南秦岭麻池河乡和沙河湾花岗岩体锆石LA-ICP-MSU-Pb年代学及Lu-Hf同位素组成.pdf

《南秦岭麻池河乡和沙河湾花岗岩体锆石LA-ICP-MSU-Pb年代学及Lu-Hf同位素组成.pdf》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。

1、第2()卷第5期地学前缘(中国地质大学(北京)；北京大学)2013年9月EarthSeienceFrontiers(ChinaUniversityofGeosciences(Eeiiing)；PekingUniversity)南秦岭麻池河乡和沙河湾花岗岩体锆石LA—ICP—MSU—Pb年代学及LU—Hf同位素组成刘春花，吴才来，郜源红，雷敏，秦海鹏，李名则大陆构造与动力学国家重点实验室；中国地质科学院地质研究所，北京100037LIUChunhua，WUCailai，GAOYuanhong，LEIMin，QINHaipeng。LIMingz

2、eStateKeyLaboratoryoJContinentalTectonicsandDynamics；InstituteofGeology，ChineseAcademyofGeologicI』zSci7lcesBeijing100037．inaLIUChunhua，WUCailai，GAOYuanhong，eta1．ZirconLA-ICP-MSU-PbdatingandLu-HfisotopicsystemofMachihecorn-tryandShahewangranitoidrockmasses，SouthQinlingbelt，

3、centralChina．EarthScienceFrontiers，2013，20(5)：036—056Abstract：MachihecountryandShahewangranitoidrockmassesarelocatedinthesouthofShangDanfault．Zirconlaserablationinductivelycoupledplasmamassspectrometry(LA—ICPMS)wasusedforUPbchronologicanalysistodeterminecrystallizationages

4、forMachihecountrygraniteandShahewanquartzmonzonitemagmaof490．8±2．9Ma(Early()rdovician)，and(240．6±1．5)一(228．2±1．5)Ma(MiddleTriassic)，respectively．Theresultsofzirconin-situLuHfisotopicanalysisindicatethatthetwostageHfmodelages(fI2)ofzirconare759—1096Maand891—1516Ma，respectiv

5、ely．Thesource-rockmaterialofMachihecountrygraniteisNeoproterozoicandMesoproterozoicdepletedmantlemateria1．ShahewanquartzmonzoniteisthemixingproductofcrustalwithmantlematerialsatdifferentlevelsintheMesoproterozoicandNeoproterozoictime．InthenorthwardsubductionoftheQinIingoce

6、aniccrustbeneathNorthQinling，theoceaniccrustandtheuppermantleinteractedtoproducethehybridized1iquidandformedMachihecountrygranitebycrystallizationdifferentiationintheLateCambriantotheEarly()rdovician．Shahewanrocknlasswasformedduringatleasttwogeologicaleventswithlargetimesp

7、ansbetween(240．6±1．5)一(228．2±1．5)Maand214—197Ma，respectively．AftertheclosureoftheMian-Itieoceanicbasinatabout250Ma，acollisioneventoccurredbetweentheYangtzeandtheNorthChinaplatesintheQinlingorogenicbelt．ThiscollisionresultedinthesubductionofthecontinentalYangtzeplatebeneath

8、SouthQinling，inwhichasmallpartofthecrustmeltedtoformtheEarly-MiddleTriassicgranitoidsat(2