铀矿
铀
钍
放射化学
矿物
铀矿石
地球化学
地质学
矿物学
核素
铀酰
化学
溶解
材料科学
冶金
物理
有机化学
物理化学
量子力学
作者
Robert M. Hazen,Rodney C. Ewing,Dimitri A. Sverjensky
出处
期刊:American Mineralogist
[Mineralogical Society of America]
日期:2009-10-01
卷期号:94 (10): 1293-1311
被引量:177
摘要
The origins and near-surface distributions of the ~250 known uranium and/or thorium minerals elucidate principles of mineral evolution. This history can be divided into four phases. The first, from ~4.5 to 3.5 Ga, involved successive concentrations of uranium and thorium from their initial uniform trace distribution into magmatic-related fluids from which the first U4+ and Th4+ minerals, uraninite (ideally UO2), thorianite (ThO2), and coffinite (USiO4), precipitated in the crust. The second period, from ~3.5 to 2.2 Ga, saw the formation of large low-grade concentrations of detrital uraninite (containing several wt% Th) in the Witwatersrand-type quartz-pebble conglomerates deposited in a highly anoxic fluvial environment. Abiotic alteration of uraninite and coffinite, including radiolysis and auto-oxidation caused by radioactive decay and the formation of helium from alpha particles, may have resulted in the formation of a limited suite of uranyl oxide-hydroxides.
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