Provenance and tectonic setting of the external nappe of the Southern Brasília Orogen

lable at ScienceDirect

Journal of South American Earth Sciences 48 (2013) 220e239

Contents lists avai

Journal of South American Earth Sciences

journal homepage: www.elsevier .com/locate/ jsames

Provenance and tectonic setting of the external nappe of the SouthernBrasília Orogen

Alice Westin*, Mario da Costa Campos NetoInstituto de Geociências, Universidade de São Paulo, Brazil

a r t i c l e i n f o

Article history:Received 20 December 2012Accepted 17 August 2013

Keywords:GeochemistryUePb LA-MC-ICP-MSLueHf LA-MC-ICP-MSNdeSr isotopesMetasediment provenanceDepositional environment

* Corresponding author.E-mail addresses: [email protected], liwestin@y

0895-9811/$ e see front matter � 2013 Elsevier Ltd.http://dx.doi.org/10.1016/j.jsames.2013.08.006

a b s t r a c t

The Brasília Orogen, located on the western and southern margins of the São Francisco Craton, corre-sponds to a horizontal nappe stack that was regionally transported eastward during the collision be-tween the Paranapanema and Central Goiás blocks and the Sanfranciscana Plate in the Ediacaran Period.

The front of the Southern Brasília Orogen, the object of this study, is represented by metapsammitesand metapelites of the Carrancas Group, with an exotic unit of metawackes which lies tectonically on topof it.

The metawackes underwent moderate chemical weathering, and the rare-earth element behaviorsuggests the presence, in the source area, of igneous rocks with crustal signature. The age distribution ofthe detrital zircon crystals is almost unimodal with dominant Neoproterozoic population and subordi-nate Paleoproterozoic ages. The most likely source area is a mature magmatic arc in the active conti-nental margin of the Paranapanema Block, and the deposition occurred between 620 and 590 Ma. Thecorrelation between these external metawackes with those occurring in the internal nappes (SantoAntônio Schist of the Andrelândia Nappe) assumes that this unit corresponds to the front of theAndrelândia Nappe. However, a syn-collisional orogenic foreland basin, installed at the edge of theSanfranciscana Plate, must be considered.

The metapelites of the Carrancas Group (Campestre Formation) have a chemical signature of sedi-mentary recycling and deposition in a tectonically stable area. Detrital zircon crystals exhibit juvenileprovenance in the Mesoproterozoic Era and mixed provenance in the Paleoproterozoic Era. The prove-nance ages correlate with the Canastra Group of the Brasília Orogen in the western craton margin but arenot similar to those of the cratonic units. The likely age for the deposition of the Campestre Formation ofthe Carrancas Group is in the TonianeCryogenian Period, in the southwestern edge of the SanfranciscanaPlate.

� 2013 Elsevier Ltd. All rights reserved.

1. Introduction

The Brasília Orogen (Fuck et al., 1993; Dardenne, 2000), locatedon the west and south margins of the São Francisco Craton (Fig. 1),is part of an orogenic system involving the Central Goiás and Par-anapanema blocks. The blocks are interpreted as independentmicroplates with their own magmatic and metamorphic histories,which were accreted to the passive continental margin of theSanfranciscana Plate during the Ediacaran collision (Brito Neveset al., 1999; Campos Neto, 2000; Fuck et al., 2008).

The Central Goiás Block is made of orthogneisses and Archeangreenstone belts, which have been orogenically reworked in the

ahoo.com.br (A. Westin).

All rights reserved.

Rhyacian (Jost et al., 1996; Queiroz et al., 1999). The eastern marginof this block consists of metavolcanosedimentary belts from theMesoproterozoic Ectasian and Tonian MaficeUltramafic complexes(Danni et al., 1982; Ferreira-Filho et al., 1994; Moraes and Fuck,2000; Moraes et al., 2006; Correia et al., 2012). Magmatic arcmetavolcanics and calc-alkaline granitoids (Mara Rosa Arc) withjuvenile isotopic signatures were accreted on the eastern edge ofthe Central Goiás Block during the TonianeCryogenian transition(Pimentel and Fuck, 1992; Pimentel et al., 1997, 2000).

The Paranapanema Block (Mantovani and Brito Neves, 2005),which is extensively covered by Phanerozoic sedimentary rocks ofthe Paraná Basin, has a Rhyacian and Statherian continental base-ment and a geophysical signature of thin continental crust andcratonic lithospheric keel (Cordani et al., 1984; Mantovani et al.,2001; Assumpção et al., 2006). Carbonate and terrigenous unitsform a passive continental margin of Mesoproterozoic Ectasian age

Delta:1_given name

Delta:1_surname

mailto:[email protected]

mailto:[email protected]

http://crossmark.crossref.org/dialog/?doi=10.1016/j.jsames.2013.08.006&domain=pdf

www.sciencedirect.com/science/journal/08959811

http://www.elsevier.com/locate/jsames

http://dx.doi.org/10.1016/j.jsames.2013.08.006



PARANAPANEMA AND CENTRAL GOIÁS EXOTIC BLOCKS

MANTIQUEIRA SYSTEM OF OROGENS - ACCREATED TERRANES

Ediacaran cratonic cover

Cryogenian-Ediacaran rift and passive continental margin sequences

Staterian to Tonian sequence of rifts

Archaen-Paleoproterozoic

A - Araçuaí Orogen B - Brasília Orogen

Ediacaran passive continental margin sequencesP - Paraguay fold-and-thrust belt Ar - Araguaia OrogenMesoproterozoic cratonic covers

Stenian Belts: S - Sunsás, A - Aguapeí, NB - Nova Brasilandia

Ectasian Paragua Terrane and (+) anorogenic granites

Ectasian-Calymmian juvenile arc accretionCalymmian-Staterian: RN-J - Rio Negro-Juruena geochronological provinceStaterian-Orosirian: RA - Rio Apa BlockOrosirian: V-T - Ventuari-Tapajós geochronological province

Archaen : Ca - Carajás geochronological province

Cryogenian-Ediacaran allochthonous accrecionary prism and flysch sequences

Cryogenian-Ediacaran magmatic arcs: MR - Mara Rosa ArcNeoproterozoic metasediments, Cryogenian mafic-ultramafic plutonic commplexand Ectasian rift-related metavolcanosedimentary sequencesArchaen-Paleoproterozoic

Ediacaran foreland basin

Cryogenian-Ediacaran magmatic arcsAccreated terranes: CF - Cabo Frio Orogen, Oc - Ocidental Terrane, Or - Oriental Terrane, E - Embu Terrane, C - Curitiba Terrane, DF - Dom Feliciano OrogenPaleoproterozoic LA - Luis Alves craton

SÃO FRANCISCO PLATE

AMAZONAS PLATE

64º 62º 60º 58º 56º 54º 52º 50º 48º 46º 44º 42º10º

12º

14º

16º

18º

20º

22º

24º

26º

28º

10º

12º

14º

16º

18º

20º

22º

24º

26º

28º64º 62º 60º 58º 56º 54º 52º 50º

48º 46º 44º

Sunsás

overp

rint

E

C

CF

Or

Oc

DF

LA

++ +

+++

+

+

RN-J

V-TCa

RA

NB

A

STucavaca A

ulacogen

Su

ban

dean

B

elt

PARANAPANEM

A B

LO

CK

CE

NTR

AL G

OIÁ

S B

LO

CK

SÃO FRANCISCO

CRATON

AMAZONAS CRATON

PAMPIA BLOCK

AB

Ar

P

Atlantic Ocean

MR

42º

Fig. 1. Tectonic Provenance Map of the Rodinia Blocks and Western Gondwana Orogens Modified from CGMW (2001) Geologic Map of South America, scale 1:5000; Campos Neto(2000), Ramos et al. (2010), Bettencourt et al. (2010).

A. Westin, M.daC. Campos Neto / Journal of South American Earth Sciences 48 (2013) 220e239 221

along the eastern margin of the Paranapanema Block (Pires, 1991;Campanha and Sadowski, 1999; Siga et al., 2011). The establish-ment of an active continental margin along the entire northern andeastern edge of this continental block occurred during the Neo-proterozoic (Campos Neto and Caby, 2000; Campos Neto, 2000;Pimentel et al., 2000; Laux et al., 2005).

The closure of the oceanic basin resulting in the collision be-tween the Sanfranciscana Plate and the Paranapanema and CentralGoiás Blocks, which was responsible for the development of theBrasília orogenic belt, occurred in the Ediacaran Period (Brito Neves

et al., 1999; Campos Neto, 2000; Trouw et al., 2000). The differentorogen segments form horizontal nappe stacks, which grade toextensive reverse faulting along the craton margin. The assemblywas regionally transported eastward (Fig. 1).

The front of the Brasília Orogen, located on the southern marginof the São Francisco Craton (Fig. 2) is the subject of this study, whichseeks to determine the provenance of metasedimentary rocks andconsequently, establish their depositional environment and tec-tonic context (Taylor and McLennan, 1985; McLennan and Taylor,1991). These objectives are achieved through studies of the

47º 46º 45º 44º

21º

22º

23º

Granites Bambuí Group (carbonate platform) Socorro-Guaxupé Nappe

Ediacaran-Cambrian remnants of post-orogenic basin

0 25 50 km

Ediacaran

RhyacianAndrelândia Nappe SystemCarrancas Nappe System

Andrelândia Nappe and Carmo da Cachoeira nappe Liberdade NappeGranulite Nappe

Lima Duarte NappeIndiscriminate thrust sheet

Alagoa Migmatite

Rio Preto Migmatite

Orthogneiss and migmatites

Archean-PaleoproterozoicMantiqueira GneissAmparo Complex

Cryogenian-Ediacaran

Late and Post-Orogenic GranitesSynorogenic GranitesMetatexite ComplexDiatexite ComplexGranulite Complex

Paleoproterozoic-MesoproterozoicSão Roque and Serra do Itaberaba Groups

Mantiqueir

a O

rogenic

Syste

m (R

ibeir

a B

elt)

Cenozoic Basin

Cenozoic Basin

nisaBánar aP

ci ozor enaSouthern São Francisco Craton

Bambuí Group (carbonate platform) Socorro-Guaxupé Nappe

Ediacaran-Cambrian remnants of post-orogenic basin

0 25 50 km

Rhyacianppe SystemNappe System

Cryogenian-Ediacaran

Late and Post-Orogenic GranitesSynorogenic Granites

Mantiqueir

a O

rogenic

Syste

m (R

ibeir

a B

elt)

Cenozoic Basin

Cenozoic Basinnic Basin

nisaBánar aP

ci ozor ena

Shear zone

Fig. 2. Geological Map of Southern Brasília Orogen (Campos Neto et al., 2010). Tpvn: Três Pontas-Varginha Nappe; pan: Pouso Alto Nappe; ak: Aiuruoca Klippe; ck: Carvalhos Klippe;snk: Serra da Natureza Klippe.

A. Westin, M.daC. Campos Neto / Journal of South American Earth Sciences 48 (2013) 220e239222

elemental and isotopic whole rock geochemistry (REE, SmeNd andRbeSr), with UePb and LueHf analysis using laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) in detrital zircon crystals.

2. Geological context

The different tectonic environments comprising the collisionalnappe stack of the Southern Brasília Orogen (Fig. 2) are describedbelow.

Metamorphic units representing the magmatic arc root envi-ronment, installed in the northern edge of the Paranapanema Plate,constitute the framework of the Socorro-Guaxupé Nappe. Thisnappe is represented by a thick slice (w15 km) of granuliteegraniteemigmatitic lower crust. The metamorphicemagmaticevolution of this terrain, prior the collision, lasted for approxi-mately 45 m.y. The earliest records dated at ca. 670 Ma are indirect,based on the provenance of detrital zircon and the isotopicbehavior of Nd and Sr from tectonic units underneath the nappe(Janasi, 2002; Campos Neto et al., 2008). Expanded calc-alkalinegranitoid suites, which are related to the mature magmatism ofthe arc, occurred between 650 and 620Ma (Ebert et al., 1996; Janasi

et al., 1997; Janasi, 1997). Large volumes of diatexite andmetatexite,which are metaluminous and peraluminous rocks, modified thisorogenic sliver. These rocks display evidence of igneous flow par-allel to the foliation and mineral lineation and evidence of mineralstretching related to the nappe system and record ages between625 and 610 Ma (Janasi, 1999; Campos Neto and Caby, 2000; Vlachand Gualda, 2000; Negri, 2002; Martins et al., 2009). Starting at610 Ma, the emplacement of syenitic, peralkaline, and post-kinematic plutons (Janasi et al., 1993; Topfner, 1996; Janasi andVlach, 1997; Janasi, 1999) mark the thinning stage of the arc lith-osphere and the onset of diachronic relaxation of the process ofductile migration of the nappe. The peak of lithospheric thinningtook place at 590e580 Ma, with the emplacement of subalkaline Atype granitic suite of the Itú Granite Province (Janasi et al., 2009).

The Andrelândia Nappes System (Trouw et al., 1982, 1983, 2000;Campos Neto and Caby, 1999; Campos Neto, 2000; Campos Netoet al., 2007), located structurally under the Socorro-GuaxupéNappe, consists of high-pressure metasediments in a tectonicallyinverted metamorphic stack metamorphosed under loweramphibolite facies conditions (staurolite and garnet) in the lowernappe (Andrelândia) to the granulite facies (rutileekyaniteegarnet-K feldspar) in the upper nappe (Três Pontas-Varginha, Pouso

Fig. 3. Geological Map of Carrancas, MG. Modified from Quéméneur et al. (2002) and Trouw et al. (2002).



Alto and correlated klippen). Blocks of retro-eclogites occur amidmetapelites in the intermediate nappe (Liberdade) (Trouw et al.,1998; Campos Neto and Caby, 1999; Santos et al., 2004). Rhyacianorthogneisses, comprising a tonaliteegranodiorite suite with ju-venile Nd isotopic signature, constitute the infrastructure of thisnappe system, which more internally contains the Meso-Archeanpolymetamorphic orthogneisses (Campos Neto et al., 2008). Thisallochthonous terrain is interpreted as a forearc domain, with asubducted accretionary prism and a forearc basin dominated bywackes originated from the rapid erosion of a proximal calc-alkaline and juvenile volcanic source area (Campos Neto et al.,2011). The collisional nappe system experienced a diachronicevolution and records a continuous orogen migration towardexternal domains. The propagation of structure andmetamorphismwas progressive and successively younger, from the upper nappe tothe lower nappe, in an interval of 25 m.y., between 620 and 595 Ma(Campos Neto et al., 2011).

The systems of external nappes, Carrancas and Lima Duarte, arefound under the Andrelândia Nappe and were transported towardthe reworked cratonic margin. The ages of structures and meta-morphism are younger (590e575 Ma), reflecting the continuousprocess of orogen migration (Campos Neto et al., 2011). The LimaDuarte Nappe consists of a thick (w250 m) metapsammitic level ona base of calcic metapelites and calc-silicate rocks, both covered bya thick metamorphic stack (w500 m) of metapelites. An ArcheanePaleoproterozoic orthogneiss complex is also involved in thestructure (Mantiqueira Gneiss). The Lima Duarte Nappe meta-morphism is of upper amphibolite facies/granulite facies, associ-ated with intense anatexis (Campos Neto et al., 2004). TheCarrancas Nappes (Trouw et al., 2000) consist of a psammitic basalstack and an upper peliteepsammitic sequence, detached in part onan immature metapsammitic sequence (Ribeiro and Heilbron,1982; Trouw et al., 1983). The units of the Carrancas Nappe Sys-tem and Lima Duarte Nappe are interpreted as paleogeographicdomains of the passive continental margin of the SanfranciscanaPlate (Paciullo et al., 2000; Trouw et al., 2000).

3. Geology of the Carrancas region

The Carrancas Group (Trouw et al., 1980) comprises a basalquartzite unit (São Tomé das Letras Formation) and an upper unit of

±

Fig. 4. Geological section through Carran

graphitic mica schists with frequent lenses of quartzite (CampestreFormation). Both units maintain a consistent distributionthroughout the nappe system (Trouw et al., 2000).

In the vicinities of Carrancas, Minas Gerais (Fig. 3), the CarrancasGroup comprises 4 lithostratigraphic units, in a 1600 m thickmetamorphic package. It is truncated by an exotic, tectonicallyhigher unit of metawackes, with a minimum thickness of 800 m.

The base of the Carrancas Group is made of platy quartzites withmuscovite interbedded with muscovite schist and muscovitequartz schist. Over this unit is a thick package of pelitic graphiteemuscovite schist, associated with frequent quartzite lenses, espe-cially at the base. The quartzites reappear at the top and arecontinuous and lithologically similar to the basal quartzites. East ofthe Serra do Pombeiro, this basal level interbeds in the quartzite/quartz muscovite schist, locally associated with thin layers ofquartzite. This metapelitic level is detached over olderorthogneisses.

The metawacke, which is tectonically above the units describedpreviously, consists of a homogeneous package of massive biotiteechloriteemuscovite quartz schist with garnet and plagioclase, withsubcentimetric quartz lenses.

The entire lithostratigraphic stack was submitted non-uniformly to intense non-coaxial deformation. Snowball garnets,mineral fish, and mica fish microstructures (Trouw et al., 2008,2010), C/S foliation sigmoids, and d- and s-type mantled porphyr-oclasts with asymmetric tails are frequent. These structures, asso-ciated with the mineral lineation and mineral stretching mostlyindicate eastward direction of transport (Trouw et al., 1983) of boththe Luminárias Nappe (higher) and the Carrancas Nappe (lower)(Fig. 3). The metasedimentary units are detached from an orthog-neissemigmatitic infrastructure and from a terrigenous andimmature metasedimentary sequence, consisting of biotite schistsand gneisses with centimetric quartzite bands and plates, as well ascalc-silicate gneisses. Maficeultramafic rocks are frequent in theorthogneisses but are rare in the terrigenous metasedimentarysequence. These rocks are intensely hydrated and retro-metamorphosed and are recognized in the infrastructure of theLuminárias and Carrancas nappes.

Themetamorphic foliation in themetasedimentary stack resultsfrom deformation and progressive metamorphism, with a thermalpost-kinematic peak confirmed by muscovite and chloritoid

cas Nappe. Section located on Fig. 3.

Table

1Major

andminor

elem

ents

wholerock

analytical

dataob

tained

byX-R

ayFluorescence

Spectrom

etry

andva

lues

ofChem

ical

Index

Alteration(CIA)from

theMW

unit,C

ampestreFo

rmationan

dSa

nto

Antônio

Schistsamples.

Values

oftheox

ides

inwt.%CIA

¼[A

l 2O3/(Al 2O3þ

CaO

þNa 2O

þK2O)]

�10

0,withox

ides

inmolecularproportion

.

Geo

logicalUnit

Sample

SiO2

TiO2

Al 2O3

Fe2O3

MnO

MgO

CaO

Na 2O

K2O

P 2O5

CIA

MW

unit

C-325

c67

.91

0.87

14.63

5.65

0.10

2.32

1.19

2.47

2.90

0.19

60.97

C-333

64.30

0.85

15.71

6.54

0.13

2.75

1.14

2.56

3.33

0.20

61.37

C-337

65.81

0.85

14.97

6.36

0.11

2.72

1.34

2.49

3.09

0.18

60.25

C-340

61.32

0.91

17.29

7.10

0.11

3.03

0.83

2.57

3.76

0.17

63.82

C-341

65.63

0.92

15.12

6.22

0.13

2.63

1.49

2.81

2.92

0.21

59.03

CM-III-25

62.60

0.80

16.61

7.17

0.10

3.02

0.42

1.88

3.88

0.12

67.34

C-410

68.09

0.86

14.14

6.04

0.09

2.51

0.64

2.78

2.69

0.18

62.05

C-411

58.25

0.92

19.69

7.92

0.10

3.45

0.22

1.79

4.61

0.14

70.26

C-430

61.31

0.93

17.70

7.55

0.13

3.48

0.87

2.33

4.00

0.16

64.49

C-431

60.19

0.93

17.81

7.73

0.13

3.26

0.80

2.07

4.69

0.16

64.19

CAR-I-51

62.83

1.03

16.46

6.68

0.17

2.76

1.90

2.92

3.20

0.22

58.41

Cam

pestre

Form

ation

This

pap

erCAR-I-32

50.85

1.02

26.99

12.46

0.16

1.84

0.36

0.36

2.02

0.33

88.72

CAR-II-76

62.83

1.03

16.46

6.68

0.17

2.76

1.90

2.92

3.20

0.22

82.75

Silva

(201

0)SC

-07

58.17

1.00

22.77

6.86

0.11

1.37

0.04

0.99

4.07

0.09

78.85

SC-08

54.65

1.06

27.71

6.11

0.07

0.84

0.14

1.63

3.31

0.09

80.96

SC-30B

42.93

1.23

33.75

6.19

0.04

0.88

0.14

0.91

8.15

0.15

76.15

SC-30C

43.79

1.14

33.97

4.89

0.05

0.97

0.08

1.03

8.21

0.15

76.00

Santo

Antônio

Schist

Cam

pos

Neto

etal.

(200

7,20

11)

62.05e

70.31

0.47

e1.07

13.83e

16.88

3.60

e7.46

0.06

e0.14

1.20

e4.06

0.71

e4.63

0.65

e4.16

1.92

e4.82

0.03

e0.22

47.85e

68.28


polygonal arcs and by mineral fish. Metamorphism in the northernsegment of the Carrancas Nappe (at Serra do Pombeiro) is in thehigh-pressure greenschist facies, transitional to amphibolite faciesconditions. The predominant mineral assemblages are white micaand chloritoid, predominantly with garnet and kyanite; morerarely, staurolite occurs associated with chloritoid. In the southernsegment of the nappe, the metasediments were metamorphosed inthe lower amphibolite facies and contain white mica, staurolite,kyanite, and garnet. Biotite and sillimanite are late stage phasesthat are related to decompression (Ribeiro and Heilbron, 1982;Trouw et al., 1984; Campos Neto and Caby, 1999; Silva, 2010). Thetectonically higher metawacke package is found throughout itsextension in the greenschist facies, with chlorite, biotite, muscovite,and garnet.

The metamorphic foliation and thrust contacts are continuouslyfolded forming asymmetric antiforms and synforms (normal toinclined) with vergence toward the NW and with hinges weaklyplunging to WeSW (Fig. 4). The largest fold, at Serra de Carrancas-Chapadão das Perdizes, has a wavelength of approximately 20 km.

4. Materials and methods

To obtain the major, minor, and trace element compositions, 13samples were analyzed (Tables Tables 1e3a, and 3b), with 11 ofthese samples from the tectonically higher metawacke unit (MW)and 2 from the graphiteemuscovite schist from the CampestreFormation (CF). Chemical data available in the literature for sam-ples of the Campestre Formation (Silva, 2010) and of metawackesfrom the Andrelândia Nappe (Santo Antônio Schiste SASe CamposNeto et al., 2007, 2011) were used in this study, in addition to otherunpublished REE data of SAS. The samples were prepared bycleaning, comminution in a hydraulic press, quartering, andgrinding in a planetary-type agate ball mill in the Sample Treat-ment Laboratory (Laboratório de Tratamento de Amostras e LTA) atthe Geosciences Institute of the University of São Paulo (Instituto deGeociências da Universidade de São Paulo e IGc-USP). The major,minor, and some trace elements were analyzed from fused andpressed pellets at the laboratory of X-Ray Fluorescence Spectrom-etry (Fluorescência de Raio-X e FRX) of the IGc-USP (Philipsautomatic equipment, model PW2400), using the methodologydescribed by Mori et al. (1999). To obtain trace element and REEconcentrations, the samples were analyzed at the Laboratory ofChemistry and ICP-AES/MS of the IGc-USP (quadrupole-typespectrometer, model ELAN 6100DRC, PerkinElmer/Sciex), usingcriteria described in Navarro et al. (2004).

The chemical weathering index was evaluated by the ChemicalIndex of Alteration (CIA) (Nesbbitt and Young, 1982) from themolecular proportions of the Ca, Na, K, and Al oxides: CIA(IAQ) ¼ [Al2O3/(Al2O3 þ CaO* þ Na2O þ K2O)] � 100 (Table 1). Thisindex, in addition to not being influenced by metamorphism,considers that the dominant process during weathering is themineral degradation of the feldspar group, concomitant with theformation of clay minerals by means of aggressive solutions thatremove the elements Ca, Na, and K from the feldspar, which causesthe Al proportion to increase. The ternary plot A (Al2O3) � CN(CaO þ Na2O) � K (K2O) (McLennan et al., 1990) was also used toevaluate the intensity of the chemical weathering and provenance.

The provenance ages from the measurements of the ratios206Pb/238U and 207Pb/235U and the εHf values were obtained indetrital zircon grains by LA-MC-ICP-MS (Finnigan Neptune coupledto an excimer ArF laser e l ¼ 193 nm e ablation system), with 29-mm and 48-mm beams, respectively, at the CPGEO of the IGc-USP(Tables 4a, 4b, and 5). Two samples were investigated, one fromthe MW and one from the CF quartzite. Heavy-mineral concentra-tion was carried out using a Wilfley table. The separation of

Table 3aTrace elements whole rock analytical data from the MW unit samples, obtained with ICP-MS. REE normalized for the chondrite values of Taylor and McLennan (1985).Eu* ¼ [(SmN)(GdN)]1/2.

Unit MW unit

Sample C-325c C-333 C-337 C-340 C-341 CM-III-25 C-410 C-411 C-430 C-431 CAR-I-51

Rb 106.9 120.3 116.7 128.3 103.8 138.5 111.9 177.1 166.5 198.3 127.9Sr 139.1 116.9 100.8 101.3 116.7 64.1 140.0 60.8 115.5 123.7 165.9Y 29.8 22.1 22.3 23.1 21.6 18.9 24.8 34.2 34.0 27.9 34.1Zr 203.5 164.1 178.5 169.7 173.3 148.0 192.3 177.8 181.5 188.4 226.8Nb 15.2 14.4 14.6 15.2 14.9 13.8 17.2 17.7 16.3 17.4 17.8Cs 7.3 8.9 7.8 9.8 7.5 9.8 9.2 11.5 10.9 13.6 7.4Ba 383.0 361.8 340.4 383.6 336.3 340.9 272.2 348.1 430.0 469.0 378.7La 35.6 13.9 16.8 31.4 16.7 29.5 34.8 67.7 47.6 39.3 31.6Ce 78.6 42.9 49.4 76.0 41.7 70.0 62.8 125.0 65.2 71.6 77.6Pr 8.7 4.2 3.9 7.7 4.5 6.9 8.3 13.1 9.9 8.8 8.0Nd 33.8 16.4 15.5 30.0 17.1 27.1 31.3 49.5 37.3 33.2 31.0Sm 6.9 3.3 3.1 6.1 3.4 5.4 6.3 9.2 7.1 6.5 6.5Eu 1.4 0.8 0.8 1.2 0.8 1.0 1.3 1.9 1.4 1.3 1.4Gd 6.1 3.0 3.0 5.1 2.9 4.4 5.4 8.0 6.5 5.6 5.7Tb 1.0 0.6 0.5 0.8 0.6 0.7 0.8 1.2 1.0 0.9 0.9Dy 5.5 3.8 3.6 4.6 3.8 3.8 4.8 6.2 5.7 4.9 5.3Ho 1.2 0.9 0.9 1.0 0.9 0.8 1.0 1.2 1.2 1.0 1.1Er 3.2 2.4 2.5 2.6 2.5 2.1 2.6 3.4 3.2 2.8 3.2Tm 0.5 0.4 0.4 0.4 0.4 0.3 0.4 0.5 0.4 0.4 0.5Yb 3.0 2.5 2.6 2.5 2.8 2.2 2.5 3.2 2.7 2.8 3.2Lu 0.4 0.4 0.4 0.3 0.4 0.3 0.4 0.5 0.4 0.4 0.5Hf 5.9 4.8 5.3 5.1 5.1 4.2 5.2 5.0 5.2 5.4 5.4Pb 19.0 18.8 19.6 19.4 18.8 19.1 18.6 14.9 21.8 24.1 17.9Th 12.5 10.4 11.7 12.7 11.8 12.1 12.6 14.3 14.1 15.2 12.8U 2.9 2.5 2.4 2.9 2.8 2.6 2.3 3.2 2.0 2.3 2.8LaN 97.1 37.9 45.7 85.6 45.6 80.4 94.8 184.4 129.6 107.0 86.2CeN 82.2 44.8 51.6 79.4 43.5 73.1 65.7 130.6 68.2 74.8 81.1PrN 63.3 30.9 28.7 55.9 32.6 50.7 60.3 95.3 72.6 64.5 58.8NdN 47.6 23.0 21.8 42.2 24.1 38.1 44.0 69.7 52.4 46.7 43.6SmN 29.8 14.5 13.4 26.6 14.9 23.6 27.3 39.7 30.7 27.9 28.2EuN 16.4 8.7 8.7 13.8 9.3 12.0 15.1 21.8 16.3 15.1 16.3GdN 19.9 9.7 9.9 16.7 9.4 14.4 17.6 26.1 21.2 18.3 18.6TbN 16.6 9.8 9.4 13.9 9.6 11.6 14.6 19.8 17.2 14.7 15.9DyN 14.5 9.9 9.5 12.1 9.9 9.9 12.6 16.3 15.0 13.0 13.9HoN 14.2 10.3 10.4 12.0 10.5 9.2 11.3 14.5 13.6 11.9 13.3ErN 12.7 9.8 9.9 10.5 10.2 8.6 10.6 13.8 12.7 11.3 12.7TmN 13.4 10.9 11.0 10.9 11.5 9.3 10.8 13.9 12.2 11.7 13.5YbN 12.3 10.3 10.5 10.0 11.2 8.8 10.1 12.9 11.0 11.2 12.8LuN 11.6 9.5 9.9 9.1 10.5 8.0 9.2 12.2 10.3 10.3 12.2EuN/Eu* 451.4 240.2 250.2 398.5 252.7 357.8 404.1 671.1 483.1 438.3 427.0LaN/YbN 319.9 151.1 161.1 289.6 160.7 266.0 292.1 519.7 353.5 320.9 297.8LaN/SmN 103.6 70.8 70.5 86.0 72.2 71.7 87.7 117.4 103.0 92.0 100.7GdN/YbN 0.7 0.7 0.8 0.7 0.8 0.7 0.7 0.7 0.6 0.7 0.7

Table 2Trace elements whole rock analytical data from the MWunit, Campestre Formation and Santo Antônio Schist samples, obtained by X-Ray Fluorescence Spectrometry. Values inppm.

Unit Sample Ba Ce Co Cr Cu Ga La Nb Nd Ni Pb Rb Sc Sr Th U V Y Zn Zr Th/Sc

MW unit C-325c 378.1 62.4 13.1 81.1 36.4 18.5 e 14.8 31.9 36.2 19.5 121.8 e 131.9 14.4 7.1 89.5 34.5 86.7 214.2 e

C-333 404.1 48.8 15.6 88.0 15.8 20.9 e 13.0 24.7 37.4 17.8 142.4 15.2 121.5 9.2 7.2 113.7 32.8 98.4 180.2 0.61C-337 371.4 66.9 18.2 87.1 34.6 19.4 e 14.5 19.4 43.1 20.4 134.5 13.7 106.8 16.2 8.2 103.1 31.2 97.2 191.1 1.18C-340 447.0 78.8 17 97.1 22.9 24.2 e 14.0 39.6 46.5 17.9 154.2 16.0 111.8 10.8 5.6 119.1 33.8 104.7 192.8 0.68C-341 355.2 54.8 14.2 89.5 30.3 20.7 e 17.3 28.7 38.6 17.7 125.9 15.1 128.4 13.0 6.6 110.6 31.8 95.8 190.6 0.86CM-III-25 400.6 e 18.4 89.4 30.7 25.0 e 12.5 32.9 43.5 19.7 161.7 14.6 67.7 12.7 7.3 120.2 29.2 102.0 160.9 0.87C-410 301.6 75.7 17.1 77.4 23.5 17.8 35.1 16.0 39.4 39.9 9.2 124.7 11.1 133.3 13.1 5.5 88.7 32.2 92.2 194.8 1.18C-411 452.9 133.9 20.4 107.5 37.2 28.9 67.0 14.5 61.2 54.1 9.9 184.4 18.3 65.7 13.3 5.1 143.2 38.9 120.0 185.6 0.73C-430 531.8 73.3 21.3 100.4 29.2 24.8 71.5 14.9 36.9 46.9 14.0 157.6 16.8 112.3 12.9 4.4 143.4 46.1 126.1 189.5 0.77C-431 582.5 89.2 22.9 96.0 28.7 24.5 43.5 14.0 42.9 53.0 16.0 192.1 17.0 120.0 14.2 5.1 146.5 38.3 118.0 197 0.84CAR-I-51 416.6 91.6 18.3 101.6 12.2 21.2 50.3 15.7 39.0 42.1 18.3 137.3 16.6 168.0 15.6 4.8 120.5 39.7 101.4 212.5 0.94

CampestreFormation

CAR-I-32 601.7 173.8 21.6 110.8 26.2 35.5 83.8 20.1 60.8 20.2 19.3 82.3 17.6 129.1 21.1 5.3 144.3 34.9 121.5 165.5 1.20CAR-II-76 740.9 96.6 18.2 144.9 14.8 33.3 57.3 13.6 54.4 30.4 24.3 126.6 19.2 166.5 14.6 6.5 151.8 31.5 96.2 180.1 0.76

Santo AntônioSchist

NESG-806e 616.2 62.4 20.2 118.5 56.9 23.3 27.7 13.9 25.9 65.8 26.6 98.1 17.3 165.6 2.7 3.2 148.8 32.8 130.3 199.8 0.16IBA-II-14 516.3 55.3 19.2 136.3 41.5 19.1 29.6 7.7 46.2 60.1 14.5 68.2 17.4 196.5 8.0 3.0 139.0 29.1 96.0 184.3 0.46NESG-833 597.7 49.1 15.9 103.5 41.9 21.4 34.1 8.3 33.5 58.0 14.4 88.5 14.7 165.4 9.7 3.0 135.0 29.1 112.6 189.6 0.66NESG-1065b 517.9 41.0 13.9 115.2 33.6 19.9 15.5 8.8 23.7 55.5 12.4 72.6 14.4 194.4 4.2 3.0 131.8 32.9 104.4 191 0.29NESG-1067 452.5 52.0 17.4 121.5 45.8 18.2 20.7 8.5 31.1 61.8 15.2 71.6 17.4 198.0 8.2 3.0 148.4 29.4 104.1 172.7 0.47NESG-1116a 438.2 39.3 17.5 136.8 34.1 18.5 22.6 9.2 32.2 60.9 16.9 69.8 15.5 191.5 7.3 3.0 147.9 28.2 100.7 195.2 0.47TG-18A 436.1 35.0 16.8 98.2 16.9 19.7 28.0 12.0 27.0 53.5 17.0 91.8 18.3 219.6 9.5 3.0 134.5 34.4 88.5 186.3 0.52


Table 3bTrace elements whole rock analytical data from the Campestre Formation and Santo Antônio Schist samples, obtained with ICP-MS. REE normalized for the chondrite values ofTaylor and McLennan (1985). Eu* ¼ [(SmN)(GdN)]1/2.

Unit Campestre formation Santo Antônio schist

Sample CAR-I-32 CAR-II-76 NESG-806E NESG-833 NESG-1065B NESG-1067 NESG 1116A IBA-II-14 TG-18A

Rb 30.0 61.9 109 86.4 75.6 69.0 70.60 83.80 88.3Sr 94.1 131.3 184 170 203 198 201.45 210.74 218Y 19.6 12.4 38.2 30.4 35.4 29.9 28.60 33.61 37.2Zr 184.5 187.8 236 161 238 129 141.65 193.28 200Nb 23.5 15.4 11.2 10.5 9.15 9.41 10.44 9.04 9.69Cs 1.5 3.0 6.37 4.84 3.97 4.61 3.98 3.97 4.94Ba 299.1 408.4 650 593 481 461 464.11 465.40 424La 70.5 38.0 30.1 27.4 23.8 27.0 26.28 21.04 17.2Ce 160.5 113.3 68.7 59.4 60.6 55.6 57.44 47.77 47.8Pr 13.7 8.3 8.08 6.97 7.11 6.89 6.82 6.26 5.17Nd 49.5 30.1 32.1 27.8 28.8 27.8 27.46 25.63 21.5Sm 8.2 5.2 6.92 5.86 6.27 5.93 5.82 5.66 5.10Eu 1.7 1.1 1.50 1.24 1.31 1.33 1.36 1.33 1.27Gd 5.3 3.4 6.33 5.28 5.97 5.44 5.22 5.47 5.25Tb 0.7 0.4 1.03 0.86 0.94 0.87 0.81 0.88 0.92Dy 3.3 2.1 5.94 4.96 5.52 4.96 4.68 5.20 5.61Ho 0.6 0.4 1.28 1.05 1.22 1.02 1.00 1.14 1.26Er 1.6 1.0 3.51 2.82 3.61 2.69 2.73 3.30 3.65Tm 0.2 0.1 0.53 0.44 0.55 0.41 0.42 0.50 0.56Yb 1.4 0.9 3.40 2.83 3.49 2.63 2.73 3.09 3.50Lu 0.2 0.1 0.52 0.44 0.57 0.40 0.41 0.50 0.57Hf 4.1 4.5 5.97 3.90 5.96 3.12 3.37 4.65 4.95Pb 14.4 20.6 19.1 15.9 14.3 13.4 14.40 14.67 19.8Th 21.8 14.8 8.46 7.79 6.64 6.33 6.73 6.80 7.50U 4.9 3.9 3.00 2.50 2.37 2.00 2.15 2.09 2.25LaN 192.0 103.4 82.1 74.5 64.8 73.6 68.6 55.5 47.0CeN 167.7 118.4 71.8 62.1 63.3 58.1 57.5 50.1 49.9PrN 100.3 60.3 59.0 50.8 51.9 50.3 47.2 45.4 37.7NdN 69.7 42.3 45.2 39.1 40.5 39.1 36.8 35.9 30.2SmN 35.3 22.6 29.9 25.4 27.2 25.7 23.9 24.9 22.1EuN 20.0 12.7 17.2 14.2 15.1 15.3 14.8 15.3 14.6GdN 17.4 11.1 20.7 17.3 19.5 17.8 16.4 18.6 17.2TbN 11.9 7.7 17.8 14.9 16.2 15.1 13.7 16.0 15.9DyN 8.8 5.6 15.6 13.0 14.5 13.0 12.0 14.6 14.7HoN 7.1 4.6 15.1 12.3 14.4 12.0 11.4 14.3 14.8ErN 6.5 4.2 14.1 11.3 14.5 10.8 10.5 14.2 14.7TmN 6.2 4.0 14.9 12.4 15.4 11.6 11.6 14.8 15.7YbN 5.7 3.6 13.7 11.4 14.1 10.6 10.7 13.2 14.1LuN 5.5 3.5 13.6 11.4 14.9 10.4 10.5 14.1 15.0EuN/Eu* 654 404 431 370 386 363 346 347 324LaN/YbN 565 347 288 252 248 247 234 212 187LaN/SmN 64 41 112 93 109 91 86 106 107GdN/YbN 0.8 0.8 0.7 0.7 0.7 0.7 0.7 0.7 0.8


magnetic minerals by a hand magnet and Frantz-type separator,and the separation of minerals with bromoform (CHBr3) andmethylene iodide (CH2I2) were conducted at the LTA of the IGc-USPand in the CPGEO Separation Laboratory of the IGc-USP. These stepswere followed by crystal collection under a magnifying glass andsubsequent mounting using epoxy resin. Cathodoluminescenceimages were obtained from the mounts, using a Quanta 250 FEGelectron microscope equipped with Mono CL3þ cath-odoluminescence spectroscope (Centaurus). Data obtained withdiscordance higher than 10% were discarded. The εHf values wereobtained only for the CF quartzite sample.

The sample from the MW unit displayed preserved zirconcrystals with sizes between 80 and 350 mm and fragments between33 and 120 mm. Crystal shapes may be subdivided into two groups:one formed by prismatic, elongated, bipyramidal, and angularcrystals, with slight local rounding at the crystal edges (Fig. 5a); andthe other consisting of equidimensional crystals, with pyramidalterminations (Fig. 5b). Both types of crystals exhibited internalzoning typical of magmatic growth. The crystals in the first grouphad little or no reworking by sedimentary processes, indicating aproximal igneous source area or explosive volcanic process. Thecrystal fragments found can also be subdivided into fragmented

needles that still preserve subrounded-to-rounded bipyramidalterminations (Fig. 5c) and fragmented crystals with no preservedoriginal morphology (Fig. 5d). The zoning in both subgroups, whenpresent, varies, with no differences between the nucleus and theedge, with concentric zoning nuclei and zoned edges truncating theprevious one, or pyramidal episodic growth internal zoning. Theovergrowth observed in some grains (independent of the group towhich they belong) is less than 5 mm.

The quartzite interbedded in graphiteemuscovite schists fromthe top of the CF displayed crystals ranging from 65 to 200 mm,most with truncated and concentric episodic growth zoning. Sub-rounded and rounded crystals predominate over the prismatic(Fig. 6). Some grains show irregular overgrowths, up to 18 mm ofthickness, without internal zoning. The crystals also show a growthzoning parallel to the C axis.

SreNd isotopic analyses (Tables 6 and 7) were obtained bythermal ionization mass spectrometry (TIMS) at the Geochrono-logical Research Center (Centro de Pesquisas Geocronológicas e

CPGEO) of the IGc-USP, using a VG354 mass spectrometer with aFaraday detector and following the analytical procedures describedby Sato et al. (1995). Sample preparation was performed at the LTAof the IGc-USP, following the same preparation steps described for


major, minor, and trace elements, with 8 samples belonging to theMW unit and 3 to the graphiteemuscovite schist from the CF.

5. Elemental geochemistry

5.1. Major elements

MW unit samples have SiO2 contents between 58 and 68 andlow contents of CaO and Na2O (0.22e1.49 and 1.79e2.92) (Table 1).The proportion of mica minerals in relation to quartz depends onthe concentrations of Al2O3, Fe2O3, K2O, andMgO and indicates thatthe presence of minerals such as muscovite, biotite, and chlorite isconditioned by the chemical composition of the precursor sedi-ments. The presence of plagioclase and carbonate in sample CAR-I-51 evinces the relatively high content of Na2O and CaO in thesample. The concentration of Na2O was also high in sample C-410,which present coarse-grained plagioclase crystals. Another char-acteristic of this unit is the negative correlation between SiO2 vs.Al2O3, Fe2O3, MgO, and K2O and the positive correlation betweenSiO2 vs. Na2O (Fig. 7). Erosion, weathering, transportation, anddeposition processes may have been responsible for this negativecorrelation, as the clay minerals, usually rich in Al, Fe, Mg, and K,tend to concentrate in the silt/clay fraction of the sediment, unlikequartz and feldspar, which tend to concentrate in sandy fractions,resulting in decreased levels of Si and Na in the silt/clay fraction(Taylor and McLennan, 1985).

The negative correlation between SiO2 vs. Al2O3, Fe2O3, MgO,and K2O and the positive correlation between SiO2 vs. Na2Oobserved in the MW unit also occurs for the SAS samples. In theHarker diagrams (Fig. 7), especially in the compositional trends ofAl, Fe3þ, and Mg oxides, a clear geochemical affinity between therocks from both units is observed. The higher concentration of CaOand lower concentration of K2O are reflected in higher concentra-tions of plagioclase and lower amounts of muscovite in the SASrocks, when compared with the MW unit samples. The concen-tration values of Al, Fe, Mg, and K of the SAS samples indicate thatthis unit is more representative of sandy-grained sediments than

Table 4aUePb results by LA-MC-ICP-MS from the MWunit. The shaded lines correspond to the anHe: 0.75 L/m.

MW unit e C-431 sample

Analysis 207Pb/235U Error (2s) 206Pb/238U Error (2s) 207Pb/206Pb Error (2s)

1.1 0.783986 0.032695 0.083980 0.002688 0.064235 0.0018332.1 0.978596 0.040552 0.109935 0.003537 0.062881 0.0017593.1 0.860949 0.037415 0.101402 0.003274 0.059686 0.0018364.1 0.862243 0.032704 0.098050 0.003112 0.064705 0.0014925.1 0.774492 0.028714 0.093162 0.002904 0.059811 0.0013416.1 0.695327 0.029348 0.084365 0.002696 0.059750 0.0017537.1 0.690443 0.026456 0.086320 0.002707 0.058348 0.0014118.1 0.706641 0.027647 0.087059 0.002739 0.058699 0.0014869.1 0.917708 0.031956 0.106555 0.003305 0.062255 0.00116610.1 0.840291 0.033085 0.098670 0.003173 0.061692 0.00153211.1 0.896135 0.033048 0.106674 0.003365 0.061786 0.00133212.1 0.879568 0.031378 0.105176 0.003347 0.060794 0.00115413.1 0.903275 0.05342 0.105811 0.003483 0.062490 0.00313314.1 0.872202 0.081188 0.099158 0.003939 0.064056 0.00543015.1 0.831146 0.075443 0.098662 0.003668 0.060951 0.00508416.1 0.861237 0.040698 0.102516 0.003968 0.061245 0.00177017.1 0.827977 0.034967 0.100782 0.003533 0.060966 0.00156018.1 0.895500 0.04049 0.105612 0.003678 0.061796 0.00188619.1 7.730038 0.375453 0.406125 0.017913 0.139776 0.00316820.1 5.091165 0.202888 0.286698 0.010006 0.129722 0.00281321.1 0.878605 0.034795 0.103778 0.003565 0.061598 0.00136122.1 1.070622 0.060239 0.103228 0.00425 0.074451 0.00295123.1 0.949475 0.081413 0.096910 0.00405 0.069631 0.005260

are the samples from the MW unit. The SAS samples also havehigher values for the ratios Na2O/K2O and Fe2O3/K2O. Higher pro-portions of volcanic lithic fragments could increase the proportionof plagioclase and ferromagnesian minerals in the sediment, whichin turn, would cause the increase of Fe3þ and the decrease of Kþ,which originates from detrital potassium feldspar. The previouslydiscussed different concentrations of CaO and K2O in the SAScorroborate this hypothesis.

The graphiteemuscovite schist of the CF shows a negative cor-relation between SiO2 and Al2O3 and between MgO and CaO, aswell as positive correlations between SiO2, Na2O, and K2O (Fig. 7). Itis noteworthy that the MWunit samples, in addition to exhibiting anegative correlation for K2O, present higher concentrations of SiO2,MgO, CaO, Na2O, and P2O5 and lower concentrations of TiO2, Fe2O3,and Al2O3. These characteristics are evidenced by the higher con-tent of aluminousmineral andminerals rich in Fe in the CF samples,such as chloritoid, staurolite, and garnet. Moreover, the samplesfrom theMWunit present higher proportions of quartz, biotite, andchlorite, with the local presence of plagioclase and apatite as amainaccessory mineral.

5.2. Chemical Index of Alteration (CIA)

The samples from the MW unit presented intermediate-to-highvalues of CIA, namely, between 58 and 70 (Table 1). The valuesobtainedwere higher in rocks rich inmicaceousminerals and lowerin samples with plagioclase as a constituent mineral or with higherproportions of quartz-rich granoblastic portions. The concentra-tions of major elements obtained when plotted on ternary plot A(Al2O3) � CN (CaO þ Na2O) � K (K2O) of the evaluation of weath-ering intensity (McLennan et al., 1990; Fig. 8) suggest a trend ofchemical weathering from initial compositions similar to that ofisland arc andesites. The SAS unit yielded lower CIA values, be-tween 47 and 68 (Table 1); however, in ternary plot AeCNeK(Fig. 8), these rocks follow the same weathering pattern as do therocks from the MWunit. Samples of the graphiteemuscovite schistof the CF yielded higher CIA values than did the previously

alysis used in the final interpretation. Conditions of the analysis: SPL117; 5 mJ; 6 Hz;

rho 206Pb/238Uage (Ma)

Error(Ma)

207Pb/235Uage (Ma)

Error(Ma)

207Pb/206Pbage (Ma)

Error(Ma)

% disc.

0.730118 520 16 588 18 749 60 31.90.738836 672 21 693 21 704 60 4.80.707228 623 19 631 20 592 67 �5.40.795170 603 18 631 18 765 49 22.20.797470 574 17 582 16 597 49 3.90.719958 522 16 536 17 595 64 12.70.776800 534 16 533 16 543 53 1.70.763478 538 16 543 16 556 55 3.30.844361 653 19 661 17 683 40 4.60.777189 607 19 619 18 663 53 9.00.812375 653 20 650 18 667 46 2.10.847915 645 19 641 17 632 41 �2.10.530960 648 20 653 28 691 107 6.50.413240 609 23 637 43 743 179 18.90.394707 607 21 614 41 638 179 5.10.791776 629 23 631 22 648 62 3.00.796387 619 21 612 19 638 55 3.10.738438 647 21 649 21 667 65 3.10.884786 2197 82 2200 43 2224 39 1.40.839788 1625 50 1835 33 2094 38 25.30.830660 637 21 640 19 660 47 3.80.710091 633 25 739 29 1054 80 41.90.473466 596 24 678 42 918 155 36.6

Table 4bUePb results by LA-MC-ICP-MS from the quartzite sample of the Campestre Formation. The shaded lines correspond to the analysis used in the final interpretation. Conditionsof the analysis: SPL117; 5 mJ; 6 Hz; He: 0.75 L/m.

Campestre Formation e CAR-II-179 sample

Analysis 207Pb/235U Error (2s) 206Pb/238U Error (2s) 207Pb/206Pb Error (2s) rho 206Pb/238

U age(Ma)

Error(Ma)

207Pb/235

U age(Ma)

Error(Ma)

207Pb/206

Pb age(Ma)

Error(Ma)

% disc.

1.1 5.025401 0.221070 0.333333 0.014286 0.110022 0.001549 0.947741 1855 69 1824 37 1800 26 �42.1 5.732629 0.293011 0.326642 0.014485 0.135739 0.003707 0.845543 1822 70 1936 43 2174 48 193.1 5.008512 0.224647 0.273498 0.011846 0.134704 0.002069 0.939906 1559 60 1821 37 2160 27 314.1 2.586322 0.114650 0.228460 0.009814 0.081605 0.001209 0.942835 1326 51 1297 32 1236 29 �85.1 5.641459 0.257210 0.273579 0.011952 0.151094 0.002483 0.933112 1559 60 1922 39 2358 28 386.1 5.033135 0.245334 0.324283 0.015068 0.111097 0.001977 0.931211 1811 73 1825 40 1817 32 07.1 1.473932 0.155106 0.106401 0.010178 0.104344 0.004693 0.904069 652 59 920 62 1703 83 658.1Borda 3.753155 0.173212 0.286964 0.012362 0.097444 0.001885 0.908295 1626 62 1583 36 1576 36 �48.2Borda 3.478894 0.154725 0.271458 0.011666 0.095032 0.001445 0.940086 1548 59 1522 34 1529 29 �18.3Núcleo 3.642337 0.161713 0.284379 0.012125 0.092325 0.001469 0.933915 1613 61 1559 35 1474 30 �119.1 1.645711 0.084467 0.155496 0.006947 0.071812 0.001951 0.848699 932 39 988 32 981 55 510.1 8.247075 0.548428 0.363031 0.022446 0.161838 0.004280 0.917591 1997 105 2259 59 2475 45 2211.1 2.808221 0.183652 0.211836 0.012323 0.098801 0.003113 0.876358 1239 65 1358 48 1602 59 2512.1 2.192296 0.081834 0.203423 0.006711 0.079063 0.001591 0.843213 1194 36 1179 26 1174 40 �213.1 3.073641 0.138063 0.248492 0.009521 0.091337 0.002328 0.823967 1431 49 1426 34 1454 48 214.1 6.464972 0.214628 0.371330 0.011845 0.126308 0.001716 0.913610 2036 55 2041 29 2047 24 115.1 2.681652 0.095885 0.227440 0.007322 0.087893 0.001626 0.856903 1321 38 1323 26 1380 36 516.1 3.232943 0.119773 0.170664 0.005946 0.143624 0.002310 0.901685 1016 33 1465 28 2271 28 6017.1 6.214894 0.216006 0.365285 0.012133 0.122834 0.001757 0.912391 2007 57 2007 30 1998 25 �118.1 7.183588 0.237085 0.396113 0.012619 0.131544 0.001737 0.917709 2151 58 2134 29 2119 23 �219.1 4.769759 0.174268 0.281919 0.009860 0.125076 0.001820 0.918148 1601 49 1780 30 2030 26 2420.1 2.021669 0.095951 0.187229 0.008361 0.077512 0.001467 0.917316 1106 45 1123 32 1134 38 321.1 2.009071 0.080693 0.187448 0.006465 0.078986 0.001808 0.822576 1108 35 1119 27 1172 45 622.1 3.568091 0.121026 0.269441 0.008706 0.095865 0.001377 0.907033 1538 44 1542 27 1545 27 123.1 6.202473 0.206435 0.361467 0.011600 0.124518 0.001661 0.917413 1989 55 2005 29 2022 24 224.1 2.401143 0.082764 0.209433 0.006737 0.083700 0.001332 0.888107 1226 36 1243 24 1286 31 525.1 7.173062 0.262559 0.393491 0.012930 0.133337 0.002530 0.856177 2139 60 2133 32 2142 33 026.1 7.311862 0.257061 0.402905 0.013054 0.130420 0.002207 0.877653 2182 60 2150 31 2104 30 �427.1 3.174938 0.107930 0.249544 0.007932 0.091135 0.001428 0.888707 1436 41 1451 26 1449 30 128.1 3.196090 0.108037 0.255757 0.008101 0.090162 0.001395 0.890296 1468 41 1456 26 1429 30 �329.1 4.830612 0.167787 0.291226 0.009319 0.122233 0.002054 0.876284 1648 46 1790 29 1989 30 1930.1 1.889837 0.076241 0.141323 0.005198 0.103353 0.002001 0.877965 852 29 1078 26 1685 36 5331.1 4.783246 0.166047 0.318489 0.010313 0.108348 0.001735 0.888336 1782 50 1782 29 1772 29 �132.1 1.562615 0.061085 0.165747 0.005428 0.068433 0.001613 0.798702 989 30 956 24 882 49 �1333.1 6.407751 0.225225 0.381539 0.012623 0.124091 0.001926 0.898262 2083 59 2033 30 2016 28 �434.1 7.697061 0.305142 0.385089 0.012916 0.148742 0.003478 0.808453 2100 60 2196 35 2332 40 1235.1 10.477790 0.463076 0.464513 0.018377 0.159913 0.003533 0.866571 2459 80 2478 40 2455 37 036.1 2.798382 0.118975 0.235053 0.009014 0.086686 0.001812 0.871300 1361 47 1355 31 1354 40 �137.1 2.496047 0.090193 0.218566 0.007081 0.080936 0.001527 0.853936 1274 37 1271 26 1220 37 �538.1 5.934693 0.231823 0.281146 0.009832 0.154512 0.003101 0.858691 1597 49 1966 33 2396 34 3839.1 13.619641 0.599229 0.525170 0.020702 0.191073 0.004194 0.867143 2721 87 2724 41 2751 36 140.1 2.813757 0.117100 0.239661 0.008936 0.086657 0.001821 0.863704 1385 46 1359 31 1353 41 �341.1 2.990977 0.117021 0.244582 0.008492 0.088259 0.001820 0.850631 1410 44 1405 29 1388 40 �242.1 2.831241 0.112029 0.239052 0.008466 0.085883 0.001742 0.859304 1382 44 1364 29 1336 39 �443.1 1.772361 0.072588 0.175340 0.006233 0.073205 0.001659 0.833555 1041 34 1035 26 1020 46 �244.1 1.087612 0.056571 0.122359 0.004552 0.065728 0.002478 0.689387 744 26 747 27 798 79 745.1 3.388065 0.150512 0.264600 0.010623 0.093652 0.002012 0.875727 1513 54 1502 34 1501 41 �146.1 0.937803 0.045359 0.091592 0.003925 0.074245 0.001824 0.861818 565 23 672 23 1048 50 4847.1 2.562418 0.132244 0.223047 0.010348 0.085447 0.002113 0.878028 1298 54 1290 37 1326 48 248.1 2.741415 0.129691 0.226750 0.009162 0.085434 0.002269 0.827988 1317 48 1340 35 1325 51 149.1 2.384784 0.113764 0.207908 0.008838 0.083244 0.001985 0.866439 1218 47 1238 34 1275 47 550.1 2.206651 0.115471 0.200550 0.008876 0.082394 0.002443 0.824217 1178 47 1183 36 1255 58 751.1 7.951399 0.353301 0.422556 0.016630 0.139120 0.003189 0.857171 2272 75 2226 39 2216 40 �352.1 10.599774 0.443981 0.438563 0.016170 0.177108 0.003940 0.847901 2344 72 2489 38 2626 37 1353.1 2.852955 0.119921 0.217815 0.008002 0.096475 0.002194 0.841672 1270 42 1370 31 1557 43 2054.1 1.948149 0.083660 0.154720 0.005544 0.092769 0.002383 0.801975 927 31 1098 28 1483 49 4055.1 1.650779 0.069845 0.128453 0.004691 0.093362 0.002202 0.830846 779 27 990 26 1495 45 5156.1 3.623337 0.154217 0.277236 0.009784 0.095284 0.002459 0.795861 1577 49 1555 33 1534 49 �357.1 1.563211 0.082157 0.127053 0.005873 0.087025 0.002344 0.858904 771 34 956 32 1361 52 4658.1 2.104037 0.089818 0.190269 0.006929 0.081117 0.001981 0.820894 1123 37 1150 29 1224 48 959.1 1.802460 0.080904 0.168001 0.006175 0.075976 0.002100 0.788553 1001 34 1046 29 1094 55 960.1 1.463195 0.063812 0.136931 0.005211 0.075162 0.001769 0.842421 827 29 915 26 1073 47 2461.1 2.878754 0.120719 0.188925 0.006854 0.112085 0.002610 0.832244 1116 37 1376 31 1833 42 4362.1 6.582935 0.292628 0.360269 0.014310 0.134959 0.003013 0.865199 1983 67 2057 38 2163 39 1063.1 1.481175 0.081468 0.111925 0.005492 0.100162 0.002682 0.873661 684 32 923 33 1627 50 6164.1 5.500304 0.286173 0.342117 0.017580 0.117111 0.001511 0.968930 1897 84 1901 44 1913 23 165.1 5.866082 0.307257 0.360159 0.018669 0.119226 0.001491 0.971240 1983 88 1956 44 1945 22 �266.1 6.858272 0.385385 0.366411 0.020228 0.136205 0.001974 0.966293 2012 95 2093 49 2179 25 967.1 6.962883 0.358885 0.384339 0.019599 0.133385 0.001668 0.970326 2097 91 2107 45 2143 22 368.1 6.696824 0.347390 0.369259 0.018923 0.133337 0.001712 0.969074 2026 88 2072 45 2142 22 6

(continued on next page)


Table 4b (continued )


Analysis 207Pb/235U Error (2s) 206Pb/238U Error (2s) 207Pb/206Pb Error (2s) rho 206Pb/238

U age(Ma)

Error(Ma)

207Pb/235

U age(Ma)

Error(Ma)

207Pb/206

Pb age(Ma)

Error(Ma)

% disc.

69.1 3.682392 0.222426 0.137658 0.007715 0.192535 0.004745 0.913093 831 44 1568 47 2764 40 7470.1 2.551647 0.136238 0.161275 0.008427 0.115764 0.001718 0.960755 964 47 1287 38 1892 27 5371.1 8.408219 0.470448 0.340553 0.018487 0.180419 0.003038 0.953790 1889 88 2276 50 2657 28 3372.1 3.296266 0.171015 0.223375 0.011382 0.108382 0.001515 0.963225 1300 60 1480 40 1772 26 2973.1 6.005042 0.364157 0.359149 0.021161 0.122880 0.002149 0.957612 1978 100 1977 51 1998 31 174.1 4.208851 0.233440 0.285818 0.014774 0.108019 0.002425 0.914551 1621 74 1676 45 1766 41 975.1 4.392672 0.231223 0.261592 0.013577 0.125586 0.001670 0.967729 1498 69 1711 43 2037 24 3076.1 1.888407 0.095630 0.172598 0.008643 0.080640 0.001009 0.969182 1026 47 1077 33 1213 25 1777.1 11.046140 0.626906 0.459913 0.022512 0.177693 0.005404 0.844490 2439 99 2527 52 2631 51 978.1 3.184863 0.196631 0.206697 0.010158 0.113154 0.004377 0.779542 1211 54 1453 47 1851 70 3879.1 1.732904 0.092055 0.139500 0.006390 0.095854 0.002751 0.841695 842 36 1021 34 1545 54 4880.1 3.633124 0.165519 0.272435 0.010374 0.094511 0.002546 0.807028 1553 52 1557 36 1518 51 �381.1 3.647989 0.167715 0.273924 0.010487 0.095174 0.002603 0.804307 1561 53 1560 36 1532 51 �282.1 2.240668 0.138684 0.139321 0.007612 0.117002 0.003599 0.867902 841 43 1194 43 1911 55 6083.1 3.060208 0.135496 0.166703 0.006354 0.137281 0.003383 0.831289 994 35 1423 33 2193 43 5984.1 2.698575 0.123220 0.138142 0.005557 0.146628 0.003491 0.853735 834 31 1328 33 2307 41 6885.1 5.835867 0.268226 0.331982 0.013337 0.128398 0.003141 0.846974 1848 64 1952 39 2076 43 1386.1 5.716002 0.261540 0.255211 0.010119 0.169663 0.004229 0.839005 1465 52 1934 39 2554 42 4887.1 9.691021 0.438536 0.304998 0.011960 0.233393 0.005764 0.838403 1716 59 2406 41 3075 39 5088.1 3.246705 0.181463 0.203159 0.010164 0.113151 0.003038 0.877234 1192 54 1468 42 1851 49 3989.1 5.317708 0.237826 0.296420 0.011645 0.131086 0.003093 0.849962 1674 58 1872 38 2113 41 24

Table 5LueHf results from the quartzite of the Campestre Formation. The analysis number is the same as the UePb analysis number (Table 6). 176Lu decay ¼ Söderlund et al. (2004);176Hf/177HfCHUR ¼ 0.282772 and 176Lu/177HfCHUR ¼ 0.0332 (Blichert-Toft and Albarède, 1997); 176Hf/177HfDM ¼ 0.283225 and 176Lu/177HfDM¼ 0.038512 (“depletedmantle” in thepresent day: Vervoort and Blichert-Toft, 1999); bulk Earth ¼ 0.015 (Vervoort, 2006). Laser conditions: GJ1 e 6 mJ, 7 Hz, spot ¼ 48 um, He ¼ 0.55 L/min, 50 cicles, AR80 ¼ 25 V.


Analysis 176Hf/177Hf Error � 2s 176Lu/177Hf Error � 2s UePb age (T1) ε Hf(0) 176Hf/177Hf (i) ε Hf(T1) TDM (2) ε Hf(TDM)

37.1 0.282200 0.000034 0.000965 0.000034 1354 �20.2 0.282176 9.00 1499 10.7441.1 0.282069 0.000027 0.000815 0.000022 1388 �24.9 0.282047 5.22 1768 9.7740.1 0.282294 0.000040 0.000736 0.000023 1353 �16.9 0.282275 12.51 1271 11.5543.1 0.282292 0.000036 0.000660 0.000012 1020 �17.0 0.282280 5.18 1487 10.7835.1 0.281208 0.000053 0.000322 0.000008 2455 �55.3 0.281193 �0.78 2969 5.3726.1 0.281642 0.000029 0.000311 0.000011 2104 �40.0 0.281629 6.66 2225 8.1133.1 0.281318 0.000032 0.000575 0.000004 2016 �51.4 0.281296 �7.21 3041 5.1128.1 0.281971 0.000046 0.000901 0.000037 1429 �28.3 0.281946 2.56 1970 9.0431.1 0.281652 0.000110 0.001264 0.000057 1772 �39.6 0.281610 �1.62 2499 7.118.2 0.281803 0.000046 0.000978 0.000014 1529 �34.3 0.281774 �1.29 2292 7.8714.1 0.281309 0.000038 0.000767 0.000014 2047 �51.7 0.281279 �7.08 3057 5.0518.1 0.281406 0.000059 0.001886 0.000016 2119 �48.3 0.281330 �3.65 2895 5.6515.1 0.282128 0.000053 0.001683 0.000080 1380 �22.8 0.282084 6.33 1690 10.0517.1 0.281670 0.000069 0.003123 0.000055 1998 �39.0 0.281551 1.46 2476 7.19

597 (3.9%)556 (3.3%)

543 (1.7%)

592 (5.4%)

704 (4.8%) 632 (2.1%)667 (3.1%) 683 (4.6%)

648 (3%)667 (3.1%)

638 (3.1%) 660 (3.8%) 2,224 (1.4%)

A

B

C D

: 100 µm

663 (9%)

Fig. 5. Back-scattered images of the analyzed detrital zircon grains from the MW unit sample analyzed. The groups AeD were divided based on the morphology of the crystals andthe type of internal zones observed. 632 (2.1%) ¼ Age (% discordance). Ages are in million years before present (Ma). The crystal with no circle did not present analytical signal.

2,751 (1.4%)

1,275 (4.9%)

1,501 (0.9%)

1,545 (0.5%)

1,454 (1.8%)

2,119 (1.8%)

2,455 (0.2%)))

2,104 (4.4%)

2,142 (0.2%)

981 (5.4%)

2,047 (0.7%)

2,022 (1.9%)

1,220 (4.9%)

1,354 (0.6%)

))))))))))

1,1,1,,,3 )))))))

1,532 (2.1%)

1,518 (2.6%)

1,020 (2.3%)

1,534 (3.2%) 1,326 (2.3%)

1,325 (0.7%)

2,216 (3%)

1,945 (2.3%)

1,388 (1.8%)

1,336 (3.8%)

1,380 (4.7%)

1,913 (1%)

1,449 (1%)

1,429 (3.1%)

1,817 (0.4%)

1,998 (1.2%)

2,143 (2.5%)

1,998 (0.5%)

1,286 (5.1%)

1,576 (3.6%)

1,529 (1.4%)

6%)%)%))%)%)%)))))

1,174 (1.9%)

1,800 (3.5%)

1,134 (2.7%)

: 100 µm

εHf = +9.00

εHf = +5.16

εHf = -1.27εHf = -7.01

εHf = -3.63

εHf = -0.90

εHf = +5.04 εHf = +6.33

εHf = +6.57

εHf = +2.36 εHf = +1.51

εHf = +12.45

εHf = -7.23

εHf = -1.66

1,236 (8.1%)

1,172 (6%)

798 (7.1%)

1,255 (6.7%)

1,094 (9.2%)

1,224 (9%)

2,163 (9.7%)

2,179 (8.9%)

2,142 (6.3%)

1,766 (9.3%)

))))))))

2,631 (8.8%)

1,353 (2.6%)

1,772 (0.7%)

2,016 (3.9%)

Fig. 6. Back-scattered images of the detrital zircons from the quartzite sample of the CF analyzed. 1275 (4.9%) ¼ Age (% discordance). Ages in million years before present (Ma). Blackcircles with black values correspond to obtained UePb ages; yellow circles with yellow values correspond to the εHf results obtained. (For interpretation of the references to colourin this figure legend, the reader is referred to the web version of this article.)


described units, namely, between 76 and 88 (Table 1). In ternaryplot AeCNeK (Fig. 8) the units are found in the final stage of therock alteration trendwith an initial chemical composition similar tothat of the upper continental crust, which is richer in potassiumfeldspar than plagioclase, distinguishing these samples from thoseof the MW and SAS units.

Table 687Sr/86Sr whole rock analytical data from the MW unit, Campestre Formation87Sr/86Sri ¼ 87Sr/86Sr � 87Rb/86Sr (lt).

Unit Sample Rb (ppm) Sr (pp

MW unit C-325c 121.8 131.9C-333 142.4 121.5C-337 134.5 106.8C-340 154.5 112.0C-341 125.9 128.4CM-III-25 161.7 67.7CAR-I-51 137.3 168.0

Campestre Formation CAR-I-32 82.3 129.1CAR-II-76 126.6 166.5

Santo Antonio Schist Campos Neto et al. (2011) e e

5.3. Trace elements

The REE patterns of the MW unit (Table 3a) are typical of post-Archean sedimentary rocks (McLennan et al., 1990), with enrich-ment of light rare-earth elements (LREE), relatively flat patterns ofheavy rare-earth elements (HREE), and negative Eu anomalies

and Santo Antônio Schist. 87Rb/86Sr ¼ (Rbppm/Srppm) � 2.8937 � 0.93047;

m) 87Sr/86Sr Error (2s) 87Rb/86Sr 87Sr/86Sr (610 Ma)

0.735323 0.000069 2.486328 0.71370.742136 0.000080 3.155656 0.71470.744590 0.000090 3.390837 0.71510.748206 0.000074 3.714209 0.71590.736814 0.000070 2.640077 0.71380.770637 0.000047 6.430981 0.71470.732507 0.000075 2.200479 0.71340.747348 0.000052 1.716443 0.73240.749280 0.000054 2.047271 0.7315e e e 0.7060e0.7116

Table

7Sm

eNdwholerock

analytical

datafrom

theMW

unit,C

ampestreFo

rmationan

dSa

nto

Antônio

Schist.Analytical

blan

kforSm

¼47

pgan

dforNd¼

114;

147Sm

/144Nd¼

[(Con

cSm/Con

cNd)�

0.60

449

1];1

43Nd/144Ndnormalized

for0.72

19(D

ePao

lo,198

1);Ave

rage

valueforthe

143Nd/144Ndratiofrom

theJN

di¼

0.51

2100�

0.000004

reference;T D

M¼

{[(143Nd/144Nd) am/0.512

638]

�1}

�10

4,w

here

143Nd/144NdCHUR¼

0.51

2638

(Ham

ilton

etal.,19

83);

εNd(0)¼

{[(143Nd/144Nd) am/0.512

638]

�1}

�10

4.

Unit

Sample

Sm(ppm)

Nd(ppm)

147Sm

/144Nd

143Nd/1

44Nd

fSm

/Nd

TDM

(Ma)

ε(0)

ε(590

Ma)

ε(610

Ma)

MW

unit

C-325

c7.11

837

.009

0.11

630.51

�0.41

1618

.1�1

2.30

�6.25

�6.05

C-333

4.30

221

.555

0.12

070.51

�0.39

1619

.1�1

1.41

�5.69

�5.49

C-337

3.68

418

.900

0.11

790.51

�0.40

1605

.7�1

1.82

�5.89

�5.69

C-340

6.81

734

.444

0.11

970.51

�0.39

1590

.2�1

1.27

�5.47

�5.28

C-341

4.03

720

.367

0.11

990.51

�0.39

1612

.8�1

1.50

�5.72

�5.52

CM-III-25

5.98

130

.314

0.11

930.51

�0.39

1627

.3�1

1.79

�5.97

�5.77

CAR-I-51

7.78

539

.395

0.11

950.51

�0.39

1613

.6�1

1.58

�5.78

�5.58

CAR-IX-129

13.418

73.351

0.11

060.51

�0.44

1550

.8�1

2.59

�6.11

�5.89

Cam

pestre

Form

ation

CAR-I-32

15.599

97.337

0.09

690.51

�0.51

2273

.5�2

5.98

�18.47

�18.22

CAR-II-76

33.127

216.79

00.09

240.51

�0.53

2047

.3�2

3.84

�15.99

�15.73

CAR-IX-11

12.379

69.118

0.10

830.51

� 0.45

2456

.4�2

5.07

�18.42

�18.19

Santo

Antonio

Schist

Cam

pos

Neto

etal.(20

11)

2.36

4e4.40

811

.454

e20

.868

0.12

35e0.13

580.51

�0.37to

�0.31

1164

.1e13

99.7

�6.96to

�5.11

�1.96to

0.17

�1.79to

0.35


(Fig. 9). The analyzed samples can be grouped into three sets: (i)higher total REE values (SREE¼ 515.65) with strong fractionation ofREE (LaN/YbN ¼ 14.29), LREE (LaN/SmN ¼ 4.64), and HREE (GdN/YbN ¼ 2.03), as well as an intermediate Eu anomaly (EuN/Eu* ¼ 0.68); (ii) lower total REE values (SREE between 231.06 and234.04), with lower fractionation of REE (LaN/YbN between 3.69 and4.37), LREE (LaN/SmN between 2.61 and 3.40), and HREE (GdN/YbNbetween 0.84 and 0.95), as well as lower negative Eu anomalies(EuN/Eu* between 0.73 and 0.79); and (iii) intermediate total REEvalues (SREE between 305.88 and 406.36) with LaN/YbN between6.75 and 11.73, LaN/SmN between 3.22 and 4.23, GdN/YbN between1.46 and 1.92, and EuN/Eu* between 0.64 and 0.71. Samples fromthe third group are the most similar to the average composition ofpelites from the post-Archean Australian Shale (PAAS) and theNorth American Shale Composite (NASC), defined by Nance andTaylor (1976) and Haskin et al. (1966), respectively.

The REEs in SAS samples (Fig. 9) present the typical patterns ofpost-Archean sedimentary rocks (McLennan et al., 1990), but havetotal REE values higher than those of the PAAS and NASC (Table 3b).These rocks exhibit lower LREE fractionation and higher total HREEcontent.

The graphiteemuscovite schist displays strong fractionation ofREE (LaN/YbN¼ 33.43e28.50), HREE (GdN/YbN¼ 3.04 and 3.05), andLREE (LaN/SmN ¼ 5.44e4.58), as well as a negative Eu anomaly of0.805 (Fig. 9). The LREE values are higher and the HREE values arelower than the comparable values suggested for the post-Archeanupper continental crust (PAAS and NASC). Because these rocks aremetapelites, the HREE depletionmay be related to the fractionationof heavy minerals during sedimentary processes (Table 3b).

5.4. UePb and LueHf in detrital zircon

Most crystals from the MW unit provided Neoproterozoic207Pb/206Pb ages, between 632 and 683Ma (Table 4a) (Fig. 10). Agesbetween 543 and 597 Ma were obtained from a prismatic andelongated crystal, fractured from group A. These ages progressivelyincrease from the right edge to the left edge of the crystal, whichsuggests an opening of the UePb system by fluid percolation (Corfuet al., 2003). This hypothesis is reinforced by the absence of ananalytical signal in another elongated and bipyramidal crystal,which is also fractured, from the same group. A crystal fromgroup B,rounded by abrasion, has an age of 592.2� 67Ma, exhibiting a highassociated error and a lowdiscordance of 6%. This valuewithin errorof themetamorphic agesmight represent amixtureof ages,with thelaser spot reaching both the crystal with igneous zoning and thelighter overgrowth edge without zoning. A crystal without zoningprovided an age of 2.224 � 39 Ma (1% discordance) for the nucleus.

The quartzite lenses within the graphiteemuscovite schists atthe top of the Campestre Formation is characterized by the pre-dominance of crystals with 207Pb/206Pb age in the MesoproterozoicEra (Table 4b) between 1020 and 1576 Ma (54% of the concordantdata) and in the Paleoproterozoic Era between 1766 and 2455 Ma(38% of the data) (Fig. 11). Two crystals had Neoproterozoic ages of798 � 26 Ma and 981 � 55 Ma, and 2 other crystals presentedArchean ages of 2631 � 51 Ma and 2751 � 36 Ma. Therefore, the NdTDM ages between 2.46 and 2.05 Ga obtained for the graphiteemuscovite schist must represent a mixture of sediments of diverseprovenance, from the Archean to the Neoproterozoic, with pre-dominance of a Mesoproterozoic source area. The age of 798 Mawas obtained in a crystal with evidence of dissolution and subse-quent overgrowth. This value might represent a mixture of agesbecause the laser spot hit both the crystal with igneous zoning andthe lighter overgrowth edge without zoning.

The εHf data calculated for the UePb zircon ages (Table 5), fromthe CF quartzite sample, were plotted on a εHf vs. time (million

40 45 50 55 60 65 70

1.0

1.5

2.0

2.5

3.0

3.5

4.0

MgO

SiO2

40 45 50 55 60 65 70

1520

2530

Al 2O

3

SiO2

FO

40 45 50 55 60 65 70

46

810

12

e 23

SiO2

40 45 50 55 60 65 70

23

45

67

8

K2O

SiO2

40 45 50 55 60 65 70

12

34

Na 2

O

SiO2

Fig. 7. Harker diagrams of SiO2 vs. major and minor elements analyzed by X-Ray Fluorescence Spectrometry of the MW unit, the graphiteemucovite schist of the CF and the SAS.Highlights to the negative and positive correlations between the elements and to the geochemical affinity between the MW and SAS samples. Blue symbols: MW unit; greensymbols: SAS rocks; orange symbols: graphiteemuscovite schist of CF. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version ofthis article.)


years) diagram (Fig. 11). For the ages between 1.35 and 1.43 Ga, theεHf values are positive between þ12.51 and þ2.56, while for agesbetween 1998 and 2119 Ma, the values vary from �7.21 to þ6.66.For the age of 1020 Ma, the obtained εHf was þ5.18. Other valuesobtained for εHf are slightly negative, �1.29, �1.62 and �0.78 forages 1529, 1772 and 2455 Ma, respectively.

6. Isotopic geochemistry

The ratios 87Sr/86Sri obtained for theMWunit are in the range of0.712 and 0.714 for the 630 Ma age (maximum depositional age

based on the youngest concordant detrital zircon age). Lower87Sr/86Sr ratios are usually associated with higher elemental con-tents of Sr and are therefore less radiogenic than the remaining(Table 6). The Nd TDM model ages (Fig. 12) ranging from 1.55 to1.63 Ga and the values of εNd630 between�5.84 and �5.07 confirmthe influence of magmatic sources in the continental crust (Table 7).The Nd TDM obtained in the Mesoproterozoic Era could reflectmixed sources (McCulloch andWasserburg, 1978) evidenced by thedetrital zircon ages (Fig. 10).

The data obtained from the SAS samples for the 87Sr/86Sr ratioare lower than the values obtained for the MWunit (Table 6). These

Muscovite

Akaolinite, gibbsite,

chlorite

Illite

Arenite

Smectite

Island Arc AndesiteUpper Crust

MORBCN K

K-Feldspar

(40)

Shale

Plagioclase

Fig. 8. Analyzed samples plotted on the ternary diagram of the molar fraction of Al2O3

(A) � CaO þ Na2O in silicates (CN) � K2O (K) after McLennan et al. (1990). Symbols asin Fig. 7.

1

10

100

1000

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

Sam

ple

/Ch

ond

rite

(Tay

lor

e M

cLen

nan

, 198

5)

PAASNASC

Fig. 9. Chondrite normalized REE diagram (Taylor and McLennan, 1985) showing theREE pattern of the analyzed samples. Values of PAAS and NASC plotted for comparison.PAAS: Post-Archean Shale (Nance and Taylor, 1976); NASC: North American Shale Com-posite (Haskin et al. (1966)). Colors as in Fig. 7.


findings indicate that the source rocks of the SAS samples had alower period of residence in the crust. The Nd TDM model ages andεNd630 are also lower (Table 7) compared with those of the MWunit (Fig. 12). The εNd630 values indicate a higher contribution ofjuvenile material, which is compatible with the low 87Sr/86Sr630ratios. The Nd TDM ages are younger, between 1.16 and 1.39 Ga, mostlikely due to a lower variety of material from the source area(Fig. 12).

The data obtained for the 87Sr/86Sr ratio and εNd values wererecalculated for 950 Ma (Tables 6 and 7), maximum depositionalage based on the youngest concordant detrital zircon age obtainedfor the quartzite of the CF. The 87Sr/86Sr950 ratio values are higherthan those from the MW unit, suggesting that the source rocks ofthe precursor sediments had a longer crustal residence time. These

207Pb/ 206Pb

Num

ber

of z

irco

ns

0

1

2

3

600 800 1000 1200 1400 1600 1800 20

667

Fig. 10. 206Pb/238U vs. 207Pb/235U concordia diagram and the probability distribution of theages are indicated in the figure. Highlights to the concentration of the data on the Criogen

rocks yield higher values of Nd TDM model ages (between 2.05 and2.46 Ga) and strongly negative εNd950 values (between �13.88and �11.20) compared with the MW samples (Fig. 12). The Nd TDMages obtained in the Paleoproterozoic confirms the older detritalzircon ages obtained for the quartzite (Fig. 11).

7. Discussion and conclusions

Based on the major elements characteristics, the tectonicallyupper metawackes that truncate the units from the CarrancasGroup exhibit chemical affinity with the metawackes of theAndrelândia Nappe (Santo Antônio Schist). Compared with the

00 2200 2400

2224500

540

580

620

660

700

740

0.08

0.09

0.10

0.11

0.12

0.6 0.7 0.8 0.9 1.0 1.1207Pb/ 235U

206 Pb

/23

8U

207Pb/206Pb ages obtained in detrital zircons of the MW unit. The most representativeianeEdiacaran Period. Modal class in 667 Ma.

Num

ber

of Z

irco

ns

0

1

2

3

2142 - 2143

1325 - 1388

1518 - 1545

1998 - 2047

1172

0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.00.6

A4

0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0

Age (Ga)

depleted mantle

CHUR

Hf

-20

-15

-10

-5

0

5

10

15

20

25

0.6

B

Fig. 11. Probability distribution of the 207Pb/206Pb ages (A) and the age (Ga) vs. εHfgraph (B) for the quartzite of the CF. The most representative ages are indicated in thefigure. Highlights to the εHf positive values on the Mesoproterozoic Era.

590

Ma

T (Ga)

Nd-

Mod

elA

geV

aria

tion

-M

W

610

Ma

0.5 1 1.5 2 2.5

30

25

20

15

10

5

0

5

10 T

0

Nd

3

Nd-

Mod

elA

geva

riat

ion

-SA

S

Nd-

Mod

elA

geV

aria

tion

-C

F

Santo Antônio Schist

Metawacke Unit

Campestre Formation

Fig. 12. Age (Ga) vs. εNdT graph for the analyzed samples. 630 and 950 Ma agesidentified for better visualization of the results. Colors as in Fig. 7.


metawackes, the metapelites from the Campestre Formation pre-sent a negative correlation pattern between K2O and SiO2; lowercontents of SiO2, MgO, CaO, Na2O, and P2O5; and higher contents ofTiO2, Fe2O3, and Al2O3. These metapelites yield intermediate-to-high values for the chemical weathering index of Nesbbitt andYoung (1982), suggesting intense recycling and alteration of theoriginal sediment through long and/or repetitive cycles of chemicalweathering or periods of warm and humid climate conditions. Themetawackes of the Carrancas region yield lower CIA values, sug-gesting moderate chemical weathering. These values are higherthan those of the metawackes from the Andrelândia Nappe, pre-dominantly affected by physical weathering from a proximal sourcearea (Campos Neto et al., 2011).

The allochthonous metawackes from the Carrancas region andthose from the Andrelândia Nappe present negative Eu anomaliescombined with low HREE fractionation, indicating the presence, inthe source area, of igneous rocks with crustal signature (McLennanet al., 1990; McLennan and Taylor, 1991; Taylor and McLennan,1985, 1995). The depletion in Sr suggests that the source rocksunderwent chemical fractionation in the presence of calcicplagioclase, as Eu2þ substitutes for Sr2þ in this mineral, causing thenegative anomalies of both elements in the residual liquid(McLennan and Taylor, 1991).

The εNd(t) vs. 87Sr/86Sr(t) vs. Th/Sc diagrams (Fig. 13aec) indicatethe prevalence of a source area related to magmatic arcs for themetawacke samples. This unit has a signature of mature magmaticarcs as opposed to a juvenile arc signature in the forearc domain forthe Andrelândia Nappe metawackes. The lower CIA and Th/Sc ratiovalues (Fig. 14b) and the higher La/Th ratios (Fig. 13d) of the SantoAntônio Schist indicate an orogenic deposition environment nearthe source area, while more distal deposits could be assumed forthe metawackes in the Carrancas region. None of the analyzedsamples indicate passive margin environments, despite thestrongly negative εNd(950), the high 87Sr/86Sr(950) ratio, and the highHf content of the samples from the Campestre Formation (Fig. 13aed).

The large provinces of sediment provenance can also be high-lighted by the ratios between some major elements (McLennanet al., 1990). The ratios Si/Al < 5 and K/Na < 1 indicate a tectonicenvironment of active continental margin for the provenance of theAndrelândia Nappe metawackes (Fig. 14a). In the Carrancas region,the metawackes present Si/Al < 5 and K/Na > 1, suggesting acontinental collision environment (foreland basins).

Most of the detrital zircon crystals from the metawackes in theCarrancas region provided 206Pb/207Pb ages with an essentiallyunimodal distribution, in the Neoproterozoic Era, late CryogenianPeriod, and a secondary contribution (two analyses) in the RhyacianPeriod. The ages between 632 and 683 Ma (Fig. 10) are younger andcomparable with the detrital and metamorphic zircon ages fromthe Santo Antônio Schist of the Andrelândia Nappe (Superior Unitof the Andrelândia Group e Belém et al., 2011; Superior SantoAntônio Schiste Santos, 2011; Santo Antônio Schiste Campos Netoet al., 2011; Lima, 2013). These ages are also similar to the assumedperiod of greater volcanic activity in the source area (670 Ma) andclose to the collision age (w620 Ma) recorded in the meta-morphism of the upper nappes (Campos Neto et al., 2011). Based onthese UePb data of detrital zircon and on the age of metamorphismof the Carrancas Nappe (Valeriano et al., 2004; Campos Neto et al.,2011), the likely age for deposition of these metawackes is in theEdiacaran Period, between 630 and 590 Ma. The source area wasfound in the internal domains of the orogen, most likely in theorogenic edge (active continental margin) of the ParanapanemaBlock. Rhyacian ages can also indicate, as provenance, the basement(Kaulfuss, 2001; Prazeres Filho, 2005; Ribeiro, 2006; Siga et al.,2011) that is tectonically uplifted at the edge of this block. These

Hf (ppm)

15

10

5

0

0 5 10 15

La/

Th

Upper Continental Crust

tholeitic ocean island source

andesitic arc source

mixed felsic/mafic source

acid arc source

passivemarginsource

D

MORB ArcAndesite

FelsicComponent

Mafic Component

Upper Crust

Old Crust

1.1.01

-20

-10

0

10

Nd

Th/Sc

A

ArcheanCanadian

Shield

MantleArray

NASC

-20

-10

0

10

0.7400.7300.7200.7100.700

7 86Sr / Sr

Nd

Fore Arc

Back Arc Continental Arc

PassiveMargin

B

MORB (upper mantle)

OCEANIC ISLANDS(Mantle Plumes/Deep Mantle)

Bulk Earth

Continental Basalts

Seawater

CONTINENTAL CRUST

UPPERLOWER

EN

RIC

HE

D

DE

PLETE

D

Nd

-30

-20

-15

-10

-5

0

+5

+10

.700 .705 .710 .715 .720 .725 .730

87 86Sr / Sr

C

Fig. 13. Th/Sc vs. εNd (A), 87Sr/86Sr vs. εNd (B and C) and Hf vs. La/Th (D) diagrams of chemical classification of sediments deposited in different tectonic settings. εNd and 87Sr/86Srratios were recalculated for 630 Ma for the MW and SAS samples and for 950 Ma for the graphiteemuscovite schist of CF samples (both maximum depositional ages). A and B:McLennan et al. (1990); C: White (2009); D: Floyd and Leveridge (1987). Symbols as in Fig. 7.

A

PassiveMargin

Active Margin Continental Collision

(SiO

/l

AO

)2

23

(K O/Na O)2 2

1

10

100

0.01 0.10 1 10 100

B

Chemical weatheringtrend

Stable source area

Physical weatheringtrend

Orogenic source area

30 42 54 66 78 90

0

1.0

2

Th/

Sc

CIA (mol)Fresh basaltic trend

Fresh granite granodiorite range

Fig. 14. K2O/Na2O vs. SiO2/Al2O3 (A) and CIA vs. Th/Sc (B) diagrams of chemical classification of sediments deposited in different tectonic settings extracted from Campos Neto et al.(2011). Symbols as in Fig. 7.


BF

SJCF

SBF

GMF

SRF

CBF

CPF

RPGF

CPF

1000 1500 2000 2500 3000 3500

SLF

PF

ITA 01

ITA 03

Campes

tre F

orm

ation

Quartzi

te

CAR-II-179

Can

astr

a G

roup

SJDRB

SOGS

Esp

inha

ço S

uper

grou

p

T (Ma)

Fig. 15. Comparative figure with the UePb ages of detrital zircon grains from quartziteof Campestre Formation, Canastra Group, São João del Rei Basin, Serra do Ouro GrossoSequence and the Espinhaço Supergroup. The orange vertical line correspond to theyoungest age obtained for the quartzite from the CF. The yellow vertical bars corre-spond to the most representative age intervals. Values of the ITA 01 and ITA 03 samplesfrom the Campestre Formation and São João del Rei Basin and Serra do Ouro GrossoSequence samples were extracted from Valladares et al. (2004). Provenance ages ofCanastra Group are from Rodrigues et al. (2010) and ages from the formations ofEspinhaço Supergroup were extracted from Chemale et al. (2012). CPF: Chapada dosPilões Formation; PF: Paracatu Formation; SLF: Serra do Landim Formation; SJDRB: SãoJoão del Rei Basin; SOGS: Serra do Ouro Grosso Sequence; RPGF: Rio Pardo GrandeFormation; CPF: Córrego Pereira Formation; CBF: Córrego Bandeira Formation; SRF:Santa Rita Formation; GMF: Galho do Miguel Formation; SBF: Sopa-Brumadinho For-mation; SJCF: São João da Chapada Formation; BF: Bandeirinhas Formation.


external metawackes can be related to a foreland orogenic basin(syn-collision), installed on the edge of the Sanfranciscana Plate. Itis suggested due to younger detrital zircon ages, Nd and Sr isotopicsignature, chemical weathering index values and K/Na ratios.

The metapelites from the Campestre Formation are derivedfrom recycled sediments with a chemical weathering signature andoriginated in a tectonically stable area. Fine-grained quartzite andmuscovite quartzite form short or elongated lenses. Despite theabsence of sedimentary structures, which were destroyed bymetamorphism and intense deformation, it is probable that theCampestre Formation represents a basin of relatively deep watersin a reductive environment, with the psammitic lobes most likelydeposited by turbidite currents (Paciullo et al., 2000).

The UePb ages of the detrital zircon crystals, which were ob-tained by LA ICP-MS in the present study, indicate provenance fromMesoproterozoic sources, between ca. 1.0 and 1.57 Ga. The ages alsoexhibit provenance from Paleoproterozoic sources from the Sta-therian to the Rhyacian (Fig. 11). Archean source areas are negli-gible. This distribution of provenance ages is comparable to the

values obtained by Valladares et al. (2004) for the Campestre For-mation and are correlated with those values obtained for theCanastra Group (Rodrigues et al., 2010; Pimentel et al., 2011), whichis a riftedrift sequence on the western edge of the SanfranciscanoBlock (Fig. 15). The results from the following sources, with theexception of the Rhyacian ages, are not comparable to the prove-nance data obtained for autochthonous quartzites of the SãoFrancisco Craton (intracontinental rift and the rift-sag lower basinunits from the Espinhaço Supergroup e Chemale et al., 2012), forthe quartzites from the Serra do Ouro Grosso Sequence (ItutingaQuartzite in Fig. 3 e Valladares et al., 2004), and for the units of theSão João del Rei Basin (Valladares et al., 2004). The maximum agefor the deposition of the metapelites with quartzite lobes of theCampestre Formation from the Carrancas Group, based on theyounger modal class of age, is within the Tonian Period.

The predominance of the Mesoproterozoic source area (with alikely age of deposition in the Tonian Period) in the southwest edgeof the Sanfranciscano Block places these processes in the Rodiniafragmentation. The configuration assumed for this supercontinent(Li et al., 2008) and oceanic arm would separate the western San-franciscana edge of theWest Africa Block and the current NE and SEside of the Amazonas Block. The main characteristic of the WestAfrica Block is the absence of events and rocks from the Meso-proterozoic Era, suggesting a quiescent period between 1.7 and1.0 Ga (Attoh and Ekwueme, 1997; Begg et al., 2012). In the SãoFrancisco Block, the deposition of the rift-sag cycles from theEspinhaço Supergroup marked part of the Mesoproterozoic Era,when orogenic events or magmatic provinces were absent (Alkmimand Martins Neto, 2011). The eastern side of the Amazonas Block isdominated by the Paleoproterozoic (from the Statherian to theRhyacian) and Neoarchean eras (Cordani and Teixeira, 2007).

The Kibaran belt, which is located between the Congo (eastern)and Tanzania Cratons, is Mesoproterozoic (1.3e1.0 Ga), with noPan-African reworking (Hanson, 2003; Begg et al., 2012). However,in addition to being distant from the studied domain, on theopposite side of the same plate (Congo-São Francisco), magmaticevents are lacking in this orogen in the Calymmian Period (1.43e1.57 Ga), the main detrital zircon mode, with an isotopic signatureof mantle that is conferred by a positive εHf(t) (Fig. 11). Thesecharacteristics are found in the Laurentian edge of the AmazonasBlock, especially in the juvenile arc magmatism of the Jauru Terrain(Bettencourt et al., 2010), which is also a domain with an unlikelyconnection to the western side of the Sanfranciscana Plate edge.

Small drifting blocks, such as the Paranapanema and CentralGoiás that were fragmented in the Tonian break-up of Rodinia (Fucket al., 2008), could have been flanked by the western Sanfranciscanaedge, as depicted in the general paleogeographical diagram fromCordani et al. (2009). Early docking (in the beginning of the Cry-ogenian Period) of the Central Goiás Block to this edge was assumedby Campos Neto (2000). The Paranapanema Block, which is exten-sively covered by sediments from the Paraná Basin, exposes orogenicMesoproterozoic belts, with expressive Calymmian basic volcanism.

Acknowledgments

The authors thankW. Sproesser and S. Souza for their assistancewith the Zr and Hf analyses in the CPGeo-USP. Detailed reviews byRudolph A.J. Trouw and an anonymous reviewer helped to improvethe manuscript. We also thank Reinhardt A. Fuck for the editorialhandling. The São Paulo Research Foundation (Fundação de Amparoà Pesquisa do Estado de São Paulo e FAPESP) funded this researchthrough projects 2005/58688-1 and 2010/11152-8. A. Westin is agrant holder at FAPESP, and M.C. Campos Neto is a CNPq (ConselhoNacional de Desenvolvimento Científico e Tecnológico/NationalCounsel of Technological and Scientific Development) researcher.


References

Alkmim, F.F., Martins Neto, M.A., 2011. Proterozoic first-order sedimentary se-quences of the São Francisco craton, eastern Brazil. Mar. Petrol. Geol. 33, 127e139.

Assumpção, M., Heintz, M., Vauchez, A., Egydio-Silva, M., 2006. Upper mantleanisotropy in SE and Central Brazil from SKS splitting: evidence of astheno-spheric flow around a cratonic keel. Earth Planet. Sci. Lett. 250, 224e240.

Attoh, K., Ekwueme, B.N., 1997. The West African shields. In: de Wit, M., Ashwal, L.D.(Eds.), Greenstone Belts. Clarendon Press, Oxford, pp. 515e527.

Begg, G.C., Griffin, W.L., Natapoov, L.M., O’Reilly, S.Y., Grand, S.P., O’Neill, C.J.,Hronsky, J.M.A., Djomani, Y.P., Swain, C.J., Deen, T., Bowden, P., 2012. The lith-ospheric architecture of Africa: seismic tomography, mantle petrology, andtectonic evolution. Geosphere 27, 23e50.

Belém, J., Pedrosa-Soares, A.C., Noce, C.M., Silva, L.C., Armstrong, R., Fleck, A.,Gradim, C., Queiroga, G., 2011. Bacia precursora versus bacias orogênicas:exemplos do Grupo Andrelândia com base em datações U-Pb (LA-ICP-MS) emzircão e análises litoquímicas. Geonomos 19 (2), 224e243.

Bettencourt, J.S., Leite, W.B., Ruiz, A.S., Matos, R., Payolla, B.L., Tosdal, R.M., 2010. TheRondonian-San Ignacio province in the SWAmazonian Craton: an overview. J. S.Am. Earth Sci. 29 (1), 28e46.

Blichert-Toft, J., Albarède, F., 1997. The Lu-Hf isotope geochemistry of chondritesand the evolution of the mantle-crust system. Earth Planet. Sci. Lett. 148, 243e358.

Brito Neves, B.B., Campos Neto, M.C., Fuck, R.A., 1999. From Rodinia to WesternGondwana, an approach to the Brasiliano-Pan African Cycle and orogeniccollage. Episodes 22, 155e166.

Campanha, G.A.C., Sadowski, G.R., 1999. Tectonics of the southern portion of theRibeira Belt (Apiaí Domain). Precambrian Res. 98 (1), 31e51.

Campos Neto, M.C., 2000. Orogenic systems from Southwestern Gondwana: anapproach to Brasiliano-Pan African Cycle and orogenic collage in SouthwesternBrazil. In: Cordani, U.G., Milani, E.J., Thomaz Filho, A., Campos, D.A. (Eds.),Tectonic Evolution of South America. 31st International Geological Congress.CPRM, Rio de Janeiro, Brazil, pp. 335e365.

Campos Neto, M.C., Caby, R., 2000. Terrane accretion and upward extrusion of high-pressure granulites in the Neoproterozoic nappes of southeast Brazil: petrologicand structural constraints. Tectonics 19 (4), 669e687.

Campos Neto, M.C., Caby, R., 1999. Neoproterozoic high pressure metamorphismand tectonic constraint from the Nappe system south of São Francisco Craton,southeast Brazil. Precambrian Res. 97, 3e26.

Campos Neto, M.C., Basei, M.A.S., Vlach, S.R.F., Caby, R., Szabó, G.A.J., Vasconcelos, P.,2004. Migração de orógenos e superposição de orogêneses: um esboço dacolagem brasiliana no sul do Cráton do São Francisco, SE e Brasil. Rev. Inst.Geocienc. e USP, São Paulo 4 (1), 13e40.

Campos Neto, M.C., Janasi, V.A., Basei, M.A.S., Siga Jr., O., 2007. Sistema de NappesAndrelândia, setor oriental: litoestratigrafia e posição estratigráfica. Rev. Bras.Geocienc. 37 (Suppl. 4), 47e60.

Campos Neto, M.C., Basei, M.A.S., Janasi, V.A., Moraes, R., Garcia, M.G.M., Siga Jr., O.,2008. Agglutination of a Neoproterozoic Proto-continent, Southern São Fran-cisco Craton: timing and tectonic setting of the Andrelândia Nappe System,Southern Brasilia Orogen. In: VI South American Symposium on Isotope Geol-ogy, Argentina (CD-ROM).

Campos Neto, M.C., Cioffi, C.R., Moraes, R., Motta, R.G., Siga Jr., O., Basei, M.A.S., 2010.Structural and metamorphic control on the exhumation of high-P granulites:the Carvalhos Klippe example, from the oriental Andrelândia Nappe System,southern portion of the Brasília Orogen. Brazil. Precambrian Res 180 (3e4),125e142.

Campos Neto, M.C., Basei, M.A.S., Janasi, V.A., Moraes, R., 2011. Orogen migrationand tectonic setting of the Andrelândia Nappe system: an Ediacaran westernGondwana collage, south of São Francisco craton. J. S. Am. Earth Sci. 32,393e406.

CGMW e Commission for the Geological Map of the World, 2001. Geologic Map ofSouth America, CPRM/DNPM.

Chemale, F., Dussin, I.A., Alkmin, F.F., Martins, M.S., Queiroga, G., Armstrong, R.,Santos, M.N., 2012. Unravelling a Proterozoic basin history through detritalzircon geochronology: the case of the Espinhaço Supergroup, Minas Gerais,Brazil. Gondwana Res. 22 (1), 200e206.

Cordani, U.G., Teixeira, W., 2007. Proterozoic accretionary belts in the AmazonianCraton. In: Hatcher, R.D., Carlson, M.P., McBride, J.H., Catalan, J.R.M. (Eds.), 4-DFramework of Continental Crust, Geological Society of America Memoir, vol.200, pp. 297e320.

Cordani, U.G., Brito Neves, B.B., Fuck, R.A., Porto, R., Thomaz Filho, A., Cunha, F.M.B.,1984. Estudo preliminar de integração do Pré-Cambriano com os eventos tec-tônicos das bacias sedimentares brasileiras. Bul. Cienc. Tec. Pet. 15, 10e70.

Cordani, U.G., Teixeira, W., D’Agrella-Filho, M.S., Trindade, R.I., 2009. The position ofthe Amazonian Craton in supercontinents. Gondwana Res 15, 396e407.

Corfu, F., Hanchar, J.M., Hoskin, P.W.O., Kinny, P., 2003. Atlas of zircon textures. In:Hanchar, J.M., Hoskin, P.W.O. (Eds.), Zircon: Reviews in Mineralogy andGeochemistry. The Mineralogical Society of America, Washington, pp. 469e500.

Correia, C.T., Sinigoi, S., Girard, V.A.V., Mazzucchelli, M., Tassinari, C.C.G.,Giovanardi, T., 2012. The growth of large mafic intrusions: comparing Nique-lândia and Ivrea igneous complexes. Lithos 155, 167e182.

Danni, J.C.M., Fuck, R.A., Leonardos, O.H., 1982. Archaean and lower Proterozoicunits in Central Brazil. Geol. Rundsch. 71, 291e317.

Dardenne, M.A., 2000. The Brasília fold belt. In: Cordani, U.G., Milani, E.J., ThomazFilho, A., Campos, D.A. (Eds.), Tectonic Evolution of South America. 31st Inter-national Geological Congress. CPRM, Rio de Janeiro, Brazil, pp. 231e257.

DePaolo, D.J., 1981. Neodymium isotopes in the Colorado Front Range and crust-mantle evolution in the Proterozoic. Nature 291, 193e196.

Ebert, H.D., Chemale Jr., F., Babinski, M., Artur, A.C., Van Schmus, W.R., 1996. Tectonicsetting and UePb zircon dating of the plutonic Socorro Complex in the Trans-pressive Rio Paraíba do Sul Shear belt, SE Brazil. Tectonics 15 (2), 688e699.

Ferreira-Filho, C.F., Kamo, S.L., Fuck, R.A., Krogh, T.E., Naldrett, A.J., 1994. Zircon andrutile UePb geochronology of the Niquelândia layered mafic and ultramaficintrusion, Brazil: constraints for the timing of magmatism and high grademetamorphism. Precambrian Res. 68, 241e255.

Floyd, P.A., Leveridge, B.E., 1987. Tectonic environment of the Devonian Gramscathobasin, south Cornwall: framework mode and geochemical evidence from tur-biditic sandstones. J. Geol. Soc 144, 531e542.

Fuck, R.A., Jardim de Sá, E.F., Pimentel, M., Dardenne, M.A., Soares, A.C.P., 1994. Asfaixas de dobramentos marginais do Cráton do São Francisco: síntese dosconhecimentos. In: Dominguez, J.M.L., Misi, A. (Eds.), O Cráton do São Francisco.SBG-SGM-CNPq, vol. 2000. Empresa Gráfica da Bahia (EGBA), Salvador, Brazil,pp. 161e185.

Fuck, R.A., Brito Neves, B.B., Schobbenhaus, C., 2008. Rodinia descendants in SouthAmerica. Precambrian Res. 160, 108e126.

Hanson, R.E., 2003. Proterozoic geochronology and tectonic evolution of southernAfrica. In: Yoshida, M., Windley, B.F., Dasgupta, S. (Eds.), Proterozoic EastGondwana: Supercontinent Assembly and Breakup, Geological Society, Kondon,Special Publications, vol. 206, pp. 427e463.

Haskin, L.A., Wildeman, T.R., Frey, F.A., Collins, K.A., Keedy, C.R., Haskin, M.A., 1966.Rare Earths in sediments. J. Geophys. Res. B Solid Earth Planets 71 (24), 6091e6105.

Hamilton, P.J., O’Nions, R.K., Bridgwater, D., Nutman, A., 1983. SmeNd studies ofArchean metasediments and metavolcanics from West Greenland and theirimplications for the Earth’s early history. Earth Planet. Sci. Lett 62 (2), 263e272.

Janasi, V.A., 1997. Neoproterozoic mangerite-granite magmatism in the south-eastern Brazil: the São Pedro de Caldas massif. An. Acad. Bras. Cienc. 69, 267e294.

Janasi, V.A., 1999. Petrogênese de granitos crustais da Nappe de Empurrão Socorro-Guaxupé (SP-MG): uma contribuição da geoquímica elemental e isotópica.Unpublished thesis. University of São Paulo (in Portuguese).

Janasi, V.A., 2002. Elemental and Sr-Nd isotope geochemistry of two Neoproterozoicmangerite suites in SE Brazil: implications for the origin of the mangerite-charnockite-granite series. Precambrian Res. 119, 301e327.

Janasi, V.A., Vlach, S.R.F., 1997. Sr and Nd isotope systematics of the Capituva andPedra Branca syenitic massifs (SW Minas Gerais, Brazil): petrogenesis andinference on Neoproterozoic lithospheric mantle reservoirs. In: South AmericanSymposium on Isotope Geology, Extended Abstracts. Campos do Jordão, 143e146.

Janasi, V.A., Vlach, S.R.F., Ulbrich, H.H.G.J., 1993. Enriched-mantle contributions tothe Itú granitoid belt, southeastern Brazil: evidence from K-rich diorites andsyenites. An. Acad. Bras. Cienc. 65, 107e118.

Janasi, V.A., Haddad, R.C., Vlach, S.R.F., 1997. Comments on the Sm-Nd isotopicsystematics of calc-alkaline granitoids from the Pinhal-Ipuíuna batholith (SãoPaulo and Minas Gerais, Brazil). In: South-American Symposium on IsotopeGeology, Extend Abstracts, pp. 147e150.

Janasi, V.A., Vlach, S.R.F., Campos Neto, M.C., Ulbrich, H.H.G.J., 2009. Associated A-type subalkaline and high-K calc-alcaline granites in the Itu Granite Province,southeastern Brazil: petrological and tectonic significance. Can. Mineral. 47,1505e1526.

Jost, H., Theodoro, S.M.C.H., Figueiredo, A.M.G., Boaventura, G.R., 1996. Propriedadesgeoquímicas e proveniência de rochas metassedimentares detríticas arqueanasdos greenstone belts de Crixás e Guarinos, Goiás. Rev. Bras. Geocienc. 26, 151e166.

Kaulfuss, G.A., 2001. Geocronologia e Geoquimica dos Núcleos do Setuva, Betara eTigre, Noroeste de Curitiba-PR, 1991. MSc. unpublished dissertation. Universityof São Paulo (in Portuguese).

Laux, J.H., Pimentel, M.M., Dantas, E.L., Armstrong, R., Junges, S.L., 2005. Two Neo-proterozoic crustal accretion events in the Brasília Belt, central Brazil. J. S. Am.Earth Sci. 18, 183e198.

Li, Z.X., Bogdanova, S.V., Collins, A.S., Davidson, A., De Waele, B., Ernst, R.E.,Fitzsimons, I.C.W., Fuck, R.A., Gladkochub, D.P., Jacobs, J., Karlstrom, K.E., Lu, S.,Natapov, L.M., Pease, V., Pisarevsky, S.A., Thrane, K., Vernikovsky, V., 2008. As-sembly, configuration and break-up history of Rodinia: a synthesis. Precam-brian Res. 160, 179e210.

Lima, R.B., 2013. Evolução tectônica da frente da Nappe Andrelândia: OrógenoBrasília Meridional. MSc. unpublished dissertation. University of São Paulo (inPortuguese).

Mantovani, M.S.M., Brito Neves, B.B., 2005. The Paranapanema lithospheric block:its importance for Proterozoic (Rodinia, Gondwana) supercontinent theories.Gondwana Res. 8, 303e315.

Mantovani, M.S.M., Freitas, S.R.C., Shukowsky, W., 2001. Tidal gravity anomalies as atool to measure rheological properties of the continental lithosphere: appli-cation to the South American Plate. J. S. Am. Earth Sci. 14, 1e14.

Martins, L., Vlach, S.R.F., Janasi, V.A., 2009. Reaction microtextures of monazite:correlation between chemical and age domains in the Nazaré Paulista mig-matite, SE Brazil. Chem. Geol. 261, 271e285.

http://refhub.elsevier.com/S0895-9811(13)00120-X/sref1
























http://refhub.elsevier.com/S0895-9811(13)00120-X/sref26a
































































http://refhub.elsevier.com/S0895-9811(13)00120-X/sref29g



















































































































McCulloch, M.T., Wasserburg, G.J., 1978. Sm-Nd and Rb-Sr chronology of continentalcrust formation. Science 200 (4345), 1003e1011.

McLennan, S.M., Taylor, S.R., 1991. Sedimentary rocks and crustal evolution: tectonicsetting and secular trend. J. Geol. 99 (1), 1e21.

McLennan, S.M., Taylor, S.R., McCulloch, M.T., Maynard, J.B., 1990. Geochemical andNd-Sr isotopic composition of deep-sea turbidities: crustal evolution and platetectonic associations. Geochim. Cosmochim. Acta 54, 2015e2050.

Moraes, R., Fuck, R.A., 2000. Ultra high temperature metamorphism in centralBrazil: the Barro Alto complex. J. Metamorph. Geol. 18, 345e358.

Moraes, R., Fuck, R.A., Pimentel, M.M., Gioia, S.M.C.L., Hollanda, M.H.B.M.,Armstrong, R., 2006. The bimodal rift-related Juscelândia volcanosedimentarysequence in central Brazil: Mesoproterozoic extension and Neoproterozoicmetamorphism. J. S. Am. Earth Sci. 20, 287e301.

Mori, P.E., Reeves, S., Correia, C.T., Haukka,M.,1999. Development of a fused glass discXRF facility and comparisonwith pressed powder pellet technique at Instituto deGeociências, São Paulo University. Rev. Bras. Geocienc. 29 (3), 441e446.

Nance, W.B., Taylor, S.R., 1976. Rare earth element patterns and crustal evolution I:Australian post-Archean sedimentary rocks. Geochim. Cosmochim. Acta 40,1539e1551.

Navarro, M.S., Andrade, S., Ulbrich, H., Gomes, C.B., Giradi, V.A.V., 2004. The directdetermination of Rare Earth Elements in basaltic and related rocks using ICP-MS: testing the efficiency of microwave oven sample decomposition pro-cedures. Geostandards and Geoanalytical Res. 32 (2), 167e180.

Negri, F.A., 2002. Petrologia das rochas charnockito-graníticas e encaixantes de altograu associadas na região de São Francisco Xavier, SP. Ph.D. unpublished thesis.São Paulo State University (in Portuguese).

Nesbbitt, H.W., Young, G.M., 1982. Early Proterozoic climates and plate motionsinferred from major elements chemistry of lutites. Nature 299, 715e717.

Paciullo, F.V.P., Ribeiro, A., Andreis, R.R., Trouw, R.A.J., 2000. The Andrelândia basin,a Neoproterozoic intraplate continental margin, southern Brasília Belt, Brazil.Rev. Bras. Geocienc. 30 (1), 200e202.

Pimentel, M.M., Fuck, R.A., 1992. Neoproterozoic crustal accretion in central Brazil.Geology 20, 375e379.

Pimentel, M.M., Whitehouse, M.J., Viana, M.G., Fuck, R.A., Machado, N., 1997. TheMara Rosa Arc in the Tocantins Province: further evidence for Neoproterozoiccrustal accretion in Central Brazil. Precambrian Res. 81, 299e310.

Pimentel, M.M., Fuck, R.A., Jost, H., Ferreira Filho, C.F., Araújo, S.M., 2000. Thebasement of the Brasília fold Belt and the Goiás Magmatic Arc. In: Cordani, U.G.,Milani, E.J., Thomaz Filho, A., Campos, D.A. (Eds.), Tectonic Evolution of SouthAmerica. 31st International Geological Congress. CPRM, Rio de Janeiro, Brazil,pp. 335e365.

Pimentel, M.M., Rodrigues, J.B., DellaGiustina, M.E.S., Junges, S., Matteini, M.,Armstrong, R., 2011. The tectonic evolution of the Neoproterozoic Brasília Belt,central Brazil, based on SHRIMP and LA-ICPMS UePb sedimentary provenancedata: a review. J. S. Am. Earth Sci. 31 (4), 345e357.

Pires, F.A., 1991. Faciologia e análise paleoambiental da seqüência deposicionalFurnas-Lageado (Group: Açungui), de idade proterozóica. Rev. Bras. Geocienc.21, 355e362.

Prazeres Filho, H.J., 2005. Caracterização geológica e petrogenética do batólitogranítico Três Córregos (PR-SP): Geoquímica isotópica (Nd-Sr-Pb), idades (ID-TIMS/SHRIMP) e d18O em zircão. Ph.D. unpublished thesis. University of SãoPaulo (in Portuguese).

Queiroz, C.L., Jost, H., McNaughton, N.J., 1999. UePb e SHRIMP ages of CrixásGranite-Greenstone belt terranes: from Archaean to Neoproterozoic. In: IISouth-American Symposium on Isotope Geology, Extended Abstracts.

Quéméneur, J.J.G., Ribeiro, A., Trouw, R.A.J., Paciullo, F.V.P., Heilbron, M., 2002.Geologia da Folha de Lavras. Projeto sul de Minas e Etapa I: COMIG-UFMG-UFRJ-UERJ. Capítulo 7.

Ramos, V.A., Vujovich, G., Martino, R., Otamendi, J., 2010. Pampia: a large cratonicblock missing in the Rodinia supercontinent. Supercont. Crustal Evol 50 (3e4),243e255.

Ribeiro, L.M.A.L., 2006. Estudo geológico-geocronológico dos Terrenos granito-gnáissicos e sequências metavulcanossedimentares da região do Betara (PR).MSc. Unpublished dissertation. University of São Paulo (in Portuguese).

Ribeiro, A., Heilbron, M., 1982. Estratigrafia e metamorfismo dos Grupos Carrancas eAndrelândia, sul de Minas Gerais. In: XXXII Congresso Brasileiro de Geologia,Salvador, Brazil, pp. 177e186.

Rodrigues, J.B., Pimentel, M.M., Dardenne, M.A., Armstrong, R.A., 2010. Age, prov-enance and tectonic setting of the Canastra and Ibiá Groups (Brasília Belt,

Brazil): implications for the age of a Neoproterozoic glacial event in centralBrazil. J. S. Am. Earth Sci. 29 (2), 512e521.

Santos, P.S., 2011. Geocronologia, area fonte e ambiente tectônico da Unidade SantoAntônio eMegassequência Andrelândia. MSc. unpublished dissertation. FederalUniversity of Rio de Janeiro (in Portuguese).

Santos, L.P., Campos Neto, M.C., Carvalho, C.H.G., 2004. Metamorphic path con-strained by metapelitic rocks from the inner Aiuruoca-Andrelândia Nappe,Southern of the São Francisco craton, SE Brazil. J. S. Am. Earth Sci. 16, 725e741.

Sato, K., Tassinari, C.C.G., Kawashita, K., Petronilho, L., 1995. Método GeocronológicoSm-Nd no IG-USP e suas aplicações. An. Acad. Bras. Cienc. 67 (2), 221e237.

Siga Jr., O., Basei, M.A.S., Nutman, A., Sato, K., McReath, I., Passarelli, C.R., Liu, D.,2011. Extensional and colisional magmatic records in the Apiaí Terrane, south-southeastern Brazil: integration of geochronological UePb zircon ages. GeologiaUSP 11, 149e175.

Silva, M.P., 2010. Modelamento metamórfico de rochas das fácies xisto verde eanfibolito com uso de pseudosseções: exemplo das rochas da Klippe Carrancas,sul de Minas Gerais. MSc. unpublished dissertation. University of São Paulo (inPortuguese).

Söderlund, U., Patchett, P.J., Vervoot, J.D., Isachsen, C.E., 2004. The 176Lu decayconstant determined by Lu-Hf and UePb isotope systematics of Precambrianmafic intrusions. Earth Planet. Sci. Lett 219 (3e4), 311e324.

Taylor, S.R., McLennan, S.M., 1985. The Continental Crust: Its Composition an Evo-lution. Blackwell, Oxford, 312 pp.

Taylor, S.R., McLennan, S.M., 1995. The geochemical evolution of the continentalcrust. Rev. Geophys. 33, 241e265.

Topfner, C., 1996. Brasiliano-granitoide in den Bundesstaaten São Paulo und MinasGerais, Brasilien-eiene Vergleichende studie. Münchner Geol. Hefte A17, 258.

Trouw, R.A.J., Ribeiro, A., Paciullo, F.V.P., 1980. Evolução estrutural e metamórfica deuma área a SE de Lavras e Minas Gerais. In: XXXII Congresso Brasileiro deGeologia, Balneário Camboriú, Brazil, pp. 2773e2784.

Trouw, R.A.J., Paciullo, F.V.P., Chrispim, S.J., Dayan, H., 1982. Análise de deformaçãonuma área a SE de Lavras Minas Gerais. In: XXXVII Congresso Brasileiro deGeologia, Salvador, Brazil, pp. 187e198.

Trouw, R.A.J., Ribeiro, A., Paciullo, F.V.P., 1983. Geologia estrutural dos Grupos SãoJoão del Rei, Carrancas e Andrelândia, sul de Minas Gerais. An. Acad. Bras. Cienc.55 (1), 71e85.

Trouw, R.A.J., Ribeiro, A., Paciullo, F.V.P., Heilbron, M., 1984. Os grupos São João delRei, Carrancas e Andrelândia interpretados como continuação dos Grupos Araxáe Canastra. In: Congr. Bras. Geol, vol. 33, pp. 3227e3240. Rio de Janeiro.

Trouw, R.A.J., Paciullo, F.V.P., Ribeiro, A., 1998. Tectonic significance of Neo-proterozoic high pressure granulites in southern Minas Gerais. In: 14th Inter-national Conference on Basement Tectonics, Ouro Preto, pp. 69e71.

Trouw, R.A.J., Heilbron, M., Ribeiro, A., Paciullo, F.V.P., Valeriano, C.M.,Almeida, J.C.H., Tupinambá, M., Andreis, R.R., 2000. The central segment of theRibeira Belt. In: Cordani, U.G., Milani, E.J., Thomaz Filho, A., Campos, D.A. (Eds.),Tectonic Evolution of South America. 31st International Geological Congress.CPRM, Rio de Janeiro, Brazil, pp. 335e365.

Trouw, R.A.J., Ribeiro, A., Paciullo, F.V.P., 2002. Geologia da Folha Caxambu. Projetosul de Minas e Etapa I: COMIG-UFMG-UFRJ-UERJ. Capítulo 5.

Trouw, R.A.J., Tavares, F.M., Robyr, M., 2008. Rotated garnets: a mechanism toexplain the high frequency of inclusion trail curvature angles around 90� and180� . J. Struct. Geol. 30 (8), 1024e1033.

Trouw, R.A.J., Passchier, C.W., Wiersma, D.J., 2010. Atlas of Mylonites- and RelatedMicrostructures. Springer, 322 pp.

Valeriano, C.M., Machado, N., Simonetti, A., Valladares, C.S., Seer, H.J., Simões, L.S.A.,2004. UePb geochronology of the southern Brasília Belt (SE-Brazil): sedimen-tary provenance, Neoproterozoic orogeny and assembly of West Gondwana.Precambrian Res. 130, 27e55.

Valladares, C.S., Machado, N., Heilbron, M., Gauthier, G., 2004. Ages of detrital zirconfrom siliciclastic successions south of the São Francisco Craton, Brazil: impli-cations for the evolution of Proterozoic basins. Gondwana Res 7 (4), 913e921.

Vervoot, J.D., Blichert-Toft, J., 1999. Evolution of the depleted mantle: Hf isotopeevidence from juvenile rocks through time. Geochim. Cosmochim. Acta 63 (3e4), 533e556.

Vlach, S.R.F., Gualda, G.A.R., 2000. Microprobe monazite dating and the ages ofsome granitic and metamorphic rocks from Southeastern Brazil. Rev. Bras.Geocienc. 30 (1), 214e218.

White, W.M., 2009. Radiogenic Isotope Geochemistry. Cornell University, Ithaca.Available in http://www.geo.cornell.edu/geology/classes/Chapters/.





































































































































































http://www.geo.cornell.edu/geology/classes/Chapters/

Documents

Provenance and tectonic setting of the external nappe of the Southern Brasília Orogen