TurkishJournalofEarthSciences (TurkishJ.EarthSci.),Vol.9, 2000,pp.91-112. Copyright©TÜB‹TAK LateDevonian(Famennian)ConodontsfromDenizliköyü, Gebze,Kocaeli,NorthwesternTurkey fiENOLÇAPKINO⁄LU KaradenizTeknikÜniversitesi,JeolojiMühendisli¤iBölümü,TR-61080Trabzon,TURKEY (e-mail:[email protected]) Abstract: LateDevonian(Famennian)conodontfaunashavebeendescribedfromtwoincompletestratigraphic sections(GDandGB)oftheAyineburnumemberoftheTuzlaformation,Denizliköyü,Gebze,Kocaeli, northwesternTurkey.ThesectionGDcomprisestheLowerandMiddleexpansa Zones,andthesectionGBcontains theMiddleandUpper expansa Zones.ZonalindicesfortheMiddle expansa ZoneareidentifiedinthesectionGB, whereasthiszoneisrecognizedonthebasisofotherkeytaxainthesectionGD.Also,anewspeciesoftheGenus Branmehla,Branmehlagediki n.sp.isdescribedfromthesectionGD. KeyWords: LateDevonian(Famennian),conodont,Gebze,Kocaeli,Turkey. Denizliköyü’nden(Gebze,Kocaeli,Kuzeybat›Türkiye)GeçDevoniyen (Fameniyen)Konodontlar› Özet: Denizliköyü(Gebze,Kocaeli,kuzeybat›Türkiye),Paleozoyikyafll›birimlerinyayg›nolarakyüzeylendi¤i alanlardanbirinioluflturur.Bualandaki,genelliklesar›ms›-kahverenkliyumruluveincekatmanl›kireçtafllar›ndan oluflan,kil-marnaraseviyeleriileözellikleüstk›s›mlar›ndadahayayg›nolankoyugrirenkliçokinceçörtbantlar›ve yumrular›içerenbirim,Ayineburnuüyesiolarakbilinir.TuzlaFormasyonu’nunenüstüyesiolanbubirimeaitiki eksikstratigrafikkesitten(GDveGB),pelajikfasiyesitemsileden,Fameniyen(GeçDevoniyen)yafll›konodont faunalar›tan›mlanm›flvebufaunalaryard›m›yla,incelenenstratigrafikkesitlerGeçDevoniyenstandartkonodont zonlamas›iledenefltirilmifltir.Yaklafl›k20metrekal›nl›ktakiGDkesiti,AltveOrta expansa Zonlar›n›;11metre kal›nl›ktakiGBkesiti,OrtaveÜst expansaZonlar›n›içerir.GDkesitindekiOrta expansa Zonu’nunalts›n›r›,zon belirleyicitaksonBispathodusaculeatus’unyoklu¤unedeniyledi¤eranahtartaksonlaryard›m›ylabelirlenmifltir.‹ki kesitten,6cinseaittoplam34konodonttürvealttürütan›mlanm›flt›r.GDkesitindeneldeedilentaksonlardanbiri, yenitürolarak(Branmehlagediki n.sp.)tan›t›lm›flt›r. AnahtarSözcükler:GeçDevoniyen(Fameniyen),konodont,Gebze,Kocaeli.Türkiye. Introduction InTurkey,theUpperDevonianrocksofthepelagic FortheLateDevonian,twoconodontzonations,basedon faciesareknownonlyfromthe“‹stanbulTerrane"(Kozur differentbiofacies,havebeenproposed:thestandard &Göncüo¤lu1999),andarerepresentedgenerallybythe conodontzonation(Ziegler,1962;Ziegler&Sandberg AyineburnuMemberoftheTuzlaFormation.Thetypical 1984,1990),andthenearshoreconodontzonation outcropsofthismemberareexposedonBüyükadaand (Sandberg&Dreesen1984).ThestandardLateDevonian ontheTuzlaPeninsula,‹stanbul,andaroundGebze, conodontzonation,basedonthepelagicfacies,hasa Kocaeli,northwesternTurkey(Figure1).Ithasa widespreadapplicability.However,thealternative completesectionneitheratitstypelocalityontheTuzla shallow-waterconodontzonation,definedfrom Peninsulanoratotherlocalitiesbecauseoffoldingand nearshorefacies,isapplicableonlylocally.TheLate intensefaulting.Acompletestratigraphicsectioncanonly Devonian,subdividedinto32-mainly Palmatolepis-based- bereconstructedbyjoiningupsmallsectionsfrommany zonesinthestandardconodontzonation(Ziegler& separatelocalities.TheAyineburnusectioninthe Sandberg1990),hasbeensubdividedintonine southwesternpartofBüyükada,‹stanbul,hasbeen icriodontid-basedzonesinthenearshoreconodont investigatedbyÇapk›no¤lu(1997)andtheUpper zonation(Sandberg&Dreesen1984). rhomboidea andLower marginifera Zoneshavebeen recognized. 91 LATEDEVONIANCONODONTSFROMNORTHWESTERN TURKEY Thefaunasexaminedinthisstudywereobtainedfrom contrastwiththeZonguldakTerranethatwasalso twoincompletesections(GDandGB)thataresituated affectedbytheCaledonianorogeny.Thestudiedsections nearDenizliköyü,approximately20kmnortheastof (GDandGB)arewithinthe‹stanbulTerraneandbelong Gebze,Kocaeli,northwesternTurkey(Figure1).Atotal totheupperpartoftheAyineburnumember,the of51sampleswerecollectedfromtwolocalities.Of uppermostmemberoftheTuzlaFormation.These these,40yieldedconodontfaunas. sectionsarelocatednearDenizliköyü,about20km northeastofGebze,Kocaeli,northwesternTurkey (Figure1).SectionGDisabout900mnortheastof Edirne BULGARIA BLACKSEA N Denizliköyü,andcropsoutabout175mnorthofthe TURKEY Gebze-Denizliköyühighwayandabout450mnortheast GREECE ofDe¤irmenbay›r›Hill.Thethicknessofthissectionis ‹stanbul 20.25meters.Thelowerboundaryisconcealed,andthe Gebze SEAOF upperboundaryisbothfaultedandcovered.SectionGB, MARMARA fartherfromtheGebze-Denizliköyühighway,isa EAGEAN Kocaeli SEA roadsideexposure,locatedabout2kmnortheastof Denizliköyü,approximately100msoutheastofthedam 50km Lake‹znik onAkçetCreek.Thethicknessis11meters.Thelower contactisafaultandtheuppercontactiscoveredby Kartal Denizliköyü colluvium.Thelithologyconsistsmainlyofgrey-beige, Pendik Demirciler yellow-beige,greyandlight-grey,generallythin-bedded, Sedefadas• ‹çmeler nodulartoevenlybeddedmudstone-wackestone,and Büyükada Tavflanl› Gebze greytobeige,laminatedshaleandmarl.Darkgreychert SEAOF Tuzla nodules,lensesandbandsarealsopresent(Figure2). MARMARA Althoughsomesamplesareeitherbarrenoforarevery 5km Dar›ca poorinconodonts,manyofthemyieldedveryabundant ostracodfauna.Afewtrilobitefragmentsandbrachiopod AkçetCreek Dam shellswerealsoobtainedfromsomesamplesasresidue followingtreatmentwithacid. SectionGB SectionGD ConodontBiostratigraphy De¤irmenbay›r› Hill ThreeLateDevonianconodontzones(Ziegler&Sandberg 1984)havebeenrecognizedinthestudiedsections(GD 29 Kumluca Hill andGB)oftheTuzlaFormation.ThesectionGDis divisibleintoLowerandMiddle expansa Zones,andthe 500m sectionGBcomprisestheMiddleandUpper expansa Denizliköyü Zones(Figure2,Tables1&2). Figure1. Locationmapsshowingstudiedsections(GDandGB)and adjacentareas. LowerexpansaZone LocalityofSectionsandLithostratigraphy TheLower expansa Zonehasbeenrecognizedinthe The"Palaeozoicof‹stanbul"comprisestwodifferent lowerpartofsectionGD(Figure2,Table1).Itsbaseis terraneswithverydifferentPaleozoic-Mesozoichistories: definedonthebasisofthelowestoccurrenceof the‹stanbulTerrane(Palaeozoic-Mesozoicsequence Palmatolepisgracilis expansa byZiegler&Sandberg around‹stanbul-Gebze)andtheZonguldakTerrane (1984).However,onlyonefragmentaryspecimenofthis (Çamda¤,Zonguldak,AmasraandSafranboluregions) specieswasfoundinsampleGD5(Table1).Also,the (Kozur&Göncüo¤lu1999).The‹stanbulTerranewas zonalindexfortheupperboundary, Bispathodus affectedonlybytheHercynianandAlpineorogeniesin aculeatus, isabsent.Thereforetherecognitionofthis 92 fiENOLÇAPKINO⁄LU Bispathodusaculeatus byZiegler&Sandberg(1984). SECTIONGD SECTIONGB GB28 ThistaxonisabsentinsectionGD.Therefore,thelower GD29 GD28 GB27 boundaryisdefinedbythelastoccurrenceofPolygnathus GB26 GB25 styriacus insampleGD11.Inaddition,basedonthe GD27 GB24 GB23 absenceofBispathodusultimus,thedefiningtaxonofthe GD26 GB22 expansaZone GB21 upperboundary,overlyingbedsarealsoassignedtothe GD25 GB20 GD24 GB19 Middleexpansa Zone(Table1,samplesGD12-GD29). GD23 GB18 Upper GB17 GD22 GB16 TheMiddle expansa Zoneisrepresentedbysamples GD21 GB15 GB14 GB2-GB16inthelowerpartofsectionGB(Table2).The GD20 GB13 GD19 GB12 lowestsample(GB2)ofthissectioniswithintheMiddle GD18 GB11 GD17 GB10 GB9 expansa Zonebasedontheoccurrenceof Bispathodus GB8 aculeatusaculeatus .SampleGB17containsthelowest expansaZone GB7 GB6 GB5 occurrenceof Bispathodusultimus definingtheupper GB4 expansaZone boundaryoftheMiddle expansa Zone(Ziegler& GD16 Middle GB3 GB2 Sandberg1984,p.184).Therefore,thebedsbelowthe GB1 Middle lowestoccurrenceof Bispathodusultimus belongtothe Middleexpansa Zone. GD15 GD14 GD13 Chert UpperexpansaZone GD12 GD11 Limestone TheUpper expansa Zoneisrepresentedbysamples GD10 GD9a Shaleandmarl GB17-GB22intheupperpartofsectionGB(Figure2, GD9 Table2).SampleGB17containsthelowestoccurrenceof GD8 Bispathodusultimus, thezonalindexforthebaseofthe GD7 expansaZone GD6 2m Upperexpansa Zone(Ziegler&Sandberg1984,p.184); GD5 GD4 SCALE 1 therefore,itiswithintheUpper expansa Zone.In GD3 Lower GD2 addition,thestratigraphicallyhighersamplesarealso GD1 0 assignedtothiszoneduetotheabsenceof Siphonodella Figure2. Stratigraphiccolumnsofthesections(GDandGB)examined. praesulcata thatdefinesthebaseoftheoverlying Samplenumbersareindicatedalongtherightsideofeachcolumn. praesulcata Zone. zonehasbeenbasedontheoccurrenceof Polygnathus styriacus.SampleGD11iswithintheLowerexpansa Zone SystematicPaleontology becauseitcontainsthehighestoccurrenceofPolygnathus ThefamilialclassificationproposedbySweet(1988)is styriacus, whichdisappearsattheendoftheLower usedinthisreport.Conodontsdiscussedherein(Table1 expansa Zone(Ziegler&Sandberg1984,Fig.2).Also, &2)belongtothePalmatolepidae,Polygnathidaeand thelowestsample(GD1)belongstotheLower expansa Spathognathodontidaefamilies.Platformelementsare Zoneduetotheoccurrenceof Bispathodusstabilis thefocusofthisstudy,althoughramiformelementsare Morphotype2,whichfirstappearsatthebaseofthe alsopresent.Illustratedspecimensandfaunalslidesare Lowerexpansa Zone(Ziegler&Sandberg1984,Fig.4). repositedatKaradenizTeknikUniversitesiintheJeoloji Therefore,thebedswithPolygnathusstyriacus insection Mühendisli¤iBölümü,Trabzon,Turkey. GDrepresenttheLower expansa Zone(Table1,samples GD1-GD11). FamilyPALMATOLEPIDAESweet,1988 MiddleexpansaZone GenusPalmatolepis ULRICH&BASSLER,1926 TheMiddleexpansa Zoneispresentinbothsections.The Typespecies.-Palmatolepisperlobata ULRICH& baseofthiszoneisdefinedonthelowestoccurrenceof BASSLER,1926 93 LATEDEVONIANCONODONTSFROMNORTHWESTERN TURKEY Table1.DistributionandabundanceofPaelementsofconodonttaxadefinedfromtheGDsection.SeeFigure2forsampleintervals. ?indicatesquestionableidentification.Abbreviations: