新疆东准噶尔锡矿北花岗斑岩的锆石LA-ICP-MS U-Pb测年

LA-ICP-MS zircon U-Pb dating from granite-porphyry rcoks in Xikuangbei, East Junggar, Xinjiang, China. Geological Bulletin of China

摘要: 对东准噶尔锡矿北花岗斑岩进行锆石LA-ICP-MS U-Pb测年，获得206Pb/238U加权平均年龄为(281±10)Ma，MSWD=9.3，206Pb/238U-207Pb/235U谐和曲线图中下交点年龄为(278±11)Ma，MSWD=7.5，两者在误差范围内完全一致，时代属于早二叠世。结果表明，锡矿北花岗斑岩形成的时代属于东准噶尔后碰撞深成岩浆活动的范围(330～265Ma)，晚于东准噶尔乌伦古河碱性花岗岩和卡拉麦里碱性花岗岩的形成时代（300Ma左右），以花岗斑岩为代表的晚古生代岩浆侵入活动延续到早二叠世晚期。

Abstract: The weighted average 206Pb/238U age from LA-ICP-MS U-Pb zircon dating of the Xikuangbei granite-porphyry in East Junggar is (281±10)Ma，MSWD=9.3，the lower intersection point of 206Pb/238U-207Pb/235U concordia curve is (278±11)Ma，MSWD=7.5，within the tolerate error range, these two results belong to Early Permian. It is indicated that formation of the Xikuangbei granite-porphyry is during post-collision hypogene magmatic activity (around 330～265Ma)，which is later than Wulunguhe and Kalamaili alkali granite (around 300Ma). Late Paleozoic intrusion represented by granite-porphyry continued to late Early Permian