Late Triassic-Early Jurassic Uplifting in Eastern Qilian Mountain and Its Geological Significance:Evidence from Apatite Fission Track Thermochronology
Peng Heng
Wang Jianqiang
Massimiliano Zattin
Liu Chiyang
Han Peng
Zhang Shaohua
Abstract：The northeastern margin of the Qilian Mountain,which is the outer zone of the uplift and eastward expansion of Ti-betan plateau,has undergone a rapid uplift and strong exhumation process since the Cenozoic.The Mesozoic tectonic evolution study remains very weak for without the chronological constraints because pre-Cenozoic strata in the area have been subjected to the later alteration.Based on the analysis of source of the clastic rocks,sedimentary characteristics and basement apatite fission track dating,this paper reveals the Mesozoic tectonic uplift timing and process of the eastern Qilian Mountains with inversion simulation of fission track thermal history,aims at further exploration of the Mesozoic intracontinental tectonic evolution and regional dynamic background in the Qin-Qi orogenic belt.The results show that the Longfengshan Formation is the rift basin sediment of near-source accumulation from the pre-Mesozoic strata.The detrital apatite fission track has not been annealed,and it still retains the history of uplift and erosion in its source area.The fission track age and the thermal history simulation show that the rapid cooling event occurred in Late Triassic (±215 Ma)in source area,which has also been recorded by thermal his-tory simulation results of the northestern granite body.Our results show the same time-space characteristics with the rapid up-lift of the West Qinling region previously revealed by 40Ar/39Ar chronology.Apatite fission track dating reveals a rapid uplift event of the study area in the Late Triassic-Early Jurassic.It is believed that the tectonic uplift event may have been a response to the closure of Mianlue Ocean and consequent collision orogeny in the Middle to Late Triassic.
Keywords：Late Triassic-Early JurassicNorth Qilianapatite fission trackcollision and orogenyuplift and erosionpetroleum geologytectonic
Publication Date：2018-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：14( 1983-1996 )