Isotopic studies of lead-depleted pitchblende, secondary radioactive minerals, and sulphides from the Rabbit Lake uranium deposit, Saskatchewan

1979 ◽  
Vol 16 (9) ◽  
pp. 1702-1715 ◽  
Author(s):  
G. L. Cumming ◽  
J. Rimsaite
Keyword(s):  
Electron Microprobe ◽  
Uranium Deposit ◽  
Uranium Mineralization ◽  
Polished Section ◽  
Radiogenic Lead ◽  
Isotopic Studies ◽  
Different Types ◽  
Northern Saskatchewan ◽  
Radioactive Minerals

Uranium–lead and lead isotopic studies have been made on different types of pitchblende, on secondary Pb-rich and Pb-poor uranium-bearing minerals, and on sulphides (radiogenic galena and pyrite) from the Rabbit Lake uranium deposit in northern Saskatchewan. Most specimens have been selected on the basis of their mineralogy and Pb/U ratios as determined by electron microprobe analyses. The Pb/U ratio varied between 1/2 and 1/665 as a result of diverse episodes of crystallization, differential losses of uranium and radiogenic lead, recrystallization of remobilized uranium and lead in different proportions in secondary radioactive minerals, and possible loss or enrichment of radon gas.All concentrates yielded discordant ages. Six samples contained an excess of radiogenic lead and yielded Pb/U ratios above the concordia curve. P-1 (primary) pitchblende samples were found to be depleted of radiogenic lead, thus grading into the Pb-depleted pitchblende of type P-2, and the data on even the "best" material can, thus, only be interpreted in terms of a discordia line which yields intersections at about 1281 and 440 Ma.A second discordia intersects the concordia curve at 1085 Ma and was obtained on concentrates containing several types of pitchblende including some samples difficult to distinguish in polished section from those of the 1281–440 Ma line, and secondary Pb-rich and Pb-poor uranyl-bearing aggregates that fell above, and at the lower end of, the concordia curve. This discordia intersection agrees well with previously published ages.The important event related to the replacement of pitchblende by sulphides, selenides, and arsenides, accompanied by marked losses of radiogenic lead and mobilization of uranium from the partly-resorbed "primary" pitchblende of type P-1, took place at a time no greater than 800–900 Ma ago. Reactions between remobilized uranium and altered silicates, and between the uranium and silica to form uraniferous phyllosilicates and coffinite, occurred 440 and ca. 200 Ma ago. Crystallization of hydrous uranyl-bearing aggregates, including precipitation of amorphous crusts in fractures of argillized rocks, continues at the present time.The Rabbit Lake deposit has been affected by superimposed alterations and recurring fracturing leaving fragments of partly resorbed and Pb-depleted pitchblende as the only remnants of the original intensive and widespread uranium mineralization.

Ages of major uranium mineralization and lead loss in the Key Lake uranium deposit, northern Saskatchewan, Canada

1984 ◽  
Vol 79 (6) ◽  
pp. 1378-1386 ◽  
Author(s):  
Linda K. Trocki ◽  
David B. Curtis ◽  
Alexander J. Gancarz ◽  
Joseph C. Banar
Keyword(s):  
Uranium Deposit ◽  
Uranium Mineralization ◽  
Northern Saskatchewan

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.

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 Paragenetic and petrographic study of uranium mineralization along the Midwest Trend, Northeastern Athabasca Basin

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Daniel Peter Ferguson ◽  
Guoxiang Chi ◽  
Charles Normand ◽  
Patrick Ledru ◽  
Odile Maufrais-Smith
Keyword(s):  
Mineral Resource ◽  
Genetic Model ◽  
Uranium Deposit ◽  
Current Model ◽  
Uranium Mineralization ◽  
Mining District ◽  
Uranium Deposits ◽  
Athabasca Basin ◽  
Technical Report ◽  
Petrographic Study

The Athabasca Basin in northern Saskatchewan is host to many world-class uranium deposits associated with the unconformity between the Paleoproterozoic sandstone of the basin and the underlying crystalline basement (Jefferson et al., 2007).  While the style and tonnage of these deposits vary, the current genetic model for unconformity-related uranium deposits has been a practical tool for exploration in the Athabasca Basin. However, the factors which control the location and formation of these deposits is still not fully understood. A paragenetic and petrographic study of mineralization along the Midwest Trend, located on the northeastern margin of the Athabasca Basin, aims to refine the current model and to address the general problem: What are the factors which control mineralization and non-mineralization? The Midwest Trend will be used as a "modèle réduit" for uranium mineralization, as it displays many features characteristic of unconformity type deposits. The Midwest Trend comprises three mineral leases that encompass two uranium deposits, the Midwest Main and Midwest A (Allen et al., 2017a, b). Mineralization occurs along a NE-trending graphitic structure, and is hosted by the sandstone, at the unconformity, and in much lesser amounts in the underlying basement rocks. Petrographic observations aided by the use of RAMAN spectroscopy and SEM-EDS, have been used to create a paragenetic sequence of mineralization (Fig.1). Future work will focus on fluid inclusion studies using microthermometry, LA-ICP-MS, and mass spectrometry of contained gases. References:Allen, T., Quirt, D., Masset, O. (2017a). Midwest A Uranium Deposit, Midwest Property, Northern Mining District, Saskatchewan, NTS Map Area 741/8: 2017 Mineral Resource Technical Report. AREVA Resources Canada Inc. Internal Report No. 17-CND-33-01. Allen, T., Quirt, D., Masset, O. (2017b). Midwest Main Uranium Deposit, Midwest Property, Northern Mining District, Saskatchewan, NTS Map Area 741/8: 2017 Mineral Resource Technical Report. AREVA Resources Canada Inc. Internal Report No. 17-CND-33-01. Jefferson, C.W., Thomas, D.J., Gandhi, S.S., Ramaekers, P., Delaney, G., Brisbin, D., Cutts, C., Portella, P., and Olson, R.A., 2007: Unconformity-associated uranium deposits of the Athabasca Basin, Saskatchewan and Alberta. Geological Survey of Canada, Bulletin 588, p. 23–67.

scholarly journals The uranium deposit at Kvanefjeld, the Ilímaussaq intrusion, South Greenland, Geology, reserves and beneficiation

1974 ◽  
Vol 60 ◽  
pp. 1-54
Author(s):  
H Sørensen ◽  
J Rose-Hansen ◽  
B.L Nielsen ◽  
L Løvborg ◽  
E Sørensen ◽  
...  
Keyword(s):  
Uranium Deposit ◽  
Element Content ◽  
Main Area ◽  
Alkaline Intrusion ◽  
Radioactive Minerals

The uranium-thorium deposit is located in part of an alkaline intrusion consisting of peralkaline, agpaitic nepheline syenites. The radioactive minerals are steenstrupine, uranium-rich monazite, thorite and pigmentary material. The radio-element content varies from 100 to 3000 ppm U and 300 to 15000 ppm Th. Reasonably assured ore in the main area with a grade of 310 ppm is calculated to 5800 metric tons of uranium in 18.6 million metric tons of ore. Estimated additional reserves with a grade of 292 ppm U are 29.4 million tons of ore with 8700 tons of uranium and 3.5 million tons of ore with a grade of 350 ppm yielding 1200 tons of uranium. Estimates of amounts of thorium ore are 2.6 times those of uranium. A method of recovery of the uranium based on sulphating roasting and subsequent leaching with water is described.

Geology, Structural Analysis, and Paragenesis of the Arrow Uranium Deposit, Western Athabasca Basin, Saskatchewan, Canada: Implications for the Development of the Patterson Lake Corridor

2020 ◽  
Author(s):  
Sean Hillacre ◽  
Kevin Ansdell ◽  
Brian McEwan
Keyword(s):  
Structural Analysis ◽  
Uranium Deposit ◽  
Regional Scale ◽  
Structural Features ◽  
White Mica ◽  
Uranium Mineralization ◽  
Fault System ◽  
Thin Sections ◽  
Athabasca Basin ◽  
Quartz Veins

Abstract Recent significant discoveries of uranium mineralization in the southwestern Athabasca basin, northern Saskatchewan, Canada, have been associated with a series of geophysical conductors along a NE- to SW-trending structural zone, termed the Patterson Lake corridor. The Arrow deposit (indicated mineral resource: 256.6 Mlb U3O8; grade 4.03% U3O8) is along this trend, hosted exclusively in basement orthogneisses of the Taltson domain, and is the largest undeveloped uranium deposit in the basin. This study is the first detailed analysis of a deposit along this corridor and examines the relationships between the ductile framework and brittle reactivation of structures, mineral paragenesis, and uranium mineralization. Paragenetic information from hundreds of drill core samples and thin sections was integrated with structural analysis utilizing over 18,000 measurements of various structural features. The structural system at Arrow is interpreted as a partitioned, strike-slip–dominated, brittle-ductile fault system of complex Riedel-style geometry. The system developed along subvertical, NE- to SW-trending dextral high-strain zones formed syn- to post-D3 deformation, which were the focus of extensive premineralization metasomatism (quartz flooding, sericitization, chloritization), within the limb domain of a regional-scale fold structure. These zones evolved through post-Athabasca dextral and sinistral reactivation events, creating brittle fault linkages and dilation zones, allowing for hydrothermal fluid migration and resulting uraninite precipitation and associated alteration (white mica, chlorite, kaolinite, hematite, quartz veins). This study of the structural context of Arrow is important as it emphasizes that protracted reactivation of deep-seated structures and their subsidiaries was a fundamental control on uranium mineralization in the southwestern Athabasca basin.

U–Pb geochronology of minerals from the Midwest uranium deposit, northern Saskatchewan

1984 ◽  
Vol 21 (6) ◽  
pp. 642-648 ◽  
Author(s):  
H. Baadsgaard ◽  
G. L. Cummino ◽  
J. M. Worden
Keyword(s):  
First Generation ◽  
Second Generation ◽  
Uranium Deposit ◽  
Paragenetic Sequence ◽  
Secondary Material ◽  
Basement Rocks ◽  
Northern Saskatchewan ◽  
Host Rocks ◽  
Sampling Problems ◽  
Late Stages

Analyses of U/Pb ratios in 30 microsamples of pitchblende and coffinite from the Midwest uranium deposit in northern Saskatchewan, as well as two altered zircons from host rocks, indicate an age of mineralization for primary pitchblende of 1328 ± 17 Ma. The primary material was remobilized at 1110 ± 28 Ma, forming the second generation of pitchblende and coffinite. First-generation pitchblende appears to have lost Pb either by diffusion or by a series of episodic losses at 300–100 Ma, whereas the secondary material proved more susceptible to Pb loss in the recent past.There is evidence of migration of pitchblende downwards into the basement rocks under the deposit at least as recently as 700 Ma ago, but we have been unable to date with certainty any late stages in the paragenetic sequence because of sampling problems associated with the small size of material clearly identifiable as stage 3 or 4 of the paragenetic sequence of Wray et al.

scholarly journals Uraninite, Coffinite and Ningyoite from Vein-Type Uranium Deposits of the Bohemian Massif (Central European Variscan Belt)

Minerals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 123 ◽  
Author(s):  
Miloš René ◽  
Zdeněk Dolníček ◽  
Jiří Sejkora ◽  
Pavel Škácha ◽  
Vladimír Šrein
Keyword(s):  
Chemical Composition ◽  
Electron Microprobe ◽  
Bohemian Massif ◽  
Uranium Deposit ◽  
Ore Deposits ◽  
Metamorphic Rocks ◽  
Uranium Deposits ◽  
Massif Central ◽  
Vein Type ◽  
Ore District

Uraninite-coffinite vein-type mineralisation with significant predominance of uraninite over coffinite occurs in the Příbram, Jáchymov and Horní Slavkov ore districts and the Potůčky, Zálesí and Předbořice uranium deposits. These uranium deposits are hosted by faults that are mostly developed in low- to high-grade metamorphic rocks of the basement of the Bohemian Massif. Textural features and the chemical composition of uraninite, coffinite and ningyoite were studied using an electron microprobe. Collomorphic uraninite was the only primary uranium mineral in all deposits studied. The uraninites contained variable and elevated concentrations of PbO (1.5 wt %–5.4 wt %), CaO (0.7 wt %–8.3 wt %), and SiO2 (up to 10.0 wt %), whereas the contents of Th, Zr, REE and Y were usually below the detection limits of the electron microprobe. Coffinite usually forms by gradual coffinitization of uraninite in ore deposits and the concentration of CaO was lower than that in uraninites, varying from 0.6 wt % to 6.5 wt %. Coffinite from the Jáchymov ore district was partly enriched in Zr (up to 3.3 wt % ZrO2) and Y (up to 5.5 wt % Y2O3), and from the Potůčky uranium deposit, was distinctly enriched in P (up to 8.8 wt % P2O5), occurring in association with ningyoite. The chemical composition of ningyoite was similar to that from type locality; however, ningyoite from Potůčky was distinctly enriched in REE, containing up to 22.3 wt % REE2O3.

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