Ontario Geological Survey
Permanent Link to this Record:
MDI41N11SE00006
| Record Name(s) | Devil's Warehouse Island - 1860, Devil's Warehouse Island Prospect - 1968 |
|---|---|
| Related Record Type | Simple |
| Related Record(s) | |
| Record Status | Occurrence |
| Date Created | 1983-Sep-13 |
| Date Last Modified | 2022-Jul-22 |
| Created By | |
| Revised By |
Primary Commodities: Manganese
Secondary Commodities: Hematite (Gemstones)
Township or Area: Alarie
Latitude: 47° 34' 18.59" Longitude: -85° 0' 4.55"
UTM Zone: 16 Easting: 650323.58 Northing: 5270648.43 UTM Datum: NAD83
Resident Geologist District: Sault Ste. Marie
NTS Grid: 41N11SE
Point Location Description: North end of vein on Devil's Warehouse Island
Location Method: Conversion from MDI
Access Description: The island is located in Lake Superior Provincial Park. The easiest access to the island is by canoe or kayak from Gargantua Harbour. Gargantua Harbour is located 15 km from Highway 17 along the Gargantua Road. Devil's Warehouse Island is located approximately 1.5 km off of the coast.
The vein has been known since at least 1860. It is suspected that the manganese and hematite on this island may have been used to paint the pictographs at Agawa. 1890: sampling. 1910: 12 trenches, 2 ddh (835 ft). 1936-42: diamond drilling. No assessment records are on file for this work.
| Office File Number | Online Assessment File Identifier | Online Assessment File Directory |
|---|---|---|
| ALARIE 0012 | 41N10NE0012 | 41N10NE0012 |
Province: Southern
Supergroup: Keweenawan Supergroup
Geological Age: Mesoproterozoic Geochronological Age: 1100 MA Geochron. Age Ref.: GOO VOL 1
Dec 07, 2005 (A Wilson) - The rocks of the Keweenawan Supergroup were deposited in and marginal to the Midcontinent Rift at approximately 1.1 Ga. They unconformably overlie the migmatites of the Ryan Mineral Location.
| Rock Type | Rank | Composition | Texture | Relationship | Breccia-unsubdivided | 1 | Rhyolite | Host |
|---|---|---|---|---|
| Felsic lava flow-unsubdivided | 2 | Rhyolite | Near | |
| Vein | 3 | Calcite | Host |
Dec 07, 2005 (A Wilson) - The vein occurs in a breccia zone along a fault. The rhyolite fragments in the breccia are angular to rounded and range in size from a fraction of an inch to several feet. Fragments are cemented by calcite, hematite, quartz, barite and manganite. The rhyolite is characterized by contorted flow layering and is very fine-grained. Rare phenocrysts of altered feldspar and hematite are seen in the rhyolite. The rhyolite is well-banded and complexly folded in several locations on the island. Jointing is common in the rhyolites exposed on the island.
| Rank | Mineral Name | Class | Economic Mineral Type | Alteration Mineral Type | Alteration Ranking | Alteration Intensity | Alteration Style |
|---|---|---|---|---|---|---|---|
| 1 | Manganite | Economic | Ore | ||||
| 2 | Hematite | Economic | Ore | ||||
| 1 | Calcite | Economic | Gangue | ||||
| 2 | Quartz | Economic | Gangue | ||||
| 3 | Barite | Economic | Gangue |
Dec 07, 2005 (A Wilson) - Manganite is the only manganese mineral identified. It is disseminated in and forms lenses in calcite pods. It is fine-grained, locally botryoidal and commonly associated with hematite. Manganite-hematite lenses are as much as 6 feet wide and although the average width is 1-2 inches. Quartz and barite form a minor component of the mineralized calcite lenses. Manganite and hematite are erratically distributed along the breccia zone. Grab samples collected by the GSC in 1942 of the high-grade manganese material returned 36.3% Mn and 7.21% Fe. A sample of the breccia returned 4.26% Mn. The OGS (1968) reports the largest high grade lens measured 4.2 m by 35 cm and assayed 29.2% Fe and 15.1% Mn. A grab sample collected in 1887 reportedly returned 45% Mn.
| Rank | Classification |
|---|---|
| 1 | Hydrothermal |
| Rank | Characteristic |
|---|---|
| 1 | Breccia |
| 2 | Vein |
| Shape | Length | Thickness | Depth | Strike | Dip | Plunge | Trend | Age | Reference |
|---|---|---|---|---|---|---|---|---|---|
| Regular | 670 | 7.6 | 328 | 60 | 1.1 MA | OGS GOO VOL 1 |
Map - Township 31, Range 19 [Alarie Township], District of Algoma
Publication Number: P0128 Scale: 1:15,840 Date: 1997
Author: Ayres L.D.
Publisher Name: Ontario Dept. of Mines
Location:
Mono - Iron deposits of Ontario
Publication Number: MDC011 Page: 30 Date: 1968
Author: Shklanka R.
Publisher Name: Ontario Dept. of Mines
Location:
Map - Townships 31 and 30, range 19, Algoma District
Publication Number: M2138 Scale: 1:31,680 Date: 1968
Author: Ayres L.D.
Publisher Name: Ontario Dept. of Mines
Location:
MonoMap - Geology of townships 31 and 30, ranges 20 and 19, District of Algoma
Publication Number: R069 Page: 78-80 Date: 1969
Author: Ayres L.D.
Publisher Name: Ontario Dept. of Mines
Location:
Publication - Manganese occurrences in Canada; Geological Survey of Canada, Paper 64-37
Publication Number: GSC Paper 64-37 Page: 29 Date: 1965
Author: Johnston, A G; Mccartney, W D
Publisher Name: Geological Survey of Canada
Location: https://doi.org/10.4095/100979
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