西藏羌塘盆地抬升冷却历史及意义

发布时间：2018-10-05 11:51

【摘要】：以地质构造背景及热演化程度为约束,运用磷灰石裂变径迹分析方法,对羌塘盆地进行了低温热年代学研究。羌塘盆地记录的抬升冷却年龄可划分为2大阶段:第一阶段主要为早白垩世晚期—晚白垩世(108.7~69.8 Ma);第二阶段主要为始新世中、晚期—中新世晚期(44.4~10.3 Ma)。第一阶段抬升冷却年龄是班公湖—怒江洋关闭后进一步会聚挤压造成羌塘盆地中央隆起地层抬升冷却的记录。第二阶段抬升冷却年龄可进一步划分为3期,分别对应44.4~30.8,26.1~22.6,10.3 Ma,其中渐新世晚期—中新世早期(26.1~22.6 Ma)为主隆升期。第二阶段抬升冷却年龄反映了印度板块与欧亚板块碰撞及之后强烈挤压造成羌塘盆地抬升冷却过程。磷灰石裂变径迹方法确定的羌塘盆地抬升冷却年龄表明,青藏高原在44.4 Ma开始挤压隆升,在26.1~22.6 Ma青藏高原大规模整体隆升,青藏高原形成,在中新世晚期(10.3 Ma)以来青藏高原继续挤压隆升。
[Abstract]:The low temperature thermal chronology of Qiangtang basin is studied by using the apatite fission track analysis method, which is restricted by geological tectonic background and thermal evolution degree. The uplift and cooling ages recorded in the Qiangtang Basin can be divided into two stages: the first stage is mainly from the late early Cretaceous to the late Cretaceous (108.7 ~ 69.8 Ma);), the second stage is mainly the middle Eocene and the late Miocene (44.410.3 Ma). The first stage of uplift and cooling age is the record of uplift and cooling of the central uplift of Qiangtang basin caused by further convergence and compression after the closure of Bangong Lake-Nujiang Ocean. The second stage can be further divided into three stages, corresponding to 44.4U 30.826.1 ~ 22.610.3 Ma, in which the Oligocene to the early Miocene (26.1 ~ 22.6 Ma) is the dominant uplift stage. The second stage uplift cooling age reflects the process of uplift and cooling of Qiangtang basin caused by collision between Indian plate and Eurasian plate and strong compression. The uplift cooling age of Qiangtang basin determined by apatite fission track method indicates that the Qinghai-Xizang Plateau began to squeeze uplift at 44.4 Ma, and the Qinghai-Xizang Plateau formed on a large scale at 26.1 ~ 22.6 Ma. Since the late Miocene (10. 3 Ma), the Tibetan Plateau has continued to squeeze and uplift.
【作者单位】：西北大学大陆动力学国家重点实验室;西北大学地质学系;中国石化科技开发部;
【基金】：国家自然科学基金(41372128) 国家重大专项(2011ZX05005-004-007HZ)资助
【分类号】：P618.13;P542

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