RESTORATION OF TOTAL THICKNESS ERODED BY MAIN UNCONFORMITIES IN TADONG AREA, TARIM BASIN AND GENETIC MECHANISMS

Total thickness restoration of eroded strata is an important task for tectonic reconstruction and hydrocarbon exploration. In this study, nine unconformities have been identified in the Tadong area by seismics, of which six major ones are closely related to the orogenic processes in the peripheral mountains of the basin, which includes the unconformities between Silurian and Upper Ordovician, between Upper Devonian and Pre-Upper Devonian, between Triassic and Pre-Triassic, between Jurassic and Pre-Jurassic, between Paleogene and Cretaceous, and between Neogene and Paleogene. Using balanced sections, the total eroded thickness of the main unconformities is reconstructed by the method of trend thickness for the Tadong area of Tarim Basin. The result suggests that the denudation is strongly controlled by the subduction and collision of the Tianshan and the Altyn Tagh orogenic belts. The denudations between the Silurian and the Upper Ordovician, and between the Upper Devonian and the Pre-Upper Devonian occurs mainly on the Tadong Uplift and the Ruoqiang Depression, and the denudation between the Upper Devonian and the Pre-Upper Devonia is more intensive. On the contrary, the denudation between the Triassic and the Pre-Triassic is on the Kongquehe Slope. The denudation between the Jurassic and the Pre-Jurassic also mainly occurs on the Tadong Uplift, in the Ruoqiang depression and on the Kongquehe slope. The denudation between the Paleogene and the Cretaceous, and the one between the Neogene and the Paleogene occur as well in the Tadong area with weaker denudation.