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 similar to 4.2 Ma), and lengths between 9.6 mu m and 13.6 mu m. The ages of zircon fission track are distributed in 106.3 similar to 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 similar to 100 Ma), Eocene (55 similar to 30 Ma), and Miocene (10 similar to 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.