Ontario Geological Survey
Permanent Link to this Record:
MDI000000001945
| Record Name(s) | Superb Lake - 1955, O'Sullivan Lake Field - 1955 |
|---|---|
| Related Record Type | |
| Related Record(s) | |
| Record Status | Occurrence |
| Date Created | 2016-Jul-06 |
| Date Last Modified | 2023-Aug-03 |
| Created By | |
| Revised By |
Primary Commodities: Lithium, Rubidium, Tantalum
Secondary Commodities: Cesium, Niobium, Tin
Township or Area: O Sullivan Lake Area
Latitude: 50° 29' 14.5" Longitude: -87° 0' 50.04"
UTM Zone: 16 Easting: 499014 Northing: 5592820.01 UTM Datum: NAD83
Resident Geologist District: Thunder Bay North
NTS Grid: 42L06NE
Point Location Description: OFR6195 p. 73, sample 02-JBS-63
Location Method: Other
Access Description: Travel west 25 klm on Road 643 from the community of Aroland. Turn right onto the Anaconda forestry haulage road and proceed north to a disused forestry road 9 km on the right. Proceed east for 2.2 kilometres on this 4X4 trail. The showing is 400 m to the ESE on a peninsula in Superb Lake.
1955: Blast pitted and sampled by unknown persons. 1980: Amax of Canada Ltd. carried out geological mapping and a VLF-EM survey. 1983: Syngold Exploration carried out reconnaissance geological mapping. 1997: Mapped and sampled by OGS staff members G. Stott and J. Parker. 2021: Medaro Mining Corp. carried out soil and rock sampling, and geological mapping. 2022: Rock Edge optioned the property from Medaro and carried out soil sampling, trenching, and a shallow drilling program. 2023: Rock Edge carried out sampling.
| Office File Number | Online Assessment File Identifier | Online Assessment File Directory |
|---|---|---|
| 2.6868 | 42L06NE0018 | 42L06NE0018 |
| 2.4519 | 42L06NE0021 | 42L06NE0021 |
Province: Superior
Subprovince: English River
Geological Age: Archean
Dec 17, 2020 (Therese Pettigrew) - The Superb Lake pegmatite occurs within medium-grade, metasedimentary rocks of the English River Subprovince directly adjacent to its boundary with the Onaman–Tashota greenstone belt in the O’Sullivan Lake area (Breaks et al, 2006).
| Rock Type | Rank | Composition | Texture | Relationship | Pegmatite | 1 | Muscovite Granite Pegmatite | Host |
|---|---|---|---|---|
| Wacke | 2 | Feldspathic Wacke | Near |
| Rank | Mineral Name | Class | Economic Mineral Type | Alteration Mineral Type | Alteration Ranking | Alteration Intensity | Alteration Style |
|---|---|---|---|---|---|---|---|
| 1 | Spodumene | Economic | Ore | ||||
| 2 | Fluorite | Economic | Ore | ||||
| 1 | Quartz | Economic | Gangue | ||||
| 2 | Feldspar | Economic | Gangue | ||||
| 3 | Muscovite | Economic | Gangue | ||||
| 4 | Sericite | Economic | Gangue |
Dec 17, 2020 (Therese Pettigrew) - The pegmatite dyke is a three meter wide, white pegmatite with crystals of feldspar, spodumene and a lithium mica (Assessment report 42L06NE0021). A large bulk sample collected from the pegmatite by G.M. Stott from the blast pit area (G.M. Stott, OGS, unpublished data, 1998) contained Ta above the detection limit of 350 ppm, 142 ppm Be, 80 ppm Nb, 1464 ppm Rb, 99 ppm Cs and 56 ppm Sn. In addition, 4 rock specimens with columbite-group minerals were provided by G.M. Stott (OGS; samples 97-GRS-215A to -215D). The pegmatite has a minimum exposed strike length of 16 m and its width varies from 2.5 m at the shoreline to a maximum of 3.7 m where an old blast pit was excavated. Most of the blasted material appears to have been removed or was blasted into the lake. The contact between the pegmatite and well foliated, biotite, metawacke and metapelite host rocks is only exposed along the south between the lake and the blast pit. The metasedimentary host rock has been metasomatized, as it contains abundant siderophyllite-zinnwaldite and muscovite and accessory apatite along the southern contact with the pegmatite. Several narrow, aplite-like veins are situated within 30 m of the main pegmatite and reveal important evidence for the style of deformation. These pegmatites are variably deformed and one dike, situated 12 m south of the Superb pegmatite has been completely dismembered into a train of Z-shaped, rotated boudins. These dikes are related to the Superb Lake pegmatite as indicated by white beryl and numerous specks of black Ta-Nb oxide minerals. The aplite wall zone of the pegmatite consists of a 50 cm wide assemblage of muscovite-quartz-albite. Transverse quartz veins, 10 to 35 cm in width and up to 1.9 m in length, are oriented normal to the dike contact. These veins are devoid of other pegmatite minerals. The sericite-rich outer zone is discontinuously evident along the southern margin of the pegmatite as a finer-grained assemblage of quartz-spodumene-sericite-albite. This unit is characterized by masses of rich in yellow-green sericite that comprise about 30 volume % of the rock. It is plausible that the yellow-green masses represent completely altered spodumene; however, no relic cores of unaltered spodumene were identified in contrast to “tiger eye” textures observed in the Tot Lake pegmatite (Breaks 1989) and at the Swole Lake pegmatite. Alternatively, the sericite masses may represent concentrations of potassium that were released during albitization of potassium feldspar. The potassium may have been redistributed during shearing deformation which obviously affects this part of the pegmatite. Purple fluorite and liberite (Li2BeSiO4) are sporadically distributed in the unit. An intermediate zone of fine-grained muscovite-quartz-spodumene-albite occurs indistinctly adjacent to the wall zone and grades into the coarser spodumene-quartz core. The central, coarser grained muscovite-potassium feldspar-spodumene-quartz core unit is 50 to 70 cm wide and 6 m in strike length. This zone contains the coarsest spodumene crystals that may be up to 4 by 35 cm in sections parallel to the long axis. These grey to pale green spodumene crystals are typically randomly oriented. A significant number of spodumene crystals are partially to completely altered to aphanitic, yellow green and dark green black secondary minerals. One large crystal that resembled blocky potassium feldspar on the surface of the outcrop was revealed to be completely albitized potassium feldspar when a channel sample was cut. Lithiophilite was identified as an accessory mineral in the spodumene core zone (Breaks et al., 2006). Sample 02-JBS-63 returned 2246 ppm Li, 2938 ppm Rb, 235 ppm Sn, and 770 ppm Cs (Tindle et al., 2006). Channel sampling in 2021 returned up to 1.15% Li2O over 5.8 m (Medaro Mining press release Oct 26, 2021).
Dec 16, 2022 (Justin Jonsson) - Channel sampling in 2022 returned up to 2.47% Li2O over 3.2 m, including 5.84% Li2O over 1.1 m (Rock Edge press release, December 14, 2022). The main Superb Lake Pegmatite is 3 to 3.8m wide in surface outcrop and can be traced for about 100 m along strike. It appears to continue undercover at both ends. The pegmatite varies from fine grained to very coarse grained spodumene, with local zones of aplite. Surface assays suggest overall better grades within its western portion (Rock Edge press release, July 18, 2023).
| Rank | Classification |
|---|---|
| 1 | Pegmatite |
Mono - Fertile Peraluminous Granites and Related Rare-Element Mineralization in Pegmatites, Superior Province, Northwest and Northeast Ontario: Operation Treasure Hunt
Publication Number: OFR6099 Date: 2003
Author: Breaks F.W., Selway J.B., Tindle A.G.
Publisher Name: Ontario Geological Survey
Location:
Mono - Fertile and Peraluminous Granites and Related Rare-Element Mineralization in Pegmatites, North-Central and Northeastern Superior Province
Publication Number: OFR6195 Page: 73-77 Date: 2006
Author: Breaks F.W., Selway J.B., Tindle A.G.
Publisher Name: Ontario Geological Survey
Location:
Article - Geology and mineralization of the O'Sullivan Lake area, Onaman-Tashota Greenstone Belt, East Wabigoon Subprovince
Publication Number: MP168.012 Date: 1997
Author: Stott G.M., Parker J.R.
Publisher Name: Ontario Geological Survey
Location:
Data - Electron Microprobe and Bulk Rock and Mineral Compositions of Barren and Fertile Peraluminous Granitic Rocks and Rare-Element Pegmatites, North-Central and Northeastern Superior Province of Ontario
Publication Number: MRD210 Date: 2006
Author: Tindle A.G., Selway J.B., Breaks F.W.
Publisher Name: Ontario Geological Survey
Location:
Map - Precambrian Geology, O'Sullivan Lake Area (East Half), Northeastern Onaman-Tashota Greenstone Belt, Eastern Wabigoon Subprovince
Publication Number: P3377 Scale: 1:20,000 Date: 1998
Author: Parker J.R., Stott G.M.
Publisher Name:
Location:
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