SHRIMP U-Pb zircon dating of the Ordos Basin basement and its tectonic significance  

作　　者：HU JianMin LIU XinShe LI ZhenHong ZHAO Yue ZHANG ShuanHong LIU XiaoChun QU HongJie CHEN Hong 

机构地区：[1]Institute of Geomechanics,Chinese Academy of Geological Sciences [2]Research Institute of Exploration and Development of Changqing Oilfield Company,PetroChina

出　　处：《Chinese Science Bulletin》2013年第1期118-127,共10页

基　　金：supported by the National Basic Research Program of China (2012CB416604 and 2012CB416603);the National Natural Science Foundation of China (91114204)

摘　　要：SHRIMP U-Pb zircon 207 Pb/206 Pb ages were obtained from two drill cores from the basement of the Ordos Basin.A garnet-sillimanite-biotite-plagioclase gneiss(QI1-1) from the western Ordos Basin basement yielded an average age of 2031 10 Ma.Based on the mineral assemblages,the source material of the gneiss is speculated to be pelitic-felsic system.A gneissic two-mica granite(Long1-1) from the eastern Ordos Basin basement yielded an average age of 2035 10 Ma.The zircons from both samples exhibit magmatic growth pattern.The shapes of the zircons suggest that the zircons should crystallize from a granitic of felsic volcanic terrain.The ages and the characters of zircons are consisitent with the other researches in the Ordos Basin and indicate that the basement of the Ordos Basin had experienced an intensive magmatic epsode during the late Paleoproterozoic period.The date from this study suggest the possible existences of a Paleoproterozoic mobile tectonic belt in the region.The reconstruction of such a belt is critical for understanding the tectonomagmatic evolution of the western block of the North China Craton.SHRIMP U-Pb zircon 207pb/206pb ages were obtained from two drill cores from the basement of the Ordos Basin. A garnet-sillimanite-biotite-plagioclase gneiss （QII-1） from the western Ordos Basin basement yielded an average age of 2031＋10 Ma. Based on the mineral assemblages, the source material of the gneiss is speculated to be pelitic-felsic system. A gneissic two-mica granite （Long1-1） from the eastern Ordos Basin basement yielded an average age of 2035＋10 Ma. The zircons from both samples exhibit magmatic growth pattern. The shapes of the zircons suggest that the zircons should crystallize from a granitic of felsic volcanic terrain. The ages and the characters of zircons are consisitent with the other researches in the Ordos Basin and indicate that the basement of the Ordos Basin had experienced an intensive magmatic epsode during the late Paleoproterozoic period. The date from this study suggest the possible existences of a Paleoproterozoic mobile tectonic belt in the region. The reconstruction of such a belt is critical for understanding the tectonomagmatic evolution of the western block of the North China Craton.

关 键 词：鄂尔多斯盆地东部 锆石U-Pb SHRIMP 盆地基底 同位素年代学 构造意义 U-PB同位素 酸性火山岩 

分 类 号：P548[天文地球—构造地质学]