泛华北区石炭系、二叠系内部的重要地质演化转折

THE IMPORTANT INFLECTIONS OF THE GEOLOGICAL PROCESS IN THE CARBONIFEROUS AND PERMIAN SYSTEMS OF THE PAN-NORTH CHINA REGION

对华北地台及邻近区域内重要露头及钻井剖面的石炭系及二叠系展开新一轮系统研究,发现在这一套地层中存在两个重要的地质演化过程转折,即下石炭统、上石炭统之间及中二叠统、上二叠统之间(相当于华北新分层系统上石盒子组与平顶山组之间)存在两个地质演化过程转折。后一转折更为显著:转折面之下,气候背景干热化特征突出,沉积序列呈显著水退趋势,盆地萎缩,石膏质或红色泥质岩系发育,层系沉积缺失或剥蚀缺失现象严重,特化生物类型发育;转折面之上,气候背景呈现降温趋势,沉积序列呈显著水进趋势,盆地覆盖范围急剧扩展,沉积层系在区域上呈大规模超覆,与强烈引张断陷活动相关的砂砾岩发育,暗色泥质岩层系随之出现,特化生物类型迅速衰退。从地球表层系统演化及盆地发育角度考虑,后一转折面在地史占有更为突出的地位,应受到充分关注。

The new study of the Carboniferous and North China Platform and its neighborhood shows Permian important outcrops and drilling sections in the that there are two notable inflections of the geological process. They are between the Mississippian（Lower Carboniferous Series） and Pennsylvanian （Upper Carboniferous Series） and between the Middle Permian Series and Upper Permian Series. Below the later inflection surface, the climate being dry and heat, sedimentary sequence indicating a striking water regression tendency, basin being shrink, gypsiferous or red argillaceous rock series being well developed, hiatus or denudation being outstanding, and specialized organic types being well developed. Above the later inflection surface, the climate indicating a temperature falling tendency, sedimentary sequence showing a water progress tendency, the area covered by basin expanding rapidly, sedimentary bed system displaying a large-scale onlap, sandy gravel rocks relative with strongly stretching fault action being developed, dark argillaceous rock bed system following immediately, and specialized organisms declining. Judging from the evolution the surface-system of the Earth and the development of the basins, the later inflection surface is very important in the geologic history and therefore full attention should be given to it.