Tectono-thermal Evolution Of Eastern Kuqa Depression In The Tarim Basin

Kuqa Depression is rich in oil and gas resources,but the study of tectonic-thermal evolution related to oil and gas generation and preservation is very weak.In this study,the apatite fission track test analysis and thermal history simulation were carried out on typical drilling samples in the eastern part of the Kuqa Depression.The tectonic-thermal evolution history of the eastern part of the Kuqa Depression since Mesozoic was accurately reconstructed,at the same time,the evolution modes of source rocks are compared and analyzed,and the maturity evolution period of source rocks was evaluated.In this thesis,the apatite fission track ages measured by in-situ LA-ICP-MS method are between 77.7 Ma and 104.5 Ma,which are much smaller than the stratigraphic age,and the rapid uplift events of Late Cretaceous are effectively recorded.The thermal history simulation reveals that the Kuqa Depression has experienced two periods of rapid uplift since Jurassic(Early Cretaceous-Late Eocene(120～40Ma)and Late Miocene-prese nt(10～0Ma)),which are caused by the remote effect of the collision between Lhasa plate,Indian plate and the southern margin of Eurasia plate.The differential tectonic uplift in Kuqa depression is caused by the subduction and compression of the southern Tianshan Mountains gradually advancing from north to south.The Jurassic source rocks in Kuqa depression show a multi-stage mature evolution model under the influence of multi-stage subsidence.Affected by tectonic uplift events,Jurassic source rocks mature evolution was at a stagnation stage from early Cretaceous to late Eocene and late Miocene.This study not only determines the tectonic-thermal evolution history of eastern Kuqa depression since Mesozoic,but also clarifies the mature evolution process of main source rocks,which have important guiding significance for regional tectonic evolution and next oilgas exploration.