In the heart of Guangxi, China, a hidden treasure trove of geothermal energy is waiting to be tapped, and recent research is shedding light on its vast potential. Xinwei Wang, a geologist from China Nonferrous Metals (Guilin) Geology and Mining Co., Ltd., has been delving into the mysteries of the Yangmeichong geothermal fields, and his findings could significantly impact the energy sector.
Wang’s study, published in the journal Carsologica Sinica (which translates to “Karst Science of China”), provides a comprehensive analysis of the geothermal resources in Yangmeichong, Hezhou. The research is a significant step forward in understanding the supply sources, cyclic evolution processes, and genesis mechanisms of geothermal resources in the region.
The geothermal fields in Yangmeichong are characterized by a belt-shaped thermal reservoir composed of the Yanshanian granite fracture zone. The Guposhan Fault (F1) plays a crucial role as the main water conducting and heat controlling structure. “The geothermal heat flow in the area is derived from both the upper mantle and deep crust, as well as the heat generated by the decay of radioactive elements in the shallow crust,” Wang explains. This dual heat source provides the necessary energy for the formation of deep circulating groundwater.
The research reveals that temperatures and geothermal gradients in the Yangmeichong geothermal fields increase from west to east and from north to south. In the vertical direction, geothermal gradients increase with depth. Temperatures within the depth range of 800–1,200 meters are between 53.5 and 73.0 degrees Celsius, with a geothermal gradient of 4.88 degrees Celsius per 100 meters.
Wang’s team measured the deep thermal storage temperatures using both silicon dioxide and potassium magnesium geothermal temperature scales, obtaining temperatures of 92.24 and 87.22 degrees Celsius, respectively. These measurements correspond to circulation depths of 3,292 and 3,069 meters.
The hydrochemical type of geothermal fluid in the area is HCO3-Na, indicating high levels of silicic acid and sodium ions due to the leaching effect of deep groundwater on granite bodies. Isotopic detection results suggest that the geothermal water supply comes from precipitation infiltration, with a tritium content of less than 2 TU. This implies that the geothermal water in Yangmeichong was formed by atmospheric precipitation before 1960.
The research establishes a fault convection geothermal model for the Yangmeichong geothermal fields. Geothermal water is supplied by atmospheric precipitation, flowing deep through fault zones and rock pores driven by hydraulic and thermal forces. After undergoing water thermal convection, the geothermal water rises along the Gupo mountain fault, forming the fault convective geothermal model observed in Yangmeichong.
The implications of this research for the energy sector are substantial. Understanding the genesis and mechanisms of geothermal fields can lead to more efficient and sustainable exploitation of geothermal resources. As Wang notes, “The research results provide a theoretical basis for the exploration and rational utilization of geothermal resources in Yangmeichong, Guangxi.”
This study not only enhances our knowledge of geothermal systems but also paves the way for future developments in geothermal energy production. By providing a clearer picture of the geothermal landscape in Yangmeichong, Wang’s research could attract investment and drive innovation in the energy sector, ultimately contributing to a more sustainable energy future.