The geochemical behavior of uranium and mineralization : South China uranium province as an example
In: ACTA PETROLOGICA SINICA;; (2020)
report
Zugriff:
Uranium is a strong incompatible element, which is continuously enriched with the evolution of magma. At the end of magma evolution, uranium is affected by the increase of structural oxygen and enters accessory minerals, such as monazite and xenotime. Magmatic evolution usually can't lead to the formation of uranium deposits. Uranium is a variable valence element which is sensitive to oxygen fugacity. During supergene weathering process, uranium in rock is oxidized to UO22+ and easily dissolved into high oxygen fugacity fluid, which is then precipitated and enriched in reducing environments, favorable for mineralization. Influenced by the Neoproterozoic Oxidation Event and the end of Marinoan ice age, more U entered water during supergene weathering. The Cambrian Explosion resulted in reducing environment in sedimentary basins, forming black shale rich in organic matter, which was favorable to the precipitation and enrichment of U, responsible for the formation of Sinian and Lower Cambrian uranium-rich black shale in South China. The uranium-rich black shale was the main uranium source for uranium deposits in South China. The Indosinian tectonic movement caused partial melting of some uranium-rich black shale, forming S-type granites, which were also the uranium source for the subsequent uranium mineralization. The tectonic-magmatic thermal events in an extensional setting in South China during the Late Yanshanian Movement provided favorable conditions for the formation of high oxygen fugacity hydrothermal fluids, which resulted in the formation of various types of uranium deposits in South China in Cretaceous. High oxygen fugacity hydrothermal fluids mainly composed of meteoric water can migrate through fissure system and extract U from uranium source rocks by oxidation of U4+ to U6+. The reductive materials related to organic-rich black shale, basic dyke and volcanic degassing are responsible for the precipitation and mineralization of U.
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The geochemical behavior of uranium and mineralization : South China uranium province as an example
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Autor/in / Beteiligte Person: | Kun, Wang ; JiangHong, Deng ; XiLuo, Hao |
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Quelle: | ACTA PETROLOGICA SINICA;; (2020) |
Veröffentlichung: | SCIENCE PRESS, 2020 |
Medientyp: | report |
DOI: | 10.18654/1000-0569/2020.01.05 |
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