贵州遵义白云岩岩溶区特色高位潜水及成因

Distinctive high-level phreatic water and genesis in the dolomite karst area of Zunyi,Guizhou

高位潜水(悬挂水)是贵州高原上的独特水文地质现象,一般具有四大特征:①含水体高悬于谷地之上,形成独立的水文地质单元;②多以暗河为排泄通道,管道底界具有相对的隔水介质;③高悬岩溶水系统主要为潜水,与大气降水的关系十分密切,动态变化大;④发育于石灰岩地层中。与上述发育于石灰岩岩溶区的高位潜水不同的是,本文所介绍的高位潜水位于白云岩发育地区,其潜水系统没有排水通道,潜水盆地的主要水源不是地表水体而是来自于上游的岩溶管道,是一个基本静止的岩溶水体。通过对研究区气象、地形地貌、区域地质背景、水文、岩溶等高位潜水形成条件的分析,表明构成该高位潜水岩溶水系统的岩溶管道水流之所以形成于钙镁比值低于1.4的白云岩地层中,是因为长期干湿交替的气候环境,造就了完整的白云岩溶蚀发展阶段的结果。

High-level phreatic water(suspended water)is a unique hydrogeological phenomenon in the Guizhou Plateau.It generally has four characteristics as follows.(1)The aquifer is suspended high above the valley,it is an independent hydrogeological unit.(2)The bottom boundary has a relative water-repellent medium.(3)The high-suspended karst water system is mainly phreatic water,which is closely related to atmospheric precipitation and has a great dynamic variation.(4)It develops in the limestone strata.Different from the above-mentioned high-level phreatic water developed in the limestone karst area,the high-level phreatic water introduced in this paper is located in the dolomite development area,and its phreatic system has no drainage channel.The main water source of the phreatic basin is not surface water but from the upstream karst pipeline.It is a basically static karst water body.Through the analysis of meteorology,topography,regional geology background,hydrology,karst and other high-level phreatic formation conditions in the study area,it is shown that the karst pipeline water flow that constitutes the high-level phreatic karst water system is formed in the dolomite stratum with a calcium-magnesium ratio lower than 1.4.It is the result of the complete dolomite dissolution development stage due to the long-term dry and wet alternating climate environment.