内蒙古锡林浩特地区拜仁达坝矿区闪长岩体锆石SHRIMP U-Pb定年及其地质意义

The SHRIMP zircon U-Pb dating and geological features of Bairendaba diorite in the Xilinhaote area, Inner Mongolia, China. G

摘要: 对拜仁达坝矿区闪长岩体中的锆石进行了SHRIMP U-Pb定年，获得13个锆石颗粒的206Pb/238U年龄的加权平均值326.5Ma±1.6Ma(MSWD=1.7)，表明岩体侵位于海西期。岩体的地球化学特征显示岩体较为明显地受到了锡林浩特杂岩的混染，具有火山弧岩浆作用成因的特点。结合区域内其他海西期岩体的年代学和地球化学特征，该区海西期经历了一次较为强烈的构造岩浆事件，也暗示该火山弧环境可能从苏尼特地区一直向东延伸至克什克腾旗的北部地区。

Abstract: The diorite in Bairendaba Ag polymetallic ore district was studied with SHRIMP zircon U-Pb and geochemical method. It has yielded a Hercynian emplacement age of 326.5±1.6Ma (MSWD=1.7), and the geochemical data suggest a volcanic arc setting genesis for the diorite, there was significant contamination with Xilinhaote complex in the magma evolvement. Combined with the geological and geochronological features of granitods in the nearby area, it shows that there has been an intensive Hercynian tectonic-magmatic event in this area, and the volcanic arc setting may extend from Sunid area to northern Hexigten.