摘要
对内蒙古达茂旗北部构造单元的巴特敖包岛弧带2个花岗闪长岩岩体样品和南部构造单元一个花岗岩岩体的2件样品进行了LA-ICP-MS锆石U-Pb定年。北部构造单元采自2个花岗闪长岩岩体的样品锆石206Pb/238U年龄分别为468Ma±2Ma和452Ma±3Ma,代表了这2个岩体的侵位时间,表明古亚洲洋向华北克拉通之下俯冲不晚于468Ma±2Ma;南部构造单元采自同一花岗岩岩体的2件样品获得的锆石206Pb/238U年龄分别为268Ma±2Ma和264Ma±2Ma,和该单元西部岩体已有的锆石年龄相符。这为华北克拉通北缘岩浆作用研究提供了新的年代学证据。
This paper reports four zircon U-Pb ages of granitoids in Darhan Muminggan Joint Banner, Inner Mongolia. Two gran- odiorite samples from Bater magmatic arc in the northern part and two granite samples from a single pluton in the southern part were dated by LA-ICP-MS zircon U-Pb method so as to define their emplacement ages and provide constraints on the subduction and collisional events of the Paleo-Asian Ocean in the central part of Inner Mongolia. The two granodiorite samples yielded zircon U-Pb ages of 468Ma±2Ma and 452Ma±3Ma, respectively, indicating that the southward subduction of the paleo-Asian ocean beneath the North China Craton started at least at 468Ma, which resulted in the formation of Bater Obo magmatic arc, and the two granite samples gave zircon U-Pb ages of 268Ma±2Ma and 264Ma±2Ma, respectively, which are within the range of prexisting age data from the western pluton, although the tectonic setting of the Middle Permian plutonism in the southern part is still uncertain.
出处
《地质通报》
CAS
CSCD
北大核心
2013年第11期1737-1748,共12页
Geological Bulletin of China
基金
国家重点基础研究发展计划(973计划)(编号:2013CB429806)
中国地质调查局项目(编号:1212011085474、1212011085476)
