Mineralogy of Holocene Sediments from the Southwestern Black Sea Shelf (Turkey) in Relation to Provenance, Sea-level and Current Regimes

(整期优先)网络出版时间:2005-04-14
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Grainsizeandmineralcompositionofcoresedimentswereusedtoinvestigateinfluencesofvariousterrestrialandmarineconditions,whichhaveprevailedonthesouthwesternBlackSeashelfduringtheHolocene.Siliciclasticmudwithsmallamountsofsandandgravelfromnearbycoastalhinterlandistheprincipalsedimenttype,whereassedimentsdepositedneartheshelfedgeandthe(I)stanbulStraitandofftheDuruLake(apaleo-rivermouth)constituedlargequantitiesofsandandgravelofbothbiogenicandterrigenicorigin.Variableamountsofaragonite,1nm-micas,quartz,feldspars,calciteanddolomiteconstitutethedominantnon-claymineralsinbulksediments.Theclaymineralassemblageinthe<2μmfractionismadeupofsmectite,illite,kaoliniteandchlorite.Aragoniteandcalcitearemainlyderivedfrombenthicaccumulations,whereasfeldspars(mainlyplagioclase)andsmectitereflectmagmaticvolcanicprovenanceandthedistributionof1nm-micasandchloritecorrelatewithnearbymetamorphicsourcesonland.Nevertheless,grainsizeandmineraldistributiongenerallyindicateacombinationofeffectsofwindandwaveclimate,longshoreandoffshorecycloniccurrents,changingsea-levelstandsandnearbysourcerockandmorphologicalconditions.ItisalsosuggestedthatatleastpartofclaymineralscouldbederivedfromthenorthwesterlyDanubeRiverinput.