Geodynamic modelling of crustal deformation of the North China block: a preliminary study

The North China block (NCB) has experienced at least two stages of crustal deformation throughout the Mesozoic as revealed by the compressional structural styles before the late Jurassic and the extensional tectonics in the late Mesozoic. The E-W structural trends of the late Triassic Qinling-Dabie and Yinshan-Yanshan orogenic belts, which respectively represent the southern and northern boundaries of the North China block, clearly indicate N-S shortening of the NCB, whereas the widely distributed NNE-trending extensional basins call for E-W-directional crustal stretching during the late Mesozoic. On the basis of the Mesozoic tectonic evolution in the NCB, we employ a mountain-basin evolution system to model these geodynamic processes. The N-S shortening (late Triassic to early late Jurassic) may result from subduction and collision between the North China and South China blocks, along with the collision between the North China-Mongolian and Siberian plates. Horizontal extensional thinning of a previously thickened, unstable lithosphere may have led to the formation of extensional basins as a consequence of so-called strike-slip collapse, which was possibly triggered by the easterly roll-back of the descending subducted slab of the ancient Pacific plate.