晚古生代右江盆地古岩溶作用研究

The palaeokarstification in the Late Palaeozoic Youjiang Basin, southwestern China

钻井、露头和区域构造资料的分析结果表明,晚古生代的右江盆地存在多期次的岩溶作用,通常具有1～3个岩溶旋回。这些古岩溶作用主要存在于上二叠统顶部、中二叠统茅口组顶部和石炭系顶部,其次是泥盆系的顶部。古岩溶作用的发生与黔桂运动、紫云运动、东吴运动等所形成的层序界面和低位体系域密切。研究区存在包括风化、区域性大气淡水溶蚀、区域性白云岩化、区域性古岩溶、区域性去白云岩化和区域性淡水胶结充填等6种岩溶作用的层序成因类型。

The integration of well logs, outcrops and tectonic data shows that the Youjiang Basin underwent several stages of palaeokarstification during the Late Palaeozoic. One to three karst cycles may be recognized mostly at the top of the Upper Permian strata, top of the Middle Permian Maokouan strata and top of the Carboniferous strata and subordinately at the top of the Devonian strata. The occurrence of the palaeokarstification is closely associated with the sequence boundaries and lowstand systems tract created by the Guizhou-Guangxi, Ziyun and Dongwu Movements. The genetic types include weathering, regional meteoric corrosion, regional dolomitization, regional palaeokarstification, regional dedolomitization and regional fresh-water cementation and filling.