Synsedimentary structures of Early-Middle Jurassic coal-accumulating period and their control on coal in Xinjiang

The contemporaneous tectonic activity accompanying the coal accumulation from the beginning to the end has direct effect on the development degree of coal-bearing strata, and the original thickness and structure of coal seams in the Early-Middle Jurassic in Xinjiang. The synsedimentary tectonic activity, controlled by the Tethys-Himalayan geodynamic system, mainly shows synsedimentary reverse thrust and normal faults in the period. As a result, the subsidence velocity and range of the basement of coal-accumulating basins differ obviously in the Early-Middle Jurassic period in Xinjiang. Under the control of the Tethys-Himalayan geodynamic system, the depocenter and coal-bearing center of the coal-accumulating basin in the Early-Middle Jurassic period in Xinjiang show a tendency of migration from the west to the east and from the south to the north. Comparing coal-bearing region scale, the coal-accumulating strength and the overall subsidence range of the basement of basin present a negative correlation; Comparing coal basin or coal field scale, the relationship between the coal-accumulating strength and the subsidence velocity of the basin basement present positive correlation, parabola and negative correlation respectively.