EXTECH IV ATHABASCA URANIUM DEPOSIT DATABASE
Geological Survey of Canada, Saskatchewan Industry and Resources, and Alberta Geological Survey


DEPNO COUNTRY LOCATION ALLNAMES COMMODITIES
40043 Canada (Nunavut) 64.20.44 N -- 097.51.54 W End Grid; End Grid deposit U

Database name: Uranium Deposits, Athabasca Basin
Custodial agency: Geological Survey of Canada
Compilers: Sunil S. Gandhi
Release date: 2007-03-02
   
Deposit name(s): End Grid; End Grid deposit
Political location(s): Canada; Province or state: Nunavut; Nearest community: Baker Lake settlement (89.5 km 271°)
NTS map data: 066A05 (Judge Sissons Lake)
Deposit clan (type): Unconformity-associated
Deposit (sub) types: Unconformity-associated - Proterozoic - fracture-bound; fracture-controlled monometallic deposit on the Kiggavik Trend in argillaceous metasiltstones, 200 to 400 m below the eroded sub-Thelon unconformity; deeper parts of the deposit lack clay alteration; Reference: Wallenberg, P., 1994: Update on the Uranium Exploration in the Thelon Basin; In Exploration Overview 1994, Edited by Goff, S. P., Annual Exploration Overview, Department of Indian and Northern Affairs, Canada, Department of Indian and Northern Affairs, Yellowknife, Canada, p. 154 - 155
Deposit status: advanced prospect; Size category: large; Status comments: closely spaced drilling in 1992-'93 outlined the Main zone and two subsidiary zones to the southwest, and provided basis for resource estimation
Geologic province: Churchill - Rae Craton
Geologic subprovince: Amer Fold Belt
Geologic district: Eastern Thelon Basin
Deposit object located: drill hole
Commodities: U
Mineralization styles: vein(s) (mineralization zone); aggregates (mineralization zone); disseminated (mineralization zone)
Geological ages: Late Paleoproterozoic (host rocks)
Middle Mesoproterozoic (mineralization)
Tectonic setting: continental marginal deformation zone-fold belt; transpressive; Formal name: Amer Fold Belt (host rocks)
continental basin-unconformity; stable; Formal name: Thelon Paleosol (host rocks)
continental fault-controlled volcano-sedimentary basins-grabens; divergent; Formal name: Dubawnt Group (country rocks)
continental basin-intracratonic; stable; Formal name: Thelon Formation (country rocks)
Coincident features: fault intersection(s) (the deposit is located at the structurally complex intersection of east-trending North Sissons fault and NE-trending fault-controlled Kiggavik Trend); Coincident feature name: North Sissons Fault and Kiggavik Trend
fault(s) (Ore lenses trend NE along the Kiggavik Trend along dip of host metasiltstones with bedding and foliation dipping gently NE); Coincident feature name: Kiggavik Trend along NE-dipping metasiltstones
unconformity (the Thelon Formation eroded in the deposit area; proximity to the unconformity indicated by effects of lateritic paleoweathering in its basement rocks); Coincident feature name: Sub-Thelon unconformity
Regional tectonic structure: fault (fault-controlled 20 km linear trend hosting 7 uranium deposits, striking NE and gently convex to the NW, between the Thelon and Sissons Lake faults) Tectonic structure name: Kiggavik Trend
fault (ENE-trending normal fault with downfaulted Thelon Formation on the north side against the basement on the south side; parallels the Sissons Lake fault) Tectonic structure name: Thelon fault
fault (ENE-trending normal fault with downfaulted sub-Thelon paleosol on the north side against the basement on the south side; parallels the Thelon fault) Tectonic structure name: Sissons Lake fault
Host rocks: (1) metamorphic; metasedimentary schist (metasiltstones more than 500 m thick; dip 15-25° to the NE); Depositional setting: platform-shelf; Metamorphic grade: greenschist (upper) - amphibolite (lower)
External host rock forms:thin bedded, fine to medium grained, foliated
Host rock protoliths:siltstone-mudstone-shale (probably equivalent of the Early Paleoproterozoic Lower Hurwitz Group to the south deposited on the Rae craton); Host rock protolith name: Judge Sissons Lake Sequence
Internal host rock structures:bedding obscure; greenish grey and buff white beds
Individual lithologies:metasiltstone (drilled to a depth of 500 m; dip gentle but locally steep; mainly somewhat greenish argillaceous and pyritic; garnetiferous sections at deeper levels)
Country rocks: (1) paragneiss-orthogneiss; (older paragneisses SW of the deposit); Country rock name: Archean Basement Complex; Metamorphic grade: amphibolite
Country rock protoliths:platform-shelf sediments (highly deformed and metamorphosed Archean supracrustal sequence of the Rae craton, associated with mafic and felsic orthogneisses); Country rock protolith name: Archean Basement Complex
Individual lithologies:quartzofeldspathic and mafic gneiss (foliated and schistose biotite and/or hornblende bearing felsic gneisses, may include metavolanic rocks; in part migmatized)

(2) meta-arkose & metapelite; (Paleoproterozoic sedimentary sequence; informal name); Country rock name: Judge Sissons Lake sequence; Metamorphic grade: amphibolite - lower
Country rock protoliths:feldspathic wackes, pelites (probably equivalent of the Lower Hurwitz Group to the south deposited on the Rae craton before intrusion of gabbro sills at 2110 Ma ); Country rock protolith name: Judge Sissons Lake sequence
Individual lithologies:meta-arkoses and metapelites (mainly drab green sulphide-bearing biotite-muscovite feldspathic wackes; metapelites and metasemipelites with minor lean oxide facies iron formation)

(3) orthoquartzite; (overlies the feldspathic wacke strata); Country rock name: Amer Group equivalent; Metamorphic grade: greenschist - upper
Country rock protoliths:supermature sandstone (similar to the basal orthoquartzite of the late Paleoproterozoic Amer Group to the north and northeast; possible unconformity with feldspathic wackes ); Country rock protolith name: Amer Group equivalent
Individual lithologies:orthoquartzite (scattered outcrops in the area 10 km to the NNE and NE of the deposit; comformable with the meta-pelite and meta-arkose; affected by paleoweathering)

(4) granite; (intrusions in the metasedimentary strata); Country rock name: Hudsonian Granites; Metamorphic grade: unmetamorphosed
Country rock protoliths:granite-granodiorite (intrusive into metasediments; probably equivalent of Hudsonian granites emplaced during 1860-1760 Ma: includes a fluorite granite stock at the deposit); Country rock protolith name: Hudsonian Granites
Individual lithologies:granite-granodiorite-monzonite (massive to gneissic; includes some diorite, syenite and porphyries of uncertain age)

(5) clastic sediments and potassic volcanics; (sedimentary-volcanic sequence deposited in the post-Hudsonian fault-controlled Baker Lake basin); Country rock name: Dubawnt Group; Metamorphic grade: unmetamorphosed
Country rock protoliths:clastic sediments and potassic volcanics (basal red conglomerate-arkose-siltstone beds; subaerial potassic mafic-intermediate flows; upper dacite-rhyolite flows; related subvolcanic intrusions); Country rock protolith name: Dubawnt Group
Individual lithologies:clastic red beds & K-rich volcanics (deposited 1.84-1.75 Ga; alluvial fan-braided stream sediments; extensive subaerial trachytic basalt and andesite, trachyte; rhyolite with minor dacite)

(6) paleo-regolith; (lateritic weathering); Country rock name: Thelon Paleosol; Metamorphic grade: unmetamorphosed
Country rock protoliths:gneisses, granites and supracrustal strata (profile up to 50 m thick; deeper along faults; weathering effects vary on different rock types); Country rock protolith name: sub-Thelon basement
Individual lithologies:Lateritic (hematization in the upper part of weathered zone; locally bleached; kaolinite is abundant in the zone and occurs as clay-clasts in the sandstone above)

(7) conglomerate-sandstone; (siliciclastic sediments; undeformed; present area 85000 sq km and thickness 1.3 km); Country rock name: Thelon Formation; Metamorphic grade: unmetamorphosed
Country rock protoliths:conglomerate-pebbly sandstone-siltstone (basal conglomerate unit with pebbly sandstone and siltstone beds; succeeded by mature sandstone, quartz arenite and lithic subarenite-siltstone units); Country rock protolith name: Thelon Formation
Individual lithologies:conglomerate-sandstone-siltstone (basal unit with matrix of quartz, authigenic clay, diagenetic illite and fluorapatite; overall fining upward sequence; fluvial transport east to west)
conglomerate-sandstone-siltstone (basal unit with matrix of quartz, authigenic clay, diagenetic illite and fluorapatite; overall fining upward sequence; fluvial transport east to west)

(8) diabase dyke; (northwest-trending, vertical or very steep dykes); Country rock name: Mackenzie diabase dyke swarm; Metamorphic grade: unmetamorphosed
Country rock protoliths:gabbroic magma (part of the largest dyke swarm in the world, related to the 1.27 Ga Mackenzie magmatic events); Country rock protolith name: Mackenzie diabase dyke swarm
Individual lithologies:diabase (medium to coarse grained gabbro-quartz gabbro; chilled at dyke margins; unaltered or little altered)
Metallogenic signatures: U
Alteration signatures: argillic alteration: sericite-illite plus kaolinite; 'white' alteration; What was altered: feldspars and mica in host rocks
hematization: red colouration; local development of redox front; What was altered: mafic silicates and iron oxides in host rocks
silicification: deposition of secondary quartz; What was altered: fractures and breccia zones
Mineralogy: (alteration): hematite, clay minerals, chlorite
(concentrations at intersecting fractures): pitchblende
(local intense fracturing and brecciation): quartz - secondary
(secondary alteration): secondary U minerals
(veins and disseminations): pyrite
(veins, aggregates, blebs and disseminations): pitchblende
Deposit shape: main zone
Deposit dimensions:length: 350 metre
width: 75 metre
height: 50 metre
Qualified comments: (Applies to: discovery and development) The deposit was discovered in 1987 by drill testing of a -0.5 milligal gravity anomaly. Drilling continued in 1988-1989. It was intensified in 1991 when 30 holes totaling 10951 m were drilled, which confirmed the mineralized zone as deposit. Drilling continued at reduced level during 1992-1993. A total of 54 holes about 50 m apart outlined the Main zone and two smaller ones 160 m to the SW. The Main zone is 350 x 75 m in plan, trends NE and occurs at a depth of 200-365 m, shallowing to the NE. It coincides with the gravity anomaly. One of the subsidiary zones to the southwest is 200 x 75 m in plan and the other on its south side is 100 x 25 m; both trend NE. The hole End 41 drilled in 1991 vertically to 425 m intersected mineralization from 277 to 366 m, with the best grade of 0.8 % U over 13.4 m. This makes the End Grid deposit the deepest one of the several along Kiggavik Trend. Drill indicated resources as of 1994 stood at 3.368 Mt averaging 0.308 % U in the Main zone, and 0.354 Mt grading 0.306 % U in two Southwestern zones, based on cut-off grade of 0.2 % U and 2.5 t per cu m of ore.

(Applies to: mineralization) The deposit is fracture-controlled and essentially monometallic like the Kiggavik Main zone; it is localized 200-400 m below the eroded sub-Thelon unconformity, hence their genetic relation is obscure. The deeper part of the deposit is in rocks that have not been bleached, argillized nor hematized, and are of normal density; the Lower lens of Andrew Lake deposit 1 km to the SW is similar in character.

(Applies to: reserve/resource descriptions) Drill indicated resources as of 1994: 3.368 Mt averaging 0.308 % U in the Main zone, and 0.354 Mt grading 0.306 % U in two Southwestern zones, based on cut-off grade of 0.2 % U and 2.5 t / cu m of ore.
Links to other databases: NUMIN; Key value: 066ASW0021
Geophysical-chemical signature: Signature type: Ground Gravity; Response type: negative (weak)
Signature type: Ground EM; Response type: positive (moderate)
References:
Bundrock, G., 1981
From Armchair Geology to a Deposit in a New Uranium Province
In Uranium Exploration Case Histories: Proceedings of an Advisory Group Meeting, Vienna, 26-29 November 1979, Edited by Anonymous, Proceedings Series (STI/PUB), International Atomic Energy Agency, Vienna, International Atomic Energy Agency, Vienna, 584, 407 p., p. 243 - 277

Cecile, M. P., 1973
Lithofacies Analysis of the Proterozoic Thelon Formation, Northwest Territories (including Computer Analysis of
M. Sc. Thesis, M. Sc. Thesis (unpublished), Carleton University, Ottawa, 119 p..

Fraser, J. A.; Donaldson, J. A.; Fahrig, W. A.; Tremblay, L. P., 1970
Helikian Basins and Geosynclines of the Northwestern Canadian Shield
In Symposium on the Basins and Geosynclines of the Canadian Shield, Edited by Baer, A. J., Paper, Geological Survey of Canada, 70-40, 265 p., p. 213 - 238

Fuchs, H.; Hilger, W.; Prosser, E., 1986
Geology and Exploration History of the Lone Gull Property
5, Section Other Helikian Unconformity-associated and Sedimentary-hosted Deposits, In Uranium Deposits of Canada, Edited by Evans, E. L., Special Volume, The Canadian Institute of Mining and Metallurgy, The Canadian Institute of Mining and Metallurgy, 33, 323 p., p. 286 - 292

Fuchs, H. D.; Hilger, W., 1989
Kiggavik (Lone Gull): An Unconformity Related Uranium Deposit in the Thelon Basin, Northwest Territories, Canada
In Uranium Resources and Geology of North America, Edited by Anonymous, TECDOC, International Atomic Energy Agency, Vienna, International Atomic Energy Agency, Vienna, Austria, 500, 529 p., p. 429 - 454

Gall, Q., 1994
The Proterozoic Thelon Paleosol, Northwest Territories, Canada
Precambrian Research, Volume 68, p. 115 - 137

Gandhi, S. S., 1989
Geology and Uranium Potential of the Thelon Basin and Adjacent Basement in Comparison with the Athabasca Basin Region
In Uranium Resources and Geology of North America, Edited by Anonymous, TECDOC, International Atomic Energy Agency, Vienna, International Atomic Energy Agency, Vienna, Austria, 500, 529 p., p. 411 - 428

Gandhi, S. S., 1995
An Overview of the Exploration History and Genesis of Proterozoic Uranium Deposits in the Canadian Shield
Exploration and Research for Atomic Minerals, Department of Atomic Energy, India, Volume 8, p. 1 - 48

Goff, S. P. Editor(s)), 1994
Exploration Overview 1994
Annual Exploration Overview, Department of Indian and Northern Affairs, Canada, Department of Indian and Northern Affairs, Yellowknife, Canada

Hasegawa, K.; Davidson, G. I.; Wallenberg, P.; Iida, Y., 1990
Geophysical Exploration for Unconformity-related Uranium Deposits in the Northeastern Part of Thelon Basin, Northwest Territories, Canada
Mining Geology, Volume 40, p. 83 - 95

LeCheminant, A. N.; Heaman, L. M., 1989
Mackenzie Igneous Events, Canada: Middle Proterozoic Hotspot Magmatism Associated with Ocean Opening
Earth and Planetary Science Letters, Volume 96, p. 38

Miller, A. R.; LeCheminant, A. N., 1985
Geology and Uranium Metallogeny of Proterozoic Supracrustal Successions, Central District of Keewatin, N.W. T. with Comparisons to Northern Saskatchewan
Chapter 3, Section Other Canadian Deposits, In Geology of Uranium Deposits, Edited by Sibbald, T. I. I.; Petruk, W., Special Volume, The Canadian Institute of Mining and Metallurgy, The Canadian Institute of Mining and Metallurgy, 32, 268 p., p. 167 - 185

Miller, A. R.; Cumming, G. L.; Krstic, D., 1989
U-Pb, Pb-Pb, and K-Ar Isotopic Study and Petrography of Uraniferous Phosphate-bearing Rocks in the Thelon Formation, Dubawnt Group, Northwest Territories, Canada
Canadian Journal of Earth Sciences, Volume 26, p. 867 - 880

Patterson, J. G., 1986
The Amer Belt: Remnant of an Aphebian Foreland Fold and Thrust Belt
Canadian Journal of Earth Sciences, Volume 23, p. 2012 - 2023

Ross, G. M., 2000
Proterozoic Stratigraphy of Western Canada: A Short Review
9, In Fluids and Basin Evolution, Edited by Kyser, K., Short Course Series Volume, The Mineralogical Association of Canada, The Mineralogical Association of Canada, 28, 262 p., p. 211 - 224

Wallenberg, P., 1994
Update on the Uranium Exploration in the Thelon Basin
In Exploration Overview 1994, Edited by Goff, S. P., Annual Exploration Overview, Department of Indian and Northern Affairs, Canada, Department of Indian and Northern Affairs, Yellowknife, Canada, p. 154 - 155

Wright, G. M., 1967
Geology of the Southeastern Barren Grounds (350)
Memoir, Geological Survey of Canada, Geological Survey of Canada, Publication code 350, 91 p., 1 maps.

Resource data:
Disclaimer - Reserves/Resource Data

Her Majesty the Queen in Right of Canada, represented by the Minister of Natural Resources (NRCan) does not warrant or guarantee the accuracy, completeness or fitness for any purpose of Reserve and Resource information (Data) contained in this database, including whether the Data is compliant with any securities regulations or standards, and NRCan does not assume any liability with respect to any damage or loss incurred as a result of the use made of the Data.

Resource and reserve figures are historical in nature. The Data source provided with each set of figures should be cited if the Data are re-reported.

Estimate date: 1994; 3.722 million metric tons ore; Combined with production?: no; Provisional entry?: no; Resource category: inferred
Grade-commodity information:U: 0.308 percent
weight-commodity information:U: 11,463 metric ton
Reference: Wallenberg, P., 1994: Update on the Uranium Exploration in the Thelon Basin; In Exploration Overview 1994, Edited by Goff, S. P., Annual Exploration Overview, Department of Indian and Northern Affairs, Canada, Department of Indian and Northern Affairs, Yellowknife, Canada, p. 154 - 155
Percent weights allocated to deposit: 100.0%

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