Ontario Geological Survey
Permanent Link to this Record:
MDI52N01SW00001
| Record Name(s) | SJ Pegmatite - 1964, Jubilee Lake Pegmatite - 1998, Johnson Pegmatite - 1964 |
|---|---|
| Related Record Type | Simple |
| Related Record(s) | |
| Record Status | Occurrence |
| Date Created | 2002-Nov-29 |
| Date Last Modified | 2023-May-10 |
| Created By | |
| Revised By |
Primary Commodities: Tantalum, Rubidium
Secondary Commodities: Niobium, Lithium, Cesium, Beryllium
Township or Area: Birkett
Latitude: 51° 1' 44.9" Longitude: -92° 23' 32.6"
UTM Zone: 15 Easting: 542609 Northing: 5653241 UTM Datum: NAD83
Resident Geologist District: Red Lake
NTS Grid: 52N01SW
Point Location Description: Point on shore at northeast tip of Jubilee Lake
Location Method: Field Visit
Access Description: Jubilee lake reached from Wenesaga road.
1964: prospector Stan Johnson discovered the pegmatite. 2001: OGS staff carried out sampling.
Province: Superior
Subprovince: Uchi
Terrane: North Caribou
Domain: Uchi
Geological Age: Archean
| Rock Type | Rank | Composition | Texture | Relationship | Pegmatite | 1 | Is |
|---|---|---|---|---|
| Arenite | 2 | Near |
Oct 18, 2021 (Therese Pettigrew) - The SJ pegmatite (also known as the Johnson pegmatite) represents the largest pegmatite in the Jubilee Lake group and is exposed over a minimum area of 35 by 30 m. This pegmatite may represent an external dike to the Allison Lake batholith hosted in metasedimentary rocks, although no external intrusive contacts were observed. The pegmatite consists of apatite-garnet-muscovite-potassium feldspar-quartz-albite with local quartz-rich patches that contain pale pink blocky potassium feldspar crystals up to 30 by 50 cm. Irregular, lime green replacement masses of muscovite-albite are obvious in the largest blast pit and contain abundant platy black ferrocolumbite (Breaks et al., 2003).
| Rank | Mineral Name | Class | Economic Mineral Type | Alteration Mineral Type | Alteration Ranking | Alteration Intensity | Alteration Style |
|---|---|---|---|---|---|---|---|
| 1 | Beryl | Economic | Ore | ||||
| 2 | Ferrocolumbite | Economic | Ore | ||||
| 1 | Albite | Economic | Gangue | ||||
| 2 | Quartz | Economic | Gangue | ||||
| 3 | Feldspar | Economic | Gangue | ||||
| 4 | Muscovite | Economic | Gangue | ||||
| 5 | Garnet | Economic | Gangue | ||||
| 6 | Apatite | Economic | Gangue |
Oct 18, 2021 (Therese Pettigrew) - A large bulk rock sample from the SJ pegmatite (sample 01-JBS-7) contained the highest tantalum value of 173 ppm Ta thus far documented in the area and consists of a green muscovite-albite greisen-like assemblage with the highest megascopic content of tantalum-niobium oxide minerals observed at the locality (see also Tindle, Selway and Breaks 2002 (MRD 111): Table 20a). This strongly peraluminous unit (A/CNK = 1.669) also contains maximum values of Rb (1227 ppm) and Nb (462 ppm) in bulk whole rock samples for the entire area. The SJ pegmatite contains manganese-rich garnet and fluorapatite and iron-rich oxide minerals. The apatite-garnet-muscovite-potassium feldspar-quartz-albite pegmatite zone of the SJ pegmatite contains fine-grained red garnet with a composition between almandine and spessartine (48-55% almandine, 43-50% spessartine, 1-2% pyrope). In the pegmatite zone, the fine-grained blue-green fluorapatite contains up to 7.6 weight % MnO and in the replacement zone, the fluorapatite contains 5.1 weight % MnO. Platy black ferrocolumbite (average of 25.2 weight % Ta2O5) occurs in the pegmatite zone and the muscovite-albite replacement zone. Electron microprobe analyses (140) of the tantalum-oxide minerals reveal an iron-dominated fractionation trend marked by a modest increase in Ta2O5. The SJ pegmatite is more evolved than the Allison Lake batholith, as it contains tantalum-oxide minerals which so far have not been found in the batholith, and the fluorapatite is significantly more manganese-rich than that in the batholith. It also has elevated Rb and Cs contents in the potassium feldspar, and the highest Ta contents in bulk whole rock samples (Breaks et al., 2003).
| Commodity | Analytical Method | Digestion Method | Result | Unit | Limit | Qualifier |
|---|---|---|---|---|---|---|
| Beryllium | Unknown | 12 | ppm | |||
| Cesium | Unknown | 47 | ppm | |||
| Lithium | Unknown | 140 | ppm | |||
| Niobium | Unknown | 462 | ppm | |||
| Rubidium | Unknown | 1227 | ppm | |||
| Tantalum | Unknown | 173 | ppm |
| Rank | Classification |
|---|---|
| 1 | Pegmatite |
| Rank | Characteristic |
|---|---|
| 1 | Intrusive |
Data - Electron Microprobe and Bulk Analyses of Fertile Peraluminous Granites and Related Rare-element Pegmatites, Superior Province, Northwest and Northeast Ontario: Operation Treasure Hunt
Publication Number: MRD111 Date: 2002
Author: Tindle A.G., Selway J.B., Breaks F.W.
Publisher Name: Ontario Geological Survey
Location:
Mono - Fertile Peraluminous Granites and Related Rare-Element Mineralization in Pegmatites, Superior Province, Northwest and Northeast Ontario: Operation Treasure Hunt
Publication Number: OFR6099 Page: 25-27 Date: 2003
Author: Breaks F.W., Selway J.B., Tindle A.G.
Publisher Name: Ontario Geological Survey
Location:
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