The high-temperature geothermal resources in the Gonghe-Guide area, northeast Tibetan plateau: A comprehensive review

Abstract The new discoveries of the high-temperature geothermal resources in the Gonghe-Guide area mark the significant breakthrough in the exploration of geothermal resources in the northeastern Tibetan Plateau. In this paper, we systematically reviewed all the available data presented in the geological, geophysical, geochemical and fundamental geothermal works that have been undertaken, in order to fully understand the characteristics of the geothermal resources in this area. The main features of the geothermal resources in this area can be summarized as follows: two distinct types of high-temperature geothermal resources have been identified, i.e., the hot dry rock (HDR) and hydrothermal geothermal resources in the Qiabuqia and Zhacang geothermal areas, respectively. The HDR reservoir in the Qiabuqia geothermal area is mainly composed of the Indosinian granitic rocks with the temperature gradient of 39 to 45.2 °C/km, thermal conductivity of 2.07 to 3.10 W/(m•K), and radiogenic heat production rate (RHPR) of 1.17 to 5.81 μW/m3. The geothermal water in the Zhacang geothermal area is meteoric origin with the relative enrichment of δ18O caused by the fluid-rock interaction under the high temperature condition. The chemical type of the geothermal water is SO4•Cl-Na. The local crustal partial melting or magma chamber at the 15 ∼ 35 km beneath the Gonghe basin, which is characterized with a relatively high geothermal background induced by the continental collision between the Indian and Eurasian plates, is the main cause of the HDR resources, whereas the hydrothermal resources in the Zhacang geothermal area are related to the deep circulation of the meteoric water in the damage zone of the west-east trending conductive Zhacang fault and upward transporting at the intersection of the Zhacang and the NNW-trending impermeable Reguang faults. Such a detailed review of the both geothermal resources can provide a glimpse of the geothermal resources of the northeastern Tibetan plateau as well as provide the direction for the subsequent searches for high-temperature resources elsewhere in China.