ZIRCON U-Pb AGE FOR GRANITE OF THE ORDOVICIAN FORMATION AND ITS TECTONIC SIGNIFICANCE IN THE SOUTHERN QILIAN
Caledonian movement is a very important tectonic deformation stage since the Early Paleozoic in Qilian.The most intense tectonic activity began to emerge between the late Silurian and Early Devonian.The granitic intrusive began to emerge in early Caledonian movement.To the late Caledonian movement,South Qiian is developed in neutral-acidic intrusive rocks,and especially in the south western part of Qilian is relatively concentrated,the rock mass around in Hala Lake and Yangkang,Zhihema,etc.We made zircon U-Pb dating for granite by LA-MC-ICPMS.Zircon U-Pb age determination results show that,the formation of granite at the age of 461.5 ± 1.6 Ma.It indicates that the geological age of granite in Saodi belongs to Middle Ordovician.Thus,the Balonggonggeer Formation should be earlier than the Middle Ordovician.
国家科技期刊平台
NSTL
万方数据
维普
