祁連山東段葫蘆河變質(zhì)基性火山巖的年代學(xué)地球化學(xué)特征及構(gòu)造意義.pdf

1、“l(fā)馴必蛾分類號：P57586X孝夫海碩士學(xué)位論文祁連山東段葫蘆河變質(zhì)基性火山巖的年代學(xué)地球化學(xué)特征及構(gòu)造意義孫仁奇導(dǎo)師姓名職稱裴先冶教授申請學(xué)位級別理學(xué)碩士學(xué)科專業(yè)名稱礦物學(xué)’巖石學(xué)、礦床學(xué)論文提交日期2007年5月25日論文答辯日期2007年5月30日學(xué)位授予單位長安大學(xué)答辯委員會主席!蔞出越縫學(xué)位論文評閱人羹壘f選壹。巍AbstractThisdissertationmainlystudiesHuluhemetabasicvolc

2、anicrocksineasternsectionofQilianorogenicbeltprimarilyinpetrographygeochemistryandisotopicgeochronologycombiningwithregionalgeologystructure，tectonics，etc，todefinetheirages，identifythecauseofformationandtectonicsettings，

3、andtodiscusstheirregionaladscriptionFurtheritillustratestheevolvinghistoryofpaleoplateinthestudyarea；Meanwhile，italsoprovidesimportantbasicscientificdatafordiscussingthecomposition，tectonicframework，formingandevolvemento

4、feasternsectionofQilianorogenicbeltandthebasiccharacteristicsofcontinentalorogenicbelts，andexploringthecontinentaldynamicsinChinaThefollowingchiefconclutionandknowledgehavebeenobtainedbythestudiesofHuluhemetabasicvolcani

5、crocks：(1)TheHuluhemetabasicvolcanicrocksaremainlycomposedofgrayishgreenmetabasaltandbasalticandesite，intercalatedbyafewoffwhitelightgreysillcaliteGeochemicalcharacteristicsofmajorelements，rareearthelementsandtraceelemen

6、ts，andthetectonicsettingsdiscriminationshowthatthemetabasicvolcanicrocksgenerallybelongtobackarcbasintholeiiticbasaltseriescalc—alkalicbasaltserieswithlowkalium，alsohavethecharacteristiesofMORBandWPBTraceelementcharacter

7、istiesshowthatthebasicmagmarootsinenrichedmantlewedgemetasomatizedbyfluidinsubductionbelt，hybridizedbycontinentalcrustmaterial(2)Usingthecathodoluminescence(CL)imagesofzirconsandLA—ICP—MSzirconU—Pbdatingobtaintheisotopic

8、agesbetween(4369157)Maand(443417)MawhichsuggestsmattheHuluhemetabasicvolcanicrocksformedinLateOrdovician(3)EasternsectionofQilianorogenicbeltsextendedinLateOrdovicianPeriod，oceanicbasinsystemswentthroughopeningandformedC

9、henjiaheGroupvolcanicsedimentaryrockseries；thoseoceanicbasinsystemswentonopeningandformedHuluhemetabasievolcanicrocksbeltofbackarcriftsmalloceanbasintectonicenvironmentinLateOrdovicianPeriod(4)Thecomparativestudiesbetwee