千米桥地区古岩溶岩的形态多种多样，根据国外岩溶角砾岩的分类三角图及鄂尔多斯盆地奥陶系岩溶岩分类方案，将其划分为岩溶残积岩、岩溶塌积岩、岩溶填积岩、岩溶淀积岩、岩溶溶蚀岩、岩溶交代岩、岩溶冲积岩和岩溶张裂岩等8类。在此基础上，通过微量元素、碳氧同位素分析及矿物流体包裹体的采样分析，认为：该地区古岩溶岩的形成过程极其复杂，是多期叠加的结果；在地质历史演化过程中，古岩溶岩先后经历了裸露期的风化壳岩溶、深埋藏期的热液岩溶和压释水岩溶。

There are various kinds of ancient karst rocks in Qianmiqiao area. According to the trigonometric classification of the foreign karst breccias and the classifying method of karst rocks in Ordos basin, this paper divides those rocks into eight types, including karst residual rock, karst colluviation rock, karst aggradation rock, karst deposition rock, karst ablation breccias, karst alternation rock, karst alleviation rock, karst tension crack rock. On the base of the classification, through the analysis of microelement, carbon oxygen isotope and fluid inclusion, the process of karst formation is very complicated. There are three periods, including the weathering crust karst during the exposed period, the hot fluid karst in the deep buried period and the compaction released water period.