Palaeodrainage systems at the basal unconformity of the Bohemian Cretaceous Basin: roles of inherited fault systems and basement lithology during the onset of basin filling

Bulletin of geosciences

ÄŒech S¹  Laurin J¹  Uličný D¹  Grygar R¹  Å pičáková L¹  Svobodová M¹ 

关键词: palaeodrainage;    Cenomanian unconformity;    Bohemian Massif;    Elbe Zone;    sequence stratigraphy;   

DOI  :  

来源: Czech Geological Survey

【 摘 要 】

ThisstudypresentsasynthesisofcurrentlyavailabledataonthedistributionofCenomanian-agepalaeodrainagesystemsintheBohemianCretaceousBasin,filledbyfluvialandestuarinestrata,andaninterpretationoftheirrelationshipstothebasementunitsandfaultsystems.Muchoftheprogress,comparedtopreviousstudies,wasmadepossiblebyarecentbasin-scaleevaluationofCenomaniangeneticsequencestratigraphy.Severallocalpalaeodrainagesystemsdevelopedinthebasin,separatedbydrainagedividesoflocalimportanceandonemajordivide–theHolice-NovéMěstoPalaeohigh–whichseparatedthedrainagebasinsoftheTethyanandBorealpalaeogeographicrealms.ThelocationsanddirectionsofpalaeovalleyswerestronglycontrolledbythepositionsofinheritedVariscanbasementfaultzones,whereasthebedrocklithologyhadthesubordinateeffectofnarrowingorbroadeningvalleysonmorevs.lessresistantsubstratum,respectively.TheintrabasinalpartofthepalaeodrainagenetworkfollowedtheslopestowardtheLabe(Elbe)Systemfaultsandwasstronglydominatedbytheconjugate,NNE-trending,JizeraSystemfaultsandfractures.Outletstreams–ultimatetrunkstreamsthatdrainedthebasinarea–areinterpretedtohavefollowedtheLužiceFaultZonetowardtheBorealprovincetotheNorthwest,andtheŽeleznéhoryFaultZonetowardtheTethyanprovincetotheSoutheast.AtboththenorthwesternandsoutheasternendsoftheBohemianCretaceousBasin,shallow-marineorestuarineconditionsareproventohaveexistedduringtheearlyCenomanian.Directevidenceforsyn-depositionalsubsidenceduringtheearlytomid-Cenomanian,fluvialtoestuarinephaseisveryrare,andtheonsetofdepositionbyfluvialbackfillingofthepalaeodrainagesystemswasdrivenmainlybythelong-termriseinglobalsealevel.Subtlesurfacewarping,mostlywithoutdetectablediscretefaulting,isinferredtohavebeenaresponsetotheonsetofthepalaeostressregimethatlater,withfurtherstressaccumulation,ledtosubsidenceinfault-boundeddepocentresoftheBohemianCretaceousBasinandupliftofnewsourceareas.

【 授权许可】

Unknown