Control of tectonic evolution on karstification and karst collapse in the Lianzhou Basin, northwestern Guangdong Province

Abstract

Objective There is still a lack of systematic understanding of the evolution process of the Lianzhou Basin since the Mesozoic and its response to karstic development. Methods Based on the comprehensive analysis of the latest field geological investigations, hydrogeological drilling, dissolution experiments, and three-dimensional geological modelling, the tectonic evolution stages of the basin can be divided, and the karstification of each stage can be discussed by considering the existing geological data. Results Before the Cretaceous, carbonate rocks with strong dissolution were successively deposited under the rise or fall movement of the crust, which laid a material foundation for karstic development. The Indosinian movement caused vertically multilayered strata to form an E-W-trending structure, and the Yanshanian movement made the straddle-oblique superimposed a NE-SW-trending structure. They controlled the geological structures, spatial distribution, and dissolution behaviors of carbonate strata. And the distribution of mountains and river system were established. However, karst generally does not develop. An intracontinental and intermountain faulted confluence lake basin formed from the Cretaceous to the Palaeogene, the slow crustal uplift strengthened the karstification around the basin, and it currently retains the early karst platform. Later, they were buried-filled-consolidated by alluvial deposits; therefore, karst basically stopped developing, generating a thick-covered red strata basin. Since the Neogene, the rapid uplift of the crust has led to the continuous elevation of mountains around the basin, deepening of rivers, and strong development of karst, shaping multilevel karst platforms. When part of the Cretaceous red strata in the basin are denuded or cut through, karstification is reactivated. After many changes and penetrations of water systems, the graben basin formed, with karst strata covered by Quaternary sediments, Tectonic evolution controls karstic development, karstification influences the internal structure of the basin, and soil structure causes karst ground collapse. Conclusion This study can provide a scientific basis and guidance for understanding karst collapse conditions in covered karst areas.

Keywords

• lianzhou basin
• tectonic evolution
• crustal movement
• karstification
• karst collapse