昆中断裂带同构造花岗斑岩锆石U-Pb年龄及其构造意义

ZIRCON U-Pb AGE FROM SYNTECTONIC GRANITIC PORPHYRY IN THE MIDDLE KUNLUN FAULT BELT AND ITS TECTONIC SIGNIFICANCE

采自格尔木南昆中断裂带两个同构造花岗斑岩中的岩浆锆石采用激光烧蚀多接收器电感耦合等离子体质谱(LA-MC-ICP MS)方法得到的206Pb/238U年龄分别为408.5±2.3 Ma和391.2±3.4 Ma。这两组年龄结果表明昆中断裂带为叠置在昆中缝合带上的新生断裂带,形成于东昆仑加里东造山晚期陆内构造变形阶段。

A measurement by LA-MC-ICP MS for two samples of zircon from granitic porphyry collected at Golmud,in south part of the middle Kunlun fault belt has yielded two U-Pb ages of 408.5 ± 2.3Ma and 391.2 ± 3.4Ma,respectively.The results show that the middle Kunlun fault belt should be a newly generated fault belt superposed on the middle Kunlun suture zone,and formed during the tectonic deformation of continental interior in late Caledonian orogeny of the east Kunlun Mountains.