中国地质调查局:广西兴安县幅(G49E015011)1∶50000地质图数据库

广西兴安县幅（G49E015011）1∶50000地质图系“桂东北岩溶系统基础地质调查”二级项目成果之一。调查区位于广西东北部，南岭西段，属于桂湘赣地层分区之桂东地层小区，岩石地层序列划分为14个组、21个段，出露地层从老至新有奥陶系、泥盆系、石炭系和第四系，以泥盆系分布最广。晚志留世的广西运动使测区褶皱成山，表现为早泥盆系角度不整合于奥陶系之上。中泥盆世晚期的区域性裂解事件（海口运动）产生了台-盆相间古地理格局分异及台缘角砾岩楔、斜坡滑塌体等同沉积构造，综上特征重建了桂东北D-C沉积演化模式。中三叠世印支运动后，测区结束了海相沉积，地貌经历了侏罗纪(J)、晚白垩世(K 2)、新近纪—第四纪(N-Q)等几个重要风化剥蚀及岩溶作用发育期，据此建立了测区地貌演化三阶段模式。岩溶地貌以峰林平原为主，集中分布于兴安—严关一带。综合物探、钻探成果表明，测区地下0-100m岩溶较发育，其中在埋深30-38m和42-60m段最为发育；沿兴安—灵川断裂带深部物探发现在1200-1800m间存在明显低阻异常带，预测其是寻找中低温地热水的有利靶区。

The 1:50000 geological map of the Xing'an County sheet (G49E015011), Guangxi, is one of the achievements of the secondary project 'Basic Geological Survey of Karst System in Northeast Guangxi'. The survey area is located in the northeastern part of Guangxi, the western section of the Nanling Mountains, and belongs to the Eastern Guangxi stratigraphic sub-area of the Guangxi-Hunan-Jiangxi stratigraphic division. The lithostratigraphic sequence is divided into 14 formations and 21 members. The exposed strata, from oldest to youngest, include the Ordovician, Devonian, Carboniferous and Quaternary, with the Devonian being the most widely distributed. The Late Silurian Guangxi Orogeny folded the survey area into mountains, which is manifested by an angular unconformity of the Early Devonian strata overlying the Ordovician strata. A regional rifting event in the late Middle Devonian (the Haikou Orogeny) gave rise to the differentiation of the paleogeographic pattern of alternating platforms and basins, as well as syn-sedimentary structures such as platform-margin breccia wedges and slope slump bodies. Based on the above characteristics, the sedimentary evolution model of the Devonian-Carboniferous (D-C) interval in Northeast Guangxi has been reconstructed. After the Middle Triassic Indosinian Orogeny, the survey area ceased marine sedimentation, and its landform experienced several key periods of weathering, denudation and karstification during the Jurassic (J), Late Cretaceous (K₂), and Neogene-Quaternary (N-Q) stages. Accordingly, a three-stage landform evolution model for the survey area has been established. The karst landforms are dominated by peak forest plains, which are concentrated in the Xing'an-Yanguan area. Comprehensive geophysical prospecting and drilling results indicate that karst is relatively developed within 0-100 m underground in the survey area, with the most developed karst occurring at burial depths of 30-38 m and 42-60 m. Deep geophysical prospecting along the Xing'an-Lingchuan fault zone detected a distinct low-resistivity anomaly zone between 1200-1800 m, which is predicted to be a favorable target area for prospecting medium-low temperature geothermal water.