Natural radioactivity and radiogenic heat production in Rundvågshetta bedrock, East Antarctica: Insights from gamma-ray spectrometry and geochemistry

This study uses gamma-ray spectrometry and geochemical analysis to provide a first assessment of natural radioactivity and radiogenic heat production (RHP) in the Rundvågshetta region, East Antarctica. Direct gamma-ray spectrometry was used to measure 238 U, 232 Th, and 40 K in samples of gneisses, granulites and migmatites. The findings reveal that felsic rocks, particularly gneisses, are enriched in U, Th, and K, generating the highest RHP (∼2.29 μW/m 3 ), whereas mafic rocks, such as granulites, exhibit lower RHP (∼0.05 μW/m 3 ). The calculated RHP values from Rundvågshetta are moderate and fall within the range of the global continental crustal average. Despite the limited number of samples, the results show clear large variability, indicating that heat-producing elements are unevenly distributed even within the small outcrop. This study, therefore, emphasises the significant role of lithological and mineralogical variability in regulating regional heat production and the necessity of an expanded RHP database in East Antarctica by performing detailed radiometric analyses.