Uplift and Exhumation during Mesozoic in Halaguole-Hatu Area, East Segment of Eastern Kunlun Mountains: Evidence from Zircon and Apatite Fission-Track Ages

Abstract

This paper discusses the uplift and exhumation processes during Mesozoic in Halaguole-Hatu area, east segment of the eastern Kunlun, by dating the zircon and apatite fission-track ages and geobarometer analysis of the hornblende of intermediate-acidic intrusive rocks. The geobarometer analysis of the hornblende of intermediate-acidic intrusive rocks in Hatu area illustrates that the total exhumation range is about 8-9 km since the Late Hercynian-Indosinian, which happened vey slowly, about (20-)40 m/Ma, from the Early Permian to the early stage of the Late Triassic. While the zircon fission-tract age dating of the samples from different elevations reveals a slow uplift process during the Middle and Late Jurassic. The uplift rate in the Middle Jurassic, 77-88 m/Ma, is correspondingly faster than that in the Late Jurassic, less than 37 m/Ma. This slowing down tendency reflects the gradual decay of the intensive uplift at the boundary time of the Early and Middle Jurassic. The zircon and apatite fission-track age pairs show the exhumation rate is normally less than 55 m/Ma since the Middle Jurassic. Meanwhile, the rock exhumation rate is basically at the same quantity grade as that of its uplift rate, implying that its exhumation and uplifting were in equilibrium on the whole.