Ontario Geological Survey
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MDI000000002326
| Record Name(s) | Gilbert Lake - 2001 |
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| Related Record Type | |
| Related Record(s) | |
| Record Status | Discretionary Occurrence |
| Date Created | 2019-Aug-27 |
| Date Last Modified | 2023-May-11 |
| Created By | |
| Revised By |
Primary Commodities: Cesium, Lithium, Rubidium, Tantalum, Niobium
Secondary Commodities: Tin, Rare Earth Elements, Gallium, Beryllium
Township or Area: Pickerel Lake Area
Latitude: 48° 43' 40.44" Longitude: -91° 26' 27.37"
UTM Zone: 15 Easting: 614652 Northing: 5398381 UTM Datum: NAD83
Resident Geologist District: Thunder Bay South
NTS Grid: 52B11NW
Point Location Description: From Sample 01-JBS-78-07 in OFR6099
Location Method: Data Compilation
Access Description: Along Highway 11
2001: Sampled by OGS staff. No assessment reports were found on file.
Province: Superior
Subprovince: Quetico
Geological Age: Archean
| Rock Type | Rank | Composition | Texture | Relationship | Pegmatite | 1 | Garnet-Muscovite | Host |
|---|
| Rank | Mineral Name | Class | Economic Mineral Type | Alteration Mineral Type | Alteration Ranking | Alteration Intensity | Alteration Style |
|---|---|---|---|---|---|---|---|
| 1 | Beryl | Economic | Ore | ||||
| 2 | Gahnite | Economic | Ore | ||||
| 3 | Pyrite | Economic | Ore | ||||
| 1 | Garnet | Economic | Gangue | ||||
| 2 | Muscovite | Economic | Gangue |
Aug 27, 2019 (Therese Pettigrew) - Rare-element mineralization was discovered by the present survey at locality 01-JBS-78 within a pegmatite-aplite dyke system 0.3 to 4 m thick. Sporadic, yellow-green beryl crystals, up to 2 cm in diameter, occur in a muscovite-potassium feldspar-quartz-rich pegmatite core rimmed by garnet-muscovite aplite. Black grains of gahnite (ZnAl2O4) and pyrite with hematite along fractures, up to 1 to 6 mm by 10 mm, occur in several parts of the pegmatite and aplite units. The white to pink aplite contains abundant fine-grained dark orange garnets with spessartine cores (51-54% spessartine, 44-48% almandine, 1% andradite, 1% pyrope) and almandine rims (50-55% almandine, 41-49% spessartine, 1-2% pyrope, 1% andradite). One zoned garnet grain had exceptionally high Mn content in the spessartine cores (68-72% spessartine, 27-31% almandine, 0.3 weight % P2O5). The fluorapatite in the aplite is manganese-rich (4.2-4.8 weight % MnO), whereas the fluorapatite in the potassic pegmatite is relatively manganese-poor (0.6-1.7 weight % MnO). The garnet-muscovite potassic pegmatite, sample 01-JBS-78-07 is the most evolved pegmatitic rock encountered by the survey. This beryl-type pegmatite contains maximum levels in this area for most rare-elements: Be (18 ppm), Cs (80 ppm), Li (99 ppm), Rb (524 ppm), Sn (177 ppm), Ta (20 ppm), Nb (42 ppm) and Ga (81 ppm) (Breaks et al., 2003).
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:
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