Unconformity-related U-Au mineralization in the middle Proterozoic Thelon Sandstone, Boomerang Lake Prospect, Northwest Territories, Canada

Davidson, Gordon I.; Gandhi, S S

doi:10.2113/gsecongeo.84.1.143

Cited by 18 publications

(7 citation statements)

References 16 publications

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“…Some of the uranium mineralization in the Thelon Basin has been related to these faults (Fuchs and Hilger 1989;Kyser et al 2000). For example, the Boomerang Lake Prospect lies along a northwest-trending fault zone and, at outcrop-scale, the zones of alteration and mineralization are associated with small-scale faults (Davidson and Gandhi 1989). We interpret the outcrop-scale faults within the Barrens Sequence as reactivations of the main, pre-existing faults sets that dissect Baker Lake Basin.…”

Section: Post-barrens Sequence Reactivationmentioning

confidence: 90%

Retro-arc extension and continental rifting: a model for the Paleoproterozoic Baker Lake Basin, Nunavut¹Geological Survey of Canada Contribution 20100436.

Hadlari

Rainbird

2011

Can. J. Earth Sci.

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Within Baker Lake sub-basin, the ca. 1.84-1.78 Ga Baker Sequence formed in two stages. At the start of the first stage, during rift initiation, half-graben were host to siliciclastic alluvial, eolian, and lacustrine deposits and to localized felsic minette volcanics. Back-stepping of facies indicate high accommodation rates and areal expansion, which, combined with extrusion of voluminous minette volcanic rocks, are interpreted to record increased extension and rift climax. Low accommodation post-rift deposits from the second stage of basin development are relatively thin and coeval felsite domes spatially restricted. Volcanic rocks and some siliciclastic units correlate between sub-basins, and hence the interpreted history of Baker Lake sub-basin is extended across greater Baker Lake Basin. This implies that the basin formed in response to regional extension and crustal thinning. The Baker Lake Basin marks the northern extent of a series of basins that trend northeastward along the Snowbird Tectonic Zone, including an inlier of the correlative Martin Group in northern Saskatchewan. The high accommodation first stage of basin development is proposed to have been the result of intra-continental retro-arc extension during ca.

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Section: Post-barrens Sequence Reactivationmentioning

confidence: 90%

Retro-arc extension and continental rifting: a model for the Paleoproterozoic Baker Lake Basin, Nunavut¹Geological Survey of Canada Contribution 20100436.

Hadlari

Rainbird

2011

Can. J. Earth Sci.

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“…Subsequent studies, including: (i) stromatolite morphologies (J.A. Donaldson, unpublished data) within the sequences; (ii) similarities in diagenetic mineral assemblages within basal siliciclastic units in all four basins (Cecile 1973;Gall 1994;Hoeve and Quirt 1984;Wilson 1985b;Renac et al 2002); (iii) the discovery of uranium and precious metal mineralization associated with the basal unconformities-paleosols beneath the four basins (Nash et al 1981;Yeo 1981;Hoeve and Quirt 1984;Roscoe 1984;Miller and LeCheminant 1985;Roscoe et al 1986;Davidson and Gandhi 1989;Gandhi and Paktunc 1989); (iv) additional age determinations of basement and basin strata (compiled in Gall 1992 and1994); and (v) the physical and chemical features of the paleosols beneath the four basin sequences (Gall and Donaldson 1990;Gall 1994); all reinforce the correlation proposed by Donaldson (1967).…”

Section: Regional Correlationmentioning

confidence: 98%

Diagenetic fluorapatite and aluminum phosphatesulphate in the Paleoproterozoic Thelon Formation and Hornby Bay Group, northwestern Canadian Shield

Gall¹,

Donaldson

2006

Can. J. Earth Sci.

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In the northwestern part of the Canadian Shield, fluorapatite and a rare-earth element-bearing hydrated aluminum phosphate-sulphate mineral (APS) occur as cements in continental successions near the base of the Paleoproterozoic Thelon Formation (Thelon Basin) and Hornby Bay Group (Hornby Bay Basin). These minerals occupy interstitial sites, form euhedral crystals, display micro-scale zonation, make up part of an unmetamorphosed paragenetic assemblage, and are distributed in correlative units across thousands of square kilometres, suggesting a diagenetic origin. Stratigraphy, geochronology, and other lines of evidence suggest that the Thelon Formation and Hornby Bay Group containing these phosphatic cements, as well as the Ellice Formation and Athabasca Group, are correlative and may have been originally interconnected. The evidence suggests that the basal Thelon Formation and the Hornby Bay Group underwent similar, and approximately coeval, diagenetic mineral paragenesis. Furthermore, the diagenetic fluids in these different locations must have been remarkably similar, especially those that produced the delicate APS mineral. Compared to phosphatic cements in the Hornby Bay and Thelon basins, unmineralized sandstone in the Athabasca Basin contains "crandallite group" and fluorapatite cements higher in the basin fill sequence (Wolverine Point Formation) in tuffaceous sandstone and as relatively early cement in the paragenetic sequence.Résumé : Dans la partie nord-ouest du Bouclier canadien, de la fluorapatite et un minéral hydraté comportant des élé-ments de terres rares, du phosphate et du sulfate d'aluminium (APS), se trouvent en tant que ciments dans des successions continentales à proximité de la base de la Formation de Thelon (bassin de Thelon) et du Groupe de Hornby Bay (bassin de Hornby Bay) tous deux datant du Paléoprotérozoïque. Ces minéraux se trouvent dans les interstices; ils forment des cristaux automorphes, montrent une zonation à très petite échelle, comprennent une partie d'un assemblage paragénétique non métamorphisé et ils sont distribués dans des unités de corrélation sur des milliers de kilomètres carrés, suggérant une origine diagénétique. D'après la stratigraphie, la géochronologie et d'autres observations, la Formation de Thelon et le Groupe de Hornby Bay contenant ces ciments phosphatés, tout comme la Formation d'Ellice et le Groupe d'Athabasca, seraient en corrélation et pourraient avoir été interconnectés à l'origine. Selon les données, la Formation Thelon basale et le Groupe de Hornby Bay auraient subi une paragenèse minérale diagénétique similaire et approximativement contemporaine. De plus, les fluides diagénétiques dans ces différents endroits devaient être remarquablement similaires, surtout ceux qui ont produit le délicat minéral APS. Par rapport aux ciments phosphatiques des bassins de Hornby Bay et de Thelon, un grès non minéralisé dans le bassin de l'Athabasca contient des ciments de fluorapatite et du « groupe de la crandallite » dans une partie supérieure de la séquence de rempl...

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“…2011), is exposed south of Aberdeen Lake and is inferred to be contiguous in the subsurface with metasedimentary units at the southern tip of the Thelon Basin that host the Boomerang Lake uranium prospect (Fig. 1), which has structural and lithologic similarities to Athabasca‐style deposits (Davidson and Gandhi 1989).…”

Section: Geologic Settingmentioning

confidence: 99%

3D geophysical inversions of the north‐east Amer Belt and their relationship to the geologic structure

Tschirhart

Morris

Jefferson

et al. 2012

Geophysical Prospecting

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The Amer Lake area is located within the Churchill Structural Province in the Kivalliq Region of Nunavut, approximately 160 km north‐west of Baker Lake. Two distinct geophysical‐geological entities are structurally intercalated: an Archean mixed granitoid gneiss – metasedimentary‐metavolcanic basement and the unconformably overlying Paleoproterozoic Amer Group metasediments. From east of Amer Lake stretching toward the south‐west, these two entities form the Amer fold and thrust belt. At the north‐east end of this belt, high‐resolution aeromagnetic data define a distinctive oval shape that has been interpreted as a south‐west trending doubly plunging synform. The outcrop within the interior of this structure is sparse resulting in limited structural data and speculative geological interpretations with multiple geometries possible. The high‐resolution aeromagnetic data compiled through an industry‐government consortium and newly acquired detailed gravity profiles were modelled to provide constraints on the geometry of this synform. We document a geophysical‐geological feedback process whereby the available geological and geophysical data were used to derive constraints on inversion models for the synform. Starting with available limited litho‐structural data the presence of a double plunging synform was directly inferred from the aeromagnetic data. Segments of the aeromagnetic data have 2D morphology and so can be modelled using a simple parametric 2D dipping slab inversion approach. Models of profiles extracted from the aeromagnetic data were used to provide preliminary dip and magnetic susceptibility constraints for the Three Lakes mudstone with iron formation and the Five Mile Lake basalt. Landsat imagery outlined the spatial limits of the stratigraphically underlying, non‐magnetic Ayagaq quartzite. Incorporating these outputs as bounds in the input / reference model for a UBC‐GIF 3D magnetic inversion helped to accentuate the geological structure in the output mesh: an enhanced inversion that incorporates both geological and geophysical constraints. The validity of the resulting inversion model was tested by computing 2D forward models of the gravity profile data. The inversion model generated by this study emphasizes the importance of integrating information from as many knowledge sources as one can find. More trust can be placed on forward and inversion models where there is agreement among all data sets and a coherency of structural style.

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Unconformity-related U-Au mineralization in the middle Proterozoic Thelon Sandstone, Boomerang Lake Prospect, Northwest Territories, Canada

Cited by 18 publications

References 16 publications

Retro-arc extension and continental rifting: a model for the Paleoproterozoic Baker Lake Basin, Nunavut¹Geological Survey of Canada Contribution 20100436.

Retro-arc extension and continental rifting: a model for the Paleoproterozoic Baker Lake Basin, Nunavut¹Geological Survey of Canada Contribution 20100436.

Diagenetic fluorapatite and aluminum phosphatesulphate in the Paleoproterozoic Thelon Formation and Hornby Bay Group, northwestern Canadian Shield

3D geophysical inversions of the north‐east Amer Belt and their relationship to the geologic structure

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Unconformity-related U-Au mineralization in the middle Proterozoic Thelon Sandstone, Boomerang Lake Prospect, Northwest Territories, Canada

Cited by 18 publications

References 16 publications

Retro-arc extension and continental rifting: a model for the Paleoproterozoic Baker Lake Basin, Nunavut1Geological Survey of Canada Contribution 20100436.

Retro-arc extension and continental rifting: a model for the Paleoproterozoic Baker Lake Basin, Nunavut1Geological Survey of Canada Contribution 20100436.

Diagenetic fluorapatite and aluminum phosphatesulphate in the Paleoproterozoic Thelon Formation and Hornby Bay Group, northwestern Canadian Shield

3D geophysical inversions of the north‐east Amer Belt and their relationship to the geologic structure

Contact Info

Product

Resources

About

Retro-arc extension and continental rifting: a model for the Paleoproterozoic Baker Lake Basin, Nunavut¹Geological Survey of Canada Contribution 20100436.

Retro-arc extension and continental rifting: a model for the Paleoproterozoic Baker Lake Basin, Nunavut¹Geological Survey of Canada Contribution 20100436.

Diagenetic fluorapatite and aluminum phosphatesulphate in the Paleoproterozoic Thelon Formation and Hornby Bay Group, northwestern Canadian Shield