Ontario Mineral Inventory

Ontario Geological Survey
Permanent Link to this Record: MDI42F05NW00004

Record: MDI42F05NW00004

General

Commodities

Primary Commodities: Copper

Secondary Commodities: Zinc

Location

Township or Area: Ramsay Lake Area

Latitude: 49° 24' 23.08"    Longitude: -85° 56' 24.36"

UTM Zone: 16    Easting: 576890.49   Northing: 5473176.19    UTM Datum: NAD83

Resident Geologist District: Thunder Bay North

NTS Grid: 42F05NW

Point Location Description: Several small pits

Location Method: Field Visit

Access Description: The Rockbound Lake copper occurrence is located approximately 32.25 km north-northwest of Manitouwadge. The occurrence is situated on the western shore of Rockbound Lake approximately 250 m south of a small creek which empties into the north end of the lake. The occurrence is accessible via motor vehicle followed by travel on foot. Alternatively, the occurrence may be accessed via air transport from Manitouwadge to Rockbound Lake followed by travel on foot. From Manitouwadge, proceed as follows: travel west and then north-northeast along the Caramat Industrial Road for approximately 42.5 km to the Lemay logging road. Proceed west along the Lemay logging road for approximately 8.9 km to the Rockbound Lake logging road. Proceed north-northeast along the Rockbound Lake logging road for approximately 5.7 km to an unnamed tertiary logging road. Proceed east along this unnamed road for approximately 400 m to a well-maintained trail (suitable for ATV's) located on the north side of the road. Proceed northeast along this trail for approximately 325 m to a small boat launch on the west shore of Rockbound Lake. Proceed southeast along the shoreline of Rockbound Lake for approximately 200 m. Several pits exposing copper mineralization are located on the high ground immediately west of the lake (within 150 m of the shore).

Exploration History

1970-1972: A. Wallace - Trenching; 1974: T. Basvik - Trenching. 1992: Lithogeochemical sampling; D.B. McKay (OGS).

Assessment Work on File

Geology

Province: Superior

Subprovince: Quetico

Geological Age: Archean  

Metamorphism Type: Regional

Metamorphism Grade: Amphibolite

Lithology

Lithology Comments

Apr 14, 2014 (D McKay) - The occurrence is located within the Quetico Subprovince and is underlain primarily by migmatitic, coarse-grained, moderately foliated (085 º/subvertical), garnet-biotite-quartz-feldspar paragneiss and diabase. Metamorphic grade in the area is upper amphibolite facies. The occurrence is spatially associated with a northwest-trending, linear topographic feature . In the vicinity of the occurrence, a 40 m wide diabase dike has intruded along this lineament. The contacts between the diabase and the host paragneiss are locally brecciated and mineralized with copper- bearing quartz-carbonate veins. The occurrence consists of erratically-distributed pyrite and chalcopyrite hosted primarily in narrow, coarse-grained quartz-calcite veins. The veins vary in width from 1 mm to 50 cm. The veins parallel the diabase-paragneiss contact, generally strike 320 º and dip vertically. The veins associated with the northern margin of the diabase dike are generally wider than those found along the southern margin. Individual veins display marked vertical and horizontal variations in size and degree of mineralization. The wall rock adjacent to the veins is commonly sheared and locally brecciated, silicified and carbonatized with calcite. Angular fragments of diabase up to 10 cm in size occur proximal to the margins of some of the wider veins.

Mineralization

Mineralization Comments

Apr 14, 2014 (D McKay) - The sulphides consist primarily of erratically distributed, fine- to coarse-grained, anhedral to euhedral pyrite and anhedral patches of chalcopyrite up to 2 cm in size. The sulphides commonly constitute 3 to 5% of the vein material, but local concentrations of up to 10% occur. Although chalcopyrite usually predominates over pyrite, the relative proportions of the sulphides vary within each vein. The host rocks, particularly the diabase, commonly contain 1 to 2% fine- to medium-grained pyrite and chalcopyrite as disseminated anhedral grains proximal to the veins. Fine-grained malachite and azurite occur along many of the fractures and foliation planes within the veins and host rocks. Grab samples collected from the occurrence in 1992 by D.B. McKay for the OGS returned assay results which included nil Au, nil Ag, 0.0176 to 1.1537% Cu, 0.0036% Zn and <0.001% Pb.

Mineral Record Details

References

Map - Stevens-Kagiano Lake area, District of Thunder Bay

Publication Number: P0362 Scale: 1:63,360    Date: 1997

Author: Coates M.E.

Publisher Name: Ontario Dept. of Mines

Location:

Mono - Mineral Occurrences in the Manitouwadge Area, Volumes 1, 2 and 3

Publication Number: OFR5906 Page: 410-416  Date: 1994

Author: McKay D.B.

Publisher Name: Ontario Geological Survey

Location:

File - Beardmore-Geraldton Resident Geologist Mineral Deposit Files

Publication Number: Min Dep Date:

Author:

Publisher Name:

Location: Thunder Bay RGO

Map - Stevens sheet, Thunder Bay District

Publication Number: M2141 Scale: 1:63,360    Date: 1967

Author: Coates M.E.

Publisher Name: Ontario Dept. of Mines

Location:

Map - Manitouwadge sheet, districts of Thunder Bay and Algoma, geological compilation series

Publication Number: P0494 Scale: 1:126,720    Date: 1997

Author: Milne V.G.

Publisher Name: Ontario Dept. of Mines

Location:

MonoMap - Geology of Stevens-Kagiano Lake area, District of Thunder Bay

Publication Number: R068 Date: 1968

Author: Coates M.E.

Publisher Name: Ontario Dept. of Mines

Location:

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Ministry Contact Information

For detailed information regarding this mineral record please contact the Thunder Bay North Resident Geologist District Office