Northeast Thelon region geoscience framework - new maps and data for uranium in Nunavut

Jefferson, C W; Pehrsson, S J; Peterson, T D; Chorlton, L B; Davis, W J; Keating, Pierre; Gandhi, S. S.; Fortin, R; Buckle, J L; Miles, W; Rainbird, R H; LeCheminant, T; Tschirhart, V; Tschirhart, Peter; Morris, William A.; Scott, J M J; Cousens, Brian; McEwan, B; Bethune, K M; Riemer, William J.; Calhoun, Lydia; White, J.C.; MacIsaac, D. A.; Leblon, Brigitte; Lentz, David L.; LaRocque, Armand; Shelat, Yask; Patterson, Jerry E.; Enright, A; Stieber, C; Riegler, Thomas

doi:10.4095/288791

Cited by 14 publications

(15 citation statements)

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“…The Thelon Basin was initiated at an unknown time after 1.75 Ga, bounded by arrays of faults trending parallel to the dyke sets mentioned earlier as well as several other trends. Major bounding faults include reactivated curvilinear shear zones such as the ϳ060°Turqavik fault and ϳ080°Thelon fault array (Jefferson et al 2011a(Jefferson et al , 2011bTschirhart et al 2013). The latter faults, some of which are occupied by the Thelon diabase dyke swarm, have right lateral offsets of up to 20 km, or more, and dip-slip offsets of tens to hundreds of metres, north-side down.…”

Section: Geological Settingmentioning

confidence: 98%

“…The spatial importance of hydrothermally altered intersecting reactivated faults, the 1.75 Ga Nueltin suite of intrusions, and Neoarchean supracrustal assemblages for uranium exploration in the northeast Thelon Basin region was outlined by Jefferson et al (2011aJefferson et al ( , 2011b. The recent focus of exploration has been on locating and testing small, intense gravity lows, which are associated with zones of greatest alteration that produced lower-density clays (Miller and LeCheminant 1985).…”

Section: Introductionmentioning

confidence: 98%

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Framework geophysical modelling of granitoid versus supracrustal basement to the northeast Thelon Basin around the Kiggavik uranium camp, Nunavut

2013

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The northeast Thelon Basin in the Kivalliq region of Nunavut is prospective for uranium deposits. Recently discovered basement-hosted, unconformity-associated prospects west of Kiggavik are restricted to deformed and metamorphosed Neoarchean psammitic enclaves of the Woodburn Lake group within 1.83 Ga Hudson granite and Martell syenite that together comprise the Shultz Lake intrusive complex (SLIC). The depth and geometry of the intrusive complex are relatively unknown as the geological constraints are poor; the drilling is sparse and of shallow depth extent as it was not targeting the basement but shallower multiply faulted and highly altered demagnetized zones. This study aims to constrain the geometry and context of the Shultz Lake intrusive complex with respect to the ore-hosting Neoarchean metasedimentary rocks and intersecting reactivated fault arrays through geophysical modelling of detailed aeromagnetic and gravity data integrated with new geological knowledge. By integrating detailed gravity, aeromagnetic, and structural geology observations measured along a series of transects with a petrophysical rock properties database, it is possible to derive constraints on the depth and thickness (200-300 m) of the SLIC. Quantitative comparison and integration of multiple hypothetical geometries favours a model wherein the SLIC, together with metasedimentary and older basement gneiss, has been structurally emplaced over the Neoarchean metasediments.Résumé : Le nord-est du bassin Thelon dans la région Kivalliq du Nunavut présente un bon potentiel de gisements d'uranium. Les indices récemment découverts dans le socle et associés aux discordances à l'ouest de Kiggavik sont restreints à des enclaves psammitiques déformées et métamorphisées (Néoarchéen) du Groupe de Woodburn Lake à l'intérieur du granite de Hudson et de la syénite de Martell (1,83 Ga) qui, ensemble, forment le complexe intrusif de Shultz Lake (SLIC). La profondeur et la géométrie du complexe intrusif sont relativement inconnues, en raison du peu d'encadrement géologique; de plus, les forages sont clairsemés et de faible profondeur puisqu'ils ne ciblaient pas le socle mais plutôt des zones peu profondes, démagnétisées et hautement altérées avec de multiples failles. La présente étude vise à encadrer la géologie et le contexte du complexe intrusif de Shultz Lake par rapport aux roches métasédimentaires néoarchéennes contenant du minerai et aux réseaux de failles réactivées qui les recoupent. Les méthodes utilisées sont la modélisation géophysique des données aéromagnétiques et gravimétriques détaillées intégrées à de nouvelles connaissances géologiques. En intégrant les observations détaillées gravimétriques, aéromag-nétique et de géologie structurale, mesurées le long d'une série de transects, avec une base de données des propriétés pétrophy-siques des roches, il a été possible d'établir des cadres quant à la profondeur et à l'épaisseur (200-300 m) du SLIC. Une comparaison quantitative et l'intégration de multiples géométries hypothétiques produisent un...

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Section: Geological Settingmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 98%

Framework geophysical modelling of granitoid versus supracrustal basement to the northeast Thelon Basin around the Kiggavik uranium camp, Nunavut

2013

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“…; Jefferson et al . , , in prep. ; Hunter , oral presentation, Nunavut Mining Symposium; Scott et al .…”

Section: Regional Settingmentioning

confidence: 99%

“…The following descriptions refer to Figs. 1 and 2, and Table 1 (geophysical properties) that list rock types in order of increasing age and provide a summary of recent geological mapping (Calhoun et al 2014;Jefferson et al 2011Jefferson et al , 2015McEwan 2012). Throughout the text, formal names (i.e., Thelon Formation) are capitalized, and informal names are not (i.e., Rumble assemblage).…”

Section: R E G I O N a L S E T T I N Gmentioning

confidence: 99%

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Basement geology beneath the northeast Thelon Basin, Nunavut: insights from integrating new gravity, magnetic and geological data

Tschirhart

Jefferson

Morris

2016

Geophysical Prospecting

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Current models for unconformity‐associated uranium deposits predict fluid flow and ore deposition along reactivated faults in >1.76 Ga basement beneath Mesoproterozoic siliciclastic basins. In frontier regions such as the Thelon Basin in the Kivalliq region of Nunavut, little is known about the sub‐basin distribution of units and structures, making exploration targeting very tenuous. We constructed a geological map of the basement beneath the unconformity by extrapolating exposed features into the subsurface. The new map is constrained by detailed geological, geophysical, and rock property observations of outcrops adjacent to the basin and by aeromagnetic and gravity data over the geophysically transparent sedimentary basin. From rock property measurements, it is clear that the diverse magnetic and density characteristics of major rock packages provide quantitative three‐dimensional constraints. Gravity profiles forward modelled in four cross sections define broad synforms of the Amer Belt and Archean volcanic rocks that are consistent with the structural style outside the basin. Major lithotectonic entities beneath the unconformity include: supracrustal rocks of the Archean Woodburn Lake group and Marjorie Hills meta sedimentary gneiss and associated mixed granitoid and amphibolitic gneiss; the Amer Mylonite Zone and inferred mafic intrusions oriented parallel and sub‐parallel; other igneous intrusions of 2.6 Ga, 1.83 Ga, and 1.75 Ga vintage; and the <2.3 Ga to >1.84 Ga Amer Group. Four main brittle regional fault arrays (040°–060°, 075°–90°, 120°, and 150°) controlled development and preservation of the basin. The reactivated intersections of such faults along fertile basement units such as the Rumble assemblage, Marjorie Hills assemblage, Nueltin igneous rocks, and Pitz formation are the best targets for uranium exploration.

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Spatial distribution and compositional variation of APS minerals related to uranium deposits in the Kiggavik-Andrew Lake structural trend, Nunavut, Canada

Riegler

Quirt²,

Beaufort

2015

Miner Deposita

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Northeast Thelon region geoscience framework - new maps and data for uranium in Nunavut

Cited by 14 publications

References 0 publications

Framework geophysical modelling of granitoid versus supracrustal basement to the northeast Thelon Basin around the Kiggavik uranium camp, Nunavut

Framework geophysical modelling of granitoid versus supracrustal basement to the northeast Thelon Basin around the Kiggavik uranium camp, Nunavut

Basement geology beneath the northeast Thelon Basin, Nunavut: insights from integrating new gravity, magnetic and geological data

Spatial distribution and compositional variation of APS minerals related to uranium deposits in the Kiggavik-Andrew Lake structural trend, Nunavut, Canada

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