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Ontario Geological Survey
Permanent Link to this Record:
MDI52H06SE00002
| Record Name(s) | Poshkokagan River Marble Occurrence - 1996 |
|---|---|
| Related Record Type | Simple |
| Related Record(s) | |
| Record Status | Occurrence |
| Date Created | 2002-May-15 |
| Date Last Modified | 2022-Apr-27 |
| Created By | |
| Revised By |
Primary Commodities: Marble (Building Stone)
Township or Area: Circle Lake Area
Latitude: 49° 21' 43.37" Longitude: -89° 9' 32.53"
UTM Zone: 16 Easting: 343236 Northing: 5469946 UTM Datum: NAD83
Resident Geologist District: Thunder Bay South
NTS Grid: 52H06SE
Point Location Description: ~21 km south of the river's mouth in Chief Bay, Lake Nipigon (~16 km west of Black Sturgeon Lake).
Location Method: Data Compilation
Access Description: There are various logging and winter roads that provide access to the river valley.
The 'marbles' of the river valley were identified and mapped by Bell (1870) and Wilson (1910). In the 1930s various prospectors explored the area and returned to Thunder Bay with samples that had potential for use as a building and ornamental stone. At that time, these deposits were used to encourage the construction of a railroad to access the area west of Lake Nipigon. This would allow for the development of the marble deposits as well as the chromite at Obonga Lake. The railway was never constructed and the area has remained inactive since. As of 1994, the area is unstaked.
Province: Southern
Subprovince: Nipigon Basin
Formation Group: Sibley Group
Geological Age: Mesoproterozoic
Dec 07, 2005 (Mark O'Brien) - Areas of the Poshkokagan River valley are underlain by Proterozoic argillaceous dolomitic limestone of the Sibley Group and intrusive Keweenawan diabase sills and dikes. The area near the river has extensive drift and overburden coverage, therefore the best exposures are within the river valley. A gorge in the upper Poshkokagan River has a depth of 43 m which is covered by talus. There are areas exposed within the cliffs that show the marble units. JOINTING: The beds within the unit reach a maximum thickness of 0.6 m and dip slightly southward. COLOUR: The prevailing colour of the stone is white or yellowish white, but some beds are mottled pale green and red. The stone weathers easily to a grey-white clay. TEXTURE: The stone is fine grained. Historical articles state that beds of white dolomite, up to 2 feet in thickness occur in a 140 foot deep gorge, found in the upper reaches of the Poshkokagan River. Although this particular occurrence was not found, the authors (Hinz et al) feel that the most likely spot to look would be at Lime Lake or at the south end of Poshkokagan Lake. With the discovery of the McCrindle Marble Occurrence in 1993, the possibility exists for other large marble occurrences to be found.
| Rock Type | Rank | Composition | Texture | Relationship | Dolomite Marble | 1 | Is |
|---|---|---|---|---|
| Limestone | 1 | Argillaceous And Dolomitic | Fine Grained | Host |
| Diabase | 2 | Diabase | Logan Sills And Dikes | Near |
Dec 07, 2005 (Mark O'Brien) - JOINTING: The beds within the unit reach a maximum thickness of 0.6 m and dip slightly southward. COLOUR: The prevailing colour of the stone is white or yellowish white, but some beds are mottled pale green and red. The stone weathers easily to a grey-white clay. TEXTURE: The stone is fine grained.
| Rank | Mineral Name | Class | Economic Mineral Type | Alteration Mineral Type | Alteration Ranking | Alteration Intensity | Alteration Style |
|---|---|---|---|---|---|---|---|
| 1 | Dolomite | Economic | Ore |
| Rank | Classification |
|---|---|
| 1 | Metamorphic |
| 2 | Sedimentary |
| 1 | Skarn |
Map - Black Sturgeon Lake sheet, Thunder Bay District
Publication Number: M2233 Scale: 1:63,360 Date: 1972
Author: Coates M.E.
Publisher Name: Ontario Dept. of Mines and Northern Affairs
Location:
MonoMap - Geology of the Black Sturgeon River area, District of Thunder Bay
Publication Number: R098 Date: 1972
Author: Coates M.E.
Publisher Name: Ontario Dept. of Mines and Northern Affairs
Location:
Map - Lake Nipigon, Thunder Bay District, Ontario
Publication Number: Map 8A Scale: 1:253,440 Date: 1910
Author: Dickison, A.
Publisher Name: Geological Survey of Canada
Location: https://doi.org/10.4095/107994
Mono - Dimensional Stone Occurrences and Deposits in Northwest Ontario
Publication Number: OFR5890 Date: 1994
Author: Hinz P., Landry R.M., Gerow M.C.
Publisher Name: Ontario Geological Survey
Location:
Publication - Geology of the Nipigon Basin, Ontario; Geological Survey of Canada, Memoir no. 1
Publication Number: GSC Memoir 1 Page: 68 Date: 1910
Author: Wilson, A.W.G.
Publisher Name: Geological Survey of Canada
Location: https://doi.org/10.4095/100476
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For detailed information regarding this mineral record please contact the Thunder Bay South Resident Geologist District Office