Application of optically stimulated luminescence in volcanic hydrothermal uranium deposits in the Guyuan Basin, North China

Abstract

Volcanic basins in North China have great potential for the discovery of volcanic-related uranium deposits. However, most of the traditional geochemical exploration that have the inadequacies of the unexpected errors, weak anti-interference ability and exception information have become untenable in exploring uranium deposits overlain by volcanic rocks and sediments. To identify and track the abnormal geochemical source, feldspar infrared stimulated luminescence (IRSL) and quartz optically stimulated luminescence (OSL) were utilized for the first time to explore deeply concealed volcanic-related uranium deposits in North China. Our results confirm that feldspar IRSL-based drill-core samples are oversaturated and therefore fail to trace the deep uranium orebodies. In contrast, quartz OSL in sedimentary covers over the drill holes hosting economic and subeconomic uranium mineralization yields older apparent ages than their actual depositional ages. The high apparent ages of quartz OSL in the sediments and low helium isotope ratios (3He/4He) of the drill core indicated that the soil radon gas (Rn) anomaly was caused by Rn migration from deeply buried uranium ore decay.