Ontario Mineral Inventory

Ontario Geological Survey
Permanent Link to this Record: MDI52I08NW00018

Record: MDI52I08NW00018

General

Commodities

Primary Commodities: Lithium

Location

Township or Area: Crescent Lake Area

Latitude: 50° 26' 38.44"    Longitude: -88° 19' 59.31"

UTM Zone: 16    Easting: 405342   Northing: 5588849    UTM Datum: NAD83

Resident Geologist District: Thunder Bay North

NTS Grid: 52I08NW

Point Location Description: Location of trench in Sovereign Gold Nov 15, 2016 news release (

Location Method: Data Compilation

Exploration History

1956-75: Dempster Mines Limited conducted mapping, trenching, sampling, DD-24, ground geophysics. 1979: Cominco Ltd. and E & B Exploration Inc. carried out mapping, sampling, and soil sampling. 2016: Sovereign Gold Company Ltd. optioned the property from Stockport Exploration Inc. and carried out prospecting, sampling, stripping, trench mapping, and drilling, including 6 DDH on the L61 showing.

Assessment Work on File

Geology

Province: Superior

Subprovince: Wabigoon

Belt: Caribou Lake

Geological Age: Archean  

Lithology

Lithology Comments

Mar 07, 2014 (A Wilson) - Two lithium pegmatite dikes, cutting granite gneiss, make up this deposit. The L61 West dike is exposed in outcrops and in trenches for a length of about 250 feet. This dike is a broadly curving body up to 10 feet wide. In its southern part it strikes N25 -30 W and in its northern part N10°W. The L61 East deposit is exposed about 30 feet east of the centre of the first dike; from this point it has been traced S25 E for about 200 feet. It ranges from 10 to 20 feet in width.

Mineralization

Mineralization Comments

Mar 07, 2014 (A Wilson) - In the L61 West dike, the spodumene crystals range from less than 1 inch to about 3 inches in length. Some of the spodumene is altered as a result of partial replacement by muscovite and sericite, but the altered spodumene is not abundant and is confined to marginal portions of the dike. The average spodumene content of the dike is approximately 20%. In the L61 East dike is coarser in texture than the west deposit. It consists of coarse- to very coarse-grained potash feldspar and spodumene in a matrix of fine-grained quartz, albite and muscovite. The spodumene content is about 20% and altered material is not abundant. The L61 West dike is "similar to the Tebishogeshik pegmatite lenses, its principal difference being a smaller granularity with prismatic spodumene crystals ranging from less than 1 inch up to about 3 inches in length. Four features are indicative of a magmatic derivation: 1. Several spodumene crystals have been broken and cemented by groundmass quartz. 2. Contacts with the enclosing granitic rocks are sharp in most places, and the margins of the pegmatite are marked by border or "chill" zones, up to one inch thick, of granitoid mica-quartz feldspar material. 3. The granularity of the pegmatite increases from the border zones inward. 4. The texture is porphyritic; prismatic crystals of spodumene and potash feldspar, oriented roughly perpendicular to the contacts, are embedded in a fine-grained matrix of other pegmatite constituents. "Some of the spodumene present is altered as a result of partial replacement by muscovite and sericite. But the altered spodumene is not abundant and is confined to marginal portions of the dike. The average spodumene content of the dike is about 20 percent. The L61 East deposit consists of coarse-to very coarse-grained individuals of potash feldspar and spodumene in a matrix of fine-grained quartz, albite, and muscovite. As before, the spodumene content is about 20 percent and altered material is not abundant. The presence in places of irregular gradational contacts with the enclosing granite gneiss, and the local orientation of pegmatite minerals parallel to the latter's foliation near the north end of the dike, indicate that some replacement of the country rock has taken place. But, as before, the porphyritic texture of the pegmatite and the presence of bent and broken spodumene crystals welded by groundmass quartz are features indicating that the pegmatite, or the bulk of it, is of magmatic origin.

Apr 10, 2019 (Therese Pettigrew) - Samples collected by Sovereign Gold in 2016 returned values between 1.25-2.43% LI2O from a bedrock showing that measured approximately 100 m by 20 m. Geological mapping identified the two mineralized pegmatite dykes and showed that minor offset of the dykes appears to occur along an east-west fractured zone that separates the north and south showing areas. The West Dyke measures 1 m in width at the south end of the L61 area and is weakly mineralized with spodumene in that area. At the north end of the L61 exposure, the West Dyke is 5 m in width and contains very strong spodumene mineralization. The East Dyke averages 6 m in width where exposed, is located approximately 13 m east of the West Dyke, and strikes north, parallel with the West Dyke. DDH CL-16-04 intersected and confirmed the existence of the two pegmatite dykes. The hole intersected the 4.5 m wide West Dyke pegmatite at a downhole depth between 5.0 m and 9.5 m and the East Dyke over 8.4 m downhole from 28.7 m to 37.1 m. Assay results have been returned for these intervals and highlights include 1.63% Li2O over 0.5 m from 5.3 m to 5.8 m in the West Dyke plus 1.61% Li2O over 5.0 m from 30.8 m to 35.8 m down hole in the East Dyke. DDH CL-16-05 was drilled as a cross-sectional under-cut hole and intersected the West Dyke below the CL-16-04 intercept. The hole intersected 7.6 m of pegmatite between 11.4 m and 19 m down hole with the best assay interval being 1.60% Li2O over 0.50 m from 16.4 to 16.9 m down hole. Hole C16-05 did not intersect the East Dyke. DDH CL-16-06 was drilled down dip on the east pegmatite dyke to test the continuity of pegmatite mineralisation to a depth of 50 m down hole. Assay results have returned a weighted average intercept of 1.17% Li2O over 49.50 m from a down hole depth of 0.5 m to 50.0 m. This intercept includes 2.07% Li2O over 22.5 m between 0.5 and 23.0 m down hole (Sovereign Gold Company press release, Nov 15, 2016).

Mineral Record Details

References

Map - Crescent Lake area, Thunder Bay District

Publication Number: M2100 Date: 1997

Author: Pye E.G.

Publisher Name: Ontario Dept. of Mines

Location:

MonoMap - Geology of the Crescent Lake area, District of Thunder Bay

Publication Number: R055 Page: 59  Date: 1968

Author: Pye E.G.

Publisher Name: Ontario Dept. of Mines

Location:

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

Publication Number: GSC EG 21 Page: 61  Date: 1968

Author: Mulligan, R.

Publisher Name: Geological Survey of Canada

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

Mono - Industrial minerals of northern Ontario-supplement 1

Publication Number: OFR5388 Page: 187-191  Date: 1982

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

Publisher Name: Ontario Geological Survey

Location:

Mono - Pegmatite mineral resources of Ontario

Publication Number: IMR021 Page: 48  Date: 1997

Author: Hewitt D.F.

Publisher Name: Ontario Dept. of Mines

Location:

Mono - Report of Activities 2016, Resident Geologist Program, Thunder Bay North Regional Resident Geologist Report: Thunder Bay North District

Publication Number: OFR6325 Page: 30-32  Date: 2017

Author: Cundari R.M., Brunelle M.R., White G.D., Tuomi R.D., Tims A.

Publisher Name: Ontario Geological Survey

Location:

Report an Error

We are continuously updating our assessment file / technical report information. If you notice errors in the data, please contact us.

Terms of Use

Please review our Terms of Use agreement for this data product.

Ministry Contact Information

For detailed information regarding this mineral record please contact the Thunder Bay North Resident Geologist District Office