Heat-producing granitoids of North Pakistan as potential geothermal prospects

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The Himalayas of North Pakistan expose numerous and in part voluminous granitoid rocks enriched in radiogenic elements. Elevated surface heat flow in the region has been attributed in part to shallow production of radiogenic heat in these rocks, in concert with rapid exhumation and potentially frictional/strain heating. We aim to explore the role of radiogenic heat production by sampling a range of typical lithologies and determining their radiogenic nuclide contents and other geochemical parameters. The data obtained will be used in numerical models. These models are designed to test the effect of variations in radiogenic content, shapes and volumes of granitoids versus background heat flux on temperatures of the shallow (down to a few km) subsurface and of hot spring waters. On the basis of a first sampling campaign and preliminary analyses of radiogenic contents we hypothesize that large-volume granitoids and gneisses with somewhat lower concentrations of radiogenic nuclides may be better targets for geothermal exploration than small, strongly enriched leucogranites and pegmatites. Improved understanding of the geothermal potential as a function of the geological framework in North Pakistan may benefit communities living in these remote regions.