西昆仑塞拉加兹塔格群地质特征及构造环境分析

摘要

The stratum of Sailajiazitage Group distributes from Akazidaban to Supikeya, located to the east of Kegang fault,which is also an important part of Tiekelike epicontinental massif in the south edge of Tarim block.Its composition are mainly bimodal volcanic rock,which contains small amounts of carbonate rock,and pyroclastic rock.And the volcanic rock is composed of basalt, quartz keratophyre and keratophyre.By means of LA-ICP-MS U-Pb dating of the zircon from quartz keratophyre in the Sailajiazitage Group,an age of (841.6 ± 2.1) Ma is determined,which should be the Qingbaik-ouan Period,and stands for the original rock age of the Sailajiazitage Rock Group.The sedimentology and geochemistry features of the volcanic rock indicate that,the volcanic rock in Sailajiazitage Group is formed under the tectonic environ-ment of epicontinental rift valleys in the later period of intraplate’s tension.%塞拉加兹塔格群主要分布在柯岗断裂以东阿喀孜达坂-苏皮克牙一带，是塔里木南缘铁克里克陆缘地块的重要组成部分。主体为一套双峰式火山岩夹少量碳酸盐岩、碎屑岩建造，火山岩主要由玄武岩、石英角斑岩、角斑岩组成。采用LA-ICP-MS方法测定锆石U-Pb年龄值（841.6±2.1）Ma，反映其时代为青白口纪，代表塞拉加兹塔格岩群原岩生成年龄。从火山岩的沉积学、地球化学特征综合分析，火山岩形成于板内拉张后期近洋壳的陆缘裂谷构造环境。