青海东昆仑东山根矿区构造活动的磷灰石裂变径迹分析

对青海东昆仑东山根矿区所采集的7个磷灰石样品进行分析，所获得的磷灰石裂变径迹年龄分布在136~67 Ma，具体分为136~112 Ma、101~95 Ma和74~67 Ma 3个年龄组，这较好地体现了该地区所经历的构造隆升事件。东山根矿区热历史可分为4个阶段：第1阶段(160~80 Ma)，是羌塘地块与拉萨地块发生向欧亚板块挤压拼贴作用的响应阶段；第2阶段(120~80 Ma)，经历了阿尔金断裂走滑，青藏高原北部隆升，以及燕山晚期冈底斯地体向北俯冲运动，直到早白垩世晚期发生快速冷却抬升；第3阶段(80~23 Ma)，构造事件相对平稳，整体呈轻微抬升，样品随地质体隆升缓慢降温；第4阶段(23 Ma至今)，快速冷却抬升,对应印度板块对欧亚板块的碰撞作用。

Apatite fission track analysis of tectonic activity in the Dongshangen mining area,East Kunlun,QinghaiTibet Plateau.

Through the analysis of seven apatite samples collected from the Dongshangen mining area of east Kunlun Mountain, Qinghai Province, we showed that the apatite fission track ages vary from 136 to 67 Ma. The ages can be divided into three groups of 136112, 10195 and 7467 Ma to better reflect the uplifting and exhumation events occurred in this region. The thermal history of the Dongshangen mining area are delineated into four stages by fission track modeling. The first stage (160120 Ma) corresponds to the compressive movement of both the Qiangtang and Lhasa blocks towards the Eurasian Plate. The second stage (12015 Ma) coincides with the Aerjin fault strike-slip, the northern Tibetan Plateau uplifting and the northward subduction movement of the Gangdese block in the Late Yanshan period. This stage experienced rapid cooling and uplifting until the end of the Early Cretaceous. In the third stage (8023 Ma) the region was relatively stable, cooling down slowly, while the fourth stage (23 Ma to present) undergoes rapid cooling and uplifting, corresponding to the collision of the Indian Plate towards the Eurasian Plate.