Environmental conditions during the Toarcian Oceanic Anoxic Event (T-OAE) in the westernmost Tethys: influence of the regional context on a global phenomenon

Bulletin of geosciences

Rodríguez-Tovar FJ¹  Reolid M¹ 

关键词: T-OAE;    geochemical proxies;    palaeoxygenation;    palaeoproductivity;    Jurassic;    Betic Cordillera;   

DOI  :  

来源: Czech Geological Survey

【 摘 要 】

AgeochemicalanalysishasbeenconductedintheFuentedelaVidrierasectionoftheExternalSubbetic(BeticCordillera,southernSpain)inordertointerprettheincidenceoftheToarcianOceanicAnoxicEvent(T-OAE)inthewesternmostendoftheTethys.Theobtainedvaluesofdetrital,redoxandpalaeoproductivityproxiesthroughoutthesuccessionshowminorfluctuations,butonlypunctualsignificantchanges.Detritalinputisnearlyconstantduringthestudiedinterval,exceptpunctuallyinthelowerpartofserpentinumZone,characterizedbyanincreaseinbothfluvialandeoliandetritaltransport.Associatedtothislocalhigherfluvialandeolianactivity,acomparativelyhigherconcentrationoforganicmatterispunctuallyregistered,asrevealedbythecomparativelyhighesttotalorganiccarbon(TOC)value(0.99wt.%).TheremainingpartofthesectionshowsTOCvaluesinthelowerrangeofthoseregisteredintheTethyanToarciansections(<0.4wt.%).Theobtainedratiosofredox-sensitivetracemetalsleadtotheinterpretationofoxictodysoxicbottom-waters,withasingularsharpdecreaseinoxygenationcorrespondingtoashortintervalwithintheserpentinumZone(sampleFV-18)correlatedtotheT-OAE.TheminorincidenceoftheT-OAEregisteredinthiswesternmostendoftheTethys,inwhichpunctualdysoxicconditionsarerestrictedonlytoadecimetre-scaleintervalrevealstheimportanceofregionalcontextandlocaloceanic-atmospheredynamicsonthelocalrecordofthisphenomenon.

【 授权许可】

Unknown