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1、F.T.BARR,B.R.WALKER44.4.LATETERTIARYCHANNELSYSTEMINNORTHERNLIBYAANDITSIMPLICATIONSONMEDITERRANEANSEALEVELCHANGESF.T.BarrandB.R.Walker,OasisOilCompanyofLibya,Inc.,Tripoli,LibyaABSTRACTAlargefossildrainagesystemofprobableupperMioceneageisrecognizedalongthenortheasternflankoftheSirte
2、Basin,northernLibya.Themainchannelhasbeentracedforabout150kmeventuallybeinglostunderthesarir,justsouthofQasrasSahabi.IthascutintomiddleMiocenelimestonetoadepthofover1300feet.Inthisregionthesurfaceisnearpresentsealevel.ItispostulatedthattheSahabidrainagesystemistheresultofanabruptd
3、ropinMediterraneansealevelofatleast1300feet,andprobablymorethan2000feet,duringthelateMiocene.DuringtheearlyPliocene,theseareturnedtoalevelaboutthesameas,oralittlelessthan,thatjustpriortothelateMioceneregression.OtherpossiblelateMiocenedrainagesystemshavebeenrecordedineasternLibyaa
4、ndthewesternDesertofEgypt;thesemayberelatedtothesamesequenceoflateTertiaryeventsthataffectedagreatportionoftheeasternMediterraneanregion.TheseNeogenegeomorphicfeaturesofnortheasternAfrica,whichhavelongbeenaperplexingproblem,nowfitwellintoanhypothesiswhichaccommodatesmuchofthenewda
5、taobtainedfromdrillingbeneaththeflooroftheMediterraneanSea.INTRODUCTIONDESCRIPTIONOFCHANNELSYSTEMThischannelsystemisrecognizedalongthenortheasternGeophysicalcrewsprospectingforoilalongtheeasternflankoftheSirteBasinbetweenlatitude29°to30°North,marginoftheSirteBasin,northernLibya,du
6、ringthelateandlongitude20°45'to22°East.Withinthisarea,the1960's,experiencedseverevelocityproblemsintheupperclosenessofthecontrolusedtodefinethissystemvaries1000to2000feetofsurfacesediments.Seismicvelocitiesconsiderably.Inafewcases,closelyspacedseriesofholesoftenchangedabruptlyinth
7、isshallowsequenceindicatinghavebeendrilledacrossthemainchannel.Inothers,andrapidlithologicchanges.Thesesharpvelocitychangesespeciallytothesouth,controldatabecomesparseandsometimescoincidedwithadrydrainagesystemthatsometimesformanymilesthechannelisonlydefinedbyaoccasionallycouldbeo
8、bservedonthedesertsurface.Itwassi