OpeningMeetingIGCP652---Program“ReadingTimeinPaleozoicsedimentaryRock”

Bremen,Germany

______________________________________________

Pre-meetingworkshop“Time-seriesanalysisofpaleoclimatesignals.”

Wednesday12thofSeptember

09:00-10:30 Physics of the climate system. How does solar insolationreachesEarth’ssurface?

10:30–11:00 Coffeebreak

11:00-12:30 Milankovitchtheory

12:30-14:00 Lunch

14:00-15:30 Theoreticalintroductiontopaleoclimatesignalsandtime-seriesanalysis

16:00-17:30 Practicalintroductiontopaleoclimatesignalsandtheirtime-seriesanalysis.

Thursday13thofSeptember

09:00-10:30 SedimentaryindicationsofMilankovitchforcing.

11:00-12:30 Paleoclimatesignalsandtheirtime-seriesanalysis:Exercise1.

12:30-14:00 Lunch

14:00-15:30 Exercise2

16:00-17:30 Exercise3

Friday14thofSeptember

09:00-16:00 Exercise4oranalysisofowndata

15:00–16:00 Presentationanddiscussionofmainresultsofthe“CyclostratigraphyIntercomparisonProject”.

Pre-meetingFieldtrip:MiddletoLatePaleozoicsedimentaryrockintheRhenishMassif

Saturday15thofSeptember201808:15 MeetinginfrontoftheMARUMbuilding.08:30 TransporttoHarz11:00–19:00 Several stops in the Harz Mountains illustrating the late

Permian “salt giants”, the Zechstein transgression, LateDevoniananoxiceventsandMiddleDevoniancarbonate reefdevelopment.

Lunchisprovidedandincludedintheregistrationfee.

19:00 LEINEHotel GronerLandstrasse55

37081GöttingenOvernightstayisincludedintheregistrationfee.Dinnerisnotincludedintheregistrationfee.

Sunday16thofSeptember201807:30 Breakfast(includedintheregistrationfee)08:15 TransporttonorthernSauerland10:30–19:00 Several stops inSauerland to illustrateGivetian-Frasnian reef

complexes, and the strongly cyclicdeep-water successionsoftheFamennian.

Lunchisprovidedandincludedintheregistrationfee.

19:00 HotelMarburgerHofElisabethstraße1235037MarburgOvernightstayisincludedintheregistrationfee.Dinnerisnotincludedintheregistrationfee.

Monday17thofSeptember201807:30 Breakfast(includedintheregistrationfee)08:15 Startoffieldtrip.08:30–15:30 Lower Devonian to Lower Carboniferous basin development

andvolcanisminthesoutheasternRhenishMassif.

Lunchisprovidedandincludedintheregistrationfee.

19:00 ArrivalinBremen.Participantscheckintotheirhotels.ParticipantshavetobooktheirownaccommodationinBremenforthisnight.

Meeting IGCP652 “ReadingTimeinPaleozoicsedimentaryRock”

Tuesday18thofSeptember2018

09:00–09:30: RegistrationCoffeeandrefreshmentswillbeserved.

09:30–09:40: WelcomeDavidDeVleeschouwer.

09:40–10:00: TimingandpacingoftheLateDevonianmassextinctioneventregulatedbyeccentricityandobliquity.DavidDeVleeschouweretal.

10:00-10:20: AstrochronologyoftheFrasnian–Famennianboundarysection(LateDevonian)atSteinbruchSchmidt.

Anne-ChristineDaSilvaetal.

10:20–10:40: DiversdepositionalandgeochemicalsignatureoftheFrasnianFamennian (F/F) global event in the western Thailand, as arecord of Paleotethyan vs. western Australian geotectonicaffinities.PeterKönigshofetal.

10:40–11:20: Coffeebreak

11:20–11:40 Tracing palaeoredox conditions across the Devonian-Carboniferousboundaryevent: a case study fromcarbonate-dominatedsettingsofBelgium,CzechRepublic,andnorthernFrance

TomášKumpanetal.

11:40–12:00 TheupperGivetian–strangemid-Palaeozoicintervalwithmaximumbiostratigraphictimeresolutionandrapideustaticfluctuations.

RalphThomasBeckerandZhorSarahAboussalam

12:00–12:30 Preliminaryreportsfromthepre-meetingworkshopontime-seriesanalysis.

Workshopparticipants

12:30–14:00Lunch

14:00–14:30: Tourofposterswithallparticipants.Poster presenters introduce their poster with 5-minutespresentations

14:30–15:00: Postersession

15:00–15:20Coffeebreak

15:20–15:40 High-resolution stratigraphy on the Ordovician strata fromsouthwesternOrdos,China

ShuangDaietal.

15:40–16:10 Keynote: Upper Katian Cyclostratigraphy of the VauréalFormation,AnticostiIsland(GulfofSt.Lawrence,Canada)

MatthiasSinnesaeletal.

16:10–16:30 Concludingremarks.

Wednesday 19th of September 2018 09:00 – 09:10: Opening of the second day. David De Vleeschouwer 09:10 – 09:30: The Lochkovian (Lower Devonian) in the Spanish Central

Pyrenees: conodont high-resolution biostratigraphy as a basis for integrating Events, oceanic, climatic changes and Milankovitch cycles.

José Ignacio Valenzuela-Ríos and Jau-Chyn Liao 09:30 - 09:50: The Givetian (Middle Devonian) in the Spanish Central

Pyrenees: conodont high-resolution biostratigraphy as a basis for testing the ties of biological and environmental evolution to astronomical forces.

Jau-Chyn Liao and José Ignacio Valenzuela-Ríos 09:50 – 10:10: Devonian (ca. 388-375 My) Horn River Group of

Mackenzie Platform (northwestern Canada) is an open-shelf succession recording global anoxic events.

Pavel Kabanov 10:10 – 10:50 Coffee break 10:50 - 11:10 Impact event stratigraphy: lessons from Paleozoic

craters, Chicxulub and the K-Pg boundary deposits Michael T. Whalen et al. 11:10 – 11:30 Magnetic polarity time scale for the Devonian…? Annique van der Boon et al. 11:30 – 12:00 Keynote: Cross recurrence plot analyses of conodont

community turnover – a model free, continuous, high-resolution correlation tool.

Andrej Spiridonov et al. 12:00 – 12:20 To see or not to see Milankovitch cycles – Example of the

Lower Devonian hemipelagic succession from Czech Republic Anne-Christine Da Silva et al.

12:20 – 14:00 Lunch 14:00 – 16:00 Where to go with IGCP 652?

Division of tasks and future paper writing. Future meetings. Concluding Remarks

Posters

Title Authors and presenter A positive test for the Greater Tarim Block at the heart of Rodinia: Mega-dextral suturing of supercontinent assembly

Bin Wen &

David A.D. Evans

Iterative speciation in Late Silurian Pristiograptine graptolites of the Baltic Basin and the value of stratigraphy in cladistics

Misha Whittingham, Sigitas Radzevičius, &

Andrej Spiridonov

The Devono-Mississippian Besa River Group of Liard Basin, Canada: stratigraphy of a world-class shale gas resource

F. Ferri, B.C. Richards, M. McMechan, Pavel

Kabanov, A. Mort, P. Thapa, J. Leslie-Panek

& E. Little,

Reassessment of the Lower Devonian and lower Middle Devonian conodont biostratigraphy in the Northwest Territories, Canada: changes in the time-rock chart for the northern Mackenzie Mountains and adjacent plains

Sofie A. Gouwy & Pavel Kabanov

The remagnetization of marine carbonate rocks of late Ordovician in Pingliang section (China)

Junhua Luo, Shuang Dai, Mark J. Dekkers, Weiguo Wang, Xiaoke Qiang, Lei Qiang, Chao Tian, Haiyu

Xi & Wout Krijgsman

Identifying cyclicities in different types of data series: a study of the Carboniferous rhythmites of the Itararé Group, Paraná Basin

Kochhann, M.V.L., Cagliari, J., Kochhann, K.G.D., Tedesco, J.,

Aquino, C.D., Souza, M.K. & Souza, L.V.

Refining the end of the Late Paleozoic Ice Age – LPIA in the Paraná Basin, southern of Gondwana

Cagliari, J., Netto, R.G. & Schmitz, D.M.

Trace Elements of the Middle-Late Ordovician in SW Ordos and Its paleoenvironmental implications

Lei Qiang, Shuang Dai, Anne-Christine da Silva, David De Vleeschouwer,

Weiguo Wang, Guoshan Li, Junhua Luo,

Haiyu Xi & Chao Tian

Magneto-cyclostratigraphy of Late Paleozoic rhythmites from Mafra Formation (Paraná Basin, Brazil)

Franco, D.R., Brandt, D., Hinnov, L.A., Ernesto, M.,

Rodrigues, P.O.C., Weinschütz, L., Zhao, X.

The Effenberg Quarry – cyclic sedimentation patterns and simplified time relationships of conodont zones (Famennian, Remscheid-Altena Anticline, Rhenish Massif)

Sven Hartenfels and Thomas Becker

Cyclostratigraphy of the marl-limestone alternations (Berriasian) in the North-South Axis (central Tunisia): geochronology and chronostratigraphic implications

Hamdi Omar, Anne-Christine da Silva, Jihede

Haj Massoud, Hela Fakhfakh and Chokri

Yaich

The Eocene – Oligocene transition in the southern Tethys: astronomical calibration of calcareous nannofossil bioevents and geochemical changes in northeastern Tunisia

Jihede Haj Massoud, Chokri Yaich, Johannes Monkenbusch, Nicolas

Thibault

OralPresentations

The upper Givetian – strange mid-Palaeozoic interval with maximumbiostratigraphictimeresolutionandrapideustaticfluctuations

RalphThomasBecker&ZhorSarahAboussalam

InstitutfürGeologieundPaläontologie,WWUMünster,Corrensstraße24,D-48149Münster,Germany,rbecker@uni-muenster.de,taghanic@uni-muenster.de

TheInternationalSubcommissiononDevonianStratigraphy(SDS)decidedin2006tosubdivide theGivetian formally into three substages.TheupperGivetianhasbeenproposed(Aboussalam&Becker2002)tocompriseroughlythetimeintervaloftheclassical lower Frasnian (do Iα) of the ammonoid-based German subdivision. It ischaracterizedbytherapidradiationofpharciceratidgoniatitesand, therefore,wasnamedbyHouse(1985)asPharcicerasStufe.ThesubstagebasewillbeplacedatthebaseoftheSchmidtognathushermanniZone, leavingtheoldestPharciceras faunasof the Upper Taghanic Crisis Interval (Aboussalam 2003) in the topmost middleGivetian(Aboussalam&Becker2001,2011).Thusdefined,theupperGivetianhadaduration of only 1.4 (Menning et al. 2006), 1.9 (Kaufmann 2006), 2.3 (GTS 2012,Beckeret al. 2012), or 1.5ma (STS2016,Menninget al. 2017).AsemphasizedbyBrett et al. (2018), and since six conodont and ammonoid zones/subzones can bedistinguishedwithin,itwasthemost“volatile”intervaloftheMiddlePalaeozoic.Theaverage (sub)zonal durationwas only 233 to 383 ka, less than a long eccentricitycycle, in comparison to the subsequent Frasnian (460-700 ka, 15 conodontzones/subzones,DeVleeschouwer&Parnell2004with6.9MadurationversusGTS2012with10.5Ma)andFamennian(25zones/subzones,532kato620ka). Itmustbestressedthatthere isnotasinglezirconageforalloftheGivetian,whichcouldrefinethecurrent,rathervariabletimeinterpolations.The short duration of the upper Givetian fits the extreme condensation of strata(mostly lessthan2m)inpelagicoutershelfcarbonatesettings.Thebestconodontand ammonoid successionswere described from the Tafilalt Platform of southernMorocco (Aboussalam&Becker2007, 2011),where all biozones areboundby re-transgression couplets. Comparisons with Europe (Aboussalam 2003) and NorthAmerica(e.g.Dayetal.2013)suggestaeustatictriggerformostorallofthem.Thebasal upper Givetian deepening is the Geneseo Transgression of the AppalachianBasin. Startingwith the global Taghanic Cricis, the upperGivetian “volatile” phasecoincidedwiththere-warmingofglobalclimateafteracool lower/middleGivetianinterval (Joachimski et al. 2009). Oxygen isotope data are still too limited torecognizetheindividualwarmingandtransgressiontimes.SandwichedbetweenthemultiphaseTaghanicandFrasnesEvents,whichcausedextinctionsandfaciesshifts,reefs flourished globally, for example in the Rhenish Massif, Ardennes, WesternCanada, South China, and Western Australia. In the offshore realm, it is highlyintriguingthatammonoidssuddenlyincreasedexceedinglytheirseptalcomplexityin

several parallel lineages of the Pharciceratacea (Becker 2009). Acceleratedmultilobation reflects the optimization of cameral liquid transport and of verticalmobility.Thiswasperhapsa response to increasingand recurrentwateragitation,e.g. by stronger storms, which required improved vertical escape mobility. Thespread of the oldest forests with large trees, e.g. the Gilboa Forest of theAppalachians, may express a corresponding change of global climate in theterrestrialrealm.Apart from climate-eustatic pulses, the middle/upper Givetian transition wascharacterizedbymajor synsedimentary tectonicmovementsandpalaeogeographicre-organization,whichmayhavebeen linked.This isexemplifiedbythe firstmajorphaseofEovariscanblockfaultingandtilltingintheEuropean-NorthAfricanVariscanSea,partlylinkedwithapeakofbasalticvolcanism(RhenishMassif;alsoTimanandsouthernSiberia),basinstarvationandsedimentarygaps(Bohemia,CarnicAlps),bythetransformationoftheAppalachianBasinintoananoxicseawithdominantblackshales,orbythespreadofradiolarites(e.g.MontagneNoire,SouthChina).Becauseofthecloselytimed,recurrentfluctuationsoffaciesandsealevel,theupperGivetianremainsachallengefordetailedcyclostratigraphicinvestigation.Pelagicsectionsareoften too condensed and partly incomplete, thick reef complexes normally lackprecise biostratigraphic dating, and seismically induced turbidites mask or erodecycles in adjacent Flinz basins. Orbital tuning of suitable sections would bemuchwelcomed.

High-resolution stratigraphy on the Ordovician strata from southwesternOrdos,China

ShuangDai1,RongxiLi2,JiweiLiang2,WeiguoWang3,Anne-ChristineDaSliva4,MarkDekkers5,JunhuaLuo1,XiaokeQiang6,LeiQiang1,ChaoTian1,HaiyuXi1,GuoshanLi3

1.KeyLaboratoryofWesternChina’sEnvironmentalSystems,MinistryofEducation&CollegeofResourcesandEnvironment,LanzhouUniversity,Lanzhou730000,China.2.KeyLaboratoryofWesternMineralResourcesandGeologicalEngineeringofMinistryofEducation&School

ofEarthScienceandResources,Chang，anUniversity,Xi，an710054,Shaanxi,China.3.Lab

ofCoastandOceanGeology,ThirdInstituteofOceanography,StateOceanicAdministration,

Xiamen, Fujian 361005, China. 4. Pétrologie Sédimentaire, B20, Boulevard du Rectorat, 15,Université de Liège, 4000 Liège, Belgium. 5. Paleomagnetic Laboratory ‘Fort Hoofddijk’,UtrechtUniversity,3584CDUtrecht,TheNetherlands. 6.StateKeyLaboratoryofLoessand

Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an710075,China

Ordos is located in the western North China block and includes Paleozoic stratawhichrecordedabundantinformationconcerningtectonicandpaleoclimaticchange.Duringthelastfivedecades,moststudiesoftheOrdovicianinsouthwesternOrdosfocusedonthestratigraphy,paleontology,sedimentology,paleogeographyandsealevel reconstructions. Here we review consensus, progresses and remainingquestions.According to the published literature, Ordos is affiliated to North China and waslocatedthroughtheEarlyPaleozoicjustsouthoftheequator.TheSWOrdoswasapassive continental margin during the Cambrian and Early Ordovician, and thenbecame a deep-water trench during theMiddle - LateOrdovician. TheOrdovicianstrata fromSWOrdos canbedivided into five Formations: carbonate rocksof theYeli and Liangjiashan Formations (Lower Ordovician), the Majiagou Formation(Middle Ordovician), and fine clastic rock of the Pingliang Formation and coarseclastic rocksand carbonate rocksof TanglingFormation (UpperOrdovician). TheseFormations contain graptolite and conodont assemblages, correlatable to globalbiozones.Subsequently,theformationscanbeassignedagesbetweenTremadocianandKatian,thispartiallycorroboratedbyZirconU-PbdatingofatuffinthePingliangFormation. The paleoenvrionments and lithologies include amuddy-dolostone flatand dolomitic-limestone flat in the Early Ordovician, a carbonate platform in theearly-middleMiddle Ordovician and a transition to platform fore-slope and deep-water trough settings in the late Middle Ordovician and early Late Ordovician.Depositional setting variations indicate two stages of regression and onetransgression, with seven sub-order transgression / regression phases. CarbonisotopicdatapointtoapositiveexcursionneartheboundarybetweenthePingliang

and Majiagou Formations, and Milankovitch cyclicities were found in PingliangFormation.However,ahigh-resolutionpaleomagneticandastrochronologymodelwouldallowto propose high-resolution age model to help our understanding details of thepaleogeography, paleoceanology and paleoclimate evolution. Our primarymagnetostratigraphy and cyclostratigraphy study provide a new insight for thesepurposes.AcknowledgementThisstudywasfundedbythefundamentalresearchfundsfortheCentralUniversities(lzujbky-2017-k27)andcontributetoIGCP652.

Astrochronology of the Frasnian–Famennian boundary section (LateDevonian)atSteinbruchSchmidt.

A.C.Da Silva1,D.DeVleeschouwer², L. Percival³,M. Sinnesael4,N.J.DeWinter4, P.Claeys4

1. University of Liege, Belgium – 2. MARUM Bremen University, Germany – 3. LausanneUniversity,Switzerland–4.VrijeUniversiteitBrussel,Belgium.

The LateDevonianmass extinctionwas the secondof five globalmass extinctionsthatshapedlifeonEarthduringthePhanerozoicEon,andoccurredattheFrasnian–Famennian boundary (FFB, 372 Ma). Here, we focus on this time interval at thefamous Steinbruch Schmidt section in Germany. This section includes the wellexposedKellwasserblackshaleintervals,theFFB,andaU-Pbdatedashlayer.Inthisstudy,we sampledan intervalof5.3maround theFFB,withanaverage samplingintervalof3cm,leadingtoacollectionofabout200samples.Oneverysample,wemeasuredcarbonandoxygenstableisotopes,magneticsusceptibilityandmicroXRFelementalgeochemistry.

Magnetic susceptibility (MS) and detrital-input-related elements such as Ti and AlarehigherduringtheKellwasser,andthereisagoodcorrelationbetweenAl,K,Ti,Fe

andMS.�13CvaluesarehighatandaroundtheKellwasser levels.Weselectedthe

MS,Ti/Aland�13Csignalsforspectralanalysis,asweexpecttheseproxiestocontainthe best-preserved astronomical signal. We applied the technique developed byMeyers (2015) on the evaluation of eccentricity-related amplitude modulationindependentlytothe3signals.Obtainedresults forthe3signalsareexactly inthesame range, with a sedimentation rate of 0.47 cm/kyr and it allows thetransformationofthesignalfromthedistancedomain(5.3m)intothetimedomain(abouta1100kyr). Ifwe filterprecession fromsignaland lookat itsenvelope,wecan seea clearmodulationby100kyr cycle, including5 to6precession cycles, asexpectedfortheDevonian.TheseresultsareinagreementwiththetimingproposedbyDeVleeschouweretal.(2017).Furthermore,asinDeVleeschouweretal.(2007),we have identified a strong obliquity Power at the FFB, which is associated atSteinbruchSchmidtwithaloweccentricitypower.Thiswouldcorrespondtoaperiodwithlowseasonalityandcouldhaveinfluencedthedevelopmentofanoxia.ThistimeframecombinedwiththedatingoftheashlayerbelowtheFFBboundary(Percivaletal.,2018)providesananchorpointforthiscyclostratigraphicframework.

DeVleeschouwer,D.,DaSilva,A.-C.,Sinnesael,M.,Chen,D.,Day,J.E.,Whalen,M.T.,Guo,Z.,Claeys,P.,2017.TimingandpacingoftheLateDevonianmassextinctioneventregulatedbyeccentricityandobliquity.NatureCommunications8,2268.Meyers,S.R.,2015.Theevaluationofeccentricity-relatedamplitudemodulationandbundlinginpaleoclimatedata:Aninverseapproachforastrochronologictestingandtimescaleoptimization.Paleoceanography30,1625–1640.

Percival,L.M.E.,Davies,J.H.F.L.,Schaltegger,U.,DeVleeschouwer,D.,DaSilva,A.-C.,Föllmi,K.B.,2018.PreciselydatingtheFrasnian-Famennianboundary:ImplicationsforthecauseoftheLateDevonianmassextinction.ScientificReports8.

ToseeornottoseeMilankovitchcycles–ExampleoftheLowerDevonianhemipelagicsuccessionfromCzechRepublic

DaSilva,A.C.1;Hladil,J.2;Chadimová,L.²;Slavík,L.²;Hilgen,F.J.3;Dekkers,M.J.3

1. Liège University, Belgium – 2. Czech Academy of Sciences, Prague, Czech Republic – 3.UtrechtUniversity,Netherlands

High-resolution time scales are crucial to understand Earth’s History in detail.Indeed,preciseandaccuratetemporalrelationsareessentialtolinkeventsandtheircausality. Inthatcontext, thePaleozoictimescalestillsuffers fromthe largesttimeuncertaintiesof thewholePhanerozoic.Abetter-calibrated time scalewouldoffermoreinsightintothemechanismsandcausesofmajorbiologicalevolutionarysteps,adaptive radiations,mass extinctions and recoveries, aswell as pattern of climatechangesoccurringthroughoutthePaleozoic.Findinggoodproxiesforclimaticcyclesis essential, but diagenesis can have a strong impact onmost of these proxies. Invarious cyclostratigraphic studies, the fit of spectral peak ratioswith those of theorbitalcycles,isclassicallyusedasanargumentforapreservedclimaticsignal.

Magnetic Susceptibility (MS) is often-used in sedimentary rocks for correlations,paleo-sealevelorpaleo-climaticreconstructionsandcyclostratigraphy,basedonthelinkbetweenMSanddetritalinput(influencedbysealevelandclimate).MSisaveryattractiveproxyparameter,becausedataacquisitionisstraightforwardenablingthecreation of high resolution records. However, the interpretation ofMS records interms of depositional environment can be less straightforward because MS is aconvolvedsignalpotentiallymixingthedesiredclimatic informationwithundesiredcontributionsrepresentingothergeologicphenomena(duringdepositionorafter).

ThePodBarrandovem section, fromCzechRepublic, recordedPragian andEmsian(LowerDevonian)hemipelagicsediments.AcompletehighresolutionMSrecordwasgenerated and clear cyclicities are identified through spectral analysis of this MSrecord (Da Silva et al. 2016). The Praha Formation spans the first 172 m of thesectionandmagnetichysteresisresultsfromthisPrahaFormationindicateaprimarymagnetic susceptibility signal, mostly carried by clay minerals. Following this andaccordingtothefitbetweensomeofthesecyclespectralratioswithorbitaltargets,these cycleswere interpretedasMilankovitch cycles, leading toproposeaprecisedurationforthePrahaFormation.Theportionofthesectionbetween174and292mcorrespondstotheZlichovFormationandhysteresisresultsindicateamuchmorecomplicated magnetic susceptibility signal, carried by various ferromagneticminerals. This probably means that the observed cycles are not related toMilankovitchcycles,despitetheoccurrenceofsimilarspectralpeakratiosthantheorbitaltargets.

DaSilva,A.C.,Hladil,J.;Chadimová,L.;Slavík,L.;Hilgen,F.J.;Bábek,O.;Dekkers,M.J.(2016)RefiningtheEarlyDevonian timescaleusingMilankovitchcyclicity inLochkovian–Pragiansediments (Prague

Synform,CzechRepublic).EarthandPlanetaryScienceletters.455,125-139

TimingandpacingoftheLateDevonianmassextinctioneventregulatedbyeccentricityandobliquity

DavidDeVleeschouwer,Anne-ChristineDaSilva,MatthiasSinnesael,DaizhaoChen,JamesE.Day,MichaelT.Whalen,ZenghuiGuo&PhilippeClaeys

1MARUM—Center for Marine Environmental Sciences, University of Bremen, Germany.2Analytical, Environmental and Geo-Chemistry (AMGC), Vrije Universiteit Brussel, Belgium.3Sedimentary Petrology Laboratory, Liège University, Belgium. 4Paleomagnetic Laboratory,UtrechtUniversity,TheNetherlands.5InstituteofGeologyandGeophysics,ChineseAcademyof Science, China. 6Department of Geography–Geology, Illinois State University, USA.7DepartmentofGeosciences,UniversityofAlaska,USA.

The Late Devonian envelops one of Earth’s big fivemass extinction events at theFrasnian–Famennian boundary (374 Ma). Environmental change across theextinction severely affected Devonian reef-builders, besides many other forms ofmarine life. Yet, cause-and-effect chains leading to the extinction remain poorlyconstrainedasLateDevonianstratigraphyispoorlyresolved,comparedtoyoungercataclysmic intervals. In this study we present a global orbitally calibratedchronologyacross thismomentous interval, applyingcyclostratigraphic techniques.Our timescale stipulates that 600 kyr separate the lower and upper Kellwasserpositive δ13C excursions. The latter excursion is paced by obliquity and is thereinsimilartoMesozoicintervalsofenvironmentalupheaval,liketheCretaceousOcean-Anoxic-Event-2(OAE-2).Thisobliquitysignatureimpliescoincidencewithaminimumofthe2.4Myreccentricitycycle,duringwhichobliquityprevailsoverprecession,andhighlights thedecisive roleofastronomically forced“Milankovitch”climatechangeintimingandpacingtheLateDevonianmassextinction.

Devonian(ca.388-375My)HornRiverGroupofMackenziePlatform(northwesternCanada)isanopen-shelfsuccessionrecordingglobalanoxicevents

P.Kabanov1

1.GeologicalSurveyofCanada–Calgary,Canada

Atleastfourhorizonsofenhancedanoxia(AHs)arerecognizedinthelatestEifelian–MiddleFrasnianmudrock-dominatedstrataoftheMackenzieValleyandPeelareaofNWCanada(Fig.1).Alumina-normalizedMoandUlogsintwocoredsectionsrevealtheAH-I at the Eifelian/Givetianboundary,AH-II in basal Frasnian, andAH-III andAH-IV bundled in the Middle Frasnian interval (Fig. 1). These four horizons arecharacterized by attenuated siliciclastic components. Spectral gamma-ray K+Th,U[gAPI],andUn(K-normalizedU[gAPI])arethebesttoolstotracethesehorizonsinwellsandoutcrops.AHsarebiostratigraphicallycorrelatedwith“black-shaleevents”in severalbasinsof theworld.Depositionalenvironment isdepictedasa stratifiedbasin where the water-column chemocline defined time-specific sedimentarypatternwithanoxicmudrocks in topographic lowsandoxic,argillaceous-carbonatefacies and isolated carbonate banks on seafloor elevations. Based on 1687 ICP*elemental data, siliciclastics-lean basinalmudrock units that host AHs are stronglyenriched in Mo (median EFMO*~97-172 EFMo/EFU*≈3-3.5 X SW*) compared tosiliciclastic-richunits(medianEFMO~17-37)andshowstrongEFU/EFMocovariation(r≈0.8inCanolFormationandBluefishMember).Supportedbyalackofgeologicalevidenceforanoceanographicbarrier,thisenrichmentindicatesunrestrictedwaterexchange with Panthalassa. At the same time, development of oligotrophy isindicatedbyalackofPenrichmentandweaktonon-existentenrichmentinZnandCu. These features are reconciled through themodel of Kidder&Worsley (2010),which involves a global shift to a warm greenhouse mode with slowed oceanicconvection,expandedOMZs,andafailureofnutrientresupplyfromupwellings.Theonsetofmassdegassing in continental LIPs* representsapotential trigger for thismid-Devonianshift.Devonianblack-shaleevents inthisscenariorepresentgenuineOAEs*markinghothouseepisodesintheirnascentform.

*Acronymy:ICP=inducedcoupledplasma;EFMoandEFU=Al-normalizedMoandUin enrichment factor notation; SW = average present-day seawater values; LIPs =largeigneousprovinces;OAEs=oceanicanoxicevents

Kabanov,P. Inpress.Devonian (ca.388-375My)HornRiverGroupofMackenziePlatform(northwesternCanada)isanopen-shelfsuccessionrecordingoceanicanoxicevents.Journal

oftheGeologicalSocietyofLondon

Figure1.Anoxichorizons(I-IV)revealedbylithogeochemicalproxiesinLittleBearN-09andLoonCreekO-06wellsandtheirSGRcorrelationinPowellCreekandRumblyCreekoutcropsections.LithogeochemicallogsaresmoothedbyLOWESSregressionwithα-tension4%;

Divers depositional and geochemical signature of the Frasnian/Famennian(F/F)globalevent in thewesternThailand,asa recordofPaleotethyanvs.WesternAustraliangeotectonicaffinities

P.Koenigshof1,G.Racki2,Z.Belka3,J.Dopieralska4,A.Pisarzowska2

1. Senckenberg Research Institute and Natural History Museum Frankfurt, Germany – 2.

UniversityofSilesia,Poland–3.AdamMickiewiczUniversity,Poland–4.AdamMickiewiczUniversityFoundation,Poland

The Frasnian-Famennian boundary beds are overall characterized by the co-occurrence of two particular dark, organic-rich shaly-limestone Kellwasser (KW)levels. The Upper KW determines a global biotic event, corresponding to amajorecosystem perturbation at the F-F boundary, as a dramatic final of the stepwiseKellwasser Crisis. Recently this biotic crisis and resulting disruption of epeiriccarbonate factory (inparticular a total collapseofmetazoan reefs) is thoughtas amass depletion of marine diversity resulted mainly from lowered origination rate(seeStanley2016andreferencestherein).

In thewestern part of Thailand,UpperDevonian rocks are representedmainly bypelagicorhemipelagiclimestones.Twosections,theThongPhaPhumsection(TPP)and the Mae Sariang section (MS) were reliably dated by conodont faunas, andcombinedwithgeochemicalandmicrofacies/sedimentologydata, includingthekeycarbonisotopicsignature(Savageetal.,2006;Dopieralskaetal.,2012;Königshofetal., 2012; Savage, 2013). This high-resolution bio- and chemostratigraphicalframeworkenablesstudyofelemental inorganicgeochemicalsignaturesacrosstheFrasnian-Famennian(F-F)boundary.

The studied Thai sections differ significantly in their geochemical signature, partlyonlyexplainablebymoremarlycharacteroflimestonesfromThongPhaPhum.Themore condensed MS record generally corresponds to the worldwide event-chemostratigraphic F-F pattern even if only brief-lasting anoxic conditions arerecognizable in thekeycrisis timespan in thesuccessionwithoutdark,organic-richintercalations.TheTPPsectionshowsspecificcharacters: (a) theC-isotopepositiveexcursion,determining theUpperKellwasser level, ispeculiarly two-staged,withadistinctly loweramplitude(below1.5‰)andahighstandplateauprolongedtotheLate triangularis Zone, and (b) elemental proxies point to only oxic and probablylargelyoligotrophic conditionsduring thebothKW intervals.ThedistinctivenessofTPP section clearly indicates its affinity with the Western Australian shelfsuccessions, characterizedbywell-known “atypical” recordof the F-F global event(George et al., 2014; Hillbun et al., 2015). The Thai sections point primarily totectonically driven episodes of distinctly increased and coarse-grained terrigenous

delivery in theKWCrisis time.Potential volcanic record is limited tohydrothermalsignalsinthePaleotethyandomainonly,provedalsobysomeHgenrichments.

Dopieralska, J., Belka, Z., Königshof, P., Racki, G., Savage, N., Lutat, P., & Sardsud, A. (2012). Nd

isotopiccompositionofLateDevonianseawaterinwesternThailand:geotectonicimplicationsfortheoriginoftheSibumasuterrane.GondwanaResearch22,1102–1109.

George,A.D.,Chow,N.,&Trinajstic,K.M.(2014).OxicfaciesandtheLateDevonianmassextinction,

CanningBasin,Australia.Geology42,327–330.

Hillbun,K,Playton,T.E.,Tohver,E.,Ratcliffe,K.,Trinajstic,K.,Roelofs,B.,Caulfield-Kerney,S.,Wray,

D., Haines, P., Hocking, R., Katz, D.,Montgomery, P., &Ward, P. (2015). Upper Kellwasser carbonisotopeexcursionpre-datestheF-FboundaryintheUpperDevonianLennardShelfcarbonatesystem,

CanningBasin,WesternAustralia.Palaeogeography,Palaeoclimatology,Palaeoecology438,180–190.

Königshof,P.,Savage,N.M.,Lutat,P.,Sardsud,A.,Dopieralska, J.,Belka,Z.,&Racki,G. (2012).LateDevonian sedimentary record of the Paleotethys Ocean – TheMae Sariang section, northwestern

Thailand.JournalofAsianEarthSciences52,146–157.

Savage,N.M.,Sardsud,A.,&Buggisch.W.(2006).LateDevonianconodontsandtheglobalFrasnian-Famennianextinctionevent,ThongPhaPhum,westernThailand.Paleoworld15,171–184.

Savage,N.M.(2013).LateDevonianconodontsfromnorthwesternThailand.BourlandPrinting/Trinity

Press,Eugene,Oregon:1–48.

Stanley,S.M.(2016).Estimatesofthemagnitudesofmajormarinemassextinctionsinearthhistory:

ProceedingsoftheNationalAcademyofSciencesoftheUnitedStatesofAmerica,v.113,p.6325–6334.

Tracing palaeoredox conditions across the Devonian-Carboniferousboundary event: a case study from carbonate-dominated settings ofBelgium,CzechRepublic,andnorthernFranceT.Kumpan1,J.Kalvoda1,O.Bábek2,M.Holá²1.MasarykUniversity,Brno,CzechRepublickumpan.tom@gmail.com–2.PalackýUniversity,Olomouc,CzechRepublicTheDevonian-Carboniferousboundary(DCB)wascoevalwithHangenbergCrisisthatisregardedasfirstordermassextinctioneventrelatedwithseveresea-levelchangesand widespread anoxia. This study aims with tracing of geochemicalpalaeoproductivity and palaeoredox proxies across the Devonian-Carboniferouscarbonate-dominated successions of the Namur-Dinant Basin (Belgium, northernFrance) and the Moravo-Silesian Basin (Czech Republic), located in the VariscanRhenohercynian Zone. Namur-Dinant Basin sections Gendron-Celles and LesArdennesexposecarbonateramplimestonesandmarlsandMoravianKarstsectionLesní lom consists of carbonate slope limestones andmarls around the DCB. Ourresearchwas focused on distribution of themain oxides (SiO2, Al2O3, Fe2O3, CaO,Na2O,K2O,TiO2,MnO)andtraceelements(Th,U,V,Zr,Mo,Zn,Pb,Ni,Cu)measuredby ICP-OES (inductivelycoupledplasmaopticalemissionspectrometry)and ICP-MS(inductively coupled plasmamass spectrometry), respectively. In total 89 sampleswere groundedandanalyzed.AsmainpalaeoredoxproxieswereusedenrichmentfactorsofMoandUandtheirratios,whereasenrichmentfactorsofZn,Cu,PbandNi were employed for tracing of palaeoproductivity changes. Enrichment factorswere calculated as Al normalized element concentrations relative to the post-ArchaeanAustralianShale(PAAS).

High values of Zr/Al2O3 (> 0.001), Ti/Al (> 0.06), Fe/Ti (> 20) and low values ofAl/(Al+Fe+Mn) (< 0.35) coinciding with increase of palaeoredox proxies suggestpossible volcanic and hydrothermal source of nutrients, related to Late Devonianand Early Carboniferous extensional magmatism in the Rhenohercynian domain.Relationshipbetweenhigherpalaeoproductivityandenhancedcontinentalrunoffofvolcanic material cannot be excluded. Succession of the Gendron-Celles and LesArdennessectionsrevealthreelevelswithsimilarvectorsofMoandUenrichments.The upper Fammenian pattern is typical for weakly restricted basins with Fe-Mnredoxcyclingaccompanyingverticalfluctuationsoftheoxic/anoxicchemoclinecloseto the sediment/water interface andwith the influenceof particulate shuttle. TheuppermostFamennianMoEFandUEFpatterns corresponding to theunrestrictedorweakly restricted basin with alternating suboxic to anoxic conditions, possiblerelatedwiththetransgressiveHangenbergBlackShaleEvent.ThelowerTournaisianMoEF andUEF fall along a vector in the direction of the strongly restrictedmarineconditionswithprevailingsuboxicconditions.

In the Moravo-Silesian Basin (Lesni lom section), upper Famennian MoEF and UEFvector indicates the unrestricted marine trend which converges with that ofrestricted systems. Redox conditions range from suboxic to euxinic. In theTournaisian,MoEFandUEFoscillatebetweenoxicandanoxicconditionsandfallalonga vector of the strongly restricted marine conditions. Increased isolation of both

studied basins during the Early Tournaisian is regarded as reflection of significanteustatic fall during Hangenberg Crisis linked to a severe episode of Gondwanaglaciation.

Researchwas supported by the Czech Science Foundation (project number GA16-11563S).

TheGivetian(MiddleDevonian) intheSpanishCentralPyrenees:conodonthigh-resolution biostratigraphy as a basis for testing the ties of biologicalandenvironmentalevolutiontoastronomicalforces

J.-C.Liao1,J.I.Valenzuela-Ríos1

1.UniversityofValencia;Spain.jau.liao@uv.es;jose.i.valenzuela@uv.es

The Givetian is related to at least fourmajor Events/Episodeswhose ultimate causes areunknown.Also,numeroussea-leveloscillationsarerecordedaroundtheworldanditseemsthat someof them, if not all, could be globally correlated. Their relation toMilankovitch-induced high order cycles still needs to be tested. Analysing the variety of environmentsrecordedinGivetianstratawouldfacilitateabettercomprehensionoftheEarthSystem.

Oneofthemaincurrentchallengesisthearrangementofallthesehappeningsindifferentpartsof theworld, theirscalingandsubsequentduecorrelation. In thiscontext,conodonthigh-resolutionbio-chronostratigraphyplaysapivotalroleandhasbecomeanessentialtool.Forinstance,currentstudiesinthePyreneeshavedemonstratedanewtransgressivephasewithinthe lateTaghanicEvent.Also,conodontsprovidedrecognitionoftwophaseswithintheKačákEpisode.Suchkindofimprovementscanonlybeachievedafterafinestandardofreferenceisbuiltanddetailedstudiesindifferentregionscanberelatedtothisscale.

Ongoing research in the Pyrenees is based on conodonts high-resolution bio andchronostratigraphy. The Pyrenean conodont succession supports the threefold subdivisionoftheGivetianStageintosubstagesandidentifiesallthestandardconodontzones,allowingintegration of Pyrenean data into a global frame and adding an extra value formultidisciplinarystudies.Theconodontzonal subdivisioncombinedwith facies studieshasalready laid out a local T-R pattern for a Pyrenean section. This shows the potential ofGivetian strata in the Pyrenees for further multidisciplinary studies, including thosepertinent to IGCP-652 major goals and for contributing to a better understanding of thehistoryofEarth.

Givetian strata measured between 30-40 ms and are studied in two different geologicalsettings(basins?).Mostsectionsarecomposedofreddish-pinkishandlightgreynodularandplaty limestone, with thin and thicker, sometimes massive, beds. A different section iscomposedoflimestonewithsubordinatedmarlbedsandfewnodularbeds.

WithintheGivetianmostfaunaldiversification, innovationandradiationeventsareclearlyage-constrained. Now, we have the opportunity to link these biotic changes to majorphenomena. The Pyrenean sequences facilitate the integration of already fine conodontbiostratigraphicscalewithothertools,astheenvisagedintheIGCP-652,withtheintentionof improving theGivetian timescale.This in turnwillhelp todocument thebiologicalandenvironmentalevolutionandchangesandtheirpossiblelinkstoastronomicalforces.

JCL is supported by theMINECO (Juan de la Cierva Postdoctoral Program, Ref. FJCI-2015-26813)andbytheMECD(JoséCastillejoResearchMobilityProgram,Ref.CAS18/00328.ThisworkrepresentsacontributiontotheIGCP-652.

Upper Katian Cyclostratigraphy of the Vauréal Formation, Anticosti Island(GulfofSt.Lawrence,Canada)

M.Sinnesael1,4,A.Mauviel2,A.Desrochers2,P.McLaughlin3,J.DeWeirdt4,P.Claeys1T.R.A.Vandenbroucke4

1.VrijeUniversiteitBrussel,Belgium(Matthias.Sinnesael@vub.be)–2.UniversityofOttawa,Canada – 3. Indiana Geological and Water Survey, Indiana University, USA – 4. Ghent

University,Belgium

Anticosti Island(GulfoftheSt.Lawrence,Canada)hassomeofthemostcomplete,thickestandmostrichlyfossiliferouscarbonatesuccessions intheworldcontainingtheOrdovician-Silurianboundary.Thisstudyfocusesonthecyclostratigraphyoftheupper Katian Vauréal Formation. Data from both continuously exposed coastalsections(WestEnd)andcompletestratigraphicdrillcores(NACPandLaloutrecores)contains high-resolution (dm-scale) proxy profiles of natural gamma ray (NGR)profiles, handheld X-Ray Fluorescence (pXRF) measurements and bulk carbonatestableisotopevaluesofoxygen(δ18O)andcarbon(δ13C).Outcropandcoredataarecorrelated using the high-resolution lithological logs and δ13C profiles. Time-seriesanalysis of the proxy series demonstrates meter-scale periodicities in lithologicalalternations(carbonateversusclaycontent),whicharehypothesizedtoresultfromsea-levelvariationsorvariationsinthesupplyofdetritalmaterial.Similarperiodicitypatternscanbeseen intheδ18Ostable isotopedata.Theavailableageconstraints(bio-andchemostratigraphy),indicatethattheprimaryobservedperiodicitiesareinthe order of the astronomical periods of precession and obliquity. The mainperiodicity(5-9m)isonalargerscalethanthetypicaltempestitealternations(dm-scale) and is thus probably not representing single events (e.g. stormdeposits) orpure diagenetical features, but long term changes in carbonate versus clay in thelocalpaleodepositionalsystem.Oneworkinghypothesisisthatastronomicalchangesininsolationweredrivingsea-levelvariationsbythewaxingandwaningoftheLateOrdovicianicesheets.Analternativehypothesissuggestschangingdetritalinputintothe basin (e.g. driven by a monsoonal system) altering the carbonate versus claycontent. Ongoing signal processing investigations can shed light on long-termamplitude modulations of the proxy records – which can help determining theprecession and/or obliquity drivennatureof the records.Our results demonstratethepotentialforconstructingahigh-resolutionagemodel(downtotheorderoftenthousandyears)fortheVauréalFormationandothersimilarformationsonAnticostiIsland. Such an astronomically based age model and corresponding climaticinterpretations should shed more light on the dynamics of the Late Ordovicianglaciationsandthemassextinctionevent.

Crossrecurrenceplotanalysesofconodontcommunityturnover–amodelfree,continuous,high-resolutioncorrelationtool

A.Spiridonov1,2,R.Stankevič1,J.Samsonė1,A.Brazauskas1,T.Meidla3,L.Ainsaar3,S.Radzevičius1

1 Vilnius University, Lithuania (andrej.spiridonov@gf.vu.lt) – 2. Nature Research Centre,Vilnius,Lithuania–3.UniversityofTartu,Estonia

ConodontsareacornerstoneofthebiozonationbasedstratigraphyofthePaleozoiceraandtheTriassicperiod.Theirhighpreservationpotential,wideenvironmentaldistribution,andco-occurrence with other time-significant taxa, makes them ideal tool for integrating allsorts of stratigraphical information in to the coherent geochronological framework.Traditional stratigraphy, including quantitative stratigraphy, uses only first and lastappearances of relatively short-lived species and sub-species of conodonts. On the otherhand there is plenty of other time-specific information which can be obtained fromconodont samples – i.e. their abundance, diversity, and compositional similarity. Usuallythese types of information are used in eco-stratigraphical applications, such as faunalgradientanalysis,mostlyinqualitativefashioninthestratigraphicalcorrelationapproach.

Here we present cross-recurrence plot and conodont community composition basedstratigraphical correlation approach. Cross recurrence plots are binary filtered similaritymatrices between two stratigraphical time series where black points represent similarstates, and white dissimilar states. The diagonal trending black points are of preeminentimportance,sincetheysuggestsimilarities incompositionalevolutionofpaleocommunitiesat two compared sites. Themajor task for the quantitative correlation is to find optimalmonotonicallyincreasingpath(correlationline)throughthecloudofrecurringstates.Inthiscontribution we explored two approaches in the search of optimal correlation(synchronization)lines:namelyclassicaldynamicaltimewarping(DTW)approach,andanewapproach which we termed moving window median (MWM) recurrence point searchalgorithm.Additionallywetreatedtheprimaryconodontdiversitydataintwoways–asrawcomposition and as reduced multivariate non-metric multidimensional scaling (NMDS1)scores.

ThepresentedapproachesweretestedonfourcoresectionfromtheLithuanianpartoftheSilurianBalticbasinspanningfromupperHomeriantotheendofLudlow.Thequantitativecorrelation patternswere tested against traditional conodont zonation andd13C trends. Itwas found that in all four cross recurrence based correlation approaches which usedconodont community compositional data (two synchronization line searchmethods * twodata representations) shown expected correlation pattern justwith the higher detail. ThebestresultswereobtainedusingNMDS1scoresasthecomparedvariableandbothDTWandMWMassynchronizationlinesearchingmethods.

Therefore our results prove the potential for using conodont community compositionaltrends inhigh-resolution correlation ina cross recurrenceplot synchronization line searchframework.Ithastheadvantageoversomeotherapproaches,suchascyclostratigraphy,innon-requiringspecificstatementsaboutthemechanismsofthecommonforcing inseveralsections.Thisapproachcouldservewell in thecomplicatedsituations (asexhibitedbyourstudied sections) where abundant hiatuses, diastems, and significant sedimentation ratevariationscouldbepresent.

TheLochkovian(LowerDevonian)intheSpanishCentralPyrenees:conodonthigh-resolution biostratigraphy as a basis for integrating Events, oceanic,climaticchangesandMilankovitchcycles

J.I.Valenzuela-Ríos1,J.-C.Liao1

1.UniversityofValencia,Spain.jose.i.valenzuela@uv.es;jau.liao@uv.es

Lochkovian (Lower Devonian) strata from eight selected sections in the SpanishCentral Pyrenees have proved to be instrumental for globally subdividing theLochkovian into substages. Besides, the fine bio-chronostratigraphic subdivisionprovidedbytherecordofseveralevolutionaryconodontlineagessupportsthemostdetailedzonationandevenfurthersubdivisionofzones.Thisinturnfosteraccurateglobal correlation, that for some intervals is estimated to be under 200 ky.Mostsections are interpreted to be deposited in a hemipelagic carbonate ramp,whereshallowwater facies below stormwave base are common. The lower part of theLochkovianinmostsectionsshowsdominantblackshaleandlimestone,whichweredepositedinacalmshallowmarineeuxinicenvironment.Overlainsedimentsclearlymarkanaugmentinoxygencontent.FinallyattheendoftheLochkovianasealevelfall is recorded. This change fromeuxinic tomore oxygenated sediments happensaftertheentryofthefirstAncyrodelloides,Anc.carlsi,however,theexacttimingonthisGeoevent seems tobediachronous in thePyrenean sections. The subsequentrapidevolutionarysteepswithinAncyrodelloides(uptosevenspeciesinlessthan3My), combinedwith the innovation and evolutionary steeps of the genera Lanea,Flajsella and Masaraella and complemented with records of Icriodus andKimognathus supports the finest subdivision of middle Lochkovian strata andsubsequentglobal correlations.MiddleLochkovian is characterisedbywell-beddedlimestone (form 5-20 cm thick) with shale-marl inter-bedded (2-4mm thick). Theupper Lochkovian is not as detailed subdivided as the middle Lochkovian, butevolutionarysteepsofMasaraellaandPedavisandan innovationwithinthegenusIcriodus, provide enough detail for global correlations. The lithological pattern iscomparable to the middle Lochkovian (limestone-marl/shale alternation) butincreasing the limestone thickness. Initial studiesonmagnetic susceptibility in twosectionshelptestingcorrelationsindependently.

This integrationofhigh-resolutionbiostratigraphy,GeoandBioEvents,well-beddedlimestone-marl (shale) alternation pattern, inferred sea level changes gives thePyrenean sections one of the best conditions for initiating detailed cycle-stratigraphic techniquesaimingatanalysing the roleofastronomical factors in thechangesalreadyobserved in thePyreneansections.Thedevelopmentof the IGCP-652 project would be a good opportunity to start with the construction of anastronomicallyconstrainedrelativetimescalefortheLochkovian,andthePyreneesoffergoodconditionsforinitiatingsuchintegrativestudies.

JCLissupportedbytheMINECO(JuandelaCiervaPostdoctoralProgram,Ref.FJCI-2015-26813).ThisworkrepresentsacontributiontotheIGCP-652.Mostactionsforobtaining the row data of this study were supported by the Alexander vonHumboldt-Stiftung(JIV-R).

MagneticpolaritytimescalefortheDevonian…?

A.vanderBoon1,C.Sprain1,M.Hounslow2,A.Biggin1

1.UniversityofLiverpool,U.K.–2.LancasterUniversity,U.K.

TheEarth’smagneticfieldishypothesisedtohavea‘heartbeat’,ofvaryingintensity,withaperiodof200millionyears.Astrongermagneticfieldisgenerallyassociatedwithmagneticsuperchrons,periodsofmillionsofyearsinwhichthemagneticfieldisextremelystable,andtherearenoreversalsofthemagneticpolesoftheearth.Ontheotherhand,aweakfieldisassociated with many reversals. This hypothesis relies heavily on the behaviour of themagneticfieldduringtheDevonian.The‘heartbeat’hypothesispredictsaweakfieldforthistime,withahigh reversal frequency.Currently, theDevonian is a relativelyunconstrainedperiodoftheglobalpolaritytimescale,mostlikelyduetotheweakfieldandhighreversalfrequency.Constrainingtheglobalpolaritytimescale(GPTS)andreversalfrequencyfortheDevonian is crucial for theunderstandingofmagnetic fieldbehaviour,andconstructionoftheGPTSprovidesavaluabletoolforagedeterminationsofotherstudies.

WeperformedapilotmagnetostratigraphystudyonsamplesoftwoquarriesinthesouthofPoland, near the city of Krakow. The quarries contain a record of latestDevonian-earliestCarboniferous carbonates, which are correlated to the Dinantian of Belgium based onforaminiferandcoralbiostratigraphy.Intotal98specimensweresubjectedtothermalandalternatingfielddemagnetisationatthepaleomagneticlaboratoryofUtrechtUniversity.

Intensitiesofthemagneticsignalwereextremelylow,intheorderoftensofmicroamperespermeter.Demagnetisationbehaviour isnotstraightforward,withmanysamplesshowingdemagnetisation along great-circle paths. Most samples show a strong reversed Permo-Carboniferous reverse (Kiaman superchron) overprint, which in some cases cannot beremoved. Around 40 percent of the samples shows directions thatwe interpret asmostlikely representative of the geomagnetic field at the time of deposition, both normal andreverseddirectionsarepresent.This indicatesthatmagneticpolaritystratigraphymightbepossible in the Devonian, provided that sections have low enough thermalmaturity. OurprojectiscurrentlyextendingtheCzatkowicequarryrecordtohigherdensitysamplingandyounger(TournaisianandViséan)rocks.

WewouldliketomakeacallouttothePaleozoiccommunitytonotifyusofadditional lowthermalmaturitysections(ideallyshowingconodontalteration indicesupto2) inordertoextendthemagnetostratigraphicrecordfurtherbackintotheDevonian.

Impacteventstratigraphy:lessonsfromPaleozoiccraters,ChicxulubandtheK-PgboundarydepositsM.T.Whalen1andtheExpedition364Scientists1.UniversityofAlaskaFairbanks,USAExtraterrestrial impacts are fundamental processes that shape the rocky planets.Well-studiedmarineimpactcraters,includingPaleozoicexamples,provideawealthof information about impacts and resulting deposits. These catastrophes produceeventdepositsovertimeframesthatdefyeventhemostpreciseagedatingmethods.Examination of the Ordovician Tvaren and Lockne craters provides insight intoprocesses in newly excavated craters implying the following series of events: 1)Collapseofthetransientcrater/watercavityandinitialresurgeofwater,2)Radiallyresurgingwater produces a centralwater plume, 3) Collapse of the centralwaterplume causes outward radiating anti-resurge, 4) Anti-resurge and reflectedwavestravelastsunamiandseichesintheopenocean.Theseprocessesresultinaseriesofdeposits that formwithinminutes followedbya seriesofwaningcurrentdepositsoverdaystoperhapsyearspost-impact.

Recentwork on IODP-ICDP Expedition 364 core, Chicxulub crater, provides insightinto these processes. Core was recovered from 505.7-1334.7 m below seafloor(mbsf), penetrating Paleogene sediments, impact breccias, melt-rock, and graniticbasement.Theimpactbrecciaandoverlyingtransitionalunitrecordthecatastrophiceventsresultingfromtheimpactandsubsequentprocesses.Thelowerbreccia(>705mbsf) is interpretedasdebris flowssimilartovolcanicpyroclastic flows.Theupperbreccia, records a remarkable succession of 25 graded packages that fine upwardfrom coarse pebble-to-sand size clasts and then sand to silt-clay-sized material.These are interpreted as the result of resurge, anti-resurge, and tsunami. Thetransition between breccia and Paleocene sedimentary rocks is an ~80 cm thickseries of 39 mm-cm thick, dark/light, fining-upward, carbonate-rich couplets withscouredbases.Maximumgrain-sizedecreasesfrom~6mm(base)to0.25mm(top)indicatingwaningcurrentdepositionwithvelocitiesof100-25cm/s.Atpost-impactwater depths (~650m) the only types of currents capable of moving such grainswould likely be tsunami, seiches or potentially storm currents. Attempts to gaugethe duration of the transitional unit provide little constraint. It contains a mix ofCretaceous foraminifera and nannofossils (K-Pg boundary cocktail) and the firstDanianfossilsinoverlyinglimestonesindicatePaleocenezonePa,estimatedat~30kyrspost-impact.Weutilized theabundanceof 3He, a commonaccumulation rateproxy, to improve constraints. 3He implies a maximum duration of 8 kyr butassuming even a small amount of 3He reworking indicates a duration below theproxy’sresolution,<~1kyr.Settlingvelocitycalculations(minimumgrainsize~2mm)yield a duration of ~6 years. Given the sedimentary features it is unlikely it wasdeposited through settling alone. It appears to record the final waning of impactenergy,tsunamiandseiches.Oneadditionalclueiswithinfine-graineddepositsnearthe top that indicate ejecta from the impact that atmospheric modeling implieswould settle in2-3years,providing the shortest-termestimate for the transitionalunit. Marine impact craters record a remarkable series of events related to the

dissipation of energy imparted by the impacts and thewell preserved deposits atChicxulubprovide a unique insight into thesedynamic and geologically short-livedprocesses.

PosterPresentations

RefiningtheendoftheLatePaleozoicIceAge–LPIAintheParanáBasin,southernofGondwanaCagliari,J.1,Netto,R.G.1,Schmitz,D.M.21UniversidadedoValedoRiodosSinos,Av.Unisinos,950.CristoRei,SãoLeopoldo,RS,93022750,Brazil.2DepartmentofGeosciences,BoiseStateUniversity,1910UniversityDrive,Boise,Idaho83725,USA.

TheParanáBasinisaPaleozoic-MezosoicintracratonicbasinlocatedinthesouthernGondwana. Itrecordsthemostspatiallyandtemporalextensive icehouse,theLatePaleozoic IceAge–LPIA.TheCapané isoneof theseveralpaleovalleyson theRioGrande do Sul shield, in the southern border of the basin, which have beeninterpreted as carved by LPIA glaciers. It preserves striated pavements indicatingthat the ice flowed northward, and a sedimentary infill composed of glacial-influenced and post-glacial deposits of the Itararé Group and Guatá Group,respectively. The Itararé Group lithologies are diamictites, conglomerates,sandstones, varve-like rhythmites, and mudstones, with dropstones in the fine-grained facies, and striated, faceted and bullet-shaped pebbles, cobbles andboulders indiamictite.A fewradiometricdatingsandpalynological studiessuggestthattheItararéGrouphasbeendepositedbetweenKasimovian(Carboniferous)andSakmarian(Permian),althoughseveralradiometricdatinginthepost-glacialdepositsoftheRioBonitoFormation(GuatáGroup)showsthatthedepositionofthisunitislikely constrained to the Carboniferous. This study presents a high precision U-PbradiometricdatingforanashfallsamplecollectedintheuppermostItararéGroup,intheCapanéPaleovalley,southernParanáBasin(RioGrandedoSul,Brazil).TenoftheyoungestzircongrainsanalyzedbyCagliarietal.(2016)byLA-ICP-MSwereselected.The analytical procedure includes thermal annealing, chemical abrasion andchemicaldissolutionof individualzirconcrystals(Mattinson,2005),followedbyionexchangechromatography,andUandPbisotopicmeasurementsmadeonamulti-collector thermal ionization mass spectrometer. The radiometric age obtained isyoungerthantheonepublishedbeforebyCagliarietal.(2016)butstillconstraintheend of the LPIA in the southern Paraná Basin to the Carboniferous. The resultreaffirms that thewholeof the ItararéGroup in thesouthernbasinwasdepositedduring the Carboniferous. Comparing glacial and post-glacial deposits of thesouthernParanáBasinwiththePaganzoandKaroobasinsindicatesthattheendoftheLatePalaeozoicIceAgeisasynchronousthoughtthesouthernGondwana.

TheDevono-MississippianBesaRiverGroupofLiardBasin,Canada:stratigraphyofaworld-classshalegasresourceF.Ferri*,B.C.Richards**,M.McMechan**,P.Kabanov**,A.Mort**,P.Thapa**,J.Leslie-Panek**,&E.Little***TenureandGeoscienceBranch,BritishColumbiaMinistryofNaturalGasDevelopment;Victoria,BC,Canada.**GeologicalSurveyofCanada–Calgary,LandsandMineralsSector,NaturalResourcesCanada;Calgary,AlbertaCanada requires new, globally competitive domestic energy sourceswhilemovingtowardslowercarbonandrenewableenergysources.Thestratigraphicknowledgeispart of fundamental geoscience which is critical in accurate assessment ofunconventional hydrocarbon resource (shale plays) and is transferable to othersources of energy such as geothermal and groundwater. As such, the applicabilityandimportanceofthisresearchlineupwithsimilarprojectsaroundtheworldandremainskeytoenergysustainability.

TheMiddleDevoniantoMiddleMississippianBesaRiverGroupintheLiardBasinof northwestern Canada is a distal, shale-dominated succession that is timeequivalent to thousands of metres of more proximal carbonates, shales, andsandstones spanning the Fort Simpson toMattson formations. Petrophysical logsallow the recognition of specific formations within northeastern subsurfaceoccurrencesoftheBesaRiverGroup,butthisisnotpossibleinthewesternoutcropandsubsurfacebeltwheretheunitremainsatformationlevel.

The Besa River Group contains 6,196 x 109m3 of marketable, dry gas within

organic-richshalesoftheExshawFormationandPatry interval. Theseunitsdefineanover200mthick,20to30kmwide,north-northeasttrendingzoneintheeasternLiard Basin. These siliceous shales occur at over 5 km depth, producing over-pressured reservoirs and resulting in prolific wells when stimulated throughhydraulicfracturing.

The Famennian Patry shales are basinal equivalents of upper Kotcho rampcarbonatesandcalcareousshales,whichinturntransitioneastwardintoWabamunFormation shelf carbonates. The upper Patry interval was deposited during a lateFamennian to early Tournaisian second-order transgressive-regressive sequence.TransgressionculminatedwithdepositionofthelowerExshawblackshaleandchert,whereasthesubsequentregressionisrecordedbytheoverlyingupperExshawandoverlyingBanffFormationOrganic-carbon-richPatryshalesreflectestablishmentofanoxicbottomwaterswithindeep,basinalenvironments. Theseanoxicconditionsspread across much of the Western Canada Sedimentary Basin as transgressionpeakedduringdepositionofthelowerExshaw.

Convergentplatetectonism,andsubsequentback-arcextension,occurredalongthe western edge of Ancestral North America during the latest Devonian andMississippian.Compressionandsubsequentextension influenceddepositionwithinLiardBasinandgrabenswithinthePeaceRiverEmbayment.FelsictufflayerswithintheExshawFormationandPatryintervalareareflectionofthewesternconvergenttectonism,plutonism,andvolcanism. Thedatingof these tuffhorizons isongoing

and will help constrain the absolute timing of the second-order transgressionrepresentedby thePatryandExshaw . Thiswill furtherourunderstandingof thismajormarine late Famennian to early Tournaisian anoxic event that included thelatestFamennianHangenbergevent.

Magneto-cyclostratigraphyofLatePaleozoicrhythmitesfromMafraFormation(ParanáBasin,Brazil) Franco,D.R.1,Brandt,D.2,Hinnov,L.A.3,Ernesto,M.2,Rodrigues,P.O.C.1,Weinschütz,L.4,Zhao,X.51ObservatórioNacional,CoordenaçãodeGeofísica,RiodeJaneiro,Brazil2 Universidade de São Paulo, Instituto de Astronomia, Geofísica e Ciências Atmosféricas,DepartamentodeGeofísica,SãoPaulo,Brazil

3GeorgeMasonUniversity,DepartmentofAtmospheric,OceanicandEarthSciences,Fairfax,USA

4UniversidadedoContestado,CENPALEO,Mafra,Brazil5TongjiUniversity,SchoolofOceanandEarthScience,Shanghai,ChinaThesignificantlackofpaleontological,palynostratigraphicandradiometricdatahasled to a historically poor chronostratigraphic framework for the rhythmites of theItararéGroup(ParanáBasin,Brazil),whichcorrespondstooneofthemainPaleozoicglaciation sequences of the Gondwana supercontinent. This is particularlychallenging given the scarcity of paleomagnetic data for the Carboniferous, theuncertainties regarding the APWP curves for the South American Plate during thelate Paleozoic, and the predominance of the Kiaman Reversed Superchronthroughout the most of Permian-Carboniferous times. In this context, theidentification of Milankovitch forcing components along the stratigraphic profilescouldprovideimportantcluesabouttheelapsedtimefortheaccumulationoftheserhythmicdeposits,andifsufficientthemeansforeliminatingthesecularvariation.In thiswork,we conductedamagneto-cyclostratigraphic studybasedonmagneticsusceptibility(MS)andanhystereticremanentmagnetization(ARM)datasetscarriedoutona~360cmthickrhythmitesectionoftheMafraFormation(ItararéGroup).Spectralanalysiswasconductedwithmultitapermethod(MTM)spectralestimatorassociated with a classical red-noise null model, and stability of the detectedfrequencieswas evaluatedwith evolutionary fast Fourier transform (FFT) analysis.Potential astronomical forcing was tested identification of frequenciescorrespondingtotheorbitaleccentricity,obliquityandprecessionindexpredictionsfor the Upper Carboniferous-Lower Permian interval (~ 300 Ma) by Berger andLoutre (1994). The MTM power spectra for the MS and ARM datasets exhibitspectral peaks indicative of variable sedimentation rate, and supported by theevolutionaryFFTanalysis,nonethelesssuggestiveforapotentialMilankovitchsignal,especially for the ARM series. Our findings suggest that the Mafra section maycomprise6-7shortorbitaleccentricitycyclesandhenceadurationof600-720k.y.

ReassessmentoftheLowerDevonianandlowerMiddleDevonianconodontbiostratigraphyintheNorthwestTerritories,Canada:changesinthetime-rockchartforthenorthernMackenzieMountainsandadjacentplainsS.A.Gouwy*&P.Kabanov*

*GeologicalSurveyofCanada,3303,33rdstNWT2L2A7Calgary(AB,Canada);sofie.gouwy@canada.ca;pavel.kabanov@canada.ca

The Lower Devonian and lower Middle Devonian in the northern MackenzieMountains is a succession of dolostone, limestone breccia andmassive limestonewith minor basal sandstone. The basal Delorme Group onlaps underlying LowerSiluriandolostoneswitha locallyangularunconformity.TheentireLowerDevonianrepresents a peritidal carbonate platform and evaporite – carbonate alternationoccurs in the platform interior in the eastern part of the study area (MackenziePlain).TheLowerDevonianperitidalcarbonatesgradeupwardintosubtidalvariouslyargillaceous and richly fossiliferous limestones of the Eifelian Hume Formation.Based on new field data and a restudy of GSC-Calgary conodont collections, thetime-rockchartforthissuccessionisupdatedtothecurrentconodontbiozonation.TheoldestDevoniandeposits, theDelormeGroup(TsetsoandCamsell formations)spantheintervalbetweentheendoftheSilurianandtheendoftheLochkovianandoverlie the sub-Devonian unconformity. The Tsetso Formation quarzarenite, atransgressive peritidal sandstone, represents the onset of the Devoniantransgression in the study area and is locally followed by the brecciateddolomudstones and interbedded anhydrites of the Camsell Formation. Conodontmaterial from theDelormeGroup is very rare, only one sample from the CamsellFormation provides enough material and indicates a Lochkovian (eurekaensis todeltazones)age.The Delorme Group is separated from the overlying Bear Rock Assemblage by anabrupt change from calcareous sandstone to clean limestone and dolostone. TheBearRockAssemblagecomprisestheBearRock,ArnicaandLandryformations.Thecrystalline, distinctly banded dolostone of the Arnica Formation and the overlyingcrystalline limestone of the Landry Formation pass laterally into the brecciatedlimestoneanddolostoneoftheBearRockFormation.ConodontdatafromtheBearRockAssemblagereconnaissancesamplesintheColvilleHillsassignthestratatothedehiscens to costatus zones (lowermost Emsian to lower Eifelian). ArnicareconnaissancesamplesfromthenorthernMackenzieMountainspointtothelowerEmsian(nothoperbonus-inversuszones).SamplesfromtheLandryFormationcontaina conodont fauna with a range from the lower Emsian to the lower Eifelian(excavatustocostatuszones).A new transgressive pulse formed of the lower unit of the Hume Formation ismarked by the deposition of argillaceous limestone and shale (HeadlessMember)

indicating a slight deepening of the environment. The upper unit of the HumeFormationisafossiliferousthin-tothick-beddedplatformlimestone.FoursectionsweresampledthroughtheHumeFormation inthemountain frontof thenorthernMackenzieMountains,allowingadetailedconodontbiostratigraphythatindicatesamiddle to upper Eifelian (australis to ensensis zones) position for the Formation(Uyenoetal.2017).ThedrowningoftheHumeplatformismarkedbytheonsetofthe black shales of the BluefishMember (Hare Indian Formation) in the ensensisZone.Uyeno,T.T.,Pedder,A.E.H.&Uyeno,T.A.,2017.ConodontbiostratigraphyandT-RcyclesoftheMiddleDevonianHumeFormationatHumeRiver(typelocality),northernMackenzieMountains,NWT,Canada.

Identifyingcyclicitiesindifferenttypesofdataseries:astudyoftheCarboniferousrhythmitesoftheItararéGroup,ParanáBasin Kochhann,M.V.L.1;Cagliari,J.1;Kochhann,K.G.D.1;Tedesco,J.1;Aquino,C.D.2;Souza,M.K.1;Souza,L.V.11UniversidadedoValedoRiodosSinos,Av.Unisinos,950.CristoRei,SãoLeopoldo,RS,93022750,Brazil.2UniversidadeFederaldoParaná,Curitiba,PR,CaixaPostal19001,CEP81531-980,Brazil.The Itararé Group records the end of the “Late Paleozoic Ice Age” (LPIA) in theParanáBasin,southernBrazil. InthesouthernmostpartoftheParanáBasin,glacialconditions are evidenced mainly by the presence of mudstones and varve-likerhythmiteswithdropstones,anddiamictiteswithstriated,facetedandbullet-shapedpebbles,cobblesandboulders,besidesstriatedpavements. It isknownthatglacialandinterglacialperiodsarecontrolledbyinsolationchangescausedbyorbitalcyclesrelatedtovariationsofEarth’sorbitthroughtime.Asaconsequence,orbitallypacedclimate changes may influence the sedimentation patterns, which can record thecyclesandenabletheirrecognitioninthegeologicalrecord.AssumingthehypothesisthatorbitalcyclesconditionedthedepositionofthesedimentarysuccessionoftheItararé Group, this research aims to (i) recognize the cyclicities preserved inrhythmites of Itararé Group in southernmost part of the Paraná Basin and (ii)compare cyclicities identified in two different data series and thus estimatesedimentation rates for the studied succession. Theanalysesweremade ina coredrilled by the BrazilianGeological Survey (CPRM),which is located in theMarianaPimentelpaleovalley,thesoutheasternborderoftheParanáBasin.Onedatasetwasobtained by measuring the lithological couplet thickness of rhythmites, and theother, by measuring the spectral reflectance of visible wavelength. Both datasetswere processed with the software R, using the Astrochron package. We usedAstrochron to perform time series analyses such as Robust Locally-WeightedRegression Spectral Background Estimation, Evolutive Harmonic Analysis, andMultitaper Method Spectral Analysis. Using these algorithms, the datasets wereinterpolatedcreatingamoredetailedscaleand reducingnoise inorder to identifycyclicities and to estimate sedimentation rates. Preliminary results enabled therecognition of frequencies ranging between 1 and 10 cycles per meter in bothcouplet thickness and reflectancemeasurements.Overall, our analysis suggests anincreasing-upward trend in sedimentation rates, basedon the lengthof the cyclesidentifiedwithin thesedimentary succession.Furthermore, the resultsobtainedsofar are in agreement with previous studies carried out in other Carboniferoussuccessions of the Paraná Basin (Santa Catarina and São Paulo states), whichidentified Milankovitch and millennial-scale cycles controlling sedimentationpatterns. Futuredevelopmentson the analysis presentedhereinwill contribute toimprovingthechronologyofdepositionoftherhythmiteswithintheItararéGroup.

TheremagnetizationofmarinecarbonaterocksoflateOrdovicianinPingliangsection(China)J.Luo1,S.Dai1,M.J.Dekkers2,W.Wang3,X.Qiang4,L.Qiang1,C.Tian1,H.Xi1,W.Krijgsman2

1.LanzhouUniversity,Lanzhou,China–2.UtrechtUniversity,TheNetherlands–3.ThirdInstituteofOceanography,StateOceanicAdministration,China–4.ChineseAcademyofSciences,China

Thenaturalremanentmagnetization(NRM)ofcarbonaterocksinparticularmustbeunderstood for the construction of a meaningful Paleozoic geomagnetic polaritytime scale. This would enable evaluating geomagnetic features (e.g. reversalfrequency) and provides a paleomagnetic dating tool. The Ordos block, centralChina,wasreportedatlowlatitudesontheSouthernHemisphereduringOrdoviciantimes.Ordovicianstrata,composedofcarbonateandfine-grainedclasticrocks,arewell developedandexposed in the SWOrdos.MotivatedbyProject IGCP652,wecollectedthreeparallelorientedpaleomagneticsamplesat21sites inthePingliangsection(SWOrdos)in2017.Withatotalthicknessof95meters,thissectioncoversthe boundary of the Majiagou Formation and Pingliang Formation, with an EarlySandbian age. The lithologies comprisemainly limestone, dolomite, siltstone,withseveral tuff layers intercalated. Most rocks are distinctly light brown, caused byweathering.

Wecutthesamplesinto2cmlengthcylindricalspecimeninthelaboratory.Asetofspecimenswasstepwisethermallydemagnetizedupto690°Cordemagnetizedwithalternating field (AF) demagnetization up to 80mT, and measured with a 2GEnterprises Model-760R superconducting rock magnetometer in a magneticallyshielded room.We identify two NRM components; the first is a low-temperaturecomponent(~250°C),interpretedasasecondaryNRM.Thesecondisamiddle-hightemperaturecomponent(between250°Cand500°C,sometimesupto580°C),whichcarried by magnetite (mostly fine particles) and would be the characteristicremanentmagnetization (ChRM). Its direction is declination atNWand inclinationpointing down, with mean direction of Ds=314.1°, Is=50.0°, alpha95=7.2°. Rock-magnetism measurements (including isothermal remanent magnetism (IRM),hysteresisloopandthefirst-orderinversioncurve(FORCs))havebeencarriedoutforfourrepresentativespecimens.Theresultsshowthatthespecimensaresaturatedinfields<300mT.Thisindicatesthatthemagneticmineralsaresoftcoercivitymineralsand low in content. In addition, thehysteresis loops arewasp-waisted, suggestingmixingofsoftandhardmagneticminerals.Finally,FORCdiagramsofthreesamplesshowamoreor less closed concentric contourmaximumat~20mT,whichwouldindicate a fair proportion of SD particles. In a Day plot, all samples plot between

superparamagnetic envelope and the single domain - multidomain mixing line.Above all, we infer the NRM-carried minerals are mainly magnetite with a bit ofpyrrhotite.ThesecondcomponentofNRMdidnotpassboththereversalandfoldtests, indicating that the rocksare remagnetized.Using theChRM to calculate thegeomagneticpolepositionyieldsPlong=23.3°,Plat=51.6°.IfweconsiderNorthChinaas part of Eurasia, this pole position is not like any one since 200 Ma, thus theremagnetizationmighthaveoccurredpriortoJurassic.Thisneedsfurtherstudy.

AcknowledgementThisstudywasfundedbythefundamentalresearchfundsfortheCentralUniversities(lzujbky-2017-k27)andcontributetoIGCP652.

TheEocene–OligocenetransitioninthesouthernTethys:astronomicalcalibrationofcalcareousnannofossilbioeventsandgeochemicalchangesinnortheasternTunisia

JihedeHajMassoud1,2,ChokriYaich2,JohannesMonkenbusch1,NicolasThibault1 1DepartmentofGeosciencesandNaturalResourceManagement,UniversityofCopenhagen,ØsterVoldgade10,DK-1350,CopenhagenC.,Denmark.2LaboratoryofSedimentDynamicsandEnvironment,SfaxNationalSchoolofEngineers,PB1173,3038,Univ.ofSfax,Tunisia,

ThelateEocene-EarlyOligocenetransitionischaracterizedbytransientchangesinenvironmental conditions fromgreenhouse to icehouse controlledby theonsetofthemajor Antarctic glaciation phase ( ~34Ma). The effects of thismajor climatictransitioninEarthhistoryhavenotbeenstudiedsofarinthesouthernTethys.Here,wepresent newdata from theAinRahma section (Northeastern Tunisia, CapBonpeninsula) across the late Eocene – early Oligocene. High-resolution magneticsusceptibility allows for an astronomical calibration of the section. Calcareousnannofossil biostratigraphy and carbon and oxygen-isotope stratigraphy permit anexcellenttietotheglobalstandardbenthicoxygenandcarbonisotopecurves.Hand-held X-ray Fluorescence (HH-XRF) analysis is used to show changes in detritalelements(Fe,Si,Al,Zr,…).TwomajorchangesarerecordedinTunisiacorrespondingtotheEocene/Oligocenetransition1event(EOT1)andtotheOi-1glaciationeventand depicted by important shifts in detrital elements and calcareous nannofossilassemblages.Thecyclostratigraphicanalysisofthesectiondemonstratesthemajorroleofobliquitydominanceand1.2MyramplitudemodulationoftheobliquityoversedimentationinthesesouthernTethysdeposits.

Figure 1. Gaussian process (left panel) applied to visualize the MS response toastronomicalforcingbetween31.5and35Ma.BluetoredcolorsdesignatehightolowMS.Thee·sinobliquityplotsrepresentasliceate·cos=0,whilethee·sin–e· cos plots show the dependency of MS over the distribution of obliquity (e iseccentricityandωisthelongitudeofperihelionmeasuredfromthespringequinox).NH—NorthernHemisphere; SH—SouthernHemisphere.CWT and theevolutionofthe173kyrand43kyrcyclesarealsopresented.

Cyclostratigraphyofthemarl-limestonealternations(Berriasian)intheNorth-SouthAxis(centralTunisia):geochronologyandchronostratigraphicimplicationsHamdiOmar1, Anne-Christine da Silva2,3, JihedeHajMassoud2,Hela Fakhfakh3andChokriYaich1

1:ResearchUnit:SedimentaryDynamicsandEnvironment,NationalEngineeringSchoolofSfax,RoadofSoukrakm3.5,PB1173,3038,Univ.ofSfax,Tunisia.LaboratoryofGeoressources,MaterialsEnvironmentandGlobalChange,FacultyofSciencesofSfax,RoadofSoukrakm3.5,PB1171,3000,Univ.ofSfax,Tunisia.2:UtrechtUniversity,DepartmentofEarthSciences,PaleomagneticLaboratory‘FortHoofddijk’,Netherlands.3:LiègeUniversity,SedimentaryPetrologyLaboratory,Belgium.4:TunisianNationalOilCompany(ETAP),Montplaisir,PB83,1002,Tunisia.

The lower Cretaceous marl-limestone alternation in central Tunisia (southernTethyan margin) offer a scenic exposure of strata outcrop extremely suitable forcyclostratigraphicstudies.However,someoutcroppingsedimentaryseriesincentralTunisia suffers from a sharp lack of accuracy affecting their chronostratigraphicframework.Amongst, theSidiKhalifFormationat JebelFaidh locality (North-SouthAxis, central Tunisia) is the most affected one. Made up of marl-limestonealternation,thisformationhasneverbeentargetedwithneitherbiostratigraphicormagnetostratigraphic study. Hence, this study was carried out (for the first timealong the southern Tethyan margin) aiming to build a reliable cyclostratigraphicframework using the Milankovitch forcing theory. These astronomical cycles arecommonlyusedasapowerfulgeochronometertorefinesomeinaccurategeologicaltimesscales.

Very high-resolutionmagnetic susceptibility record (5 to 10 cm sampling interval)wasemployedtotrackastronomicalcyclesfromourstudiedsection.Atotalof2187samples were collected from the outcropping Sidi Khalif Formation and weremeasured for magnetic susceptibility as a paleoclimate proxy. We performedmultiplespectralanalysisandstatisticaltechniquessuchastheContinuousWaveletTransform, EvolutiveHarmonicAnalysis,Multi-tapermethod andAverage SpectralMisfit, to obtain the best astronomicalmodel. The sectionwas divided into threepartsassumingastablesedimentaccumulationrateforeachandtheprevioustimesseriesanalysistechniqueswereappliedforeachsub-sectionandshowedapervasivedominanceofE405-kyreccentricitycycles.Thecombinationoftheseresultsallowedus to review and build a new chronostratigraphic framework of the Sidi KhalifFormationatJebelFaidhasfollow:11longeccentricitycyclesE405wereextractedinadditionwhichpointtoadurationestimateof4.7MyrwithanaverageSARof2.317cm/kyr. This value of SAR goes in line with deepmarine environment successionwhichhadbeendepositedunder a passivemargin associatedwith theopeningofthepaleotethyanoceanduringtheJurassic-Cretaceousboundary.

TraceElementsoftheMiddle-LateOrdovicianinSWOrdosandItspaleoenvironmentalimplications

L.Qiang1,S.Dai1,A.-C.DaSilva2,D.DeVleeschouwer3,W.Wang4,G.Li4,J.Luo1,H.Xi1,C.Tian1

1. Lanzhou University, China – 2.Université de Liège, Belgium – 3.MARUM, University ofBremen,Germany–4.ThirdInstituteofOceanography,StateOceanicAdministration,China

TheOrdovicianwascharacterizedbyapeakofgreenhouseclimate inEarthhistory,withextremehighsea levelandatmosphericCO2concentrationsaswellasagreatdevelopmentofmarinelife intheEarly-MiddleOrdovician,anditfollowedaglacialclimate condition andmass extinction in the latest Late Ordovician. These eventshaveattractedmoreattentionwhichgaverise toagreatdealofstudies in the lastdecades.TheNorthChina is themostwell-developedsiteofOrdovician,but studyforthoseissueshasbeenstilllack.Thiscontributionpresentsasetoftraceelementsdataofcarbonaterocksandfinegrained-sizeclasticrocksinthesouthwesternOrdos(southwest North China), with aims to try uncovering their paleoenvironmentalsettingswhendeposited.

TheOrdovicianstrataarecomposedofcarbonaterocks(namedasYeli,Liangjiashan,Majiagou Formations upward) and fine grained-sized clastic rocks (PingliangFormation) in SW Ordos. We collected 50 samples from Majiagou (MiddleOrdovician) and Pingliang Formations (Late Ordovician) along the Qishan section.PreviousstudiesindicateMajiagouFormationdepositedinacarbonateplatformandPingliangFormationdidinaplatformforeslopeanddeeptrough.Ourdatashowthatthecontentsofallmeasured traceelements, suchasV,Cr,Th,Zretc,arebasicallylower in Majiagou Formation (with averaged of V 1.38 ppm, Cr 0.93 ppm, Th0.08ppmandZr1.16ppm,respectively) than inPingliangFormation (withaveragedofV64.56ppm,Cr42.54ppm,Th12.11ppmandZr163.3ppm,respectively).Inthesecond order, contents of carbonate rocks are lower than that of clastic rocks inPingliangFormation,butalsohigherthanincarbonaterocksofMajiagouFormation.ComparisontothePAASoruppercrust,themostsamplesaredepletedintheredoxsensitive elementsofV,Mo,Ni, Cu. ForUandTh, they areenriched in the clasticrocksofPingliangFormation,andtheydepletedintheMajiagouFormationandalsocarbonate rocks of the Pingliang Formation. These variations would indicatecarbonate rocks (MajiagouFormationandpartial Pingliang Formation) formed in ashallow sea and suboxic environment, but clastic rocks (main Pingliang Formation)deposited in an anoxic environment and relative higher paleoproductivity.Subsequently, the interbedded carbonate rocks in Pingliang Formation reveal thealternativechangeof sedimentarysettingsand/orpaleoclimate. In theotherhand,the Sr/Ba ratio is much higher (47-363) in Majiagou Formation than in PingliangFormation(0.11~14.5,averagedat2.02),whichsuggestthattheseawateraremoresaltywhenMajiagouFormationdeposited.

AcknowledgementThisstudywasfundedbythefundamentalresearchfundsfortheCentralUniversities(lzujbky-2017-k27)andcontributetoIGCP652.

A positive test for the Greater Tarim Block at the heart of Rodinia:Mega-dextralsuturingofsupercontinentassemblyB.Wen1,*,D.A.D.Evans11.YaleUniversity,NewHaven,USA(bin.wen@yale.edu;benwen2013@gmail.com)

The Tarim craton and neighboring terranes in Central Asia, i.e., theGreater TarimBlock(GTB),havebeenproposedtooccupya“missing-link”positionattheheartoftheNeoproterozoicRodiniasupercontinentbetweenAustraliaandLaurentia.SuchareconstructionistestedwithnewpaleomagneticdatafromtheGTB,anditisfoundthathigh-qualitypaleomagneticpolesconformtoastablemissing-linkconfigurationenduringfromca.900to720Ma. Integratingthenewresultswithcompilationsoftectonomagmatic activity and geochronology throughout the GTB, we propose anovel paleogeographicmodel for Rodinia assembly. In ourmodel, following initialphases of quasi-orthogonal subduction and collisions between southern GTB-Australia and northern GTB-Laurentia at ≥1070 Ma, the Rodinia supercontinentcompleted its assembly throughamega-dextral transpressional shearingalong theTarimianorogen.This scenariohasnoteworthyparallels to thehistoryofcollisionsthat created Pangea, and implies a more complicated geodynamic process forsupercontinentalassemblythanpreviouslyproposed.

Iterative speciation in Late Silurian Pristiograptine graptolites of the BalticBasinandthevalueofstratigraphyincladistics

M.Whittingham1,S.Radzevičius1,A.Spiridonov1

1.FacultyofGeology,VilniusUniversity,Vilnius,Lithuania

Conductingcladisticanalysesusingexclusivelyfossildatapresentsaslewofuniquechallenges. The absence of genetic material and loss of morphological charactersduringpreservationgreatlyreducestheamountofavailableusablecharacters,givingresultsmoresusceptibletoconvergencebiases.Stratocladisticbuildsontraditionalmorphological parsimony by adding a unique characteristic of fossil data:stratigraphy.Theadditionofastratigraphiccomponentallowsbothfortheinferenceof anagenic ancestor-descendent relationships and greater consistency of resultswiththeavailabledata.ThecaseoftheLateSilurianmonograptidsisideallysuitedtothe employment of stratocladistics, asmany of the samemorphologies appear indifferent speciesover large spansof time. Inaddition, thegraptolitesof theBalticBasin are associated with especially high-resolution stratigraphy, makingstratocladistic analysis less vulnerable to preservation bias. The inclusion ofstratigraphy intheanalysisofmonograptidevolutionallowedforustoparseapartmorphologically similar but temporally disparate taxa. Using this analyticaltechnique,wewereabletoindicatethepresenceofiterativespeciationeventsfromacentralstemlineageinthePristiograptinaeoftheWenlockandLudlow.