Outcrop and remote predictive geology of the Amer Belt and basement beside and beneath the northeast Thelon Basin, in parts of NTS 66-A, B, C, F, G and H, Kivalliq Region, Nunavut

Jefferson, C W; White, J.C.; Young, Grant M.; Patterson, Joseph E.; Tschirhart, V; Pehrsson, S J; Calhoun, Lydia; Rainbird, R H; Peterson, T D; Davis, W J; Tella, S; Chorlton, L B; Scott, J M J; Morris, William A.; Keating, Pierre; Anand, A; Shelat, Yask; MacIsaac, D. A.

doi:10.4095/296825

Cited by 12 publications

(30 citation statements)

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“…; Jefferson et al . ). The Hudson Suite forms thick, gently west‐dipping slabs of the magnetically intense Schultz Lake Intrusive Complex (SLIC; Miller and Peterson ; Scott et al .…”

Section: Regional Settingmentioning

confidence: 97%

“…; Tschirhart, Morris, and Jefferson c) that intrudes the Neoarchean Marjorie Hills assemblage on the southeast side of the sub‐basin (Jefferson et al . ).…”

Section: Regional Settingmentioning

confidence: 97%

“…), and upper Itza Lake formations (Jefferson et al . ). Their high magnetic susceptibilities are caused by layers of abundant disseminated euhedral magnetite within siltstone.…”

Section: Regional Settingmentioning

confidence: 97%

“…The early Paleoproterozoic Amer and Ketyet River groups are essentially correlative (Jefferson et al . ), underlie the strata described above, are locally intruded by Hudson and Nueltin granitoid rocks, and are structurally intercalated with older rocks. However, they occupy discrete belts separated from each other by Archean rocks and multiple faults.…”

Section: Regional Settingmentioning

confidence: 99%

“…a; Jefferson et al . )—their relative ages are undefined. Large SIS plutons are visible on the aeromagnetic map as high amplitude, broad oval anomalies exceeding 50 km width in places (Fig.…”

Section: Regional Settingmentioning

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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“…; Jefferson et al . ). The Hudson Suite forms thick, gently west‐dipping slabs of the magnetically intense Schultz Lake Intrusive Complex (SLIC; Miller and Peterson ; Scott et al .…”

Section: Regional Settingmentioning

confidence: 97%

“…; Tschirhart, Morris, and Jefferson c) that intrudes the Neoarchean Marjorie Hills assemblage on the southeast side of the sub‐basin (Jefferson et al . ).…”

Section: Regional Settingmentioning

confidence: 97%

“…), and upper Itza Lake formations (Jefferson et al . ). Their high magnetic susceptibilities are caused by layers of abundant disseminated euhedral magnetite within siltstone.…”

Section: Regional Settingmentioning

confidence: 97%

Section: Regional Settingmentioning

confidence: 99%

Section: Regional Settingmentioning

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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Geochemistry and geochronology of the Kiggavik uranium deposit, Nunavut, Canada

et al. 2020

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Geochemistry of magnetite and hematite from unmineralized bedrock and local till at the Kiggavik uranium deposit: Implications for sediment provenance

Makvandi

Beaudoin

McClenaghan

et al. 2017

Journal of Geochemical Exploration

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The petrography and mineral chemistry of magnetite and hematite from igneous, metasedimentary, and sedimentary bedrock in the area of the Kiggavik unconformity-related uranium deposit, and from till covering the deposit were investigated using optical microscopy, scanning electron microscopy (SEM), electron probe micro-analyzer (EPMA), and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The R-package rob-Compositions method was used to treat censored values in the EPMA and LA-ICP-MS geochemical data, and the results were transformed using a centered log-ratio transformation prior to data analysis using partial least squares-discriminant analysis (PLS-DA). The Kiggavik rock samples are from a wide range of lithologies including granite, leucogranite, syenite, metagreywacke, quartzite, and quartz arenite. The integration of petrography and mineral chemistry identifies four origins for iron oxides in the Kiggavik bedrocks: magmatic, hydrothermal, diagenetic, and weathering. The igneous bedrocks mainly contain magmatic magnetite replaced by mostly hydrothermal and rarely by weathering related hematite. Higher concentrations of trace elements such as Mg, Al, Ti, and Zr in hydrothermal hematite from leucogranite, granite and Martell syenite relative to parent magnetite suggest that hematite crystallized from high-temperatures hydrothermal fluids. By contrast, relative trace elements depletion in hematite replacing V-Cr-rich magnetite from Schultz Lake Intrusive Complex syenite may indicate hematite precipitation from low-temperature oxidizing fluids. The high U content (450 ppm averagely), rounded shape, and altered edges of hematite grains from metagreywacke indicate that the iron oxide is detrital, originally precipitated from U-rich hydrothermal fluids. Quartzite also contains hydrothermal hematite. Distinct chemical compositions of hydrothermal hematite from Kiggavik metasedimentary and igneous basement demonstrate different compositions and temperatures of parental hydrothermal fluids, as well as different compositions of replaced minerals/host rocks.

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Outcrop and remote predictive geology of the Amer Belt and basement beside and beneath the northeast Thelon Basin, in parts of NTS 66-A, B, C, F, G and H, Kivalliq Region, Nunavut

Cited by 12 publications

References 0 publications

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

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

Geochemistry and geochronology of the Kiggavik uranium deposit, Nunavut, Canada

Geochemistry of magnetite and hematite from unmineralized bedrock and local till at the Kiggavik uranium deposit: Implications for sediment provenance

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