鄂尔多斯盆地水文地质特征及地下水系统分析

HYDRO-GEOLOGICAL CHARACTERISTICS AND GROUNDWATER SYSTEMS OF THE ERDOS BASIN

鄂尔多斯盆地是我国西北地区东部的一个大型构造沉积盆地,蕴藏着丰富的矿产资源,是我国正在建设 的重要能源基地;鄂尔多斯盆地同时也是一个巨型地下水盆地,赋存相对丰富的地下水资源,将为能源基地建设提 供重要水源。鄂尔多斯盆地是由多种不同类型岩石上下叠置构成的构造沉积盆地,因此它也是一个由不同含水岩 类的多个含水层系统上下叠置构成的巨型地下水盆地。鄂尔多斯盆地总体上构成一个半开启型的地下水盆地,盆 地内不同含水层系统地下水交替循环的方式和深度不同,以寒武系-奥陶系碳酸盐岩类岩溶含水层系统和白垩系 碎屑岩类孔隙-裂隙含水层系统的交替循环深度较大(可达1200～1800m);新生界松散岩类孔隙含水层系统和 石炭系-侏罗系碎屑岩类裂隙含水层系统的交替循环深度较小(一般小于300m)。鄂尔多斯盆地实际上包含了周 边岩溶地下水、白垩系自流盆地地下水和东部黄土区地下水共3个地下水大系统。在各地下水大系统内,又可根 据各自的地质-水文地质结构特征、地下水循环条件以及和地表水系的关系等,再进一步划分成7个地下水系统 及16个地下水亚系统。文章在对鄂尔多斯盆地的地质-水文地质结构特征和地下水循环条件进行分析的基础 上,对整个盆地地下水系统进行初步分析。

The Erdos Basin is a large-scale sedimentary basin in NW China, where abundant mineral resource is present and one of the important energy bases in China. It is also a large-scale groundwater basin in arid-semiarid area, in which groundwater can be used for the construction and development of the energy base. Geologically, the basin is characterized by superposition of water-bearing formations; thereby it is hydro-geologically a multiple groundwater systems in vertical. The Erdos Basin is a half-open groundwater basin, in which the carbonate karst groundwater system in Cambrian-Ordovician rocks and the clastic pore-fissure groundwater system in Cretaceous rocks have a deep circulation (up to 1 200～1 800m). The Cenozoic groundwater system and the clastic fissure groundwater system in Carboniferous and Jurassic have shallow circulation depth (less than 300m). Three major groundwater systems, the karst groundwater system, Cretaceous artesian groundwater system, and the groundwater system in the loess-covering area are present in the basin. Based on the hydrogeology and groundwater circulation conditions, 7 groundwater systems and 16 subsystems are subdivided. A discussion is presented on groundwater systems in the basin, based on the analysis on geological and hydro-geological structure of the basin and groundwater circulation conditions of various groundwater types, which provide a basis for further investigation and rational development.