A NUMERICAL APPROACH OF COUPLING BETWEEN MESOZOIC SEDIMENTARY BASIN AND OROGENIC BELT IN JIANGHAN OVERLAIN BASIN AND ITS ADJACENT AREA

Jianghan overlain basin is located on the Middle Yangtze platform, between Qinling-Dabie and Jiangnan orogenic belts. It went through the continent-continent collision in the North and the extrusion orogeny in the South, occurs in fault-rift basin and rift basin in turn. Here the tectonic system has changed a lot, since it shows complex and united multitudinous geological phenomena and went through four stages of basin formation, i.e., stages of marine, coal, salt, and continent-wide basin formation since Mesozoic. The basin has detailedly recorded the kinetic processes that show the uniting of South China Continent and North China Continent and the conversion of the tectonic systems in Northeast Asia Continent. Jianghan overlain basin is also one of the pivotal areas where the deep dynamical and geological processes that occurred in the east Eurasia Continent were fully understood. On the basis of knowledge concerning the tectonic evolution of the basin, we reconstructed the basic stratigraphic framework, in which four supersequences are divided in all four basin-formation stages during Mesozoic and Cenozoic. The sedimentary filling sequences of the basin are generalized into three types, i.e., foreland, rifting and depression. Analysis of structural styles and movement modes of the basin and orogenic belt shows that the early foreland stage of Jianghan overlain basin grew with the collision orogenic stage or the early post-orogenic stage, the rift-fault and depression stage grew with the later post-orogenic stage and the orogen-splitting stage. Continent geodynamics numerical simulation (by using FLAC method) results show that the basin evolution was controlled by the Indosinian and early Yanshanian continent-continent rotation-type collision between the Southern and Northern China Continent Plates, by the late Yanshanian post-orogenic stress adjustment and slab breaking and mantle convection, and by the Himalayan interaction between Pacific Ocean plate and Eurasia Continent, in turn. In this paper a new idea and research method of kinetic solution for minitype and middletype overlain basins in South China were suggested.