Ontario Geological Survey
Permanent Link to this Record:
MDI52J16NE00003
| Record Name(s) | Greenbush - 2009, East Pashkokogan Lake - 1965 |
|---|---|
| Related Record Type | Simple |
| Related Record(s) | |
| Record Status | Occurrence |
| Date Created | 1982-Nov-25 |
| Date Last Modified | 2023-May-26 |
| Created By | |
| Revised By |
Primary Commodities: Lithium, Rubidium
Secondary Commodities: Cesium, Beryllium, Niobium, Tantalum
Township or Area: Greenbush Lake Area
Latitude: 50° 57' 25.2" Longitude: -90° 14' 2.28"
UTM Zone: 15 Easting: 694255.27 Northing: 5648686.09 UTM Datum: NAD83
Resident Geologist District: Thunder Bay North
NTS Grid: 52J16NE
Point Location Description: Li depicted on north shore of southeast bay of East Pashkokogan Lake
Location Method: Conversion from MDI
Access Description: Highway 599 north to Pickle Lake; boat access from Pashkokogan Lake to East Pashkokogan Lake.
This occurrence was discovered by D. Cooper in 1955 (MP72 p 48). A 50 foot chip sample by OGS personnel returned 1.25% Li2O with trace beryllium, cesium and rubidium (p55 GR 42). Belove Mines Ltd. completed a magnetometer survey over the pegmatite zone of East Pashkokogan Lake in April of 1980 and Placer Development Limited reported 0.01% Ta from a grab sample. Michael Stares staked an 8 unit claim (124-567) over the occurrence in April of 2000 for potential tantalum, cesium, etc. mineralization. 2009: Canadian Orebodies staked the property and conducted prospecting and sampling.
| Office File Number | Online Assessment File Identifier | Online Assessment File Directory |
|---|---|---|
| 2.46170 | 20000005572 | 20000005572 |
| 52J16NE0011B1 | 52J16NE0010 | 52J16NE0010 |
Province: Superior
Subprovince: Uchi
Terrane: North Caribou
Domain: Uchi
Belt: Lake St. Joseph
Geological Age: Neoarchean
Aug 27, 2007 (Mark Puumala) - The East Pashkokogan Lake spodumene pegmatite is described by Breaks et al. (2003) as an intrusion that consists of alternating layers of spodumene and aplite and stringers of tourmaline. The exposure of this intrusion is found on the northeast shore of the southeast bay of Pashkokogan Lake, and covers an area approximately 10 m wide and 12 m long (Kay and Stott 1985). The layers were mapped in detail by Kay and Stott (1985) and strike approximately northeast-southwest. Kay and Stott (1985) also identified three smaller pegmatite dikes in the immediate vicinity of the main intrusion. Kowalczyk (1980) indicates that the pegmatite intrudes felsic volcanic breccia. The spodumene zones contain abundant coarse-grained (up to 2.5 cm) green and white spodumene that is often altered to to a waxy dark green mineral (Breaks et al. 2003). The spodumene zones also contain abundant potassium feldspar, albite and quartz. Accessory minerals found in this zone are reported to include dark green to black tourmaline, silver and green muscovite, zircon, tantalum-tin oxides, montebrasite, fluorapatite, and cesium-rich beryl. The aplite zones are reported to contain fine-grained tourmaline and fluorapatite. Breaks et al. (2003) report the presence of two additional pegmatite dikes in close proximity to the spodumene pegmatite. Both intrusions are hosted by metasedimentary rocks.
| Rock Type | Rank | Composition | Texture | Relationship | Pegmatite | 1 | Intrudes |
|---|---|---|---|---|
| Felsic lava flow-unsubdivided | 2 | Volcanic Breccia. | Adjacent | |
| Terrigenous-Clastic-Unsubdivided | 3 | Host |
| Rank | Mineral Name | Class | Economic Mineral Type | Alteration Mineral Type | Alteration Ranking | Alteration Intensity | Alteration Style |
|---|---|---|---|---|---|---|---|
| 1 | Spodumene | Economic | Ore | ||||
| 2 | Tourmaline | Economic | Ore | ||||
| 3 | Beryl | Economic | Ore | ||||
| 4 | Ferrocolumbite | Economic | Gangue | ||||
| 5 | Ferrotantalite | Economic | Gangue | ||||
| 6 | Montebrasite | Economic | Gangue |
May 26, 2023 (Mark Puumala) - The first dike is located approximately 1 km to the south of the East Pashkokogan Lake pegmatite, in the southeastern portion of East Pashkokogan Lake (UTM Zone 15, 693245E, 5648182N). This intrusion is described as a 3 to 4 m wide dike comprised of potassium feldspar, plagioclase, quartz and minor green muscovite. Accessory mineral that have been identified in this dike include ferrocolumbite and ferrotantalite. The second dike is located approximately 500 m from the East Pashkokogan Lake pegmatite at UTM Zone 15, 693445E, 5648332N. It is reported to consist of quartz, white potassium feldspar and minor blue fluorapatite, with green muscovite along fractures. Aplite and biotite muscovite granite are also reported to occur in the vicinity of the pegmatite. The aplite contains tourmaline that is zoned with elbaite cores and schorl rims. The schorl is reported to be rich in lithium (Breaks et al. 2003). Goodwin (1965) reported a LiO2 assay value of 1.25% from a chip sample collected across the width of the spodumene pegmatite. Low assay values for beryllium (0.03%), cesium (0.03%) and rubidium (0.15%) were also reported. Grab samples collected by Kay and Stott are reported to have assayed up to 0.71% LiO2. Kowalczyk (1980) reported a tantalum assay of 0.01% Ta from a grab sample collected for Placer Development.
Apr 15, 2016 (Therese Pettigrew) - The pegmatite is leucocratic and consists of foliated (locally saccharoidal to aplitic) albitemicrocline-quartz with local relatively undeformed pegmatitic zones of microcline and spodumene. Fine-grained tourmaline (mostly schorl but some elbaite) is abundant locally as is silvery muscovite. The spodumene crystals are a rather opaque whitish beige colour and are locally altered to a bright green muscovite (clay). No lepidolite was observed. A rare silver oxide mineral with a platy cleavage was also observed possibly representing a Nb-Ta oxide. Nearly all of the grab samples collected by Canadian Orebodies in 2009 returned with anomalous results. Four of the 10 grab samples returned with assay results greater than 4,000 ppm lithium up to 9,120 ppm lithium (0.95% to 1.96% Li2O), along with associated anomalous spikes in berylium, cesium, gallium, niobium, rubidium, tin and tantalum. Sample H181060 returned the highest lithium value at 9,120 ppm Li, and the hand sample was reported to contain an odd, fine grained, locally platy, silver green oxide mineral, possibly a Nb-Ta oxide. Conversely, the lowest lithium values came from samples H181063, H181067 and H181068. Sample H181063 was sampled from a small, 20cm wide pink aplitic pegmatite dike to the east of the larger lithium pegmatite dike, and does not appear to be connected to the lithium pegmatite dike. The other two samples, H181067 and H181068, were sampled on two of the three small branches emanating to the west off the main lithium pegmatite dike. It appears the highest lithium values came from samples concentrated where the bulk of the lithium pegmatite is exposed at surface. It is unknown how far the pegmatite(s) extends under the lake to the south and east. (AFRI 20000005572).
| Rank | Classification |
|---|---|
| 1 | Pegmatite |
| Rank | Characteristic |
|---|---|
| 1 | Intrusive |
Map - Pashkokogan Lake sheet, Thunder Bay District
Publication Number: M2094 Scale: 1:31,680 Date: 1997
Author: Goodwin A.M.
Publisher Name: Ontario Dept. of Mines
Location:
Map - Sioux Lookout-Armstrong, geological compilation series, Kenora and Thunder Bay districts
Publication Number: M2442 Scale: 1:253,440 Date: 1981
Author: Breaks F.W.
Publisher Name: Ontario Geological Survey
Location:
MonoMap - Geology of Pashkokogan Lake-eastern Lake St. Joseph area, districts of Thunder Bay and Kenora
Publication Number: R042 Page: 39, 54-55 Date: 1997
Author: Goodwin A.M.
Publisher Name: Ontario Dept. of Mines
Location:
MonoMap - Preliminary geological synthesis of the English River Subprovince, northwestern Ontario and its bearing upon mineral exploration
Publication Number: MP072 Page: 48-49 Date: 1978
Author: Breaks F.W., Bond W.D., Stone D.
Publisher Name: Ontario Geological Survey
Location:
Mono - Industrial minerals of northern Ontario-supplement 1
Publication Number: OFR5388 Page: 200-201 Date: 1982
Author: Vos M.A., Abolins T., Smith V.
Publisher Name: Ontario Geological Survey
Location:
Map - Geological series, Precambrian geology, Lake St. Joseph area, east half, districts of Thunder Bay and Kenora (Patricia Portion)
Publication Number: P3051 Scale: 1:50,000 Date: 1987
Author: Stott G.M., Kay S.V., Sanborn M.
Publisher Name: Ontario Geological Survey
Location:
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