Genesis Mechanism of Heat Source in Mianhuakeng Uranium Deposit, South China: Insights from Radiogenic Heat Production of Granite Bodies

Abstract

The Mianhuakeng uranium deposit, characterized by uranium-rich granite, serves as a key site for research into crustal radioactive heating. Based on 45 rock samples, this study reviews that the host granite in the Mianhuakeng uranium deposit has a high radioactive heat production rate (avg. 5.50 μW/m³) and a low Th/U ratio (avg. 2.62). Uranium-rich granite and its alteration zone within the upper crust (0–5 km depth) contribute about 45% of the total radioactive heat production, wich is crucial for controlling geothermal resource distribution. For uranium-thermal at tectonic plate margins, a symbiotic geological model was proposed: Firstly, subduction of the Pacific Plate caused upwelling of the asthenosphere, generating a high heat-flow background. Secondly, heat transfer is enhanced by major faults such as the Youdong and Mianhuakeng faults. Subsequently, uranium was mobilized, transported, and enriched within the granite through deep siliceous hydrothermal activity and associated alteration. Ultimately, the uranium enrichment in granite leads to increased radioactive heat production, resulting in local thermal anomalies. This model provides a theoretical support for exploring and developing uranium-thermal symbiotic resources in South China.

Keywords

uranium-rich granite / radiogenic heat production / heat source / genesis mechanism / Mianhuakeng uranium deposit

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2026 Geological Society of China