北祁连东段石炭纪古地理与构造关系初探

本区地质演化受北西西向深断裂组及贺兰—六盘山深断裂组制约,对泥盆系、石炭系的沉积、古地理景观,海侵方向及矿产的形成均起明显的控制作用。

ON THE RELATIONSHIP BETWEEN CARBONIFEROUS PALEOGEOGRAPHY AND TECTONICS IN THE EAST PART OF THE NORTH QILIAN MOUNTAINS

The Qilian Mountains is located on the north border of the Gansu-Qinghai-Tibet plate. The Caledonian orogeny took place at the end of the Silurian period has given rise to the mutual collision between the Tarim-North China plate and the Chaidamu plate, that facilitated the oceanic crust of Early Palaeozoic subducting and Vanishing gradually along the deep fracture, and that formed the Qilian Caledonian Folding Belt and the Hexi Corridor Transition Belt. Then,for Late Palaozonic the geologic history of the research area become the evolution of the continetal crust.On the west edge of the Ordos Platform there are some fault zones of north to south stretch, which are jointed at its south termination by the north structural belt of the West Qinling Mountains and, therefore, formed the east boundary of the North Qilian. The fracture groups of NWW -SEE stretch developed in the east part of the North Qilian Folding Belt, and considered not only as the boundary between the north and the south parts of the research area, but also as the marker of its tectonic deviding.During the Carboniferous period the reseach area seems to be an epicontinetal sea with some features of gulf. The sedimentary constructiven-ess is mainly composed of coal-bearing formation, which belongs to the littoral facies of barrier coast area. The activities of the fracture zones have cauesed the block move-ments of the sedimentary base in this area. Therefore, there are different features of lithofacies-palaeogeography among parts of the research area. The north Qilian depression belt is especially much complicated than the Corridor transition belt in tectonic aspects and sedimentation etc.