地质科学2012，Vol.47Issue(1)：221-239,19.
阿尔泰南缘麦兹盆地康布铁堡组变质酸性火山岩年龄及岩石成因
Geochronology and genesis of the meta-felsic volcanic rocks in the Kangbutiebao Formation from the Maizi Basin at the southern margin of the Altay, Xinjiang
摘要
Abstract
LA-ICP-MS U-Pb zircon ages and geochemical data of whole rocks are reported for meta rhyolites from the Kangbutiebao Formation in the Maizi Basin at the southern margin of Altay orogenic belt. The zircon U-Pb isotopic data constrain their magmatic emplacement at 410. 5±1. 3 Ma and 400. 4 ± 2. 1 Ma, respectively. The results presented in this study indicate that metarhyolites are characterized by high concentrations in SiO2 ( 72. 15% to 81. 26% ), total alkali (Na2O+K2O)(7. 23% to 11.55%), and low concentrations in Al2 0,(10. 56% to 14.87%), TiO2 (0. 16% to 0. 27% ), MgO (0. 04% to 0.14% ) , CaO ( 0. 04% to 2.42% ) and TFe2O3 (0.11% to 1. 64% ). They display obvious negative anomaly of Ti,P,Sr,Ba,Nb and Ta,obvious enrichment of Th,U,Pb,Zr,Hf and LREE. Most samples show noticeable negative Eu anomalies (5Eu = 0. 48 ~ 0.91). These features, together with the regional geology characteristics, indicate that these felsic volcanic rocks were generated by partial melting of lower crust in an active continental margin. The primitive magma was likely resulted from the underplating, and underwent fractional crystallization and minor wall-rocks assimilation during the ascending of magma.关键词
变质酸性火山岩/地球化学/LA-ICP-MS锆石U-Pb定年/阿尔泰南缘Key words
Meta-felsic-volcanic rocks/ Geochemistry/ LA-ICP-MS Zircon U-Pb dating/ Southern margin of the Altay分类
天文与地球科学引用本文复制引用
柴凤梅,杨富全,刘锋,耿新霞,张志欣,陈斌..阿尔泰南缘麦兹盆地康布铁堡组变质酸性火山岩年龄及岩石成因[J].地质科学,2012,47(1):221-239,19.基金项目
国家自然科学基金项目(编号:40863001)、“十一五”国家科技支撑计划项目(编号:2011BAB06803-02,2006BAB07B02-01)和公益性行业科研专项(编号:201211073),新疆维吾尔自治区自然科学基金项目(编号:2010211A08)和新疆大学“天山学者”特聘教授(陈斌)启动经费项目资助. （编号:40863001）
