Composition of Large Zoned Aluminum Phosphate Sulfate Minerals: Implications For Fluid Evolution In the Centennial Uranium Deposit Area, Athabasca Basin, Saskatchewan, Canada

2016 ◽  
Vol 54 (5) ◽  
pp. 1205-1228
Author(s):  
Kyle D. Reid ◽  
Kevin Ansdell ◽  
Steven Creighton ◽  
Eric G. Potter
2007 ◽  
Vol 92 (2-3) ◽  
pp. 267-280 ◽  
Author(s):  
S. Gaboreau ◽  
M. Cuney ◽  
D. Quirt ◽  
D. Beaufort ◽  
P. Patrier ◽  
...  

Author(s):  
Daniel Peter Ferguson ◽  
Guoxiang Chi ◽  
Charles Normand ◽  
Patrick Ledru ◽  
Odile Maufrais-Smith

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.


1993 ◽  
Vol 30 (4) ◽  
pp. 653-673 ◽  
Author(s):  
P. Bruneton

The Cigar Lake uranium deposit occurs within the Athabasca Basin of northern Saskatchewan, Canada. Like other major uranium deposits of the basin, it is located at the unconformity separating Helikian sandstones of the Athabasca Group from Aphebian metasediments and plutonic rocks of the Wollaston Group. The Athabasca Group was deposited in an intra-continental sedimentary basin that was filled by fluviatile terrestrial quartz sandstones and conglomerates. The group appears undeformed and its actual maximum thickness is about 1500 m. On the eastern side of the basin, the detrital units correspond to the Manitou Falls Formations where most of the uranium deposits are located. The Lower Pelitic unit of the Wollaston Group, which lies directly on the Archean basement, is considered to be the most favourable horizon for uranium mineralization. During the Hudsonian orogeny (1800–1900 Ma), the group underwent polyphase deformation and upper amphibolite facies metamorphism. The Hudsonian orogeny was followed by a long period of erosion and weathering and the development of a paleoweathering profile.On the Waterbury Lake property, the Manitou Falls Formation is 250–500 m thick and corresponds to units MFd, MFc, and MFb. The conglomeratic MFb unit hosts the Cigar Lake deposit. However, the basal conglomerate is absent at the deposit, wedging out against an east–west, 20 m high, pre-Athabasca basement ridge, on top of which is located the orebody.Two major lithostructural domains are present in the metamorphic basement of the property: (1) a southern area composed mainly of pelitic metasediments (Wollaston Domain) and (2) a northern area with large lensoid granitic domes (Mudjatik Domain). The Cigar Lake east–west pelitic basin, which contains the deposit, is located in the transitional zone between the two domains. The metamorphic basement rocks in the basin consist mainly of graphitic metapelitic gneisses and calcsilicate gneisses, which are inferred to be part of the Lower Pelitic unit. Graphite- and pyrite-rich "augen gneisses," an unusual facies within the graphitic metapelitic gneisses, occur primarily below the Cigar Lake orebody.The mineralogy and geochemistry of the graphitic metapelitic gneisses suggest that they were originally shales. The abundance of magnesium in the intercalated carbonates layers indicates an evaporitic origin.The structural framework is dominated by large northeast–southwest lineaments and wide east–west mylonitic corridors. These mylonites, which contain the augen gneisses, are considered to be the most favourable features for the concentration of uranium mineralization.Despite the presence of the orebody, large areas of the Waterbury Lake property remain totally unexplored and open for new discoveries.


2020 ◽  
Author(s):  
Sean Hillacre ◽  
Kevin Ansdell ◽  
Brian McEwan

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.


Author(s):  
Paul Alexandre

Abstract A large data set comprising near-total digestion analyses of whole rock samples from the Athabasca Basin, Saskatchewan, Canada (based principally on the Geological Survey of Canada open file 7495), containing more than 20,000 analyses, was used to define the average chemical composition of Athabasca Group sandstones and of unconformity-related uranium deposits hosted by the basin. The chemical composition of unaltered and un-mineralized Athabasca Group sandstones is dominated by Al (median Al2O3 of 1.14 wt.%), Fe (median Fe2O3 of 0.24 wt.%), and K (median K2O of 0.11 wt.%; Si was not measured), corresponding mostly to the presence of kaolin, illite, and hematite, in addition to the most-abundant quartz. The median concentration of U in the barren sandstones is 1 ppm, with 5 ppm Th, 3 ppm Pb, and 56 ppm ΣREE. Other trace elements present in significant amounts are Zr (median of 100 ppm), Sr (median of 69 ppm), and B (median of 43 ppm), corresponding to the presence of zircon, illite, and dravite. The elements most enriched in a typical Athabasca Basin unconformity-related uranium deposit relative to the barren sandstone are U (median enrichment of ×710), Bi (×175), V (×77), and Mg (×45), followed by five elements with enrichment factors between 20 and 30 (Co, Mo, K, As, and Ni). These correspond to the presence in the ore bodies of alteration minerals (dravite, kaolinite, illite, chlorite, aluminum-phosphate-sulfate minerals, and a suite of sulfide minerals) and are similar to what has been observed before. These elements are similar to the typical pathfinder elements described above known deposits, but their usefulness has to be assessed based on their relative mobility in the predominantly oxidizing Athabasca Basin sandstones.


Geosciences ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 285
Author(s):  
Norbert Clauer

Previously published K-Ar dating results of <2 μm illite separates from uranium-hosting and associated barren rocks from Dominique Peter district of the Carswell circular structure in the Athabasca Basin (Canada) were considered to trace four distinct tectonic-thermal events at 1447 ± 45, 1282 ± 40 and 1184 ± 15 (all errors at ± 2 Ma, with a younger, less constrained episode at ~900 Ma. Recent analyses of K-Ar ages of additional <0.2 μm illite fractions from a few initial samples demonstrate that the intermediate ages at ~1280 and ~1185 Ma result, in fact, from mixing of two generations of illite that precipitated at ~1450 and ~900 Ma. They have, therefore, no stratigraphic value, while the two tectonic-thermal episodes at 1448 ± 48 and 937 ± 39 Ma appear to be historically sound. In fact, the analytical procedure of isotopic dating clay materials is of more importance than is often stated. For instance, a safe way to evaluate and constrain best numerical isotopic data of clay separates into ages is combining data of two size splits from several samples. If such age data, especially from size fractions of indurated host rocks, are scattered and point towards the higher data of the coarser fractions, they are potentially enriched in earlier crystallized K-rich components, and should consequently be discarded. The occurrence of detrital or early-crystallized components in clay-rich separates becomes a serious concern when comparing ages generated by various isotopic methods on mineral separates of various whole rocks. It is especially verified in very old, metal-rich deposits such as the uranium-rich deposits of the Saskatchewan Basin. These deposits and their host rocks were studied extensively by a large spectrum of isotopic methods on many types of rocks in a widely dispersed area, and for which the numerical statistics became, sometimes, more central in the interpretation than the specificity of the successive events in the host rocks.


2017 ◽  
Vol 54 (8) ◽  
pp. 850-868 ◽  
Author(s):  
Brandi M. Shabaga ◽  
Mostafa Fayek ◽  
David Quirt ◽  
Charlie W. Jefferson ◽  
Alfredo Camacho

The Thelon Basin located in Nunavut, Canada, shares many similarities with the U-producing Athabasca Basin in Saskatchewan. The Kiggavik project area, located near the northeastern edge of the Thelon Basin, contains U deposits and showings along the ∼30 km long NE–SW Kiggavik – Andrew Lake structural trend. The Andrew Lake deposit is near the southern end of this trend. Pre-mineralization is characterized by quartz ± carbonate veins that occupy fault systems later reactivated as conduits for U-mineralizing fluids. A four-phase genetic model is proposed for the Andrew Lake deposit. Phase 1 comprises vein-style uraninite (U1; 1031 ± 23 Ma) that is associated with illite and hematite, and contains variable PbO contents (0.2–9.5 wt.%). Phase 2 is characterized by altered uraninite (U2; ∼530 Ma) that is associated with coffinite. Altered uraninite (U3; <1 Ma) characterizes phase 3 and occurs as centimetre-scale “roll-fronts”. In phase 4, all three uraninite stages, and coffinite, are altered to boltwoodite. Although the oldest uraninite U–Pb age is ∼1030 Ma, illite associated with the U mineralization gives 40Ar/39Ar ages of 941 ± 31 and 1330 ± 36 Ma. The younger age is similar to the age for U1, suggesting that there was a fluid event that either precipitated U1 or reset the U–Pb isotopic system at ∼1000 Ma. While the older age for illite (1330 Ma) does not correlate with Andrew Lake U–Pb uraninite ages, it does correlate with ages previously reported for uraninite and clay alteration minerals in the Kiggavik area.


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