内蒙古科尔沁右翼中旗花岗斑岩年代学研究

STUDY ON THE CHRONOLOGY OF GRANITIC PORPHYRY IN HORQIN YOUYI ZHONGQI, INNER MONGOLIA

摘要: 对内蒙古科尔沁右翼中旗花岗斑岩的同位素年代学研究结果表明，花岗斑岩LA-ICP-MS锆石U-Pb加权平均年龄为163.3±2.9 Ma，显示花岗斑岩体侵位于中侏罗世晚期.花岗斑岩具A型花岗岩特征，代表伸展构造岩浆活动.结合区域地质资料和前人相关研究，该区中侏罗世花岗斑岩可能形成于造山后伸展环境.花岗斑岩的期次厘定为松辽盆地的成生演化关系提供了新资料.

Abstract: The isotopic chronological study indicates that the LA-ICP-MS zircon U-Pb weighted-average age of the granitic porphyry in Horqin Youyi Zhongqi, Inner Mongolia, is 163.3±2.9 Ma, suggesting the rock body emplaced at the late period of Middle Jurassic. Characterized by A-type granite, the granitic porphyry represents extensional tectonic magmatic activity. Combining the regional geological data and previous research, the Middle Jurassic granitic porphyry is possibly the product of post-orogenic extensional environment. The determination of its phases can provide new data for the formation and evolution of Songliao Basin.