The Mesozoic And Cenozoic Uplift Events And Tectonic Significance Of Zhuozishan Area In The Northwest Margin Of Odros Basin

Zhuozishan is located in the northwestern Ordos basin, the tectonic uplift study of this region is weak. Mesozoic and Cenozoic formation of this area is fully exposed and the mine lithological type is sandstone. The area is strongly affected by different tectonic movement at different times in Mesozoic and Cenozoic. The fault and fold structure are well formed, and most of the construct tracks distribute to north and south. Thrust tectonic is the largest structure characteristics in the region and is most damaged by the fault. From the formation contact relationship diagram, seismic profiles, residual strata thickness figures parallel unconformity and angle unconformity can be seen between the strata with certain erosion at different level.From fission track data of Zhuozishan area, it is concluded that this area experienced three periods of rapid uplift since Triassic, which are Late Jurassic to Early Cretaceous (155-110Ma), Late Cretaceous to Early Paleogene(45-85Ma), since Neogene(20-0Ma), and the rest of the time is a slow uplift process. From the differences uplift process of the both side of eastern Zhuozishan Fracture since Neogene by testing the sample, we can know there have different uplift processes in this area. From the thermal simulation of the samples, we can calculate that the uplift and denudation thickness of zhuozishan is more than 3000 meters during Mesozoic and Cenozoic. The uplift and denudation of this area are corresponding to certain tectonic events.Zhouzishan area was strongly influenced by tectonic activities since late Triassic. Late Triassic, influenced by the Indosinian movement, the inland depression sedimentary environment of this area finished slowly, meanwhile, part of this area suffered from erosion. Early to middle Jurassic, Zhouzishan area under weak extensive environment and certain part of this area began to deposit. In Late Jurassic, Zhuozishan area began to uplift strongly. As the same time, the main fracture began to appear. The uplift and denudation amount in Jurassic are about 700 m. In Early cretaceous the uplift rate reduced. In Late cretaceous to Early Paleogene, this area began to uplift strongly, and the tectonic deformation was further developed, the folds and fractures in this area began to appear. The topography of this area is closed to today. The uplift and denudation amount in Cretaceous are about 1100 m. In Cenozoic, the Zhuozishan area affected by Himalayan movement further, and uplift rapidly from Pliocene. The uplift and denudation amount in Cenozoic are about 1300 m.Zhuozishan area is affected by multiple blocks around it since Mesozoic and Cenozoic. The comprehensive function of these blocks made the complicated stress conditions in this area. This is the source of the complex tectonic phenomena of Zhuozishan area. The uplift in different periods is closely related to the regional tectonic activity, which is controlled by the deep geodynamic environment.