Possible uranium sources for the largest uranium district associated with volcanism: the Streltsovka caldera (Transbaikalia, Russia)

摘要

The uranium deposits of the Late Jurassic Streltsovka caldera (Transbaikalia, Russia) represent the largest uranium field associated with volcanics in the world (280,000 t U) and Russia's largest uranium resources. About one third of the caldera stratigraphic pile consists of rhyolites which are strongly altered. The rhyolitic magma preserved as melt inclusions in quartz phenocrysts corresponds to a mildly peralkaline melt (1.04