Investigating the Formation of Hot-Dry Rock in Gonghe Basin, Qinghai, China

The Gonghe Basin, Qinghai Province, China, has rich geothermal and hot-dry rock resources. Through a magnetotelluric survey line with 400 points, combined with regional geology data, the deep geoelectrical structural background and thermal source mechanisms of the Gonghe Basin were explored. The results showed that (1) a deep structure with high conductivity may exist at a depth of 15 km in the basin, and could be compared to the layer-shaped, low-velocity, high-conductivity structure in the eastern part of the Qinghai-Tibet Plateau; (2) the rushing reverse fault played a crucial role in heat control and conduction from the hot field; and (3) high-temperature heat storage existed, including four layers of geothermal resources. This study proposed a triple-polymorphism model of hot-dry rock in the area; that is, the high-conductivity layer in the Middle-Late Cenozoic crust was the principal heat source; the Middle-Late Triassic granite was the essential heat-storing body, as well as a parent rock to the hot-dry rock; and the Cenozoic sedimentary rock was the effective caprock. This model is critical to understanding geothermal causes, predicting geothermal resources, and planning, on the Qinghai-Tibet Plateau.

Automated summary

This study explores the deep geoelectrical structural background and thermal source mechanisms of the Gonghe Basin, Qinghai Province, China, through a magnetotelluric survey line combined with regional geology data. The results reveal the existence of a deep structure with high conductivity, comparable to the structure in the eastern part of the Qinghai-Tibet Plateau. The rushing reverse fault plays a crucial role in heat control and conduction, and high-temperature heat storage is found in four layers of geothermal resources. The proposed triple-polymorphism model of hot-dry rock provides critical insights into geothermal causes, resource prediction, and planning in the Qinghai-Tibet Plateau.