| 滇东南南洞地下河系统源区洞穴特征及其成因演化机制 |
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| 引用本文： | 潘玉峰,吴建标,李社宏,潘明.滇东南南洞地下河系统源区洞穴特征及其成因演化机制[J].中国岩溶,2022,41(1):133-142. |
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| 作者姓名： | 潘玉峰 吴建标 李社宏 潘明 |
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| 作者单位： | 1.广西壮族自治区二七三地质队，广西 贵港537100 |
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| 基金项目： | 广西自然科学基金项目2018GXNSFAA281260中国地质调查局地质调查项目DD20190022 |
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| 摘 要： | 滇东南岩溶地貌发育，岩溶洞穴是该区典型空洞体系。文章以滇东南南洞地下河系统源区典型岩溶洞穴为研究对象，基于地学理论和地球化学分析，对该区地貌特征、成因及演化机制开展科学研究。研究表明，NW向的张性断裂、区内可溶部分最高个旧组碳酸盐岩以及杨柳河向西流动的水动力作用是南洞地下河系统源区洞穴发育的主要成因；全新世中期6 kaBP以来，该地区洞穴演化过程经历了三个阶段，其中，主体形成时间为6~4 kaBP；此外，建立石洞洞穴与地下河发育模式。本次研究对南洞地区地下水资源评价具有实际意义。
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| 关 键 词： | 滇东南 南洞地下河系统 洞穴成因 演化机制 |
| 收稿时间： | 2021-05-20 |
Cave characteristics and its genesis and evolution in the source area of Nandong underground river system in Nandong area,Southeast Yunnan |
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| Abstract: | With its typical cavity system， the karst landform is developed in southeast Yunnan （one of the important karst areas in China）. There are few large karst springs but highly developed underground rivers in the east Yunnan fault depression basin. The distribution of underground rivers controls the distribution of karst groundwater resources in this area. The Nandong underground river system is a typical ultra-large karst plateau underground river system in the southeast Yunnan fault depression basin. Composed of many underground rivers， it is an underground river system with complex runoff paths and large water volumes. Karst caves are very developed and closely related to underground rivers. The runoff of the Nandong underground river in southeastern Yunnan is not only restricted by the hydrogeological conditions but also closely related to the regional rainfall characteristics， rock weathering， and other factors. The underground river system is the basic unit for the independent circulation of karst groundwater， which controls the transport of karst water migration and enrichment， hydrochemical evolution characteristics， resource composition， and environmental geological issues. All of those mentioned above provide a hydrological basis for cave evaluation research that takes the typical karst caves in the source area of Nandong underground river system in southeastern Yunnan as the research object. Based on geological research theory， this research summarizes the origin of karst caves in Nandong area through systematic cave analysis and geochemical analysis， establishes the development model of caves and underground rivers， discusses the formation and evolution mechanism of caves， and comprehensively explores the hydrological characteristics and karst control mechanism of large underground river systems， in order to provide more complete theoretical guidance for hydrogeological investigations. Research shows that the NW-trending extensional faults， developed in Triassic carbonate rocks， Permian clastic rocks and carbonate rocks， play an important role in the formation of caves in this area. The pure carbonate rock with strong rock dissolution of the highest Gejiu formation and the development of karst phenomena such as dry valleys， dissolved caves， dissolved pores and dissolved pipes on the surface also play an important role in the formation of caves in this area. Besides， the good development of hydrodynamic conditions for the westward flow of Yangliu river guarantees the cave development in the source area of the Nandong underground river system. Finally， human activities in the modern period contribute to the weak acidity of surface water in the area. And then the acid and alkali concentrations in the aqueous solution significantly affect the karstification of carbonate rock， so does acid and alkaline water solution. All of these mentioned above accelerates the development of karst caves. The study area was raised to sea level after the middle Triassic， and has been in the exposed stage since then. Carbonate rocks have been dissolved for a long time. Especially since the Quaternary， the topography and geomorphology as well as the climate change in this area have been stable， and the karst development have continued. Since 6 kbps in the middle of the Holocene. the caves in this area have experienced three stages of evolution， during which the formation time of the main body of the Shidong and Xianren cave is 6-4 kbps. In addition， through the exploration and analysis of the cave and the results of the tracer experiment， the development model of the stone cave and the underground river is established. In short， this study is of practical significance for the evaluation of groundwater resources in the Nandong area. |
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