馬里亞納海槽熱液活動(dòng)區(qū)玄武巖巖石地球化學(xué)研究.pdf

1、中國海洋大學(xué)碩士學(xué)位論文馬里亞納海槽熱液活動(dòng)區(qū)玄武巖巖石地球化學(xué)研究姓名：田麗艷申請學(xué)位級別：碩士專業(yè)：海洋地質(zhì)指導(dǎo)教師：趙廣濤2003.6.1TheStudyofPetroIogicaIGeochemistryofBasaItsfromHyrothermaIFieIdsMarianaTroughAbstractTheMarianaTroughisanactivelyopeningbackarcbasinthatliesattheeas

2、ternedgeofthePhilippineSeaplate，andinthetransitiontimefromrifttoseafloorspreadingThispaperreportstheresultofapetologicalgeochemistrystudyofeightbasalticsamplesfromtheMarianaTroughhydrothermalfields(near18N)Thesamplesareb

3、asaltorbasalticandesite，belongingtocalalkalicseries：comparedtoMORB，theyhavehigherAl203、Na20and10werTi02TheyareenrichedinLILEandLREE：REEpatternsareright—leaned(LaFlO68～2264，(ta／Vb)、=161～247)，andhavepositiveEuanomalyInPMno

4、rmalizingplotssevensamplesareobviouslydepletedinNb：HFSE／ttPSE，LILE／HFSE，LILE／LIFEvalueshavewidechangebetweenMORBandEMIThevaluesofSr，Nd，Pbalsohavewidechange(“Sr—汪卸702蛐7034，N件腳51307猢513182，￡Nd=84—1o7，3‰悱178如1829，=Pb／a甲b=15

5、4亂l562，蠲Pb—Pb：374粥&18)A11c]tLrBctersaboveshowthatthemglTlaisderivedfromuppermantlealteredoreffectedbysubductioncomposition；mantlesourcehasheterogeneityanditmaybethecombinationofDMMandEMIItispresentedthatthehydrousfluxing

6、aswellasadiabaticdecompressionplaysanimportantroleinmeltingof)iORBlikemantlebeneathMarinaTroughComparedwithbasaltsfromotherbackarcbasins，itconcludesthatthemagmavariesfromMOPBliketoARC—likewiththeevolution；duringtheearlie