 Ma

CR 6-3 MaCR 35-6 Ma

SP see (c)

344 217 201324

Region

II III IVPhase

206 204Pb Pb

051275

051280

051285

051290

051295

051300

051305

051310

aGP at 90 Ma

GP at 60 Ma

499-448

Region

PI 75-39 Ma

543400

170 200

Region Phase VI

central

PAN SAA CBA

Region Phase I

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

051280

051285

051290

051295

051300

051305

051310

051315

051275

Time (Ma)7090 80100 60 50 40 30 20 10 0

PIIIPIV

PVIPICLIP

age of accreted

central CR

SW NICNW

NICeastern

OIB in western CR

Burica(N = 5)

PAN SAA CBA

CR GA NIC eastern

central NW NW SW

52 Nd isotopes

6 Discussion

50 700

Mantle melting

Basalt

Rhyolite

Andesite

Basalt

CLIP crust

SiO wt 2

K55(t3)

K55(t2)

K55(t1)

K55(t3)

K55(t2)

K55(t1)

fractio

nation

mix ing

crustal melt

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

IBMVAB

Time (Ma)70 60 50 40 30 20 10 0

PVa micro = 06955

Region

CR NIC

PANCRNICall

MORBIBMVAB

MORBIBM

OIBBCC

IBMVAB

OIBBCC

IBMVAB

BCC (11)

Time (Ma)

IBMVAB

OIB (280)BCC

70 60 50 40 30 20 10 0

CR PIV micro = 5855

Region

CR NIC

OPB (grey lined)

BCC OIB (199 ppm)

IBMVAB

IBMVAB20

Time (Ma)

070 60 50 40 30 20 10 0

OPB (grey lined)

Region

CR NIC

PVbadaks

PVa arc alks

(602 wt SiO )2

PI PIV

Phase interval (Ma)

PI (75-39) PII (35-16)PIII (16-6)

PIV (6-3)PVI (26-0)

PII 35-16 Ma

PIII 16-6 Ma

PIV 6-3 Ma

PVI 26-0 Ma

PI 75-39 Ma

OIB (97)

IBMVAB

OIB (222)

OIB BCC

OPB (grey lined)

IBM (19)

MORBIBMVABc

PVb micro = 10255

PVa micro = 28655

PVb micro = 6855

Region

CR NIC

IBMVAB (771)

70 60 50 40 30 20 10 0

51 Pb isotopes

IBMVAB

b 55 g

IBMVAB

300350

IBMVAB

NIC PIV micro = 702

OPB (grey line)

IBMVAB10

Time (Ma)70 60 50 40 30 20 10 0

IBMVAB

MORB BCC

IBMVAB

OPB (grey lined)

MORBamp OIB

IBMVAB

IBMVABMORB

09CR micro = 111

Region

CR NIC

Region

Va VbPhase

PVI26-0 Ma

CR NIC

SW NIC

NE CR central CR

NW NIC

Miocene Nicaragua

Miocene Costa Rica

PII-PIV35-3 Ma

Region

II III IVPhase

19-6 Ma

75-39 M

NIC Miocene

CR 35-16 Ma

CR 16-6 Ma

CR 6-3 Ma

CR NIC

subducting

SP (NGD)

subducting CCR (C

CocosNazca Plate

PI 75-39 Ma

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

206 204Pb Pb

Region

200 185

CR NW NIC NW SW

Region Phase VI

central

eastern

PAN SAA CBA

Region Phase I

central

CR NIC

051280

051285

051290

051295

051300

051305

051310

051275

051280

051285

051290

051295

051300

051305

051310

051315

subductin g

Seamount Province

Region

Va VbPhase

051275

PVI26-0 Ma

d051275

051280

051285

051290

051295

051300

051305

051310

PII- PIV35-3 Ma

CCR (CGD)

CocosNazca Plate

107142 86

H26-6 Ma CRVF

CR PANDM

CR 75-66 Ma

CR 6-3 MaCR 35-6 Ma

SP see (c)

344 217 201324

Region

II III IVPhase

206 204Pb Pb

051275

051280

051285

051290

051295

051300

051305

051310

aGP at 90 Ma

GP at 60 Ma

499-448

Region

PI 75-39 Ma

543400

170 200

Region Phase VI

central

PAN SAA CBA

Region Phase I

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

051280

051285

051290

051295

051300

051305

051310

051315

051275

Time (Ma)7090 80100 60 50 40 30 20 10 0

PIIIPIV

PVIPICLIP

age of accreted

central CR

SW NICNW

NICeastern

OIB in western CR

Burica(N = 5)

PAN SAA CBA

CR GA NIC eastern

central NW NW SW

52 Nd isotopes

6 Discussion

50 700

Mantle melting

Basalt

Rhyolite

Andesite

Basalt

CLIP crust

SiO wt 2

K55(t3)

K55(t2)

K55(t1)

K55(t3)

K55(t2)

K55(t1)

fractio

nation

mix ing

crustal melt

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

MORBIBMVAB

MORBIBM

OIBBCC

IBMVAB

OIBBCC

IBMVAB

BCC (11)

Time (Ma)

IBMVAB

OIB (280)BCC

70 60 50 40 30 20 10 0

CR PIV micro = 5855

Region

CR NIC

OPB (grey lined)

BCC OIB (199 ppm)

IBMVAB

IBMVAB20

Time (Ma)

070 60 50 40 30 20 10 0

OPB (grey lined)

Region

CR NIC

PVbadaks

PVa arc alks

(602 wt SiO )2

PI PIV

Phase interval (Ma)

PI (75-39) PII (35-16)PIII (16-6)

PIV (6-3)PVI (26-0)

PII 35-16 Ma

PIII 16-6 Ma

PIV 6-3 Ma

PVI 26-0 Ma

PI 75-39 Ma

OIB (97)

IBMVAB

OIB (222)

OIB BCC

OPB (grey lined)

IBM (19)

MORBIBMVABc

PVb micro = 10255

PVa micro = 28655

PVb micro = 6855

Region

CR NIC

IBMVAB (771)

70 60 50 40 30 20 10 0

51 Pb isotopes

IBMVAB

b 55 g

IBMVAB

300350

IBMVAB

NIC PIV micro = 702

OPB (grey line)

IBMVAB10

Time (Ma)70 60 50 40 30 20 10 0

IBMVAB

MORB BCC

IBMVAB

OPB (grey lined)

MORBamp OIB

IBMVAB

IBMVABMORB

09CR micro = 111

Region

CR NIC

Region

Va VbPhase

PVI26-0 Ma

CR NIC

SW NIC

NE CR central CR

NW NIC

Miocene Nicaragua

Miocene Costa Rica

PII-PIV35-3 Ma

Region

II III IVPhase

19-6 Ma

75-39 M

NIC Miocene

CR 35-16 Ma

CR 16-6 Ma

CR 6-3 Ma

CR NIC

subducting

SP (NGD)

subducting CCR (C

CocosNazca Plate

PI 75-39 Ma

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

206 204Pb Pb

Region

200 185

CR NW NIC NW SW

Region Phase VI

central

eastern

PAN SAA CBA

Region Phase I

central

CR NIC

051280

051285

051290

051295

051300

051305

051310

051275

051280

051285

051290

051295

051300

051305

051310

051315

subductin g

Seamount Province

Region

Va VbPhase

051275

PVI26-0 Ma

d051275

051280

051285

051290

051295

051300

051305

051310

PII- PIV35-3 Ma

CCR (CGD)

CocosNazca Plate

107142 86

H26-6 Ma CRVF

CR PANDM

CR 75-66 Ma

CR 6-3 MaCR 35-6 Ma

SP see (c)

344 217 201324

Region

II III IVPhase

206 204Pb Pb

051275

051280

051285

051290

051295

051300

051305

051310

aGP at 90 Ma

GP at 60 Ma

499-448

Region

PI 75-39 Ma

543400

170 200

Region Phase VI

central

PAN SAA CBA

Region Phase I

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

051280

051285

051290

051295

051300

051305

051310

051315

051275

Time (Ma)7090 80100 60 50 40 30 20 10 0

PIIIPIV

PVIPICLIP

age of accreted

central CR

SW NICNW

NICeastern

OIB in western CR

Burica(N = 5)

PAN SAA CBA

CR GA NIC eastern

central NW NW SW

52 Nd isotopes

6 Discussion

50 700

Mantle melting

Basalt

Rhyolite

Andesite

Basalt

CLIP crust

SiO wt 2

K55(t3)

K55(t2)

K55(t1)

K55(t3)

K55(t2)

K55(t1)

fractio

nation

mix ing

crustal melt

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

BCC OIB (199 ppm)

IBMVAB

IBMVAB20

Time (Ma)

070 60 50 40 30 20 10 0

OPB (grey lined)

Region

CR NIC

PVbadaks

PVa arc alks

(602 wt SiO )2

PI PIV

Phase interval (Ma)

PI (75-39) PII (35-16)PIII (16-6)

PIV (6-3)PVI (26-0)

PII 35-16 Ma

PIII 16-6 Ma

PIV 6-3 Ma

PVI 26-0 Ma

PI 75-39 Ma

OIB (97)

IBMVAB

OIB (222)

OIB BCC

OPB (grey lined)

IBM (19)

MORBIBMVABc

PVb micro = 10255

PVa micro = 28655

PVb micro = 6855

Region

CR NIC

IBMVAB (771)

70 60 50 40 30 20 10 0

51 Pb isotopes

IBMVAB

b 55 g

IBMVAB

300350

IBMVAB

NIC PIV micro = 702

OPB (grey line)

IBMVAB10

Time (Ma)70 60 50 40 30 20 10 0

IBMVAB

MORB BCC

IBMVAB

OPB (grey lined)

MORBamp OIB

IBMVAB

IBMVABMORB

09CR micro = 111

Region

CR NIC

Region

Va VbPhase

PVI26-0 Ma

CR NIC

SW NIC

NE CR central CR

NW NIC

Miocene Nicaragua

Miocene Costa Rica

PII-PIV35-3 Ma

Region

II III IVPhase

19-6 Ma

75-39 M

NIC Miocene

CR 35-16 Ma

CR 16-6 Ma

CR 6-3 Ma

CR NIC

subducting

SP (NGD)

subducting CCR (C

CocosNazca Plate

PI 75-39 Ma

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

206 204Pb Pb

Region

200 185

CR NW NIC NW SW

Region Phase VI

central

eastern

PAN SAA CBA

Region Phase I

central

CR NIC

051280

051285

051290

051295

051300

051305

051310

051275

051280

051285

051290

051295

051300

051305

051310

051315

subductin g

Seamount Province

Region

Va VbPhase

051275

PVI26-0 Ma

d051275

051280

051285

051290

051295

051300

051305

051310

PII- PIV35-3 Ma

CCR (CGD)

CocosNazca Plate

107142 86

H26-6 Ma CRVF

CR PANDM

CR 75-66 Ma

CR 6-3 MaCR 35-6 Ma

SP see (c)

344 217 201324

Region

II III IVPhase

206 204Pb Pb

051275

051280

051285

051290

051295

051300

051305

051310

aGP at 90 Ma

GP at 60 Ma

499-448

Region

PI 75-39 Ma

543400

170 200

Region Phase VI

central

PAN SAA CBA

Region Phase I

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

051280

051285

051290

051295

051300

051305

051310

051315

051275

Time (Ma)7090 80100 60 50 40 30 20 10 0

PIIIPIV

PVIPICLIP

age of accreted

central CR

SW NICNW

NICeastern

OIB in western CR

Burica(N = 5)

PAN SAA CBA

CR GA NIC eastern

central NW NW SW

52 Nd isotopes

6 Discussion

50 700

Mantle melting

Basalt

Rhyolite

Andesite

Basalt

CLIP crust

SiO wt 2

K55(t3)

K55(t2)

K55(t1)

K55(t3)

K55(t2)

K55(t1)

fractio

nation

mix ing

crustal melt

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

PVbadaks

PVa arc alks

(602 wt SiO )2

PI PIV

Phase interval (Ma)

PI (75-39) PII (35-16)PIII (16-6)

PIV (6-3)PVI (26-0)

PII 35-16 Ma

PIII 16-6 Ma

PIV 6-3 Ma

PVI 26-0 Ma

PI 75-39 Ma

OIB (97)

IBMVAB

OIB (222)

OIB BCC

OPB (grey lined)

IBM (19)

MORBIBMVABc

PVb micro = 10255

PVa micro = 28655

PVb micro = 6855

Region

CR NIC

IBMVAB (771)

70 60 50 40 30 20 10 0

51 Pb isotopes

IBMVAB

b 55 g

IBMVAB

300350

IBMVAB

NIC PIV micro = 702

OPB (grey line)

IBMVAB10

Time (Ma)70 60 50 40 30 20 10 0

IBMVAB

MORB BCC

IBMVAB

OPB (grey lined)

MORBamp OIB

IBMVAB

IBMVABMORB

09CR micro = 111

Region

CR NIC

Region

Va VbPhase

PVI26-0 Ma

CR NIC

SW NIC

NE CR central CR

NW NIC

Miocene Nicaragua

Miocene Costa Rica

PII-PIV35-3 Ma

Region

II III IVPhase

19-6 Ma

75-39 M

NIC Miocene

CR 35-16 Ma

CR 16-6 Ma

CR 6-3 Ma

CR NIC

subducting

SP (NGD)

subducting CCR (C

CocosNazca Plate

PI 75-39 Ma

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

206 204Pb Pb

Region

200 185

CR NW NIC NW SW

Region Phase VI

central

eastern

PAN SAA CBA

Region Phase I

central

CR NIC

051280

051285

051290

051295

051300

051305

051310

051275

051280

051285

051290

051295

051300

051305

051310

051315

subductin g

Seamount Province

Region

Va VbPhase

051275

PVI26-0 Ma

d051275

051280

051285

051290

051295

051300

051305

051310

PII- PIV35-3 Ma

CCR (CGD)

CocosNazca Plate

107142 86

H26-6 Ma CRVF

CR PANDM

CR 75-66 Ma

CR 6-3 MaCR 35-6 Ma

SP see (c)

344 217 201324

Region

II III IVPhase

206 204Pb Pb

051275

051280

051285

051290

051295

051300

051305

051310

aGP at 90 Ma

GP at 60 Ma

499-448

Region

PI 75-39 Ma

543400

170 200

Region Phase VI

central

PAN SAA CBA

Region Phase I

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

051280

051285

051290

051295

051300

051305

051310

051315

051275

Time (Ma)7090 80100 60 50 40 30 20 10 0

PIIIPIV

PVIPICLIP

age of accreted

central CR

SW NICNW

NICeastern

OIB in western CR

Burica(N = 5)

PAN SAA CBA

CR GA NIC eastern

central NW NW SW

52 Nd isotopes

6 Discussion

50 700

Mantle melting

Basalt

Rhyolite

Andesite

Basalt

CLIP crust

SiO wt 2

K55(t3)

K55(t2)

K55(t1)

K55(t3)

K55(t2)

K55(t1)

fractio

nation

mix ing

crustal melt

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

PII 35-16 Ma

PIII 16-6 Ma

PIV 6-3 Ma

PVI 26-0 Ma

PI 75-39 Ma

OIB (97)

IBMVAB

OIB (222)

OIB BCC

OPB (grey lined)

IBM (19)

MORBIBMVABc

PVb micro = 10255

PVa micro = 28655

PVb micro = 6855

Region

CR NIC

IBMVAB (771)

70 60 50 40 30 20 10 0

51 Pb isotopes

IBMVAB

b 55 g

IBMVAB

300350

IBMVAB

NIC PIV micro = 702

OPB (grey line)

IBMVAB10

Time (Ma)70 60 50 40 30 20 10 0

IBMVAB

MORB BCC

IBMVAB

OPB (grey lined)

MORBamp OIB

IBMVAB

IBMVABMORB

09CR micro = 111

Region

CR NIC

Region

Va VbPhase

PVI26-0 Ma

CR NIC

SW NIC

NE CR central CR

NW NIC

Miocene Nicaragua

Miocene Costa Rica

PII-PIV35-3 Ma

Region

II III IVPhase

19-6 Ma

75-39 M

NIC Miocene

CR 35-16 Ma

CR 16-6 Ma

CR 6-3 Ma

CR NIC

subducting

SP (NGD)

subducting CCR (C

CocosNazca Plate

PI 75-39 Ma

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

206 204Pb Pb

Region

200 185

CR NW NIC NW SW

Region Phase VI

central

eastern

PAN SAA CBA

Region Phase I

central

CR NIC

051280

051285

051290

051295

051300

051305

051310

051275

051280

051285

051290

051295

051300

051305

051310

051315

subductin g

Seamount Province

Region

Va VbPhase

051275

PVI26-0 Ma

d051275

051280

051285

051290

051295

051300

051305

051310

PII- PIV35-3 Ma

CCR (CGD)

CocosNazca Plate

107142 86

H26-6 Ma CRVF

CR PANDM

CR 75-66 Ma

CR 6-3 MaCR 35-6 Ma

SP see (c)

344 217 201324

Region

II III IVPhase

206 204Pb Pb

051275

051280

051285

051290

051295

051300

051305

051310

aGP at 90 Ma

GP at 60 Ma

499-448

Region

PI 75-39 Ma

543400

170 200

Region Phase VI

central

PAN SAA CBA

Region Phase I

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

051280

051285

051290

051295

051300

051305

051310

051315

051275

Time (Ma)7090 80100 60 50 40 30 20 10 0

PIIIPIV

PVIPICLIP

age of accreted

central CR

SW NICNW

NICeastern

OIB in western CR

Burica(N = 5)

PAN SAA CBA

CR GA NIC eastern

central NW NW SW

52 Nd isotopes

6 Discussion

50 700

Mantle melting

Basalt

Rhyolite

Andesite

Basalt

CLIP crust

SiO wt 2

K55(t3)

K55(t2)

K55(t1)

K55(t3)

K55(t2)

K55(t1)

fractio

nation

mix ing

crustal melt

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

OIB (97)

IBMVAB

OIB (222)

OIB BCC

OPB (grey lined)

IBM (19)

MORBIBMVABc

PVb micro = 10255

PVa micro = 28655

PVb micro = 6855

Region

CR NIC

IBMVAB (771)

70 60 50 40 30 20 10 0

51 Pb isotopes

IBMVAB

b 55 g

IBMVAB

300350

IBMVAB

NIC PIV micro = 702

OPB (grey line)

IBMVAB10

Time (Ma)70 60 50 40 30 20 10 0

IBMVAB

MORB BCC

IBMVAB

OPB (grey lined)

MORBamp OIB

IBMVAB

IBMVABMORB

09CR micro = 111

Region

CR NIC

Region

Va VbPhase

PVI26-0 Ma

CR NIC

SW NIC

NE CR central CR

NW NIC

Miocene Nicaragua

Miocene Costa Rica

PII-PIV35-3 Ma

Region

II III IVPhase

19-6 Ma

75-39 M

NIC Miocene

CR 35-16 Ma

CR 16-6 Ma

CR 6-3 Ma

CR NIC

subducting

SP (NGD)

subducting CCR (C

CocosNazca Plate

PI 75-39 Ma

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

206 204Pb Pb

Region

200 185

CR NW NIC NW SW

Region Phase VI

central

eastern

PAN SAA CBA

Region Phase I

central

CR NIC

051280

051285

051290

051295

051300

051305

051310

051275

051280

051285

051290

051295

051300

051305

051310

051315

subductin g

Seamount Province

Region

Va VbPhase

051275

PVI26-0 Ma

d051275

051280

051285

051290

051295

051300

051305

051310

PII- PIV35-3 Ma

CCR (CGD)

CocosNazca Plate

107142 86

H26-6 Ma CRVF

CR PANDM

CR 75-66 Ma

CR 6-3 MaCR 35-6 Ma

SP see (c)

344 217 201324

Region

II III IVPhase

206 204Pb Pb

051275

051280

051285

051290

051295

051300

051305

051310

aGP at 90 Ma

GP at 60 Ma

499-448

Region

PI 75-39 Ma

543400

170 200

Region Phase VI

central

PAN SAA CBA

Region Phase I

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

051280

051285

051290

051295

051300

051305

051310

051315

051275

Time (Ma)7090 80100 60 50 40 30 20 10 0

PIIIPIV

PVIPICLIP

age of accreted

central CR

SW NICNW

NICeastern

OIB in western CR

Burica(N = 5)

PAN SAA CBA

CR GA NIC eastern

central NW NW SW

52 Nd isotopes

6 Discussion

50 700

Mantle melting

Basalt

Rhyolite

Andesite

Basalt

CLIP crust

SiO wt 2

K55(t3)

K55(t2)

K55(t1)

K55(t3)

K55(t2)

K55(t1)

fractio

nation

mix ing

crustal melt

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

51 Pb isotopes

IBMVAB

b 55 g

IBMVAB

300350

IBMVAB

NIC PIV micro = 702

OPB (grey line)

IBMVAB10

Time (Ma)70 60 50 40 30 20 10 0

IBMVAB

MORB BCC

IBMVAB

OPB (grey lined)

MORBamp OIB

IBMVAB

IBMVABMORB

09CR micro = 111

Region

CR NIC

Region

Va VbPhase

PVI26-0 Ma

CR NIC

SW NIC

NE CR central CR

NW NIC

Miocene Nicaragua

Miocene Costa Rica

PII-PIV35-3 Ma

Region

II III IVPhase

19-6 Ma

75-39 M

NIC Miocene

CR 35-16 Ma

CR 16-6 Ma

CR 6-3 Ma

CR NIC

subducting

SP (NGD)

subducting CCR (C

CocosNazca Plate

PI 75-39 Ma

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

206 204Pb Pb

Region

200 185

CR NW NIC NW SW

Region Phase VI

central

eastern

PAN SAA CBA

Region Phase I

central

CR NIC

051280

051285

051290

051295

051300

051305

051310

051275

051280

051285

051290

051295

051300

051305

051310

051315

subductin g

Seamount Province

Region

Va VbPhase

051275

PVI26-0 Ma

d051275

051280

051285

051290

051295

051300

051305

051310

PII- PIV35-3 Ma

CCR (CGD)

CocosNazca Plate

107142 86

H26-6 Ma CRVF

CR PANDM

CR 75-66 Ma

CR 6-3 MaCR 35-6 Ma

SP see (c)

344 217 201324

Region

II III IVPhase

206 204Pb Pb

051275

051280

051285

051290

051295

051300

051305

051310

aGP at 90 Ma

GP at 60 Ma

499-448

Region

PI 75-39 Ma

543400

170 200

Region Phase VI

central

PAN SAA CBA

Region Phase I

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

051280

051285

051290

051295

051300

051305

051310

051315

051275

Time (Ma)7090 80100 60 50 40 30 20 10 0

PIIIPIV

PVIPICLIP

age of accreted

central CR

SW NICNW

NICeastern

OIB in western CR

Burica(N = 5)

PAN SAA CBA

CR GA NIC eastern

central NW NW SW

52 Nd isotopes

6 Discussion

50 700

Mantle melting

Basalt

Rhyolite

Andesite

Basalt

CLIP crust

SiO wt 2

K55(t3)

K55(t2)

K55(t1)

K55(t3)

K55(t2)

K55(t1)

fractio

nation

mix ing

crustal melt

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

Region

Va VbPhase

PVI26-0 Ma

CR NIC

SW NIC

NE CR central CR

NW NIC

Miocene Nicaragua

Miocene Costa Rica

PII-PIV35-3 Ma

Region

II III IVPhase

19-6 Ma

75-39 M

NIC Miocene

CR 35-16 Ma

CR 16-6 Ma

CR 6-3 Ma

CR NIC

subducting

SP (NGD)

subducting CCR (C

CocosNazca Plate

PI 75-39 Ma

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

206 204Pb Pb

Region

200 185

CR NW NIC NW SW

Region Phase VI

central

eastern

PAN SAA CBA

Region Phase I

central

CR NIC

051280

051285

051290

051295

051300

051305

051310

051275

051280

051285

051290

051295

051300

051305

051310

051315

subductin g

Seamount Province

Region

Va VbPhase

051275

PVI26-0 Ma

d051275

051280

051285

051290

051295

051300

051305

051310

PII- PIV35-3 Ma

CCR (CGD)

CocosNazca Plate

107142 86

H26-6 Ma CRVF

CR PANDM

CR 75-66 Ma

CR 6-3 MaCR 35-6 Ma

SP see (c)

344 217 201324

Region

II III IVPhase

206 204Pb Pb

051275

051280

051285

051290

051295

051300

051305

051310

aGP at 90 Ma

GP at 60 Ma

499-448

Region

PI 75-39 Ma

543400

170 200

Region Phase VI

central

PAN SAA CBA

Region Phase I

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

051280

051285

051290

051295

051300

051305

051310

051315

051275

Time (Ma)7090 80100 60 50 40 30 20 10 0

PIIIPIV

PVIPICLIP

age of accreted

central CR

SW NICNW

NICeastern

OIB in western CR

Burica(N = 5)

PAN SAA CBA

CR GA NIC eastern

central NW NW SW

52 Nd isotopes

6 Discussion

50 700

Mantle melting

Basalt

Rhyolite

Andesite

Basalt

CLIP crust

SiO wt 2

K55(t3)

K55(t2)

K55(t1)

K55(t3)

K55(t2)

K55(t1)

fractio

nation

mix ing

crustal melt

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

central

CR NIC

051280

051285

051290

051295

051300

051305

051310

051275

051280

051285

051290

051295

051300

051305

051310

051315

subductin g

Seamount Province

Region

Va VbPhase

051275

PVI26-0 Ma

d051275

051280

051285

051290

051295

051300

051305

051310

PII- PIV35-3 Ma

CCR (CGD)

CocosNazca Plate

107142 86

H26-6 Ma CRVF

CR PANDM

CR 75-66 Ma

CR 6-3 MaCR 35-6 Ma

SP see (c)

344 217 201324

Region

II III IVPhase

206 204Pb Pb

051275

051280

051285

051290

051295

051300

051305

051310

aGP at 90 Ma

GP at 60 Ma

499-448

Region

PI 75-39 Ma

543400

170 200

Region Phase VI

central

PAN SAA CBA

Region Phase I

184 186 188 190 192 194 196 198

206 204Pb Pb

184 186 188 190 192 194 196 198

051280

051285

051290

051295

051300

051305

051310

051315

051275

Time (Ma)7090 80100 60 50 40 30 20 10 0

PIIIPIV

PVIPICLIP

age of accreted

central CR

SW NICNW

NICeastern

OIB in western CR

Burica(N = 5)

PAN SAA CBA

CR GA NIC eastern

central NW NW SW

52 Nd isotopes

6 Discussion

50 700

Mantle melting

Basalt

Rhyolite

Andesite

Basalt

CLIP crust

SiO wt 2

K55(t3)

K55(t2)

K55(t1)

K55(t3)

K55(t2)

K55(t1)

fractio

nation

mix ing

crustal melt

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

051280

051285

051290

051295

051300

051305

051310

051315

051275

Time (Ma)7090 80100 60 50 40 30 20 10 0

PIIIPIV

PVIPICLIP

age of accreted

central CR

SW NICNW

NICeastern

OIB in western CR

Burica(N = 5)

PAN SAA CBA

CR GA NIC eastern

central NW NW SW

52 Nd isotopes

6 Discussion

50 700

Mantle melting

Basalt

Rhyolite

Andesite

Basalt

CLIP crust

SiO wt 2

K55(t3)

K55(t2)

K55(t1)

K55(t3)

K55(t2)

K55(t1)

fractio

nation

mix ing

crustal melt

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

52 Nd isotopes

6 Discussion

50 700

Mantle melting

Basalt

Rhyolite

Andesite

Basalt

CLIP crust

SiO wt 2

K55(t3)

K55(t2)

K55(t1)

K55(t3)

K55(t2)

K55(t1)

fractio

nation

mix ing

crustal melt

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

52 Nd isotopes

6 Discussion

50 700

Mantle melting

Basalt

Rhyolite

Andesite

Basalt

CLIP crust

SiO wt 2

K55(t3)

K55(t2)

K55(t1)

K55(t3)

K55(t2)

K55(t1)

fractio

nation

mix ing

crustal melt

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

50 700

Mantle melting

Basalt

Rhyolite

Andesite

Basalt

CLIP crust

SiO wt 2

K55(t3)

K55(t2)

K55(t1)

K55(t3)

K55(t2)

K55(t1)

fractio

nation

mix ing

crustal melt

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

7 Conclusions

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

Cocos Plate

Farallon Plate

Seamount Province

alkalic basalts

slab tear

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

Acknowledgements

Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

Abstract

1 Introduction




4 Results







51 Pb isotopes

52 Nd isotopes

6 Discussion




622 Nd isotopes










7 Conclusions

Acknowledgements


Funding

References

Documents

Arc magmatic evolution and the construction of continental ...rjstern/pdfs/WhattamStern.IGR.15.pdfcontinental crust formation and arc–continent collision and the subsequent accretion