青藏高原东北缘中新生代构造演化: 来自磷灰石和锆石裂变径迹的证据

青藏高原东北缘隆升机制和过程一直以来备受争议，本文为了进一步限定北祁连山及其北缘地区山体的隆升历史，在旱峡、白杨河和红山以及酒泉盆地以北的黑山和金塔南山进行了磷灰石和锆石裂变径迹分析.测试结果表明，研究区基岩样品的磷灰石裂变径迹年龄分布在晚白垩世—上新世（82~4.2 Ma），径迹长度介于9.6~13.6 μm；锆石裂变径迹年龄分布范围为106.3~480.5 Ma，多数介于106~195 Ma.结合镜质体反射率，热史模拟曲线揭示了中新生代三期主要的冷却降温事件：早白垩世期间（140~100 Ma）、始新世期间（55~30 Ma）、中新世（10~8 Ma）以来.早白垩世期间的隆升剥露冷却过程可能由于拉萨地块的北向拼贴碰撞引起；始新世期间的隆升剥露冷却事件可能是印度与欧亚板块碰撞远程快速响应的结果；中新世以来的隆升剥露冷却过程与北祁连山逆冲断层的构造活动有关.

Meso-Cenozoic tectonic evolution in the northeastern margin of the Tibetan Plateau:Evidence from apatite and zircon fission tracks

The uplift mechanism of the northeast edge of the Tibetan Plateau has always been a hotspot of debate among geologists.In order to further define the uplift history of the northern Qilian Shan,apatite and zircon fission track analyses were carried out on the Hanxia,Baiyanghe,and Hongshan in the northern Qilian Shan,and Heishan and Jintananshan to the north of Jiuquan basin.The results show that apatite fission track dating of the bedrock samples in the study area has yielded ages from the Late Cretaceous to the Pliocene (82~4.2 Ma),and lengths between 9.6 μm and 13.6 μm.The ages of zircon fission track are distributed in 106.3~480.5 Ma,most of which are between 106 Ma and 195 Ma.Combined with the vitrinite reflectance,the thermal history simulation curves reveal three major cooling events in the Meso-Cenozoic eras: early Cretaceous (140~100 Ma),Eocene (55~30 Ma),and Miocene (10~8 Ma).The early Cretaceous uplift was probably due to the northbound collage collision of the Lhasa block.The uplift and exhumation during Eocene may be the result of the far-field rapid response of Indo-Eurasia collision.The uplift and exhumation since the Miocene were related to the tectonic activity of the thrust fault in the northern Qilian Shan.