文勇ibt黄金阅读及答案pdf：地中海的地质历史

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1、智课网TOEFL备考资料maintenancemeasures,thereisabigsecurityrisk,managementhashadagreatimpacttothecity.3.1-8busterminalstationstatusinYibincitylayouts(4)hoursofoperationmostofYibincitybuslinesin5:30-6:20,andbasicallymeettheYibintravelneeds.Bus文勇ibt黄金阅读及答案pdf：地中海的地质历史摘要：最新版刘文勇新托福

2、黄金阅读7.0版本高清PDF格式支持免费下载，一共71篇，包括刘文勇黄金阅读29篇，下面是小编整理的文勇ibt黄金阅读及答案pdf：地中海的地质历史，希望对大家备考托福阅读考试有所帮助。文勇ibt黄金阅读及答案pdf：TheGeologicHistoryoftheMediterranean地中海的地质历史In1970geologistsKennethJ.HsuandWilliamB.F.RyanwerecollectingresearchdatawhileaboardtheoceanographicresearchvesselGlom

3、arChallenger.AnobjectiveofthisparticularcruisewastoinvestigatetheflooroftheMediterraneanandtoresolvequestionsaboutitsgeologichistory.Onequestionwasrelatedtoevidencethattheinvertebratefauna(animalswithoutspines)oftheMediterraneanhadchangedabruptlyabout6millionyearsago.Mo

4、stoftheolderorganismswerenearlywipedout,althoughafewhardyspeciessurvived.AfewmanagedtomigrateintotheAtlantic.Somewhatlater,themigrantsreturned,bringingnewspecieswiththem.Whydidthenearextinctionandmigrationsoccur?AnothertaskfortheGlomarChallenger’sscientistswastotrytodet

5、erminetheoriginofthedomelikemassesburieddeepbeneaththeMediterraneanseafloor.Thesestructureshadbeendetectedyearsearlierbyecho-soundinginstruments,buttheyhadneverbeenpenetratedinthecourseofdrilling.WeretheysaltdomessuchasarecommonalongtheUnitedStatesGulfCoast,andifso,whys

6、houldtherehavebeensomuchsolidcrystallinesaltbeneaththeflooroftheMediterranean?Withquestionsuchastheseclearlybeforethem,thescientistsaboardtheGlomarChallengerprocessedtotheMediterraneantosearchfortheanswers.OnAugust23,1970,theyrecoveredasample.Thesampleconsistedofpebbles

7、ofgypsumandfragmentsofvolcanicrock.Notasinglepebblewasfoundthatmighthaveindicatedthatthepebblescamefromthenearbycontinent.Inthedaysfollowing,samplesofsolidgypsumwererepeatedlybroughtondeckasdrillingoperationspenetratedtheseafloor.Furthermore,thegypsumwasfoundtopossesspe

8、culiaritiesofcompositionandstructurethatsuggestedithadformedondesertflats.Sedimentaboveandbelowthegypsumlayerc