摘要
加格达奇大黑山地区早石炭世花岗质糜棱岩主体为糜棱岩化二长花岗岩,糜棱岩化花岗闪长岩少量出露,为查明其形成时代,笔者对糜棱岩化二长花岗岩进行了锆石LA-ICP-MS U-Pb定年研究。结果显示:锆石多为短柱状到长柱状,自形到半自形,多具有较好的振荡环带构造,锆石普遍发育变质增生边,宽度较窄,Th/U比值多数为0.1-0.4之间,少数大于0.4,显示岩浆型锆石特征并遭受变质,获得两组206Pb/238U加权平均年龄为170Ma和125.5Ma,通过分析研究及区域对比,认为170Ma可能代表了岩石最近遭受动力变质作用时期,125.5Ma与早白垩世岩浆活动有关。
Jiagedaqi Daheishan area in Early Carboniferous granitic mylonite body for mylonitized granite two,mylonitized granodiorite exposed a small amount,in order to find out the formation time,the author has carried on the dating of the zircon LA-ICP-MS U-Pb of mylonitize granite two.The results showed that zircon is a short column to the long column,by euhedral subhedral,with oscillatory zoning to construct good,common development of zircon overgrowth,narrow width,the ratio of Th/U to 0.1-0.4 between the majority,minority is greater than 0.4,showing magmatic zircons and metamorphic suffered,two group of 206Pb/238 U weighted the average age of 170 Ma and 125.5Ma,through the analysis and regional comparison,that 170 Ma may represent a rock recently suffered metamorphism during the early Cretaceous magmatism related to 125.5Ma.
出处
《世界有色金属》
2017年第3期126-127,共2页
World Nonferrous Metals
