黔中九架炉、祥摆、旧司组特征及其地质意义──以乌当地区为例

在贵阳乌当断层南北两侧 ,下石炭统九架炉组、祥摆组和旧司组的分布和沉积特征存在明显的变化。九架炉组基本分布于乌当断层北西侧 ,祥摆组由北向南的沉积环境向浅海相呈有规律的变化 ,旧司组则仅在乌当断层南侧分布。这些地层的分布规律、沉积环境的变化说明了乌当断层为黔中隆起南侧边缘断层 ,且该断层自早古生代形成后 ,为一多期次活动断层。

CHARACTERISTICS OF THE JIUJIALU, XIANGBAI AND JIUSI FORMATIONS AND THEIR GEOLOGICAL SIGNIFICANCE

Along the south and north flanks of the Wudang fault apparent changes are observed in the distribution and depositional characters of the Jiujialu, Xiangbai and Jiusi formations (Lower Carboniferous). The Jiujialu Formation is distributed only in the north of the Wudang fault. From north to south, the depositional environment of the Xiangbai Formation changed regularly from lagoon to shallow sea facies. The Jiusi Formation is distributed only in the south of the Wudang fault. The stratigraphic distribution and various depositional environments showed that it is the Wudang fault that constitutes the southern boundary of the Middle Guizhou Uplift, and the fault was formed in Early Palaeozoic and it was still active in Late Palaeozoic.