Evolution and Structural Deformation of Continental Clastic Rocks in the Western Sichuan Basin.

Thick continental clastic rocks, which are important exploration layers, are deposited in the western Sichuan Basin. Based on the analysis of stratigraphic distribution, cross sections and regional setting, the evolution processes and structural deformation of continental clastic rocks in the western Sichuan Basin were discussed. The results show that because of the differential uplifting of peripheral orogens, the depocenters of continental clastic rocks in Sichuan Basin migrate regularly; the depocenter locates in the western Sichuan foreland basin in Late Triassic, and then shifts into the northeastern Sichuan foreland basin in Early-Middle Jurassic; the continental clastic rocks in the western Sichuan Basin are influenced by multi-phase tectonic events, including the Indosinan, Yanshanian and Himalayan movements; during the various tectonic movements, the basin types of the western Sichuan Basin change from an intra-cratonic rift basin in Early-Middle Triassic to a continental margin basin in Early Late Triassic, and then to an intracontinental foreland basin in the subsequent stages; thrust faults and folds are the most distinctive deformation characteristics of the continental clastic rocks in the western Sichuan Basin, and some major faults also have weak strike-slipping movement; the main structural styles involve imbricate thrust systems, pop-ups, fault-related folds and klippes, etc.; the zonation of structural deformation is horizontal, which has also controlled the zonation of traps. [ABSTRACT FROM AUTHOR]