羌塘盆地白垩纪以来快速隆升剥蚀的热年代学证据

Thermo chronological evidence for rapid uplift and denudation since Cretaceous in the Qiangtang basin

利用磷灰石裂变径迹测年方法,研究青藏高原腹地羌塘盆地中央隆起带的杂岩体隆升与剥蚀。结果表明:研究区15件磷灰石裂变径迹样品的表观年龄为(57.0±5.0)～(118.0±7.0)Ma,混合年龄分解的峰年龄为(33.0±6.0)～(132.0±7.0)Ma;结合磷灰石裂变径迹热演化史反演结果,羌塘盆地的构造隆升主要发生于早白垩世、晚白垩世和新生代,其中晚白垩世(100.0～80.0Ma)是构造隆升的主体阶段,构造隆升剥蚀的厚度约为3.200km。该结果对青藏高原腹地的隆升过程研究具有参考意义。

The uplifting and denudation of complex rock mass in the central uplift zone of the Qiangtang basin in the hinterland of the Qinghai-Tibet Plateau were studied based on apatite fission-track dating method.The results showed that the apparent ages of 15 apatite fission-track samples were(57.0±5.0)^(118.0±7.0)Ma,and the peak ages decomposed from the mixed ages were(33.0±6.0)^(132.0±7.0)Ma in the study area.The tectonic uplift of the Qiangtang basin mainly occurred in the early Cretaceous,late Cretaceous and Cenozoic stages suggested by the inversion results of apatite fission-track thermal evolution history and other evidence.The late Cretaceous uplift(100.0~80.0)Ma is the main uplift among the three tectonic uplifts,and its uplift and denudation thickness was about3.200 km.The results have reference significances for the study of the uplift process in the hinterland of the Qinghai-Tibet Plateau.