TurkishJournalofEarthSciences (TurkishJ.EarthSci.),Vol.13, 2004,pp.201-213. Copyright©TÜB‹TAK UpperPermian(Changxingian)RadiolarianCherts withintheClasticSuccessionsofthe “KarakayaComplex”inNWAnatolia M.CEMALGÖNCÜO⁄LU1,KIYOKOKUWAHARA2,U.KA⁄ANTEK‹N3 &NECAT‹TURHAN4 1DepartmentofGeologicalEngineering,MiddleEastTechnicalUniversity,TR-06531Ankara- Turkey (e-mail:[email protected]) 2DepartmentofGeosciences,OsakaCityUniversity,558-8585Osaka-Japan 3DepartmentofGeologicalEngineering,HacettepeUniversity,TR-06532Ankara- Turkey 4DepartmentofGeologicalResearch,GeneralDirectorateofMineralResearchandExploration(MTA), TR-06520Ankara- Turkey Abstract: Thearkosicsandstoneswitholistostromeswithinthe“KarakayaComplex”inNWAnatoliatothesouth ofGeyveincludeathinlayerofgreenchertwithradiolaria.BasedonthecompositionofAlbaillellids,theradiolarian assemblagecorrespondstotheNeoalbaillellaornithoformis assemblage,anditsageisassignedtotheChangxingian (LatePermian).ThisisthefirstfindingofsynsedimentaryradiolarianchertswithintheKarakayaunitsandthe indicationoflatestPermianriftingoftheKarakayabasinwithintheMidiancarbonateplatformanditspre-Permian basementintheSakaryaCompositeTerrane. KeyWords: Karakayabasin,radiolaria,Changxingian,rifting Kuzeybat›Anadoluda“KarakayaKompleksi”ninK›r›nt›l›Birimlerinde GeçPermiyen(Changxingian)Yafll›Radyolaryal›çörtler Özet: Geyvegüneyinde,“KarakayaKompleksi”içindeyayg›nolarakyüzeylenenolistostomluarkozikkumtafl›birimi içerisindeincebirradyolaryal›çörttabakas›yüzeylemektedir.Buçörtlerdenal›nanörnek,içerdi¤iAlbaillellid’lere göre Neoalbaillellaornithoformis ToplulukZonuilekoreleedilmekteveGeçPermiyeninÇangzingiyenyafl›n› vermektedir.Karakayabirimleriiçerisindeilkkezbelirlenenbusinsedimanterolufluk,Karakayabasenininengeç Permiyen’deOrtaSakaryaKompozitBirli¤i’ninMidiyenPlatformuvePermiyenöncesitemeliüzerinderiftleflmeile aç›ld›¤›n›göstermektedir. AnahtarSözcükler:Karakayabaseni,radyolarya,Çanzingiyen,riftleflme Introduction 2002)orwithin-plate-type(Pickett&Robertson1996) TheKarakayaComplexintheSakaryaCompositeTerrane volcanicrocksandassociatedsedimentswitha (Göncüo¤lu etal. 1997)inNWAnatolia(Figure1) questionableMiddleTriassic(Kaya&Mostler1992) comprisesseveraltectonostratigraphicunitseachwith depositionalage.Theageofmetamorphismisassignedto characteristiclithologic,stratigraphicandstructural theendofTriassicinBand›rma(Okay&Monié1997)and features.ThesewereseparatedandnamedbyOkayetal. northofEskiflehir(Okayetal. 2002).TheOrtaobaUnit, (1991,1996)astheNilüfer,Çal,OrhanlarandHodul ontheotherhand,isdominatedbyMORB-typepillow units.Pickett&Robertson(1996)includedtheOrtaoba lavas(Pickett&Robertson1996),micriticlimestonesand UnitintheEdremitareaintheComplex.Theformation radiolarianchertswithMiddleTriassicradiolarians(TPAO ages,tectonicsettingsandrelationshipsoftheseunitsare 1998,unpublisheddata). amatterofdebate. TheOrhanlarUnitisdominatedbygreywackeswith blocksofonlyLowerCarboniferous(Visean– Fromthese,theNilüferUnitismainlycharacterisedby Serpukhovian,Leven&Okay1996)limestonesinitstype hot-spotrelatedoceanisland-type(Yal›n›z&Göncüo¤lu 201 CHANGXINGIANRADIOLARIANCHERTSWITHINTHEKARAKAYACOMPLEX BLACK SEA N ÝSTANBUL ANKARA Study Area ÝZMÝR 0 100 km AEGEAN SEA Intra-Pontide Suture Belt MEDITERRANEAN SEA Sakarya Composite Terrane Figure1. DistributionoftheSakaryaCompositeTerraneinnorthernTurkey(afterGöncüo¤lu etal. 1997)andlocationofthestudyarea. area.TheTriassicageassignedtothisunitisbasedonthe whichdisplaylocallypreservedstratigraphiccontactsand presenceofPermianblocksintheBursa- bothverticalandlateralgradationalcontactstoeach Mustafakemalpaflaarea.However,therockunitsinthis other. areaaresimilartotheupperpartoftheHodulUnit, Unfortunatelythereisnochanceforacomparisonof wheregreywackeshavealsobeenreported(Okay etal. thetectonostratigraphic(e.g.,Okay etal. 1991)and 1996).Hence,thereisnoevidencefortheTriassicagein lithostratigraphic(e.g.,Alt›neretal. 2000)units,andthe theOrhanlarUnit.TheÇalUnitincludesmainlydebris- confusionresultingfromnumerousnames,differencesin flowconglomerates,maficvolcanicrocks,and ages,andsuggestedprimaryrelationshipshindersany volcanogenicsandstones.Themosttypicalfeatureofthis correlationofthemandtheconstructionofareliable unitisthepresenceoflimestoneblocksthatrangefrom evolutionaryscheme. afewcentimeterstoafewhundredmetersinsize(Okay etal. 1991).Thedepositionageofthisunitisassignedto AlongtheYeniflehir-Geyveridge(Figure2)tothe EarlyPermiantoatleastMiddleTriassic(Leven&Okay southofGeyve,theauthorsrevisitedtheKarakayaunits 1996).TheHodulUnitconsistsofaseveral-km-thick describedpreviouslybyGöncüo¤lu etal. (1987)and packageofquartzofeldspathicsandstonesinitslower recognisedalmostallofthetectonostratigraphicand half.Theyarefollowedby Halobia-bearingshalesof lithostratigraphicentitiesmentionedabove.Themost Norianageandfinallybydebris-flowconglomerateswith criticalfinding,however,wasthepresenceofan insitu limestoneblocksofMiddleCarboniferoustoLatePermian radiolarianchertlayerwithinthearkosicsandstones, ages.ThedepositionalageisclaimedtobeLateTriassic whichcanbeassignedtotheKendirliFormation(Gençet (Norian)byOkayetal. (1996). al. 1986;Alt›ner&Koçyi¤it1993)ortotheHodulUnit ofOkayetal. (1991).Therefore,nowell-definednames ThetectonostratigraphicclassificationoftheKarakaya hadbeenutilisedforthestudiedunitsintheGeyvearea. unitsbyOkay etal. (1991)hadnotbeenfollowedby Theaimofthisstudywillberestrictedtodefiningthe variousauthors(e.g.,Alt›ner&Koçyi¤it1993;Genç& geologicalfeatures,radiolarianfaunaandageofthisnew Y›lmaz1995;Kozur&Kaya1994;Alt›ner etal. 2000). findinganddiscussingtheevolutionofthe“Karakaya Theypreferredadivisionofthe“KarakayaComplex”on Complex”withinageneralframework. thebasisofdistinctlithostratigraphicunitsorformations, 202 M.C.GÖNCÜO⁄LU,K.KUWAHARA,U.K.TEK‹N&N.TURHAN N Bahaiye (Esenköy) EXPLANATIONS Muttalip Göçük D. post-Triassic cover Ýyiceelma D. Alýplar Pazarkaya T. Karaoluk T. pillow basalt-limestone Karþýköy association Asarkaya T. Koca D. arkosic sandstone unit Triassic Yukarýyayla U. Permian- Derbent Limestone Çinetaþý T. Figure 3 Canbazkaya Formation U. Permian Sindir D. granodiorite Meþelik D. Cumalý black recrystallized limestones 0 500 1000 m Kayýplar Kabaklý D. (Aragat) Kadirler pre-Permian micaschists, metacherts, metarhyolites (undifferentiated) normal reverse contact foliation bedding a fault fault Figure2. Simplifiedgeologicalmapofthestudyareaandlocationoffossilfinds. GeologicalSetting predominantarkosesandarkosicsandstonesisexposed. ThestudyareaislocatedontheeasternpartoftheE–W- Towardthesouth,thisunitisjuxtaposedwithbasement trendingYeniflehir-GeyveridgetothesouthofGeyve rocksandtheirUpperPermiancoveralonganormalfault (Figure2)inNWAnatolia.Onbothmarginsoftheridge, (Figure2);thereforetheprimaryrelationofthisunit theUpperCretaceous–LowerTertiaryGölpazar›Group withthepre-Permianbasementoritsautochthonous unconformablyoverliesacomplexconsistingof Permiancovercouldbeobserved.Tothesouthofridge metamorphicrocksandgranitoids,Permianlimestones, aroundPazarkayaandKaraolukhills(Figure2),the Karakaya-typesedimentaryandvolcano-sedimentary “pillowbasalt-limestoneassociation”restswithatectonic successions,andtheirLiassiccover(Saner1978).The contactabovehighlyshearedandmyloniticarkosic detailedgeologyofthebasementrocksandtheirMidian sandstones. (UpperPermian)coverwiththeCanbazkayaandDerbent Theunitasawholeisextremelydisrupted,and formationsisalreadygiveninTurhan etal. (2004). sheared;boundariesseparatesedimentarypackagesof Thereforethispaperwillmainlydealwiththerockunits variablethicknesses.Thus,theunitdisplaysthetypical ofthe“KarakayaComplex”. appearanceofa“brokenformation”.Themore-or-less comprehensivepackages,upto110-mthick,exhibit intactinternalstratigraphy.Thetectonicboundariesin KarakayaUnits somecasesfollowtheperipheryofthedistinctrock ConsideringthedifficultiesdiscussedintheIntroduction, packages,butcanalsobelocatedwithinthesame theKarakayaunitsinthestudyareaareinformallynamed lithologicalpackage.Thisfeatureisindicativeofa the“arkosicsandstoneunit”andthe“pillowbasalt- sedimentarymélangecharacterfortheoriginal limestoneassociation”. deposition. AlongthesectionbetweenYukar›yaylaandPazarkaya ArkosicSandstoneUnit Hill(Figure2),thelowermostpackageincludesseveral tens-of-meters-thickdebris-flowconglomerates.The AlongaNE–SW-trendingzoneinthecentralpartofthe pebblesaremore-or-lessroundedandrangefromafew Yeniflehir-Geyveridge,aninternallydisruptedunitwith 203 CHANGXINGIANRADIOLARIANCHERTSWITHINTHEKARAKAYACOMPLEX millimetersupto15centimetersinlength.Alargeblock Thisunitconsistsofwhite,algal-pisoliticshallow- ofrecrystallisedlimestoneoccurswithinthe marinelimestonesandpillowlavas.Itdiffersfromthe conglomeratestotheSWofYukar›yayla.Thepebblesare sliceoflimestonesandbasiclavaswithinthe“arkosic mainlyslightlyrecrystallisedLowerandUpperPermian sandstoneunit”bytheabsenceofchertsandred-violet limestones,deformedgranitoids,quartzschistandblack mudstones,andthedominanceofwhiteshallow-marine metachert.Allofthesewerederivedfromthepre- limestones.Thevolcanicrocks,mainlypillowbasaltsin KarakayametamorphicbasementanditsPermiancover. thisunit,arecloselyassociatedwiththedepositionofthe Thenextslice,almost80metersthick,includes limestones,indicativeofcontemporaneousformation. basalticlavasinterlayeredwithgrey,micriticlimestones Thepillowbasalt-limestoneassociationresemblesthe andred-violetmudstones.Thevolcanicrocksare AbadiyeformationofGenç etal. (1986),Bahçecik amygdoidal,clinopyroxene-phryicpillowandmassive formationofKoçyi¤it etal. (1991,inAlt›ner&Koçyi¤it lavaswithwell-developedflowtexture.Theintra-pillow 1993)andtheOrtaçaltepelimestoneofGöncüo¤lu