Ontario Mineral Inventory

Ontario Geological Survey
Permanent Link to this Record: MDI52F15SE00038

Record: MDI52F15SE00038

General

Commodities

Primary Commodities: Lithium

Secondary Commodities: Niobium, Tantalum, Tourmaline, Phosphate

Location

Township or Area: Brownridge

Latitude: 49° 48' 51.92"    Longitude: -92° 40' 9.6"

UTM Zone: 15    Easting: 523789   Northing: 5518050    UTM Datum: NAD83

Resident Geologist District: Kenora

NTS Grid: 52F15SE

Point Location Description: General

Location Method: Conversion from MDI

Access Description: The Mavis Lake property is approx. 19 km NE by road from Dryden and can be reached from the city by driving east for approx. 8 km on Trans-Canada Highway 17 to the junction with Thunder Lake Road, then travelling approx. 3 km to the intersection of Thunder Lake Road and Ghost Lake South Road. From this point, drive north on Ghost Lake South Road for approx. 1 km and then east along the Mine Road for approx. 4 km, and finally north along a subsidiary gravel road to the eastern claims of the property.

Exploration History

1956: Lun-Echo Gold Mines Ltd. drilled 50 DDH totalling 2234.19 m immediately south of Mavis Lake. Milestone Mines conducted trenching work and limited DD east and southeast of Mavis Lake. 1978: R.J. Fairservice staked the property and then optioned the property to Selco Mining Corp Ltd. 1979-81: Selco conducted geological mapping, lithogeochemical surveys and drilled 8 DDH totalling 351.4 m. 1982: Tantalum Mining Corp of Canada Ltd (Tanco) optioned the Fairservice property and conducted line cutting, a geophysical survey and a lithogeochemical survey. 2002: Emerald Field Resources optioned the property from R.F. Fairservice. 2003: Emerald Field conducted prospecting, trenching, geological mapping, and drilled 4 DDH. 2009: TNR Gold and International Lithium Corp. (ILC) optioned the property from Rich Resource Investments Ltd. ILC conducted geological mapping and sampling. 2011: ILC drilled 20 DDH totalling 1753 m. 2012-13: ILC drilled 19 DDH totalling 2072.1 m. 2016: ILC conducted a ground magnetometer survey and sampling. 2017: ILC drilled 12 DDH totalling 1305 m. 2018: Pioneer Resources optioned the property from ILC and drilled 9 DDH totalling 1,591 m. 2022: Critical Resources Ltd. acquired the property.

Assessment Work on File

Geology

Province: Superior

Subprovince: Wabigoon

Geological Age: Archean  

Geology Comments

Feb 09, 2011 (C Ravnaas) - In the regional context, the Mavis Lake Property lies within a 2733 to 2706 Ma collisional tectonic zone known as the Sioux Lookout Domain (SLD) in the western Wabigoon Subprovince (WS) that evolved during the Kenoran orogeny. The 150 by 900 km WS is a granite-greenstone terrain and comprises metavolcanic and subordinate metasedimentary rocks, ranging in age from 3.0 Ga to 2.71 Ga, and intruded by 3.0 to 2.69 Ga granitoid batholiths, gabbroic sills and stocks. The Property is located on the north limb of a westerly plunging syncline that lies adjacent to the Thunder Lake anticline. Mafic metavolcanic and clastic metasedimentary rocks predominantly underlie the property. Intermediate to felsic volcanics occur as minor intercalations within the volcanic sequences. Intruded into these units are ultramafic dikes, small alkalic stocks and numerous granite pegmatite dikes. Reference Clark, G. International Lithium Corporation Technical Report on the Mavis Lake Lithium Property, Feb 2010

Lithology

Lithology Comments

Feb 09, 2011 (C Ravnaas) - Eleven rare-element granitic pegmatites are known on the Mavis Lake Property and vary in strike length from 11 to >240m, and thicknesses in 0.3 to >2.4m range. These bodies are mainly hosted in the 2733 Ma Brownridge mixed felsic-mafic metavolcanic unit of the Neepawa group that is intensely deformed by at least 4 folding events that culminated with development of a regional shear zone (Wabigoon fault) and metamorphism to middle amphibolite grade Pegmatites of the Dryden area were initially described and named by as the “Dryden Pegmatite Field” (DPF). The DPF has been subdivided into two distinct pegmatite populations 1 Mavis Lake Pegmatite Group (MPG), and, 2) Gullwing -Tot Lakes Pegmatite Group (GTG) The majority of the rare metal pegmatites within the MPG strike parallel to the foliation of their host rocks and exhibit localized effects of late tectonic deformation such as weakly strained contacts, internal ductile shearing, pull-apart structures involving tourmaline and spodumene and buckling and boudinage of pegmatite granite dikes near the GLG contact. The MPG consists of a 0.8 to 1.5 by 8 km, east trending swarm of pegmatites and related metasomatic zones hosted mostly within the mafic rocks. Pegmatites of this group exhibit a classic regional zonation with increasing distance from the parent GLB, as defined by systematic changes in mineralogy, chemical association and extent of post magmatic replacement. Reference Clark, G. International Lithium Corporation Technical Report on the Mavis Lake Lithium Property, Feb 2010

May 26, 2015 (Therese Pettigrew) - Numerous granitic pegmatite dikes, ranging from the primary spodumene-bearing to albite-rich, tantalum-enriched varieties occur on the property. The dikes are generally found within the mafic metavolcanic sequences. These pegmatites are linked to the Ghost Lake batholith (GLB), and a part of the Mavis Lake Pegmatite Group (MPG). The MPG is characterized by east-trending concentration of rare elements-bearing pegmatites and related metasomatic zones. . These pegmatites fall into two zones according to the initial classification of Breaks (1989), based upon systematic variation in rare-element mineralogy and petrochemistry: 1) Spodumene-beryl-tantalite zone (Li-Rb-Be-Ta>Nb-B) and 2) Albite-type pegmatite zone (Li>Rb-Be-Ta>Nb and Rb>Li-Be-Ta>Nb). These pegmatites represent a mix of albite-spodumene-type, albite-type and complex-type pegmatite dykes. The granitic pegmatite bodies exhibit an arcuate east to northeast strike pattern around the southeast corner of Mavis Lake. Dips are generally steep to the north. Tops, determined from pillowed flows, are to the south, indicating that the north limb of the syncline has been overturned. Sets of both steep and shallow dipping joints occur throughout the property. In the western portion of the property the pegmatites appear to have an affinity for the steep dipping set, whereas in the eastern portion of the property the pegmatites tend to have shallow dips (Clark et al., 2010). A pegmatite dyke, trending E-W and dipping between 45-60 degrees towards the north, outcrops approx. 300 m south of Mavis Lake. The pegmatite mobilizate has intruded the surrounding host mafic metavolcanic rocks (coarse-grained amphibolite flows) and is conformable with the E-W trending metavolcanics. The dyke is approx. 4.6 m wide on this particular outcrop. The dyke pinches out towards the east and a metamorphic aureole of coarse-grained tourmaline crystals in a matrix of hornblende, mica and chlorite has developed up to 5 cm in thickness. Tourmaline crystal halos have also developed around inclusions of mobilizate in the host metavolcanic rocks. The tourmaline halo is also present along the exposed contact of the pegmatite dyke and the surrounding metavolcanics (Vos et al., 1982).

Mineralization

Mineralization Comments

Feb 09, 2011 (C Ravnaas) - The mineralization is specifically contained within the 1.8-3 by 8 km Mavis Lake pegmatite group (MPG), that comprises a swarm of rare-element class granitic pegmatites and associated metasomatic zones genetically related to the 2685 Ma, S-type, peraluminous, fertile Ghost Lake batholith (GLB). Strong mineralogical zonation of pegmatite types has been documented with increasing eastward distance from this parental granite: beryl-bearing pegmatitic granite units in the GLB àexternal beryl-type pegmatite zoneàalbite-spodumene-type pegmatite zoneàalbite-type pegmatite zone. The rare-element granitic pegmatites of the area also belong to the LCT-geochemical family (Lithium-Cesium-Tantalum). The highest lithium values on the Mavis Lake Property occur in albite-spodumene-type pegmatites with Li2O values up to 1.22 wt.% over 5.3 meters from a composite channel sample across part of Pegmatite 18 documented in 2009 work by the Company. Numerous grab samples with elevated tantalum, cesium and rubidium were encountered in sodic aplite and albitite dykes within a 500 by 800 m area of the albite-type pegmatite zone. The highest values for Ta2O5 (1349 ppm), Rb2O (1.0 wt %) and Cs2O (1537 ppm) were encountered in these high sodium units (6 to 10.5 wt% Na2O). The eastern and southeastern limits of the rare-element mineralization, associated with albite-type pegmatites on the Mavis Lake Property, remains open to the east and southeast. A swarm of these pegmatites occurs within a minimum area of 500 by 800 m on the Property and consist of sodic aplite and albitite mineralized with tantalite, columbite, wodginite, white beryl and local green lithium tourmaline and amblygonite-montebrasite series minerals. TNR has recently documented maximum levels of Ta2O5 (1349 ppm), Cs2O (1537 ppm) and Rb2O (1.0 wt%) on the property to date in northwestern Ontario (TNR Gold Corp. News-Release - December 9, 2009). Historical exploration for rare-elements has focused upon the lithium potential of the albite-spodumene-type pegmatites and tantalum potential in the albite-type pegmatites situated on the Mavis Lake and adjacent Fairservice properties. The latter property contains a resource of 500,000 tons averaging 1.0 wt% Li2O Reference Clark, G. International Lithium Corporation Technical Report on the Mavis Lake Lithium Property, Feb 2010.

Aug 24, 2018 (Therese Pettigrew) - During the 2011 drill program, 17 of the 20 holes drilled intersected one or more intervals of pegmatite greater than 2 m and up to 78 m in length. 13 of 17 drill holes intersected pegmatites greater than 2 m. Coarse grains (>5 cm wide) of spodumene were common. Significant intervals of Li2O include: DDH MF11-05: 1.01% Li2O over 6.1 m (0.9-7 m); MF11-07: 1.48% Li2O over 4.9 m (4.1-9 m); MF11-08: 1.83% Li2O over 8.75 m (2.25-11 m); MF11-09: 2.58% Li2O over 7.8 m (18.85-26.65 m) including 3.08% Li2O over 5 m (20-25 m); MF11-11: 1.27% Li2O over 4.1 m (2-6.1 m); MF11-12: 1.15% Li2O over 4 m (29-33 m) and 1.22% Li2O over 28.45 m (116.95-145.4 m) including 1.63% Li2O over 16 m(125-141 m), and 1.86% Li2O over 26.25 m (152-178.25 m); MF11-13: 1.08% Li2O over 8.7 m (17.1-25.8 m) including 1.44% Li2O over 5 m (19-24 m); MF11-14: 2.91% Li2O over 3 m (24-27 m); MF11-15: 1.38% Li2O over 6.6 m (78.4-85 m); MF11-16: 1.23% Li2O over 4.65 m (89.35-94 m) (ILC news release Jan 12, 2012). "Coarse and fine, green and white spodumene in random orientation, associated with very coarse white feldspar and quartz, occurs in irregular lenses and masses within the dyke. These are exposed here and there through about 2,200 feet along the general strike of the zone, and some parts are very rich. Other parts of the dyke, especially along contacts are low grade or barren, consisting mainly of aplite with locally abundant black tourmaline and small grains of blue apatite. These contrasting assemblages constitute a general but rough form of internal zoning. Some of the spodumene is altered to dark green and buff, and some pale greenish mica appears to be pseudomorphous after spodumene. Both spodumene and feldspar are locally stained pink by alteration processes (Vos et al., 1982). Significant intercepts from the 2012-13 drill program include hole MF12-24 grading 1.51 wt% Li2O over 21.4 m that includes 9.2 m grading 2.37 wt% Li2O and hole MF-12-28 grading 2.53 wt% Li2O over 6 m (AFRI 20000015336).

Mineral Record Details

Mineral Zones - Size and Shape

References

Publication - Technical Report (NI 43-101) on the Mavis Lake Lithium Property

Publication Number: 2010 43-101 Date: 2010

Author: Clark, G., Breaks, F.W., and Osmani, I.A.

Publisher Name: International Lithium Corporation

Location: SEDAR (under TNR Gold)

Mono - An evaluation of the industrial mineral potential of parts of the districts of Kenora and Rainy River

Publication Number: OFR5718 Page: 151-160  Date: 1990

Author: Storey C.C.

Publisher Name: Ontario Geological Survey

Location:

MonoMap - Columbium (niobium) deposits of Ontario

Publication Number: MDC014 Page: 48  Date: 1971

Author: Ferguson S.A.

Publisher Name: Ontario Dept. of Mines and Northern Affairs

Location:

Publication - A Catalogue of Canadian Minerals; Geological Survey of Canada, Paper 69-45

Publication Number: Paper 69-45 Page: 161  Date: 1970

Author: Traill, R.J.

Publisher Name: Geological Survey of Canada

Location: https://doi.org/10.4095/102924

Publication - Geology of Canadian Lithium Deposits; Geological Survey of Canada, Economic Geology Report 21

Publication Number: GSC EG 21 Page: 63-64  Date: 1965

Author: Mulligan, R.

Publisher Name: Geological Survey of Canada

Location: https://doi.org/10.4095/102454

Article - 1982 report of the Kenora Resident Geologist

Publication Number: MP107.001 Page: 10  Date: 1997

Author: Blackburn C.E., Hailstone M.H.

Publisher Name: Ontario Geological Survey

Location:

Map - Precambrian Geology of the Thunder Lake Area

Publication Number: P3529 Scale: 1:20,000    Date: 2003

Author: Beakhouse G.P., Pigeon L.

Publisher Name: Ontario Geological Survey

Location:

Map - Kenora-Fort Frances sheet, geological compilation series, Kenora, Rainy River districts

Publication Number: M2115 Scale: 1:253,440    Date: 1967

Author: Davies J.C., Pryslak A.P.

Publisher Name: Ontario Dept. of Mines

Location:

Map - Precambrian geology, Flambeau Lake-Larson Bay area, western part, District of Kenora

Publication Number: P3111 Scale: 1:4,800    Date: 1988

Author: Parker J.R., Schienbein R.

Publisher Name: Ontario Geological Survey

Location:

Mono - Industrial minerals of northern Ontario-supplement 1

Publication Number: OFR5388 Page: 122-123  Date: 1982

Author: Vos M.A., Abolins T., Smith V.

Publisher Name: Ontario Geological Survey

Location:

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