东兰地区以石炭-三叠系地层分布最广，泥盆系地层零星出露，这些地层的沉积古环境以海相为主，海陆过渡相次之，陆相地层很少。岩性主要为碳酸盐岩（主要为灰岩、白云岩等），另有少量碎屑岩（砂岩、泥岩、复理石等）。 The Carboniferous - Triassic strata were the most widely distributed in Donglan region, with the Devonian strata outcropping sporadically. The sedimentary paleoenvironment of these strata is mainly marine facies, with some marine and continental transitional facies strata and few continental strata. The lithology is mainly carbonate rock (mainly limestone, dolomite, etc.), and a small amount of clastic rock (sandstone, mudstone, flysch, etc.). 区域位于“广西山字型构造”前弧西翼中段，以北西向构造和旋卷构造为主，东西向构造片段局部隐现。这些构造带及其派生的构造形迹形成极为复杂的区域构造。 The region is located in the middle section of front arc west wing of Guangxi epsilon- type structure, dominated by NW trending structure and convolute structure. The east-west tectonic section exposed partially. These tectonic belts and their associated structural features formed extremely complex regional structures.大规模的碳酸盐岩是形成喀斯特地貌的物质基础，各种构造面（断层、节理、层面等）为喀斯特地貌发育提供条件，湿润多雨的气候是雕琢大地的一双巧手。 Large-scale carbonate rocks are the material basis of the formation of karst landform. All kinds of structure planes (fault, joint, stratum, etc.) provide conditions for karst landscape development. The humid and rainy climate caves the earth.