Dizhi lixue xuebao (May 2024)
Karst groundwater enrichment law in Laiwu Basin
Abstract
Objective The Laiwu Basin is a typical monocline fault basin in the central and southern regions of Shandong Province. It has a complex geological structure and an uneven distribution of groundwater resources within the region. Previous researchers have conducted a large number of hydrogeological and spring water protection studies, but no relevant research has been conducted on the relationship between the development laws of fissure karst and the distribution of karst groundwater. Methods In this study, karstification and groundwater enrichment characteristics were investigated in the Laiwu Basin through research methods of data collection, field geological surveys, hydrogeological drilling, and rock and mineral testing. Results Carbonate strata are concentrated in the southern part of the Laiwu Basin, with a monoclinal structure controlled by the geological structure, which is scattered sporadically in the northern and eastern regions. Karst development is affected by many factors, such as formation lithology, geological structure, groundwater dynamic conditions, and magma intrusion. The principal surface karst features are grikes and karst valleys. In addition, the principal underground karst features were dominated by dissolution fissures and holes at 400 m depth. Karst groundwater is primarily concentrated in multistage structural fault basins, hanging walls formed by water-blocking faults, groundwater pressure discharge areas, and karst development areas on the anticlinal flank of the mine. Conclusion The karst water cycle in the Laiwu Basin has a general regularity of monoclinic basins but is influenced by multiple factors, forming karst water systems of varying sizes that are relatively independent. Significant differences were observed in the development characteristics and water abundance patterns of karsts in different regions. Fault structures and geological water-blocking areas have relatively abundant karst water, whereas the shallow karst water has a strong runoff cycle. [ Significance ] This study provides scientific and technical support for the exploitation and utilization of groundwater resources in water-scarce mountainous areas of central and southern Shandong Province.
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