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ID:37697620
大小:3.16 MB
页数:16页
时间:2019-05-29
《冈底斯带中段中新世埃达克质岩浆作用的年代学、地球化学及Sr-Nd-Hf同位素制约》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、10000569/2014/030(08)225368ActaPetrologicaSinica岩石学报冈底斯带中段中新世埃达克质岩浆作用的年代学、地球化学及SrNdHf同位素制约陈希节许志琴孟元库贺振宇CHENXiJie,XUZhiQin,MENGYuanKuandHEZhenYu中国地质科学院地质研究所,大陆构造与动力学国家重点实验室,北京100037StateKeyLaboratoryforContinentalTectonicsandDynamics,InstituteofGeology,CAGS,Beijing100037,China2014
2、0201收稿,20140519改回ChenXJ,XuZQ,MengYKandHeZY.2014PetrogenesisofMioceneadakiticdioriteporphyriteinmiddleGangdesebatholith,southernTibet:Constraintsfromgeochemistry,geochronologyandSrNdHfisotopesActaPetrologicaSinica,30(8):2253-2268AbstractThepetrogenesisandgeodynamicsettingofth
3、eMioceneadakiticmagmatisminmiddleGangdesebeltwhichiscloselyrelatedtotheporphyrycopperdepositbeltremaincontroversialInordertorevealthisissue,weinvestigatethebulkrockmajorelement,traceelement,SrNdisotopesandzirconHfisotopesofthedioriteporphyriteexposedinthewestofXigazeCitytoimposeso
4、merestrictionsonthegeodynamicsettingofMiocenemagmatismTheLAICPMSanalysisonzirconsfromtwodioriteporphyritesyieldedsimilaragesat139Maand143Marespectively,andcanbeconsideredasrepresentingoneoftheMidMiocenemagmaticrockbodiesinthesouthernGangdeseAllsamplesshowanadakiticaffinityandm
5、ediumKalkalinecharacterize,andexhibithighSiO2(5919%~6366%),highAl2O3(1655%~1716%)withA/CNKvaluesof091~113,highNa2OandlowK2Ocontents(K2O=11~209%;Na2O=553~617%)withlowK2O/Na2Oratios(018~037),highSr,lowY,Yb,highSr/Yratios-6-6-6-6(852~1417)andrelativehighcompatibleelementco
6、ncentration(Cr=35×10~104×10,Ni=292×10~483×10).Thedioriteporphyritesarecharacterizedbyareenrichedinlargeionlithophileelement(LILE)andPb,anddepletedinhighfieldstrengthelements(HFSE)andBa,togetherwithslightenrichmentinLREEcontentsanddepletioninHREEcontentswithslightnegativeEuanomalie
7、s(085~094)TheXigazedioriteporphyritesareheterogeneousinzirconεHf(t)values(-175~+735)andHfisotopiccompositions(0282714~0282982),yieldingyoungerzirconHfcrustalmodalagesof640~1151MaThecharactersofThNbZrincompatibleelementshowobviouslytheaffinityofpartialmeltingofsubductedocean
8、crust
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