Metallogenic Mechanism of Typical Carbonate-Hosted Uranium Deposits in Guizhou (China)

Research on topics such as geological–tectonic evolution, metallogenic models of deposits (gold, mercury, lead, zinc, etc.), and ore-forming fluids’ evolution has been conducted in Guizhou. However, few studies have uranium (U) (especially carbonate-hosted U deposits). Moreover, the relationship between hydrocarbon fluids U-mineralization not addressed at all. Typical (including some ore spots) Guizhou Province investigated through close field work, petrography, mineralogical, micro-spectroscopy, organic geochemical C isotope studies. The central part U-ore body is often black (the alternation zone) outcrop, its sides are gray gray-brown zone); color gradually becomes lighter (black to gray) from center out sides. Petrographic observations, microscopic laser Raman spectroscopy, infrared spectroscopic scanning electron microscope analyses indicated that U-minerals (pitchblende coffinite), pyrite “black” matter (OM) closely co-dependent, with OM having typical characteristics bitumen. Large light oil fluid inclusions were found rocks (besides body) strong blue fluorescence properties, indicating may came same U-bearing fluids. values 13C value, a biomarker trace elements, REEs U-ores, be similar here those local paleo-petroleum reservoir, bitumen originate deeply intruding reservoir. precipitation related cracking differentiation As result, neither sedimentary diagenesis type, nor superimposed leaching hydrothermal transformation described by previous scholars. To exact, deposit controlled fault fluids, so it can defined structural hydrocarbon–carbonate-type deposit. A new model was proposed this study. Here, U, molybdenum, other metals mainly lower stratum (presumably Niutitang Formation), migrated together form tiny mineral inclusions. (containing brine) caused upon entering fracture zone, which point materials (U, pyrite, metals) released precipitated.