赣南白垩纪碎屑岩裂隙水的水文地质及电性响应特征

Hydrogeology and electrical response of fissure water in the Cretaceous clastic rocks of Southern Jiangxi

为了进一步研究赣南红层区水文地质特征和电性响应规律,选择赣南典型地区开展综合地球物理勘探工作。通过分析白垩纪碎屑岩裂隙水的水文地质特征,发现该区地下水类型主要为白垩纪孔隙水和裂隙水。该区含水层含泥岩夹层,孔隙水的富水性相对较差;构造主要为断层和裂隙,裂隙水的富水性相对较好。采用音频大地电场法、音频大地电磁法和激电法对白垩纪碎屑岩裂隙水进行对比研究,发现完整的白垩纪碎屑岩具有相对较高的电阻率和相对较低的极化率和半衰时,断层和裂隙发育处的地层电阻率较低,但极化率和半衰时较大,曲线形态存在明显异常。研究白垩纪碎屑岩裂隙水的电性响应特征,可提高该区找水成功率,对解决赣南地区水资源短缺问题具有重要意义。

To further study the hydrogeological characteristics and electrical response regularity of red bed areas in Southern Jiangxi,the typical areas are selected for comprehensive geophysical prospecting.By analyzing the hydrogeological characteristics of fissure water in the Cretaceous clastic rocks,it is found that the groundwater types in the area are mainly Cretaceous pore water and fissure water.The aquifer contains mudstone interlayer and the water abundance of pore water is relatively poor.Moreover,the structures are mainly faults and fissures,and the fissure water is relatively rich in water.The audio frequency electric method,audio magnetotelluric method and IP method are used for a comparative study of the fissure water in Cretaceous clastic rocks,the results show that when intact Cretaceous clastic rocks have relatively high resistivity,low polarizability and half-decay time,the resistivity of strata where faults and fissures are developed is low.While the polarizability and half-decay time are large,the curve shape is obviously abnormal.The study of electrical response characteristics can improve the success rate of water exploration and provide important references for solving the problem of water shortage in Southern Jiangxi.