黔东北地区晚奥陶世岩相古地理

黔东北地区上奥陶统出露宝塔组、临湘组、五峰组和观音桥组.根据沉积物、沉积相特征变化,将黔东北地区上奥陶统划分为有障壁碳酸盐岩台地沉积、无障壁碳酸盐岩缓坡沉积和浅海陆棚沉积.板块构造运动在晚奥陶世开始变得剧烈,黔东北大部分地区因华夏板块挤压而隆起.宝塔期,黔东北地区发育碳酸盐岩缓坡模式,碳酸盐岩台地逐渐淹没,形成由古隆起...

Lithofacies palaeogeography of the Late Ordovician in northeastern Guizhou Province

The Upper Ordovician is made up of the Baota，Linxiang，Wufeng and Guanyinqiao Formations in northeastern Guizhou Province.The Upper Ordovician in northeastern Guizhou can be divided into barrier carbonateplatform，non-barrier carbonate ramp and shallow marine shelf according to the sediment and sedimentary facies changes.Plate tectonics became intensive in the Late Ordovician，most areas uplifted due to the squeeze and compression of the Cathaysia Plate.Carbonate ramp was developed in the Baota Age and the carbonate platform was gradually drowned. The lithofacies paleogeographic framework changed from the paleouplift-tidal flat to carbonate ramp.The carbonate platform terminated since the Linxiang Age，and the plate movement made the uplifting area expanded;The Qianzhong-Wuling paleouplift and Chuanzhong paleouplift was more expanded during the Wufeng Age，and most sea area decreased significantly.The Yangtze marine area became a semi-limited-limited shallow sea surrounded by paleouplifts，and black shale occupied most region of the study area. Black shale series of the Wufeng and Longmaxi Formations is an important oil-producing rock of the Upper and Middle Yangtze Area.