Ontario Geological Survey
Permanent Link to this Record:
MDI000000000332
| Record Name(s) | Lake St. Joseph South Zone - 1982 |
|---|---|
| Related Record Type | |
| Related Record(s) | |
| Record Status | Developed Prospect With Reported Reserves or Resources |
| Date Created | 2007-Jun-21 |
| Date Last Modified | 2023-Mar-23 |
| Created By | |
| Revised By |
Primary Commodities: Iron
Township or Area: Carling Island Area
Latitude: 51° 1' 53.26" Longitude: -90° 31' 12.34"
UTM Zone: 15 Easting: 673885 Northing: 5656250.01 UTM Datum: NAD83
Resident Geologist District: Thunder Bay North
NTS Grid: 52O02SE
Point Location Description: Goodwin (1965).
Location Method: Data Compilation
Province: Superior
Subprovince: Uchi
Terrane: North Caribou
Domain: Uchi
Belt: Lake St. Joseph
Geological Age: Neoarchean
Jun 21, 2007 (Mark Puumala) - The Lake St. Joseph iron prospect consists of two low-grade magnetite iron formation deposits (North and South Zones) hosted within a clastic metasedimentary rock-dominated sequence (Goodwin 1965). The metasedimentary sequence is reported to consist of a variety of lithologies ranging from conglomerate to argillite, and is intercalated with metavolcanic tuff and amphibolite units. The iron formations are reported by Goodwin (1965) to be closely associated with argillaceous schist units that occur near the upper (northern) contact of the metasedimentary sequence with an overlying metavolcanic rock-dominated assemblage. The iron formation is described by Goodwin (1965) as banded iron formation consisting of alternating 1 to 25 cm thick layers of black magnetite-rich material, white quartz-rich layers, and grey, green or brown silicate-rich (clastic sediment-dominated) layers. The richest zones in each iron formation (i.e., with highest concentration of magnetite layers) are reported to occur near the northern contacts of each deposit. Goodwin (1965) reports that the rocks of this area lie on the north limb of an east-northeast-trending, and east-northeast-plunging (35 to 60 degrees) anticline. This limb of the structure is overturned, with bedding generally reported to dip between 60 to 80 degrees toward the south. Smaller-scale complex folding of the iron formation is also reported by Goodwin (1965), with numerous reversals in younging direction noted in various portions of the deposits.
| Rock Type | Rank | Composition | Texture | Relationship | Ironstone-unsubdivided | 1 | Is |
|---|---|---|---|---|
| Sandy Conglomerate | 2 | Conglomerate To Argillite | Adjacent | |
| Intermediate Tuff | 3 | Tuff | Near | |
| Amphibolite | 4 | Amphibolite | Near |
| Rank | Mineral Name | Class | Economic Mineral Type | Alteration Mineral Type | Alteration Ranking | Alteration Intensity | Alteration Style |
|---|---|---|---|---|---|---|---|
| 1 | Magnetite | Economic | Ore |
Jun 21, 2007 (Mark Puumala) - The South Zone deposit is located approximately 2.5 km to the southwest of the North Zone (MDI52O01SW00003), which may represent a folded repetition of the same iron formation (Goodwin 1965). This deposit is reported by Goodwin (1965) to have a minimum strike length of 3.65 km, and ranges in width from approximately 100 to 245 m. The deposit strikes approximately 075 at its eastern end and 110 at the west end and dips toward the south at angles ranging from 60 to 80 degrees. Goodwin (1965) reports that diamond drilling has outlined the South Zone deposit to a depth between 90 and 150 m. Sage and Breaks (1982) report a reserve estimate of 280,030,000 tonnes grading 22.19% Fe for this zone.
| Rank | Classification |
|---|---|
| 1 | Sedimentary |
| Rank | Characteristic |
|---|---|
| 1 | Stratabound |
| Zone | Year | Category | Tonnes | Reference | Comments | Commodities |
|---|---|---|---|---|---|---|
| South Zone | 1982 | Unclassified | 280030000 | Sage and Breaks (1982). | Estimated grade is 22.19% Fe. This reserve calculation pre-dates NI 43-101. | Iron 22.19 % |
MonoMap - Geology of the Cat Lake-Pickle Lake area, districts of Kenora and Thunder Bay
Publication Number: R207 Date: 1982
Author: Sage R.P., Breaks F.W.
Publisher Name: Ontario Geological Survey
Location:
MonoMap - Geology of Pashkokogan Lake-eastern Lake St. Joseph area, districts of Thunder Bay and Kenora
Publication Number: R042 Date: 1997
Author: Goodwin A.M.
Publisher Name: Ontario Dept. of Mines
Location:
We are continuously updating our assessment file / technical report information. If you notice errors in the data, please contact us.
Please review our Terms of Use agreement for this data product.
For detailed information regarding this mineral record please contact the Thunder Bay North Resident Geologist District Office