Present‐Day Geothermal Characteristics in South China

TLDR

The study constructed geothermal gradient and heat flow maps of South China using 418 gradient and 418 heat flow measurements. The analysis shows that South China’s geothermal gradients range from 7.8 to 162.5 °C/km (mean 24.1 °C/km) and heat flows from 22 to 220 mW/m² (mean 64.2 mW/m²), with higher values in the southeast coast, southwestern Yunnan, east and southwest regions, linked to tectonothermal settings, fault structures, and crustal properties.

Abstract

Abstract Based on 418 geothermal gradient and 418 heat flow values from South China, both the geothermal gradient map and the heat flow map of South China have been constructed. The present‐day distributions of geothermal gradient and heat flow have been analyzed. The characteristics of the geothermal gradients distribution show that the geothermal gradients in South China range from 7.82 to 162.5°C/km with a mean of 24.1°C/km. The southeast coastal regions and southwestern Yunnan are characterized by relatively higher temperature gradients than that of Yangtze block. The geothermal gradients are controlled by tectonothermal settings and significantly affected by subsurface hydrothermal activities and thermal conductivities of the rocks. Heat flows in South China vary from 22 to 220mW/m 2 with an average value of 64.2mW/m 2 . The heat flows in the east and southwest of South China are higher than that in the central areas of Yangtze block and almost all of the significant anomalies of high heat flow values distribute along deep faults or plate boundaries (sutures). The heat flow values are related to tectonic activities, the epoch of the last thermal event, the extension of lithosphere, the thickness of crust and the burial depth and/or thickness of high conduction layers in the crust.