Hydrothermal Circulation and Sustainable Geothermal Development Potential in the Waliguan–Duohemao Tectonic Belt, Northeastern Tibetan Plateau

The Waliguan–Duohemao tectonic belt on the northeastern Tibetan Plateau hosts Qinghai’s highest-temperature hot springs (Zhacanggou 98 °C, Qunaihai 97 °C) and deep hot dry rock resources in the Gonghe Basin. However, the mechanisms governing hydrothermal circulation in this region remain poorly understood, limiting the assessment of its sustainable geothermal development potential. Through integrated fluid geochemistry, borehole temperature logging, and crustal thermal structure analyses, this study reveals the dual “water–heat” control exerted by the fault zone. The fault acts as a dominant pathway for deep meteoric water circulation, controlling mixing between deep hydrothermal fluids and shallow cold water, as evidenced by continuous hydrochemical and isotopic trends. Heat flow analysis indicates surface heat flow values up to 134.66 mW/m2 in the Gonghe Basin (with a 78.6% crustal contribution), decreasing to 57.4% in the Guinan area. A deep intra-crustal partial melting layer provides additional heat in the Gonghe Basin, whereas the Guide and Tongren areas rely primarily on radiogenic heat generation. The systematic increase in crustal heat flow from southwest to northeast confirms the fault zone as an efficient conduit for deep thermal transport, highlighting the region’s substantial deep geothermal energy potential. To overcome the “heat without water” exploration bottleneck and promote sustainable resource development, we propose differentiated exploration strategies tailored to the structural heterogeneity of the belt: (1) in the western Gonghe Basin, prioritize heat source characterization and enhanced geothermal system (EGS) feasibility assessment; (2) in the central Guide area, employ high-resolution geophysical methods to detect water-conducting fault zones; and (3) in the eastern Tongren area, evaluate water source conditions and fault connectivity with recharge areas. These strategies collectively minimize exploration risks and support the long-term, sustainable utilization of geothermal resources in this high-altitude region.