Ontario Geological Survey
Permanent Link to this Record:
MDI52E07NE00002
| Record Name(s) | Coste Island Prospect - 1987, French Portage Occurrence - 9999 |
|---|---|
| Related Record Type | Simple |
| Related Record(s) | |
| Record Status | Prospect |
| Date Created | 1987-May-20 |
| Date Last Modified | 2022-Sep-27 |
| Created By | |
| Revised By |
Primary Commodities: Soapstone
Secondary Commodities: Talc
Township or Area: Astron Bay Area
Latitude: 49° 25' 11.99" Longitude: -94° 42' 12.82"
UTM Zone: 15 Easting: 376451 Northing: 5475541.583 UTM Datum: NAD83
Resident Geologist District: Kenora
NTS Grid: 52E07NE
Point Location Description: Occurrence
Location Method: Conversion from MDI
Access Description: The occurrence is located 41.5 km south-southwest of the town of Kenora on the southeastern shore of a small island in Lake of the Woods. The island is located just north of Falcon Island between the southeastern part of Coste Island and the western part of the Auineau Peninsula. The island is accessible by boat. The recommended route from Kenora (from Canadian Hydrographic Service Maps 6218, 6212, 6216) is to follow the Main Track until the Southern Track branches off at Whisky Island. The Southern Track leads to French Portage and Coste Island.
Lawson (1886) noted that indigenous peoples had used this stone to make ceremonial pipes for many years. 1975: Frank Thorgrimson of Keewatin, held a quarry permit on the ground. He extracted a small amount of stone for carving ornamental pieces. Zone is 600 m by 64 m wide.
Province: Superior
Subprovince: Wabigoon
Geological Age: Archean
Dec 07, 2005 (R Degagne) - The area was mapped by Lawson (1886), Thomson (1937), and Ayer et al (1989). The geology of the area comprises ultramafic to intermediate metavolcanics and syenitic intrusive rocks.
| Rock Type | Rank | Composition | Texture | Relationship | Intermediate lava flow-unsubdivided | 1 | Near |
|---|---|---|---|---|
| Syenite | 2 | Near | ||
| Ultramafic Schist | 3 | Tc-Chl-Amp Schist | Fine Grained | Host |
Dec 07, 2005 (R Degagne) - The soapstone occurs within fine-grained, dark green, ultramafic metavolcanics; now talc-chlorites-amphibole schist. Pillows are evident within the metavolcanics at the north end of the small island. At the south end of the island, mica is evident along fracture surfaces within the metavolcanics.
| Rank | Mineral Name | Class | Economic Mineral Type | Alteration Mineral Type | Alteration Ranking | Alteration Intensity | Alteration Style |
|---|---|---|---|---|---|---|---|
| 1 | Talc | Economic | Ore | ||||
| 1 | Chlorite | Economic | Gangue | ||||
| 2 | Amphibole | Economic | Gangue | ||||
| 3 | Dolomite | Economic | Gangue | ||||
| Talc | Alteration | Steatization | 1 | ||||
| Chlorite | Alteration | Steatization | 2 | ||||
| Dolomite | Alteration | Steatization | 3 |
Dec 07, 2005 (R Degagne) - STONE DESCRIPTION: The stone is fine grained, dark grey in colour, soft and highly suited to carving. X-ray diffraction mineral analysis reported by Storey (1986) indicated the rock is variable in composition. One sample was predominately talc and chlorite with amphibole and dolomite; a second sample contained primarily chlorite and amphibole with lesser talc. The second sample is presumably a less altered rock than the first.
| Shape | Length | Thickness | Depth | Strike | Dip | Plunge | Trend | Age | Reference |
|---|---|---|---|---|---|---|---|---|---|
| Unknown | 2.5 | 60 |
Date: Feb 24, 1997
Geologist: R Degagne
Notes: DESCRIPTION OF SITE: On the southeast shore of the island there is a small pit, approximately 1 m wide, where material has been removed. Previous workers have described the soapstone unit as approximately 60 m in width (Storey 1986; Resident Geologist's files, MNDM, Kenora). The authors noted only a 2 m to 3 m wide unit of material soft enough to the shore of the island (060?) and dips very steeply.
Part - Geology of the north central part of the Lake of the Woods
Publication Number: ARV45-03.001 Date: 1997
Author: Thomson J.E.
Publisher Name: Ontario Dept. of Mines
Location:
Mono - Talc in Ontario
Publication Number: IMR040 Date: 1998
Author: Hewitt D.F.
Publisher Name: Ontario Dept. of Mines and Northern Affairs
Location:
Mono - Building and ornamental stone inventory in the districts of Kenora and Rainy River
Publication Number: MDC027 Page: 168 Date: 1986
Author: Storey C.C.
Publisher Name: Ontario Geological Survey
Location:
Mono - Soapstone in Ontario
Publication Number: OFR5764 Page: 45-46 Date: 1991
Author: Gerow M.C., Sherlock E.J., Bellinger J.A.
Publisher Name: Ontario Geological Survey
Location:
Mono - Industrial minerals of northern Ontario-supplement 1
Publication Number: OFR5388 Date: 1982
Author: Vos M.A., Abolins T., Smith V.
Publisher Name: Ontario Geological Survey
Location:
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