Underemphasized processes of uranium mineralization

1977 ◽  
Keyword(s):  
Uranium Mineralization

scholarly journals Correlation of VLF-EM Data with Radiometric Measurements: Implications for Uranium Exploration around Beldih, South Purulia Shear Zone, India

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Saurabh Mittal ◽  
S. P. Sharma ◽  
Arkoprovo Biswas ◽  
D. Sengupta
Keyword(s):  
Shear Zone ◽  
High Surface ◽  
Uranium Mineralization ◽  
Subsurface Structure ◽  
High Radiation ◽  
Background Radiations ◽  
Radiometric Measurements ◽  
Uranium Exploration ◽  
Radioactive Minerals ◽  
Open Cast

This study is an attempt to correlate VLF-EM data with the radiometric measurements to decipher the subsurface structure and to locate uranium mineralization in the shear zone. The study area is around Beldih mine which is an open cast apatite mine located on the South Purulia Shear Zone. VLF method has been applied to map the structure and the presence of radioactive minerals has been delineated by the detection of highαandγcounts with respect to the background radiations. High radiation counts and high surfaceγactivity are found just above the higher apparent current-density zones in all the profiles studied, at various locations, indicating uranium and/or thorium mineralization as well as good correlation between these techniques.

Secondary uranium mineralization in southern Finland and its relationship to recent glacial events

2008 ◽  
Vol 60 (3-4) ◽  
pp. 235-249 ◽  
Author(s):  
David Read ◽  
Stuart Black ◽  
Tracy Buckby ◽  
Karl-Heinz Hellmuth ◽  
Nuria Marcos ◽  
...  
Keyword(s):  
Uranium Mineralization

The Coupling Relationship Research between Sandstone Type Uranium Mineralization and Yili Basin Sedimentary-tectonic Evolution

2014 ◽  
Vol 88 (s2) ◽  
pp. 1377-1378
Author(s):  
Chengyu PAN ◽  
Hongxu LIU ◽  
Zhengle CHEN ◽  
Fei GAO ◽  
Xiao ZHANG ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Uranium Mineralization ◽  
Coupling Relationship

The Coles Hill Uranium Deposit, Virginia, USA: Geology, Geochemistry, Geochronology, and Genetic Model

2022 ◽  
Vol 117 (2) ◽  
pp. 273-304
Author(s):  
S. M. Hall ◽  
J. S. Beard ◽  
C. J. Potter ◽  
R. J. Bodnar ◽  
L. A. Neymark ◽  
...  
Keyword(s):  
Shear Zone ◽  
Titanium Oxide ◽  
River Basin ◽  
Host Rock ◽  
Uranium Deposit ◽  
Uranium Mineralization ◽  
Late Triassic ◽  
Pb Isotope ◽  
Igneous Complex ◽  
Mineralizing Fluids

Abstract The Coles Hill uranium deposit, with an indicated resource of about 130 Mlb of U3O8, is the largest unmined uranium deposit in the United States. The deposit is hosted in the Taconian (approx. 480–450 Ma) Martinsville igneous complex, which consists of the Ordovician Leatherwood Granite (granodiorite) and the Silurian Rich Acres Formation (diorite). The host rock was metamorphosed to orthogneiss during the Alleghanian orogeny (approx. 325–260 Ma), when it also underwent dextral strike-slip movement along the Brookneal shear zone. During the Triassic, extensional tectonics led to the development of the Dan River Basin that lies east of Coles Hill. The mineralized zone is hosted in brittle structures in the footwall of the Triassic Chatham fault that forms the western edge of the basin. Within brittle fracture zones, uranium silicate and uranium-bearing fluorapatite with traces of brannerite form veins and breccia-fill with chlorite, quartz, titanium oxide, pyrite, and calcite. Uranium silicates also coat and replace primary titanite, zircon, ilmenite, and sulfides. Sodium metasomatism preceded and accompanied uranium mineralization, pervasively altering host rock and forming albite from primary feldspar, depositing limpid albite rims on igneous feldspar, altering titanite to titanium oxide and calcite, and forming riebeckite. Various geothermometers indicate temperatures of less than ~200°C during mineralization. In situ U-Pb analyses of titanite, Ti-oxide, and apatite, along with Rb/Sr and U/Pb isotope systematics of whole-rock samples, resolve the timing of geologic processes affecting Coles Hill. The host Leatherwood Granite containing primary euhedral titanite is dated at 450 to 445 Ma, in agreement with previously obtained ages from zircon in the Martinsville igneous complex. A regional metamorphic event at 330 to 310 Ma formed anhedral titanite and some apatite, reequilibrated whole-rock Rb/Sr and U-Pb isotopes, and is interpreted to have coincided with movement along the Brookneal shear zone. During shearing and metamorphism, primary refractory uranium-bearing minerals including titanite, zircon, and uranothorite were recrystallized, and uranium was liberated and mixed locally with hematite, clay, and other fine-grained minerals. Uranium mineralization was accompanied by a metasomatic episode between 250 and 200 Ma that reset the Rb-Sr and U-Pb isotope systems and formed titanium oxide and apatite that are associated and, in places, intimately intergrown with uranium silicate dating mineralization. This event coincides with rifting that formed the Dan River Basin and was a precursor to the breakup of Pangea. The orientation of late-stage tectonic stylolites is compatible with their formation during Late Triassic to Early Jurassic basin inversion, postdating the main stage of uranium mineralization and effectively dating mineralization as Mesozoic. Based on the close spatial and temporal association of uranium with apatite, we propose that uranium was carried as a uranyl-phosphate complex. Uranium was locally reduced by coupled redox reactions with ferrous iron and sulfide minerals in the host rock, forming uranium silicates. The release of calcium during sodium metasomatic alteration of primary calcic feldspar and titanite in the host rock initiated successive reactions in which uranium and phosphate in mineralizing fluids combined with calcium to form U-enriched fluorapatite. Based on the deposit mineralogy, oxygen isotope geochemistry, and trace element characteristics of uranium silicate and gangue minerals, the primary mineralizing fluids likely included connate and/or meteoric water sourced from the adjacent Dan River Basin. High heat flow related to Mesozoic rifting may have driven these (P-Na-F-rich) fluids through local aquifers and into basin margin faults, transporting uranium from the basin or mobilizing uranium from previously formed U minerals in the Brookneal shear zone, or from U-enriched older basement rock.

scholarly journals The Mineral Chemistry of Chlorites and Its Relationship with Uranium Mineralization from Huangsha Uranium Mining Area in the Middle Nanling Range, SE China

Minerals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 199 ◽  
Author(s):  
Dehai Wu ◽  
Jiayong Pan ◽  
Fei Xia ◽  
Guangwen Huang ◽  
Jing Lai
Keyword(s):  
Mining Area ◽  
Uranium Mining ◽  
Uranium Mineralization ◽  
Formation Mechanisms ◽  
Chemical Compositions ◽  
Type I ◽  
Low Oxygen ◽  
Nanling Range ◽  
The Relationship ◽  
Uranium Mining Area

The Huangsha uranium mining area is located in the Qingzhangshan uranium-bearing complex granite of the Middle Nanling Range, Southeast China. This uranium mining area contains three uranium deposits (Liangsanzhai, Egongtang, and Shangjiao) and multiple uranium occurrences, showing favorable mineralization conditions and prospecting potential for uranium mineral resources. Chloritization is one of the most important alteration types and prospecting indicators in this mining area. This study aims to unravel the formation environment of chlorites and the relationship between chloritization and uranium mineralization, based on detailed field work and petrographic studies of the wallrock and ore samples from the Huangsha uranium mining area. An electron probe microanalyzer (EPMA) was used in this study to analyze the paragenetic association, morphology, and chemical compositions of chlorite, to classify chemical types and to calculate formation temperatures and n(Al)/n(Al + Mg + Fe) values of chlorite. The formation mechanism and the relationship with uranium mineralization of the uranium mining area are presented. Some conclusions from this study are: (1) There are five types of chlorites, including the chlorite formed by the alteration of biotite (type-I), by the metasomatism of feldspar with Fe–Mg hydrothermal fluids (type-II), chlorite vein/veinlet filling in fissures (type-III), chlorite closely associated with uranium minerals (type-IV), and chlorite transformed from clay minerals by adsorbing Mg- and Fe-components (type-V). (2) The chlorite in the Huangsha uranium mining area belongs to iron-rich chlorite and is mainly composed of chamosite, partly clinochlore, which are the products of multiple stages of hydrothermal action. The original rocks are derived from argillite, and their formation temperatures vary from 195.7 °C to 283.0 °C, with an average of 233.2 °C, suggesting they formed under a medium to low temperature conditions. (3) The chlorites were formed under reducing conditions with low oxygen fugacity and relatively high sulfur fugacity through two formation mechanisms: dissolution–precipitation and dissolution–migration–precipitation; (4) The chloritization provided the required environment for uranium mineralization, and promoted the activation, migration, and deposition of uranium.

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