Ontario Mineral Inventory

Ontario Geological Survey
Permanent Link to this Record: MDI53H13SW00006

Record: MDI53H13SW00006

General

Mineral Record Identification
Record Name(s) Ernie Island - 1971
Related Record Type
Related Record(s)
Record Status Occurrence
Date Created 1985-Aug-20
Date Last Modified 2022-Mar-02
Created By
Revised By

Commodities

Primary Commodities: Copper



Location

Township or Area: Post Island Area, Beardy Creek Area

Latitude: 53° 45' 2.44"    Longitude: -89° 47' 34.3"

UTM Zone: 16    Easting: 315859   Northing: 5959403    UTM Datum: NAD83

Resident Geologist District: Thunder Bay North

NTS Grid: 53H13SW

Point Location Description: Precise

Location Method: Conversion from MDI



Exploration History

1912: Reconnaissance scale mapping by J.B. Tyrrell of the Geological Survey of Canada. 1964: Ontario Department of Mines reconnaissance scale mapping by P.P. Hudec. 1971: Ontario Geological Survey completed more detailed mapping by Thurston. OGS grab sample from vein on a small island off NW corner of Ernie Island: 1.05% Cu. As of 2009, this area has been alienated by the province and is not open for staking. No assessment files were found on record.


Geology

Province: Superior

Subprovince: Sachigo

Terrane: North Caribou

Geological Age: Archean  



Lithology

Lithology Data
Rock Type Rank Composition Texture Relationship
Mafic lava flow-unsubdivided 1 Basalt To Andesite
Vein 2 Quartz Host

Mineralization

Mineralization and Alteration
Rank Mineral Name Class Economic Mineral Type Alteration Mineral Type Alteration Ranking Alteration Intensity Alteration Style
1ChalcopyriteEconomicOre
2PyriteEconomicOre
3PyrrhotiteEconomicOre

Mineralization Comments

Aug 16, 2018 (Therese Pettigrew) - On a small island off the northwest corner of Ernie Island a 30 cm wide quartz vein located along the contact between pillowed mafic metavolcanics to the south and massive metavolcanics to the north carried chalcopyrite and pyrite mineralization. A grab sample of the vein material taken OGS staff returned 1.05 percent copper upon analysis by the Geoscience Laboratories. On the southwest tip of Ernie Island a shear zone 30 m wide cuts massive to pillowed mafic metavolcanics. The shear zone trends S85E, dips vertically, and contains numerous quartz veins and stringers 2 to 5 cm in width parallel to the schistosity. These veins contain up to 5 percent pyrite. Samples of the vein material taken by OGS staff for assay returned negligible values. For a distance up to 1.5 km east from the southwest tip of Ernie Island minor chalcopyrite, pyrite, and pyrrhotite occur as disseminated grains and in association with quartz veins. The greatest concentration of mineralization is 20 to 30 m north of the contact between a flow top breccia (9 m thick) and an overlying massive flow. The metavolcanics strike east to S85E, roughly parallel to the shoreline, and dip vertically. The copper showing reported by Hudec (1964, Map 2045) on the south shore of Ernie Island was relocated by this field party. The showing consists of a 43 cm wide quartz vein occupying the centre of a 18 m wide shear zone. The intensity of shearing decreases in both directions away from the vein. The vein is exposed for a length of 3.5 m and was observed to continue out under the waters of Big Trout Lake. Mineralization consists of disseminated pyrite and chalcopyrite. A chip sample across the vein taken by the author returned 0.40 percent copper and a grab sample of more highly mineralized material 0.34 percent copper (assays by the Geoscience Laboratories). Negligible gold values were reported (Thurston et al., 1979).



Mineral Record Details

Classification
RankClassification            
1 Vein
Characteristics
Rank Characteristic            
1 Vein

References

Map - Big Trout Lake-North Caribou Lake, geological compilation series, Kenora District

Publication Number: M2292 Scale: 1:253,440    Date: 1974

Author: Bennett G., Riley R.A., Thurston P.C., Siragusa G.M., Sage R.P.

Publisher Name: Ontario Division of Mines

Location:


MonoMap - Geology of Winisk Lake area, District of Kenora, Patricia Portion

Publication Number: R193 Scale:     Date: 1980

Author: Thurston P.C., Sage R.P., Siragusa G.M.

Publisher Name: Ontario Geological Survey

Location:


Map - Geological series, Operation Winisk Lake, Wunnummin Lake-Big Trout Lake, District of Kenora (Patricia Portion)

Publication Number: P0712 Scale: 1:126,720    Date: 1997

Author: Thurston P.C., Sage R.P., Siragusa G.M.

Publisher Name: Ontario Dept. of Mines and Northern Affairs

Location:


MonoMap - Geology of the Big Trout Lake area, District of Kenora (Patricia Portion)

Publication Number: R023 Scale:     Date: 1997

Author: Hudec P.P.

Publisher Name: Ontario Dept. of Mines

Location:


Map - Big Trout Lake area, Kenora District, Patricia Portion

Publication Number: M2045 Scale: 1:126,720    Date: 1997

Author: Hudec P.P.

Publisher Name: Ontario Dept. of Mines

Location:


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