scholarly journals Structural Controls of Uranium Mineralization in the Basement of the Athabasca Basin, Saskatchewan, Canada

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-30
Author(s):  
Antonio Benedicto ◽  
Maher Abdelrazek ◽  
Patrick Ledru ◽  
Cameron MacKay ◽  
Dwayne Kinar
Keyword(s):  
Regional Scale ◽  
Structural Data ◽  
Shear Zones ◽  
Uranium Mineralization ◽  
Uranium Deposits ◽  
Athabasca Basin ◽  
Structural Controls ◽  
The Right ◽  
Drill Holes

The occurrence of unconformity-related uranium mineralization requires the combination of three components: fluids with the right composition, geochemical traps with the right agents that produce precipitation, and structural traps with the right geometry. In the Athabasca Basin unconformity-related uranium deposits, while basinal brines are commonly accepted as the principal mineralized fluids and graphite and gases (CH4, CO2, and H2S) are well known as the reductants, only few case studies describing structural traps are published. A number of recent works, including numerical modelling, have improved the understanding of the role of inherited shear zones on fluid flow and the development of uranium deposits at a micro- and regional-scale. Nevertheless, there is still a lack of knowledge about the meso- or deposit-scale structural controls that lead to the present (and potentially predictive) localization of uranium deposits along a given shear zone. The present work examines new structural data from drill holes and deals with (i) the identification of mesoscale structural traps that lead to the formation of the Athabasca unconformity-related uranium deposits hosted within the basement and (ii) with the understanding of the role and mode of reactivation of the inherited shear zones. The Sue deposits (McClean Project), the Tri-Island showing (Martin Lake Project) in the Eastern Athabasca, and the Spitfire prospect (Hook Lake Project) in the Western Athabasca have been selected for a detailed analysis of structures and related uranium mineralization. The structural analysis performed brings new insights about the mesoscale structural controls, the role the inherited ductile fabric had on the mode of brittle reactivation and to trap mineralization, and the tectonic regime to which basement-hosted uranium deposits may be associated in the Athabasca Basin.

Stable isotope constraints on the role of graphite in the genesis of unconformity-type uranium deposits

1989 ◽  
Vol 26 (3) ◽  
pp. 490-498 ◽  
Author(s):  
T. K. Kyser ◽  
M. R. Wilson ◽  
G. Ruhrmann
Keyword(s):  
Fluid Flow ◽  
Stable Isotope ◽  
Uranium Deposit ◽  
Shear Zones ◽  
Limited Range ◽  
Hydrothermal Fluids ◽  
Uranium Deposits ◽  
Athabasca Basin ◽  
Ore Zones

The Key Lake unconformity-type uranium deposit occurs in a shear zone where it intersects the unconformity between Archean and Aphebian gneisses and the overlying Proterozoic Athabasca Group sandstones. The roots of the Key Lake and many other unconformity-type uranium deposits in the Athabasca basin are close to gneisses rich in graphite and most deposits have small amounts of carbonaceous materials (bitumen and hydrocarbon buttons) within and around altered basement and sandstone ore zones. In many Athabasca uranium deposits, hydrothermal fluids have destroyed graphite disseminated in the strongly altered gneisses in the vicinity of the deposits, prompting some to suggest that graphite was converted to CH4, which reduced and precipitated the uranium and partially condensed to form bitumen. The δ13C values of graphite collected from unaltered and altered gneisses around the Key Lake deposit have a limited range (−25 ± 5) and are not a function of distance from the mineralization or the intensity of alteration or deformation. The uniformity of these δ13C values suggests that the destruction of graphite was due predominantly to oxidation by basinal fluids from the sandstone and that the graphite near the deposits did not react to form substantial amounts of 12C-rich phases such as CH4. Most of the bitumen samples, which have higher H/C ratios than the graphite, have δ13C values identical to those of the graphite (−25 ± 5). The similarity in the isotopic compositions of carbon in the bitumen and in the graphite indicates that the bitumen formed from degradation of graphite as a result of reactions with no significant isotopic fractionations, such as ones involving radiolysis of graphite. The hydrocarbon buttons and a few samples of bitumen have petrographic relations and 13C/12C ratios (δ13C values less than −30) that are indicative of reduction of graphite by H2 produced from water by radiolysis. Graphite in these deposits did not play a central role as a reducing agent for uranium, rather it represents a critical structural factor by providing shear zones along which fluid flow can be focussed.

Advanced Use of Borehole Acoustic Televiewer (ATV) for Structural Interpretation of Unconformity-Related Uranium Deposits

2021 ◽  
Author(s):  
Antonio Benedicto ◽  
Grant Harrison ◽  
Brandon Eccles ◽  
Patrick Ledru
Keyword(s):  
Fault Reactivation ◽  
Added Value ◽  
Reverse Fault ◽  
Uranium Deposits ◽  
Athabasca Basin ◽  
Structural Interpretation ◽  
Structural Controls ◽  
Core Recovery ◽  
Direct Observations ◽  
Drill Holes

Abstract The structural controls on unconformity-related uranium deposits of the Athabasca basin, Saskatchewan, Canada, are a matter of debate regarding the role of inherited fault systems and their reactivation. This can be related to the lack of outcrops allowing for direct observations, the strong clay alteration halos wrapping deposits that often obliterate structures, and the poor core recovery related to drilling strongly altered and mineralized intervals, which limits observation of structures and reliable oriented measurements. Borehole imaging technology is an invaluable alternative for obtaining oriented data through challenging drilling intervals. The use of borehole Acoustic Televiewer (ATV) has been integrated in recent exploratory campaigns in the Athabasca basin by Orano Canada. Here, we present the inputs and benefits of the use of the ATV in the exploration of unconformity-related uranium deposits and the structural analysis of oriented data from seven inclined diamond drill holes completed in 2016 during the McClean project (Sue deposits). The main objectives were to precisely identify the structural controls of the basement-hosted mineralization, and to test the tool in a well-known site. This work shows the applicability and added value of using televiewer probes to provide reliable oriented data in zones where there is much less information available. The ATV data structural interpretation supports the concept of mineralization of dilational jogs opening during preexisting shear-related foliation under right-lateral reverse fault reactivation. The ATV provides robust oriented data, allowing for a better understanding of the meaning of flat-lying mineralized structures along the Sue trend.

scholarly journals Uranium deposits of Franceville basin (Gabon): Role of organic matter and oil cracking on uranium mineralization

2020 ◽  
Vol 123 ◽  
pp. 103579
Author(s):  
Andreï Lecomte ◽  
Raymond Michels ◽  
Michel Cathelineau ◽  
Christophe Morlot ◽  
Marc Brouand ◽  
...  
Keyword(s):  
Organic Matter ◽  
Uranium Mineralization ◽  
Uranium Deposits ◽  
Oil Cracking

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.

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.

Structural evolution and related implications for uranium mineralization in the Patterson Lake corridor, southwestern Athabasca Basin, Saskatchewan, Canada

2020 ◽  
pp. geochem2020-030
Author(s):  
Dillon Johnstone ◽  
Kathryn Bethune ◽  
Colin Card ◽  
Victoria Tschirhart
Keyword(s):  
Structural Evolution ◽  
Uranium Mineralization ◽  
Ductile Deformation ◽  
Normal Faults ◽  
Uranium Deposits ◽  
Content Type ◽  
Athabasca Basin ◽  
Basement Rocks ◽  
Transfer Faults ◽  
Dextral Strike Slip

The Patterson Lake corridor is situated along the southwest margin of the Athabasca Basin and contains several basement-hosted uranium deposits and prospects. Drill core investigations during this study have determined that granite, granodiorite, mafic and alkali intrusive basement rocks are entrained in a deep-seated northeast-striking subvertical heterogeneous high-strain zone defined by anastomosing ductile to semi-brittle shears and brittle faults. The earliest phases of ductile deformation (D1/2), linked with Taltson (1.94–1.92 Ga) orogenesis, involved interference between early fold sets (F1/2) and development of an associated ductile transposition foliation (S1/2). During subsequent Snowbird (ca. 1.91–1.90 Ga) tectonism, this composite foliation was re-folded (D3) by northeast-trending buckle-style folds (F3), including a regional fold centered on the Clearwater aeromagnetic high. In continuum with D3, a network of dextral-reverse chloritic-graphitic shears, with C-S geometry, formed initially (D4a) and progressed to more discrete, spaced semi-brittle structures (D4b; ca. 1.900–1.819 Ga). Basin development (D5a; <ca. 1.819 Ga) was marked by a set of north-striking normal faults and related east- and northeast-striking transfer faults that accommodated subsidence. Primary uranium mineralization (D5b; ∼1.45 Ga) was facilitated by brittle reactivation of northeast-striking basement shears in response to west-southwest - east-northeast-directed compressional stress (σ1). Uraninite was emplaced along σ1-parallel extension fractures and dilational zones formed at linkages between northeast- and east-northeast-striking dextral strike-slip faults. Uranium remobilization (D5c) occurred after σ1 shifted to west-northwest – east-southeast, giving rise to regional east- and southeast-striking conjugate faults, along which mafic dykes (1.27 Ga and 1.16 Ga) intruded.Thematic collection: This article is part of the Uranium Fluid Pathways collection available at: https://www.lyellcollection.org/cc/uranium-fluid-pathways

Topographic features of the sub-Athabasca Group unconformity surface in the southeastern Athabasca Basin and their relationship to uranium ore deposits

2015 ◽  
Vol 52 (10) ◽  
pp. 903-920 ◽  
Author(s):  
Zenghua Li ◽  
Kathryn M. Bethune ◽  
Guoxiang Chi ◽  
Sean A. Bosman ◽  
Colin D. Card
Keyword(s):  
Cross Sections ◽  
Regional Scale ◽  
Three Dimensional ◽  
Shear Zones ◽  
Ore Deposits ◽  
Athabasca Basin ◽  
Topographic Features ◽  
Dominant Sets ◽  
Lake Deposits ◽  
Unconformity Surface

Topographic features of the sub-Athabasca unconformity surface, such as paleovalleys, topographic highs, and fault scarps, have been documented locally in the eastern Athabasca Basin, and available data indicate that they are spatially associated with mineralization. However, the mechanisms by which such topographic features were generated, their size and distribution at the regional scale, as well as their relationship to mineralization, are still not completely understood. A 100 by 60 square kilometre area of the southeastern Athabasca Basin, encompassing the McArthur River, Phoenix, and Key Lake deposits, was selected to study the relationship between these topographic features and U mineralization. In this region three dominant sets of sub-vertical faults were identified on the basis of aeromagnetic data: northeast-trending, north–northwest-trending, and northwest-trending. A detailed three-dimensional (3-D) model of this part of the basin was constructed using data from more than 1200 drill holes. This model reveals numerous dominantly northeast-trending ridges and valleys in the unconformity surface. Among these, a prominent northeast-trending ridge is situated close to the McArthur River – Key Lake deposits trend. Structural interpretation and cross-sections illustrate that the topographic features that have been documented in previous studies are a function of three principal factors: (i) pre-Athabasca group ductile-brittle faulting and alteration; (ii) differential weathering and erosion; and (iii) syn- to post-Athabasca ductile-brittle reactivation of pre-existing graphite-rich ductile shear zones. The topographic features and associated faults may have acted as conduits and barriers to fluid flow and thus controlled alteration patterns and uranium mineralization.

scholarly journals Alteration of Granitoids and Uranium Mineralization in the Blatná Suite of the Central Bohemian Plutonic Complex, Czech Republic

Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 821
Author(s):  
Miloš René
Keyword(s):  
Czech Republic ◽  
Low Temperature ◽  
Shear Zones ◽  
Uranium Mineralization ◽  
Granitic Rocks ◽  
Uranium Deposits ◽  
Magmatic Complex ◽  
Central European ◽  
Plutonic Complex ◽  
European Variscides

The Bohemian magmatic complex belongs to granitoid plutons of the Central European Variscides. Hydrothermal uranium mineralization evolved in the small uranium deposits Nahošín and Mečichov is associated with N–S shear zones occurring on the SW margin of the Central Bohemian plutonic complex formed by amphibole-bearing biotite granodiorites of the Blatná suite. The purpose of presented study is description of uranium mineralization bounded on brittle shear zones, which is coupled with intense low-temperature hydrothermal alteration of granitic rocks. Uranium mineralization, formed predominantly of coffinite, rare uraninite, and thorite, is accompanied by intense hematitization, albitization, chloritization, and carbonatization of original granitic rocks that could be described as aceites. These alterations are accompanied by the enrichment in U, Ti, Mg, Ca, Na, K, Y, and Zr and depletion in Si, Ba, and Sr. The analyzed coffinite is enriched in Y (up to 3.1 wt % Y2O3). Uraninite is enriched in Th (up to 9.8 wt % ThO2) and thorite is enriched in Zr (up to 5.7 wt % ZrO2). The REE-elements are concentrated in the REE-fluorcarbonate synchysite-(Ce).

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