| 地球关键带与岩溶关键带: 结构、特征、底界 |
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| 引用本文： | 蒲俊兵.地球关键带与岩溶关键带: 结构、特征、底界[J].地质科技通报,2022,41(5):230-241. |
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| 作者姓名： | 蒲俊兵 |
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| 作者单位： | a.重庆师范大学地理与旅游学院, 重庆 401331 |
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| 基金项目： | 国家重点研发计划项目2021YFE0107100国家自然科学基金项目41977166重庆师范大学基金项目21XRC002UNESCO国际地学计划IGCP661 |
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| 摘 要： | 地球关键带已成为表层地球系统科学的重要研究领域, 代表了未来地球系统科学研究的新理念和发展趋势。岩溶分布面积约占全球陆地面积的15.2%。岩溶关键带是一个独特的关键带类型。目前对岩溶关键带的科学内涵还缺乏统一的认识, 对岩溶关键带的结构、特征和底界等问题还缺少相关的讨论。在回顾地球关键带科学发展的历程和归纳其主要特征的基础上, 梳理了岩溶关键带概念提出的背景、发展的过程, 总结了岩溶关键带的特征, 并对仍存在较大争议的岩溶关键带底界问题进行了分析讨论, 同时对岩溶关键带的进一步发展方向进行了分析。总结表明, 岩溶关键带是在可溶岩地区岩石圈、水圈、大气圈、生物圈、土壤圈界面上物质循环、能量流动所塑造的地球关键带类型。岩溶关键带的范围是可溶岩地区的植被冠层到岩溶含水层底板, 包括了植被层、土壤层、表层岩溶带、包气带、饱水带。岩溶关键带具有典型地表、地下双层地质结构及特殊的以碳水钙耦合循环为主的地球化学过程, 对环境变化敏感。通过对比发现, 岩溶关键带具有以下8个主要特征: ①碳酸盐岩积极参与关键带物质循环过程; ②对环境变化敏感; ③多层次水文地质结构; ④横向空间异质性强; ⑤地下空间网络庞大; ⑥具有大跨度的生物群; ⑦具有基岩-植被-水直接相互作用的独特的生态水文过程; ⑧横向边界受分水岭变迁的控制。岩溶关键带的底界为地表以下一定范围降雨补给来源的水体对碳酸盐矿物(方解石、白云石等)的溶解已没有影响且已没有可能产生进一步溶解碳酸盐矿物能力的深度。根据学科发展趋势和国家需求, 今后应进一步关注以下4个方面的研究: ①我国不同类型岩溶关键带的结构、形成及演化机制; ②退化岩溶生态区关键带服务功能与区域可持续发展; ③工程活动对我国岩溶关键带结构、属性和演化过程的影响; ④气候变化与我国岩溶关键带结构、功能、属性变化的耦合过程。
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| 关 键 词： | 地球关键带 岩溶关键带 结构 特征 底界 |
| 收稿时间： | 2022-07-20 |
Earth's critical zone and karst critical zone: Structure,characteristic and bottom boundary |
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| Affiliation: | a.School of Geography and Tourism, Chongqing Normal University, Chongqing 401331, Chinab.Chongqing Key Laboratory of Wetland Science Research of the Upper Reaches of the Yangtze River, Chongqing Normal University, Chongqing 401331, Chinac.Chongqing Key Laboratory of Surface Process and Environment Remote Sensing in the Three Gorges Reservoir Area, Chongqing Normal University, Chongqing 401331, China |
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| Abstract: | Critical zone science has become an important research area in Surface-Earth system science, representing a future new concept and developing trend in Earth system science. The karst critical zone, a unique type, covers approximately 15.2% of the global ice-free continental land, which is a typical case and represents the Earth's critical zone. However, there is still a lack of a unified understanding of the scientific connotation of the karst critical zone (KCZ) and a lack of related discussions on the structure, characteristics and lower boundary of the KCZ at present. On the basis of reviewing the history of the scientific development of the Earth's critical zone and summarizing its main characteristics, this study sorts out the background and development processes of the concept and summarizes the characteristics of the KCZ. The bottom boundary of the KCZ, which is still controversial, is analyzed and discussed, and the further development direction of the KCZ is also analyzed. These results show that the KCZ is a unique type of Earth's critical zone shaped by material circulation and energy flow at the interface of the lithosphere, hydrosphere, atmosphere, biosphere as well as pedosphere in soluble rock areas. The spatial span of the KCZ ranges from the vegetation canopy to the lower boundary of the karst aquifer in the soluble rock area, including the vegetation layer, soil layer, epikarst, vadose zone and saturated zone, which are sensitive to environmental changes and have surface and subsurface double geological structures and special geochemical processes characterized by coupling cycles of carbon, water and calcium. By comparison, the KCZ has eight following characteristics: active involvement of carbonate rock in the material cycle, sensitive response to external environmental changes, multilayer hydrogeological structures, strong horizontal spatial heterogeneity, large underground space network, large-span biota structure, unique ecohydrological processes with carbonate rock water-vegetation interaction as well as varying lateral boundary controlled by subsurface divide change. The bottom boundary of the KCZ is the depth at which the groundwater recharged by precipitation has no influence on the dissolution of carbonate minerals (calcite, dolomite, etc.) and has no ability to further dissolve carbonate minerals (calcite, dolomite, etc.) in a certain range below the surface. According to the development trend of the disciplines and national strategic demands, further attention should be paid to the following four directions: the structure, formation and evolution mechanisms of different types of the KCZ; the ecological service function and regional sustainable development in degraded karst ecological zones; the impacts of engineering activities on the structure, attributes and evolution process of the KCZ; and the coupling process between climate change and the change in the structure, function and attributes of the KCZ. |
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