Uranium Sources

1945 ◽  
Vol 48 (7) ◽  
pp. 101
Keyword(s):  
Uranium Sources

Release of Uranium from Uraninite in Granites Through Alteration: Implications for the Source of Granite-Related Uranium Ores

2021 ◽  
Author(s):  
Long Zhang ◽  
Zhenyu Chen ◽  
Fangyue Wang ◽  
Noel C. White ◽  
Taofa Zhou
Keyword(s):  
Uranium Concentration ◽  
Geochemical Data ◽  
Uranium Deposits ◽  
Bulk Rock ◽  
Calc Alkaline ◽  
Alkaline Granite ◽  
Compositional Evolution ◽  
High K ◽  
Backscattered Electron ◽  
Uranium Sources

Abstract Uraninite is the main contributor to the bulk-rock uranium concentration in many U-rich granites and is the most important uranium source for granite-related uranium deposits. However, detailed textural and compositional evolution of magmatic uraninite in granites during alteration and associated uranium mobilization have not been well documented. In this study, textures and geochemistry of uraninites from the Zhuguangshan batholith (South China) were investigated by scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). The geochemical data indicate that the Longhuashan and Youdong plutons are peraluminous leucogranite, the Changjiang pluton is highly fractionated high-K calc-alkaline granite, and the Jiufeng pluton belongs to a high-K calc-alkaline association. Uraninites from the Longhuashan and Youdong granites have lower concentrations of ThO2 (0.9–4.0 wt %) and rare earth elements (REE)2O3 (0.1–1.0 wt %) than those from the Changjiang and Jiufeng granites (ThO2 = 4.4–7.6 wt %, REE2O3 = 0.7–5.1 wt %). Uraninites observed in the Longhuashan, Youdong, Changjiang, and Jiufeng granites yielded chemical ages of 223 ± 3, 222 ± 2, 157 ± 1, and 161 ± 2 Ma, respectively. The samples (including altered and unaltered) collected from the Longhuashan, Youdong, and Changjiang granites are characterized by highly variable whole-rock U concentrations of 6.9 to 44.7 ppm and Th/U ratios of 0.9 to 7.0, consistent with crystallization of uraninite in these granites being followed by uranium leaching during alteration. Alteration of uraninite, indicated by altered domains developing microcracks and appearing darker in backscattered electron (BSE) images compared to unaltered domains, results in the incorporation of Si and Ca and mobilization of U. In contrast, the least altered samples of the unmineralized Jiufeng granite have low U concentrations (5.3–16.4 ppm) and high ΣREE/U (13.6–49.4) and Th/U ratios (2.1–5.6), which inhibit crystallization of uraninite, as its crystallization occurs when the U concentration is high enough to exceed the substitution capacity of other U-bearing minerals. These results indicate that the Longhuashan, Youdong, and Changjiang granites were favorable uranium sources for the formation of uranium deposits in this area. This study highlights the potential of uraninite alteration and geochemistry to assist in deciphering uranium sources and enrichment processes of granite-related uranium deposits.

scholarly journals Mineral extinction

2019 ◽  
Vol 83 (5) ◽  
pp. 621-625 ◽  
Author(s):  
Stuart J. Mills ◽  
Andrew G. Christy
Keyword(s):  
Biological Evolution ◽  
Time Dependent ◽  
Mineral Species ◽  
Geochronological Data ◽  
Secondary Minerals ◽  
Geological Record ◽  
Biological Concept ◽  
Secondary Species ◽  
Mineral Occurrence ◽  
Uranium Sources

Abstract‘Mineral evolution’ has attracted much attention in the last decade as a counterpart of the long-established biological concept, but is there a corresponding ‘mineral extinction’? We present new geochronological data from uranium-bearing secondary minerals and show that they are relatively recent, irrespective of the age of their primary uranium sources. The secondary species that make up much of the diversity of minerals appear to be ephemeral, and many may have vanished from the geological record without trace. Nevertheless, an ‘extinct’ mineral species can recur when physiochemical conditions are appropriate. This reversibility of ‘extinction’ highlights the limitations of the ‘evolution’ analogy. Mineral occurrence may be time-dependent but does not show the unique contingency between precursor and successor species that is characteristic of biological evolution.

A fingerprinting method for the identification of uranium sources in alluvial aquifers: An example from the Khan and Swakop Rivers, Namibia

2014 ◽  
Vol 72-75 ◽  
pp. 34-42 ◽  
Author(s):  
J.T. Hamutoko ◽  
B.S. Mapani ◽  
R. Ellmies ◽  
A. Bittner ◽  
C. Kuells
Keyword(s):  
Alluvial Aquifers ◽  
Fingerprinting Method ◽  
Uranium Sources

scholarly journals Using Pb isotopes in surface media to distinguish anthropogenic sources from undercover uranium sources

2015 ◽  
Vol 347 (5-6) ◽  
pp. 215-226 ◽  
Author(s):  
Kurt Kyser ◽  
Larry Lahusen ◽  
Garth Drever ◽  
Colin Dunn ◽  
Evelyne Leduc ◽  
...  
Keyword(s):  
Pb Isotopes ◽  
Anthropogenic Sources ◽  
Uranium Sources

scholarly journals Estimation of Uranium Sources in Environmental Samples Using the Isotopic Ratio Determination

2020 ◽  
Author(s):  
Junko Shikimori ◽  
Takeshi Ohno ◽  
Yusuke Fukami ◽  
Yasuhito Igarashi
Keyword(s):  
Environmental Samples ◽  
Isotopic Ratio ◽  
Ratio Determination ◽  
Uranium Sources

Scattered gamma rays from thick uranium sources

1957 ◽  
Keyword(s):  
Gamma Rays ◽  
Uranium Sources

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

2003 ◽  
Vol 38 (2) ◽  
pp. 127-140 ◽  
Author(s):  
Aliouka Chabiron ◽  
Michel Cuney ◽  
Bernard Poty
Keyword(s):  
Uranium Sources

Genesis and Uranium Sources of Leucogranite-hosted Uranium Deposits in the Gaudeanmus Area, Central Damara Belt, Namibia: Study of Element and Nd Isotope Geochemistry

2017 ◽  
Vol 91 (6) ◽  
pp. 2126-2137 ◽  
Author(s):  
Honghai FAN ◽  
Jinyong CHEN ◽  
Shengyun WANG ◽  
Jingyang ZHAO ◽  
Dazhao GU ◽  
...  
Keyword(s):  
Isotope Geochemistry ◽  
Uranium Deposits ◽  
Nd Isotope ◽  
Uranium Sources
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