Statistics and Formation Mechanism Analysis on the Basin-Range Patterns of Granite Bodies in Hunan Province, China

Abstract This paper presents the results of statistical analysis on the basin-range relations between the granite rock bodies and surrounding rocks in Hunan Province of China. Among the 44 granitoids in Hunan Province, 28 are basins, 14 are ranges, and only 2 cannot be directly classified. The basin-range properties of granite bodies are closely related to the lithology of surrounding rocks. Among the 28 granite basins, 24 are surrounded by slate, 3 by sandstone, and only 1 by glutenite, while 11 of 14 ranges are surrounded by carbonate rocks. From the perspective of endodynamic process, tectonic movements played an important role in the evolution of the terrain in the granite areas. Firstly, tectonism shaped the large-scale tectonic framework which deter-mined the distribution of some granite mountains in Hunan Province. In addition, tectonic compression or extension formed some granite compressional uplifts or horsts, which present as ranges now. From the perspective of differential weathering, the difference of resistance to weathering between granite and their surrounding rocks is an essential factor for the development of granite basin or range. When their surrounding rocks are carbonate rocks, the granite areas mostly present as ranges for the high solubility of carbonate minerals. When their surrounding rocks are slate rocks, the granite areas are mostly basins for their lower resistance to weathering than slate rocks determined by their more unstable minerals to weathering and more conductive soils to rainfall infiltration.