Typical structural geology and groundwater dynamics in red beds basins of Ganjiang River Basin, South China

Continental red-beds are widely distributed in China, accounting for 9.5% of the total land area.A large number of urban residents and agricultural planting areas are located in different continental red-bed basins.The groundwater resources in the red-beds area are generally in short supply, and the drought is becoming more and more serious, which has become the focus of poverty alleviation.The red-beds basins in Ganjiang River Basin are typical examples in South China.Red-beds layers are mainly distributed in NE trending fault basins.Their formation and evolution, spatial distribution and structural style are controlled by NE trending regional extensional faults.The deformation in red-beds basins are characterized by NE trending extensional faulting and local gentle folding.The poor separability and complete iron cementation of the thick red glutenite in the basin make them characterized by low porosity and low permeability, which are the main reasons for the lack of groundwater and low recharge efficiency in the red-beds basin.The faults and associated fractures in the basin provide the main storage space for groundwater and also provide migration and seepage channels for the exchange of surface water and groundwater.The recharge of groundwater, the leaching and enrichment of gypsum minerals and heavy metals in red-beds, and the infiltration of agricultural and industrial wastewater and pollutants are all controlled by the faults in the basin.The spatial distribution, resource quantity, recharge efficiency and quality of groundwater are strongly controlled by the local deformed structures in the basin and are characterized by significant heterogeneity.The development, activity and associated fracture network of faults in red-beds basin have important significance for groundwater resource evaluation, dynamic monitoring and efficient utilization.