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Ontario Geological Survey
Permanent Link to this Record:
MDI52E10NE00016
| Record Name(s) | Corkscrew Island Graphite - 1936 |
|---|---|
| Related Record Type | Partial |
| Related Record(s) | |
| Record Status | Occurrence |
| Date Created | 1990-Dec-08 |
| Date Last Modified | 2022-Feb-14 |
| Created By | |
| Revised By |
Primary Commodities: Graphite
Township or Area: Clearwater Bay Area
Latitude: 49° 40' 46.11" Longitude: -94° 43' 2.02"
UTM Zone: 15 Easting: 376118 Northing: 5504410 UTM Datum: NAD83
Resident Geologist District: Kenora
NTS Grid: 52E10NE
Point Location Description: approximate location of sampling
Location Method: Data Compilation
Access Description: The deposit can be reached from Lake of the Woods.
The property is now part of a park
Province: Superior
Subprovince: Wabigoon
Geological Age: Archean
| Rock Type | Rank | Composition | Texture | Relationship | Chert | 1 | Graphitic | Vesicular | Is |
|---|---|---|---|---|
| Intermediate lava flow-unsubdivided | 2 | Carbonaceous | Strained | Contains |
Jan 20, 2014 (A Wilson) - The chert is vesiculated and always occurs as part of a band of black slate, massive chert or lean iron formation. The maximum observed width of these sedimentary zones was 25 ft. They are always interbedded with altered acid or basic lavas. The deposit is composed of lens shaped masses of vesicular graphitic metasediment in fine grained black slaty metasediments intercalated between fine grained grey-green schistose metasediments. At the point examined the black slaty unit is 3 m. Sericite and carbonate alteration were noted by the OGS in 1986.
| Rank | Mineral Name | Class | Economic Mineral Type | Alteration Mineral Type | Alteration Ranking | Alteration Intensity | Alteration Style |
|---|---|---|---|---|---|---|---|
| 1 | Graphite | Economic | Ore | ||||
| 2 | Pyrite | Economic | Gangue | ||||
| 3 | Marcasite | Economic | Gangue |
Jan 20, 2014 (A Wilson) - Freshly broken samples of the vesicular chert show a dense, black slate-like ground mass. The cavities range from ½ inch in diameter to microscopic dimensions. Most are empty, but some are partly filled with rounded masses of graphite, others contain a framework of graphitic flakes and fibres. At a few exposures, the vesicles are filled with pyrite or marcasite, but this is rare. An analysis of the carbonaceous rock by Lawson returned 5.77% C and an analysis by Greenland returned 8.24% carbon. Samples collected by the OGS in 1989 returned assays of total CO2 of 0.65% and non-carbonate carbon (graphite) of 4.4% C.
| Rank | Characteristic |
|---|---|
| 1 | Sheared |
Part - Geology of the north central part of the Lake of the Woods
Publication Number: ARV45-03.001 Scale: Date: 1997
Author: Thomson J.E.
Publisher Name: Ontario Dept. of Mines
Location:
Mono - An evaluation of the industrial mineral potential of parts of the districts of Kenora and Rainy River
Publication Number: OFR5718 Scale: Date: 1990
Author: Storey C.C.
Publisher Name: Ontario Geological Survey
Location:
Book - UN TO STU,GEO SER,1939,N.42,141-150
Publication Number: N/A Scale: Date: 1996
Author:
Publisher Name:
Location:
MonoMap - Precambrian geology, Clearwater Bay area
Publication Number: R280 Scale: Date: 1991
Author: Ayer J.A.
Publisher Name: Ontario Geological Survey
Location:
Map - North central part of the Lake of the Woods, District of Kenora, Ontario
Publication Number: ARM45B Scale: 1:63,360 Date: 1997
Author: Thomson J.E.
Publisher Name: Ontario Dept. of Mines
Location:
Map - Precambrian geology, Clearwater Bay area
Publication Number: M2549 Scale: 1:20,000 Date: 1991
Author: Ayer J.A., Sweeny J.M.
Publisher Name: Ontario Geological Survey
Location:
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For detailed information regarding this mineral record please contact the Kenora Resident Geologist District Office