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1、TheIndus–YarlungZangboophiolitesfromNangaParbattoNamcheBarwasyntaxes,southernTibet:Firstsynthesisofpetrology,geochemistry,andgeochronologywithincidencesongeodynamicreconstructionsofNeo-TethysAbstract:Thepurposeofthisfirstsynthesisistosummarizefindingson
2、theYarlungZangboSutureZone(YZSZ)ophiolitesanddiscussstillremainingproblems.TheYZSZstudiedforalmost30yearsandistheyoungestofthesuturesrecognizedonTibetPlateau.ItisnowacknowledgedthattheYZSZisacomplexassemblageofsedimentary,metamorphicandigneousrockscreat
3、edduringandshortlyafterthecollisionbetweenIndiaandEurasia.TheagesofthevariouslithologiesspanatimeintervalfromtheJurassictotheMiddleMiocene,withsomePermianandDevonianexoticblocksfrommélangezone.TheYZSZischaracterizedbyophioliticcomplexesandophioliticméla
4、nge.Theophiolitesareoftwotypes:nondismemberedanddismemberedsections.Thenondisturbedsections,althoughtectonicallyreworked,areobservedalongthesegmentfromDazhuqutoJidinginXigazeareaandSpontangophiolite.Thedismemberedsequencesarefoundinvariouslocationssucha
5、sNidar,Kiogar,Jungbwa,Saga,Sangsang,Xigugabu,andLuobusa.Theincompletestratigraphiclogcouldbeconnectedtointraoceanicororogeneticorigins.Theophiolitesaredistributedintotwogroupsofages:theLuobusa,ZedangandKiogarsequencesbeingJurassic-LowerCretaceouswhereas
6、allothersequencesareofLowerCretaceousage.Compilationofgeochronologicaldatasuggestthatsomeophiolitesequencesmighthaveevolvedforovermorethan70Myfromtheirinitialgenesistoobductionwhichoccurredaround70–90Myago.Ophiolitesdifferintermsofpetrologicalandgeochem
7、icalaspectshowever,theywereallgeneratedinsuprasubductionzoneandmorespecificallyinarc(fewfore-arc)andback-arcsettings.Synthesisofmorethan700geochemicalanalysesshowvariablemixingofcomponentsfromN-MORB-typetoIAT-CABandtoOIBend-members.TheJurassicophiolites
8、showthemaximumofarccomponentwhiletheLowerCretaceousonesshowlittletostrongmixing.Inaddition,mostophioliteswerecreatedinshortlived(30My)basinsandgeneratedclosetotheEurasiaticcontinentalmargin.WeproposethatLadakh–Tibetophioliteswere
