Can biogeochemistry aid in the palaeoenvironmental/early diagenesis reconstruction of the ˜187 Ma (Pliensbachian) organic-rich hemipelagic series of the Lusitanian Basin (Portugal)?

Bulletin of geosciences

Silva TF¹  Mendonca Filho JG¹  Ferreira R¹  Azeredo AC¹  Duarte LV¹  da Silva FS¹  Silva RL¹ 

关键词: biogeochemistry;    black shale (s.l.) intervals;    Pliensbachian;    Early Jurassic;    Lusitanian Basin;   

DOI  :  

来源: Czech Geological Survey

【 摘 要 】

Dataonlipids,carbohydratesandproteinsofthemostexpressiveblackshale(s.l.)intervalsoftheEarly-LatePliensbachian(EarlyJurassic,tilde;187Ma)organic-richhemipelagicseriesoftheLusitanianBasin(Portugal)weredeterminedusingamethodthathasbeensuccessfullyappliedoverthelasttwodecadesinthecharacterizationofbiomassandveryimmaturesediments.Thegoalofthispaperistotesttheapplicabilityofthesetechniquestotheancientgeologicalrecord.Toourknowledge,thisisthefirsttimethatthistypeofbiogeochemicaldatafromsedimentaryseriesolderthanOligoceneisreportedandtentativelyusedforpalaeoenvironmental/diageneticinferences.Carbohydratesandproteinsarepresentinlowconcentrations,reachingupto385.13and451.13mu;g/grock,respectively.Themainvariationsareobservedinthelipidcontents,rangingfrom197.67to8446.36mu;g/grock.Thesampleswiththehighestamountsoflipidsseemtocorrelatewithlow[O2]timeintervalsdeterminedbyindependentdata,suchasorganicpetrography,micropalaeontologyandsedimentology.Thiswasprobablyrelatedwithselectivelipidpreservationunderoxygenandhydrogensulfide-richdepletedenvironments.Thegoodoverallmatchbetweenthedeterminedlipidcontentsandspecificdepositional/earlydiageneticalconditionsseemtofavortheideathattheeasytoperformandinexpensivemethodappliedherehasthepotentialtoaddusefulinformationtothestudyofancientorganic-richcarbonatesedimentaryseries.

【 授权许可】

Unknown