Basin-range tectonic evolution and its coal-controlling action in Northwest China

The paper discussed emphatically the basin-range tectonic evolution and its coal-controlling action during Meso-Cenozoic in Northwest China through systematic analysis and comparison of formation integrity, unconformity distribution and its type variety, sedimentary formation and on the basis of tectonic sequence division, concluding that, Current tectonic framework of basin-range system in Northwest China was shaped rapidly in mid-late period of Himalayan movement. The Meso-Cenozoic tectonic evolution of Northwest China was controlled by multiple northward collisions from the south, the southward increase of formation unconformity and lacuna was totally the passive responses to the long-range and short-range tectonic compression from the south. The significant difference in scale and shape between "surrounded -type basins" and "sandwiched-type basins" during Indosinion movement has laid the differentiation foundation of spatial distribution and structural deformation of coal resources. Peak coal accumulation took place in the period of convergent evolution of basin-range system in a weak compressional or weak extensional stress field, while extensive basin highly developed. Coal strata deformation which presents centripetally circular differentiation in "surrounded-type basins" and axially banded differentiation in "sandwiched-type basins" is dominated by the stress energy decreasing gradually from edge to inside.