An Early Silurian (Aeronian) cephalopod fauna from Kopet-Dagh, north-eastern Iran: including the earliest records of non-orthocerid cephalopods from the Silurian of Northern Gondwana

Bulletin of geosciences

Ghobadi Pour M¹  Popov LE¹  Evans DH¹  Jahangir H¹ 

关键词: Llandovery;    Aeronian;    Cephalopoda;    palaebiogeography;    peri-Gondwana;   

DOI  :  

来源: Czech Geological Survey

【 摘 要 】

ThecephalopodfaunafromtheAeronianQarebilLimestoneofnorth-easternIrancomprisesthefirstcomprehensiverecordofearlySiluriancephalopodsfromperi-Gondwana.Althoughconsistingofrelativelyfewtaxa,theassemblageincludesmembersoftheordersOncocerida,Discosorida,BarrandeoceridaandOrthocerida.CoevalrecordsofseveralofthesetaxaarefromlowpalaeolatitudelocationsthatincludeLaurentia,Siberia,BalticaandAvalonia,andareotherwiseunknownfromperi-GondwanauntillaterintheSilurian.ThecephalopodassemblageoccursincephalopodlimestonesthatcurrentlyrepresenttheoldestrecordofsuchlimestonesintheSilurianoftheperi-Gondwanamargin.Theappearanceofthesecephalopods,togetherwiththedevelopmentofcephalopodlimestonesmaybeattributedtotherelativelylowlatitudinalpositionofcentralIranandKopet-DaghcomparedwiththatofthewestMediterraneansectorduringtheAeronian.This,combinedwiththecontinuedpost-glacialwarmingaftertheHirnantianglaciation,facilitatedtheinitiationofcarbonatedepositionandconditionssuitableforthedevelopmentofthecephalopodlimestoneswhilstpermittingthemigrationofcephalopodtaxa,manyofwhichwerepreviouslyrestrictedtolowerlatitudes.

【 授权许可】

Unknown