地质通报2012，Vol.31Issue(12)：2052-2062,11.
新疆东准噶尔阿尕什敖包地区火山岩LA-ICP-MS锆石U-Pb年龄及地球化学特征
Zircon dating and geochemical characteristics of Agashen Obo volcanic rocks in eastern Junggar, Xinjiang
摘要
Abstract
The Agashen Obo volcanic rocks are developed in "Jiangzeer Kuduke" Formation in eastern Junggar, Xinjiang. The characteristics of major elements suggest that the rocks are basaltic andesites of calc-alkaline series, whose chondnte normalized REE patterns are of rightly-oblique type characterized by LREE enrichment and HREE depletion((La/Yb)N=4.69~8.19). Primitive-mantle normalized patterns show evident geochemical characteristics of depletion of (HFSE) Nb, Ta, Zr, Hf and relative enrichment of (LILE) Cs, Rb, Ba, Pb. These geochemical data and the correlation diagram indicate that the rocks had typical island arc features, the magma source was related to plate subduction and experienced certain degrees of crustal contamination, but without the mixture of subduction sedimentary melt. LA-ICP-MS zircon 206Pb/238U age of 388.0Ma±6.7Ma shows that the island arc environment lasted at least until late Middle Devonian, the oceanic crust might have represented the subduction of Aermantai ophiolite melange towards North Siberia, and the Agashen Obo volcanic rocks were probably generated from partial melting of the nunde wedge enlarged by rising upper subduction fluid. There existed subducted accretion product of Armantai ocean belt in Paleozoic period, which constituted part of continued southward accretion of the southern margin of the Siberia plate.关键词
东准噶尔/LA-ICP-MS锆石U-Pb年龄/中泥盆世/岛弧火山岩/俯冲增生Key words
eastern Junggar/LA-ICP-MS zircon U-Pb dating/Middle Devonian/island arc volcanic rocks/subduction and accretion分类
天文与地球科学引用本文复制引用
李现冰,徐学义,陈隽璐,唐卓,张越,孙小攀..新疆东准噶尔阿尕什敖包地区火山岩LA-ICP-MS锆石U-Pb年龄及地球化学特征[J].地质通报,2012,31(12):2052-2062,11.基金项目
中国地质调查局项目《阿尔泰-准噶尔北缘成矿带基础地质综合研究》(编号:2011085009)、《新疆阿尔泰康布铁堡组厘定与划分》(编号:1212011121093)、《基础地质调查成果集成与综合研究——西北地区》(编号:1212011121137)、《天山成矿带基础地质综合研究》(编号:1212011085055)和《天山-兴蒙成矿带火山岩浆作用对成矿制约的综合研究》(编号:1212010050503) （编号:2011085009）
