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


DGNO COUNTRY LOCATION ALLNAMES COMMODITIES
40002 Canada (Saskatchewan) 58.22.35 N -- 109.32.00 W Cluff Lake deposits; Cluff Lake mines; Cluff Lake Project U; Au; Se; Bi; Ni; Co

Database name: Uranium Deposits, Athabasca Basin
Custodial agency: Geological Survey of Canada
Compilers: Sunil S. Gandhi
Release date: 2007-03-02
   
Deposit group name(s): Cluff Lake deposits (occurrence name); Cluff Lake mines (mine name); Cluff Lake Project (mine name)
Political location(s): Canada; Province or state: Saskatchewan; Nearest community: La Ronge (555 km NW)
NTS map data: 074K05 (Cluff Lake)
Deposit clan (type): Unconformity-associated
Deposit (sub) types: Unconformity-associated - Proterozoic - fracture-bound; most of the deposits are basement-hosted close to the sub-Athabasca Group unconformity; others are in overlying siliclastic beds; basement structural complexity compounded by Carswell meteorite impact; Reference: Koning, E., 2006: The Cluff Lake Deposits, West Athabasca Basin, Saskatchewan, Canada; In Field Trip 3: Cluff Lake and Shea Creek Deposits; September 13-14; 2006 CIM Field Conference; Uranium: Athabasca Deposits and Analogues, Edited by Koning, E.; Robbins, J.; Carroll, J., Field Trip Guidebook, Canadian Institute of Mining and Metallurgy, CIM Geogolical Society, Saskatoon Section, 48 p., p. 1 - 32
Deposit group status: past producer; Size category: large; Status comments: production from 5 open pits and 5 underground mines at Cluff Lake during 1979-2002; high grade D orebody mined in first 2 years; others mined after 1984; milling done at site, with some gold recovery
Geologic province: Rae Craton
Geologic subprovince: Taltson-Thelon Magmatic Zone
Geologic district: Western Athabasca Basin / Carswell Impact Crater
Deposit object located: deposit centre (surface proj.)
Commodities: U; Au; Se; Bi; Ni; Co
Mineralization styles: fracture fillings (mineralization zone); massive (mineralization zone); dissemination (mineralization zone)
Geological ages: Middle Paleoproterozoic - Middle Mesoproterozoic (mineralization)
Middle Paleoproterozoic - Early Mesoproterozoic (host rocks)
Tectonic setting: continental craton-basin; stable; Formal name: Athabasca Basin (host rocks)
Coincident features: unconformity (most of the deposits are basement-hosted close to the sub-Athabasca Group unconformity, which was structurally disrupted during the meteorite impact); Coincident feature name: Sub-Athabasca Group Unconformity
fault intersection(s) (mineralization is controlled mainly at intersections of the steep, northerly trending major faults and their subsidiary faults at low angle to them); Coincident feature name: basement faults and subsidiary fractures
Regional tectonic structure: domal structures related to one or both major thermotectonic events during 2.3-2.2 Ga and 2.1-1.9 Ga (uranium deposits occur within a few hundred metres of the domes of orthogneiss complex in the surrounding paragneiss complex) Tectonic structure name: Earl River Gneiss domes
Host rocks: (1) metamorphic; paragneiss (mainly the meta-arkosic rocks of the Peter River gneiss, including their mylonitized equivalents, host majority of the deposits of Cluff Lake group); Depositional setting: shallow marine; Metamorphic grade: amphibolite; Component: basement at unconformity
External host rock forms:gneissic
Host rock protoliths:arkose (close to boundary with the Earl River orthogneiss complex; part of the basement of Athabasca Group); Host rock protolith name: Peter River Gneiss
Internal host rock structures:foliated
Individual lithologies:quartzofeldspathic gneiss (variable contents of mafic silicates; in part mylonitised)
Host rock stratigraphy:Peter River Metamorphic Suite

(2) sedimentary; siltstone-conglomerate (a few deposits of the group have mineralized remnants of basal siliciclastic beds of Athabasca Group and of underlying paleoregolith); Depositional setting: continental; Metamorphic grade: unmetamorphosed; Component: above unconformity
External host rock forms:tabular sedimentary body
Host rock protoliths:sandstone-conglomerate; Host rock protolith name: Athabasca Group
Internal host rock structures:fine grained to coarse
Individual lithologies:sandstone
Host rock stratigraphy:Athabasca Group
Country rocks: (1) gneiss; (Earl River, Peter River and Transition gneisses form the Cluff Lake series of the southwest part of the 18 km diameter core of the Carswell Structure); Country rock name: Earl River Gneiss; Metamorphic grade: amphibolite - upper
Country rock protoliths:mafic volcanics (mainly calc-alkaline volcanic rocks and some related sedimentary rocks, as indicated by chemical data; minor komatiites; indications of K-metasomatism); Country rock protolith name: Earl River Gneiss
Individual lithologies:amphibolite (mixed feldspathic gneisses, ranging from granitoid to biotite-rich, some with hypersthene; and mafic two pyroxene granulite and amphibolitic gneisses)
paragneiss (mixed feldspathic gneisses, ranging from granitoid to biotite-rich, some with hypersthene; and mafic two pyroxene granulite and amphibolitic gneisses)

(2) gneiss; (garnetiferous granitoid gneisses transitional between the volcanic-dominated Earl River gneisses and sediment-dominated aluminous Peter River gneisses); Country rock name: Transition Gneiss; Metamorphic grade: amphibolite - upper
Country rock protoliths:arkose-siltstone-mudstone (chemical data indicate shale and arkose protoliths; most rocks appear to be non-equilibrium melting products with xenolithic aluminous restite phases); Country rock protolith name: Transition Gneiss
Individual lithologies:granitoid (70 to 90 % felsic minerals; varying amounts of potash feldspar, oligoclase, quartz, biotite, garnet, with minor amounts of cordierite and sillimanite)

(3) gneiss; (compositionally banded mafic and intermediate aluminous gneisses; stratigraphically lower intermediate gneisses grade below into the Transition Gneiss); Country rock name: Peter River Gneiss; Metamorphic grade: amphibolite - upper
Country rock protoliths:arkose-siltstone-mudstone (chemical data indicate derivation of mafic gneiss from shale and of intermediate gneiss form shale and arkose; the latter grade into Transition Gneiss); Country rock protolith name: Peter River Gneiss
Individual lithologies:garnet-cordierite gneiss (main phases are garnet, cordierite, sillimanite, biotite, K-feldspar and quartz; in the mafic gneisses the aluminous minerals exceed 50 % of the rock)

(4) gneiss; (Northern Aluminous Gneisses and Charnokitic Complex comprise the Carswell Lake series of the northeast part of the core of Carswell circular structure); Country rock name: Northern Aluminous Gneisses; Metamorphic grade: amphibolite - upper
Country rock protoliths:arkose-siltstone-mudstone (mafic and intermediate gneisses comparable with those in Peter River Gneisses; hence protolith similar; a few granitic bands occur throughout the unit); Country rock protolith name: Northern Aluminous Gneisses
Individual lithologies:garnet-cordierite gneiss (banded gneiss with garnet, cordierite, sillimanite, biotite, K-feldspar, quartz and oligoclase; cordierite altered to pinnite or replaced by sericite)

(5) gneiss; (Comparable to the Earl River Gneiss but with fewer granitoids; includes granodiorite, diorite and alkali gabbro phases characterized by two pyroxenes); Country rock name: Charnokitic Complex; Metamorphic grade: amphibolite (upper) - granulite
Country rock protoliths:mafic volcanics (mainly calc-alkaline volcanic and related sedimentary rocks, as in case of the Earl River Gneiss; geochronological data indicate Paleoproterozoic age); Country rock protolith name: Charnokitic Complex

(6) sandstone-conglomerate; (remnants of sandstone in core of the Carswell structure; rimmed outward by conglomerate, sandstone-siltstone and dolostone units more than 400m thick); Country rock name: Athabasca Group; Metamorphic grade: unmetamorphosed
(7) sandstone-shale; (Inner rim around the basement core is 5 km wide, and comprises highly disturbed, inverted and thrusted strata of a local subgroup of Athabasca Group); Country rock name: William River Subgroup; Metamorphic grade: unmetamorphosed
(8) mudstone-dolostone; (Inner rim around the basement core is 5 km wide, and comprises highly disturbed, inverted and thrusted strata of a local subgroup of Athabasca Group); Country rock name: Upper Athabasca Group; Metamorphic grade: unmetamorphosed
Metallogenic signatures: U
U-Au
U-Ni-Co-As
Alteration signatures: illite alteration: illite; What was altered: basement gneiss and sandstone at unconformity; Component: basement at unconformity
chlorite alteration: Mg-chlorite ; What was altered: mafic silicates; Component: basement mineralization
Mineralogy: (alteration - undifferentiated / mineralization zone): hydrocarbon
(alteration - undifferentiated / alteration halo): chlorite, illite, dravite, quartz
(alteration - undifferentiated / mineralization zone): hematite
(alteration - undifferentiated / regional alteration): kaolinite
(mineralization / mineralization zone): uraninite, pitchblende, gold, galena, clausthalite, chalcopyrite, pyrite, marcasite, brannerite
Radiometric ages: Object dated: country rocks(1); Age - Ma: 2,320; +20; -20; Dating method: U-Pb; Concentrate: zircon; Source rock: quartzofeldspathic gneiss; Formal name: Earl River complex south of DP deposit (?); Event dated: country rock; Interpretive comment: age reflects a 2.3-2.2 Ga old tectonic event on west side of Rae craton (Bostock and Breemen, 1994); Reference: Bell, K., 1985: Geochronology of the Carswell Area, Northern Saskatchewan; In The Carswell Structure Uranium Deposits, Saskatchewan, Edited by Lainé, R.; Alonso, D.; Svab, M., Special Paper, Geological Association of Canada, Geological Association of Canada, 29, 230 p., p. 33 - 46

Object dated: country rocks(1); Age - Ma: 2,130; +22; -22; Dating method: U-Pb; Concentrate: zircon; Source rock: quartzofeldspathic gneiss; Formal name: uncertain; Event dated: country rock; Interpretive comment: age reflects collision of the Slave and Rae cratons during the Taltson-Thelon Orogeny 2.1-1.9 Ga ago; Reference: Bell, K., 1985: Geochronology of the Carswell Area, Northern Saskatchewan; In The Carswell Structure Uranium Deposits, Saskatchewan, Edited by Lainé, R.; Alonso, D.; Svab, M., Special Paper, Geological Association of Canada, Geological Association of Canada, 29, 230 p., p. 33 - 46
Qualified comments: (Applies to: discovery and development) Deposits of the group were discovered over the period 1969-1995. They occur in an oval area about 4.5 long in WNW direction and 2.5 km wide. Initial exploration was done by Mokta (Canada) Ltd. (later Amok Ltd.), owned by three French companies, namely Compagnie Générale des Matières Nucléaires (Cogema), Compagnie Française de Mokta and Pechiney. The company had been exploring in Canada since 1963, and conducted an airborne radiometric survey in Cluff Lake area in 1967. Follow-up detailed airborne scintillometer survey and intensive surface exploration led to the discovery of the deposits that outcropped or were beneath extensive glacial drift. The first discoveries in 1969 were of the D and N deposits. Others found subsequently are as follows: OP in 1970, Claude in 1971, the largest Dominique-Peter (DP) in 1981, Dominique-Janine North (DJN) in 1984, DJ Extension or South (DJX) in 1986, and West DJ, West West DJ (WDJ and WWDJ) and DJ North and South Pods in 1995. Ten deposits were mined during 1979-2002, 5 by open pit and 5 underground. Mine-mill complex started in 1979 with open pitting of the high grade D ore body. It was depleted in 1980, but ore was processed till 1984 and gold from leach tailings was extracted in 1987-'88. Second phase of mining started in 1983, with Claude open pit and OP underground mine, operated by Cogema Resources Canada Inc. (Areva Resources Canada Inc. since 2006). Depletion of OP in 1985, was overlapped by production from DP underground mine in 1984 that lasted till 2000. Closure of the Claude open pit in 1989 was followed immediately by opening of the DJN open pit, which was mined out by the end of 1991. The DJX open pit produced ore during 1994-'97. The DJU underground mine, which was accessed by a decline, operated during 1996-2000. The last phase of 1999-2002 involved WDJ and WWDJ underground mines accessed from the DJU decline, and the DJ North Pod open pit. The ore was processed through 2003, followed by reclamation work.

(Applies to: regional geology) The Cluff Lake deposits occur in the Carswell meteorite-impact crater 39 km in diameter. Its core zone is 18 km in diameter and comprises Paleoproterozoic crystalline basement uplifted more than 1 km through the Mesoproterozoic Athabasca Group. It has tangential faults at the perimeter and offsetting radial faults. Inner rim around the core is 5 km wide, and has highly disturbed, inverted and thrusted siliciclastic strata of the basal Fair Point and Lazenby Lake formations of the group. Remnants of these strata occur in the core zone, with unconformity and related paleosol preserved in some places. These and the basement rocks are intruded by the impact-related bodies of fused melt called the Cluff Breccias. K-Ar ages on the breccias range from 518 to 385 Ma. Outer two rims of the crater are of the Douglas and Carswell Formations, of mudstone-siltstone and dolostone, respectively, whose combined thickness is about 800 m. The uranium deposits are clustered in the southwest part of the core zone, and are hosted mainly the by the gneisses and in some places by the Athabasca Group. The gneisses comprise the Earl River, Peter River and Transitional Gneiss complexes. The Earl River complex includes amphibolite and paragneiss ranging from granitoid to biotite-rich, and some mafic, two pyroxene granulite. It is derived mainly from calc-alkaline volcanic rocks, associated sedimentary rocks and minor komatiites. The younger Peter River complex includes compositionally banded mafic and intermediate aluminous gneisses, characterized by garnet and cordierite. It is derived from an arkose-siltstone-mudstone sequence. The meta-arkoses grade into the granitoid Transitional Gneiss between the Earl River and Peter River gneisses. The gneisses in the northeast part of the core zone are comparable to them but are of higher metamorphic grade. U-Pb zircons ages of two quartzofeldspathic gneisses of unknown origin from the core zone are 2.32 and 2.13 Ga.

(Applies to: regional structure) The gneissic core of the Carswell Structure is part of the western Lloyd Domain of the Rae Craton, which evolved with two major thermotectonic events during 2.3-2.2 Ga and 2.1-1.9 Ga. These events are attributed to terrane accretions at the west margin of the craton. The better known younger event is the accretion of the Buffalo Head Terrane and Slave Craton during the Taltson-Thelon Orogeny. The 1.92-1.80 Ga Trans-Hudson orogeny may have had some effects in the Cluff Lake area that are not readily apparent. The deposit area has a roughly equal proportion of high grade orthogneisses of the Earl River complex and paragneisses of the Peter River complex. Three phases of ductile deformation are recognized in them: the S1 gneissic foliation, which is isoclinally folded about gently plunging F2 axes, followed by D3 deformation characterized by open, doubly plunging folds with north-trending, steeply dipping axial surfaces. Brittle deformation is associated with the D3 event. The Earl River complex forms three domal structures in areas of the West Claude, Dominique-Peter (DP) and N-OP deposits. The domes apparently intrude the Peter River gneisses. The middle dome in the DP area is draped by a mylonitic zone along the boundary with the Peter River gneisses. The structural framework of the gneissic core is apparently little affected by the Carswell meteorite impact, and near the centre of the crater they are surprisingly undisturbed. The paragneisses are dominantly quartzofeldspathic, and include pelitic migmatite to diatexite, rare oxide to silicate facies iron formation, and coarse grained mafic to ultramafic rocks. They are lithologically comparable with the metasediments intersected in drill holes at the Shea Creek deposits 15 km to the south, outside the Carswell Structure. They represent a supracrustal sequence broadly similar to that seen in other parts of the Lloyd Domain to the south, and to the Murmac Bay Group at Lake Athabasca to the northeast.

(Applies to: mineralization) Deposits of this group are at or very close to the sub-Athabasca Group unconformity, in a position they might have been before the metamorphic core was uplifted by the Carswell meteorite impact. They include the sandstone-hosted D deposit, which occurs at the overturned unconformity, and the DJ North deposit that contains slivers of sandstone and regolith. These deposits have complex ore mineralogy that includes uranium minerals with varying amounts of Co-Ni arsenides, Au, Bi, Se and Te minerals, and some base metal sulphides. Other deposits are basement-hosted vein-type and mineralogically simple. They contain essentially uranium minerals, except for the DP deposit that has complex mineralogy. The main alteration minerals common to all deposits are illite and Mg-chlorite. The favourable basement rocks are at or close to the boundary between the Earl River gneissic domes and the Peter River paragneisses. The Dominique dome at north end of Cluff Lake has the OP, DP and Claude deposits on its east side along a well developed mylonite zone trending north-northwest, and the Dominique-Janine (DJN, DJX, DJU, North Pod) deposits on its west side in a long north-trending fault zone. Mineralization is localized mainly at intersection of steep major faults with subsidiary faults at low angles. At the DP deposit, it is in the openings created by later listric normal faults. Mylonitization at the D, Claude and DJN deposits have formed zones of ellipsoidal balls of host rocks sandstone or gneiss (zone à boules), which are wrapped in clay and ore. The WDJ, WWDJ and West Claude vein systems are farther west from the main DJ trend and parallel to it. The N and the smaller R and F occurrences nearby are on the east side of another dome east of the Dominique dome. Mineralization in these and the Claude deposit occurs along gently dipping shear zones subsidiary to the major steep faults. Isotopic ages on uranium minerals have yielded the oldest ages in 1050 to 1300 Ma range, and younger ones from 300 to 400 Ma.
Links to other databases: SMDI; Key value: 1150a
SMDI; Key value: 1150b
SMDI; Key value: 1151
SMDI; Key value: 1173a
SMDI; Key value: 2153
SMDI; Key value: 2154
Geophysical-chemical signature: Signature type: Airborne Radiometrics; Response type: positive (moderate)
Signature type: Ground Radiometrics; Response type: positive (strong)
Signature type: Ground IP Resistivity; Response type: positive
References:
Baudemont, D.; Fedorowich, J., 1996
Structural Control of Uranium Mineralization at the Dominique-Peter Deposit, Saskatchewan, Canada
Economic Geology, Volume 91, p. 855 - 874

Bell, K., 1985
Geochronology of the Carswell Area, Northern Saskatchewan
In The Carswell Structure Uranium Deposits, Saskatchewan, Edited by Lainé, R.; Alonso, D.; Svab, M., Special Paper, Geological Association of Canada, Geological Association of Canada, 29, 230 p., p. 33 - 46

Bostock, H. H.; van Breemen, O., 1994
Ages of Detrital and Metamorphic Zircons and Monazites from a Pre-Taltson Magmatic Zone Basin at the Western Margin of Rae Province
Canadian Journal of Earth Sciences, Volume 31, p. 1353 - 1364

Koning, E., 2006
The Cluff Lake Deposits, West Athabasca Basin, Saskatchewan, Canada
In Field Trip 3: Cluff Lake and Shea Creek Deposits; September 13-14; 2006 CIM Field Conference; Uranium: Athabasca Deposits and Analogues, Edited by Koning, E.; Robbins, J.; Carroll, J., Field Trip Guidebook, Canadian Institute of Mining and Metallurgy, CIM Geogolical Society, Saskatoon Section, 48 p., p. 1 - 32

Lainé, R., 1985
Conclusion: the Carswell Uranium Deposits - An Example of Not So Unique Unconformity-Related Uranium Mineralization
In The Carswell Structure Uranium Deposits, Saskatchewan, Edited by Lainé, R.; Alonso, D.; Svab, M., Special Paper, Geological Association of Canada, Geological Association of Canada, 29, 230 p., p. 225 - 230

Lainé, R.; Alonso, D.; Svab, M. Editor(s)), 1985
The Carswell Structure Uranium Deposits, Saskatchewan
Special Paper, Geological Association of Canada, Geological Association of Canada, 29, 230 p..

Lainé, R. T., 1986
Uranium Deposits of the Carswell Structure
Chapter 4, Section Saskatchewan Unconformity-associated and Sedimentary-hosted Deposits of Helikian Age, 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. 155 - 169

Ramaekers, P.; Jefferson, C. W.; Yeo, G. M.; Collier, B.; Long, D. G. F.; Drever, G.; McHardy, S.; Jiricka, D.; Cutts, C.; Wheatley, K.; Catuneanu, O.; Bernier, S.; Kupsch, B.; Post, R., 2007
Revised geological map and stratigraphy of the Athabasca Group, Saskatchewan and Alberta
In EXTECH IV: Geology and Uranium EXploration TECHnology of the Proterozoic Athabasca Basin, Saskatchewan and Alberta, Edited by Jefferson, C. W.; Delaney, G., Bulletin, Geological Survey of Canada, 588

Saskatchewan Geological Survey, 2003
Geology, and Mineral and Petroleum Resources of Saskatchewan
Miscellaneous Report, Saskatchewan Industry and Resources, Publication code 2003-7, 173 p., 4 maps.

Tona, F.; Alonso, D.; Svab, M., 1985
Geology and Mineralization in the Carswell Structure - A General Approach
In The Carswell Structure Uranium Deposits, Saskatchewan, Edited by Lainé, R.; Alonso, D.; Svab, M., Special Paper, Geological Association of Canada, Geological Association of Canada, 29, 230 p., p. 1 - 18

Production data: Report period: from 1979 until 2002; 3,178,231 metric ton ore; Provisional entry?: yes; Yearly or summary?: S
Grade-commodity information:U: 0.78 percent
Reference: Koning, E., 2006: The Cluff Lake Deposits, West Athabasca Basin, Saskatchewan, Canada; In Field Trip 3: Cluff Lake and Shea Creek Deposits; September 13-14; 2006 CIM Field Conference; Uranium: Athabasca Deposits and Analogues, Edited by Koning, E.; Robbins, J.; Carroll, J., Field Trip Guidebook, Canadian Institute of Mining and Metallurgy, CIM Geogolical Society, Saskatoon Section, 48 p., p. 1 - 32
Percent weights allocated to camp: 100.0%
Associated deposit(s): D Zone (40028), N Deposit (40029), Claude Deposit (40030), OP Deposit (40031), DP (40032), DJ (40033)

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