Ontario Mineral Inventory

Ontario Geological Survey
Permanent Link to this Record: MDI42F05NE00004

Record: MDI42F05NE00004

General

Commodities

Primary Commodities: Copper

Location

Township or Area: Thomas Lake Area

Latitude: 49° 22' 39.26"    Longitude: -85° 43' 18.48"

UTM Zone: 16    Easting: 592780.983   Northing: 5470215.517    UTM Datum: NAD83

Resident Geologist District: Thunder Bay North

NTS Grid: 42F05NE

Point Location Description: Shoreline outcrop

Location Method: Based on Assessment

Access Description: The Beavercross Lake (South) copper occurrence is located approximately 29.1 km north-northeast of Manitouwadge. The occurrence is situated on the east shore of the southeastern arm of Beavercross Lake. The occurrence is accessible via motor vehicle followed by travel on foot and then by canoe. Alternatively, the occurrence may be accessed via air transport from Manitouwadge to Beavercross Lake followed by travel on foot. From Manitouwadge, proceed as follows: travel west then north-northeast along the Caramat Industrial Road for approximately 43.4 km to the Sonley logging road. Proceed east along the Sonley logging road for approximately 7.25 km to an unnamed, secondary logging road. Proceed northeast along this unnamed road for approximately 1.9 km to a small, deteriorated log bridge which crosses a shallow creek. Proceed across the bridge and continue travelling northeast for approximately 100 m to a poorly marked trail located on the south side of the road. Proceed east along this trail through swampy brush for approximately 100 m to a creek which flows into the southwest arm of Beavercross Lake. Proceed, via canoe, for approximately 3.5 km to the tip of the southeast arm of Beavercross Lake. The occurrence is located on the east shore approximately 120 m northwest of the tip (Condon 1965).

Exploration History

1965: Line cutting, trenching, stripping, geological mapping, ground geophysical surveys (MAG, VLEM) and diamond drilling (1 hole, 99.06 m long, located approximately 1.4 km southeast of the occurrence); Mining Corp. of Canada (1964) Ltd. Geological mapping; M.E. Coates (ODM). 1978-1979: Regional lake sediment and water geochemical survey; GSC-MNR. A sample collected from Beavercross Lake contained slightly anomalous amounts of Cu and Ni. 1989: Geological mapping; H. Williams and F. Breaks (OGS). Dighem airborne geophysical survey; Noranda Exploration Company, Limited and Noranda Minerals Inc. (Geco Division). 1991-1992: Reconnaissance till sampling survey; GSC. Samples collected southwest of the occurrence contained slightly anomalous amounts of gold and zinc.

Assessment Work on File

Geology

Province: Superior

Subprovince: Quetico

Geological Age: Archean  

Metamorphism Type: Regional

Metamorphism Grade: Amphibolite

Geology Comments

Dec 07, 2005 (D McKay) - The occurrence is located within the Quetico Subprovince and is underlain primarily by migmatitic, coarse-grained, moderately foliated, garnet-biotite-quartz-feldspar paragneiss and diabase. The paragneiss commonly displays a well-developed lit-par-lit structure. The gneissosity in the rocks is variable, but tends to strike west and dip steeply to the north (268 degrees/85 degrees N). Garnet porphyroblasts, up to 5 mm in diameter, locally comprise up to 5% of the paragneiss. Metamorphic grade in the area is upper amphibolite. The occurrence is spatially associated with a northwest-trending (318 degrees) linear topographic feature (Coates 1968, Map 2141). This lineament has been interpreted by Condon (1965) to represent the trace of an oblique, dextral fault. A diabase dike has intruded along this lineament in the vicinity of the Beavercross Lake (North) copper-silver occurrence, located approximately 2.9 km to the northwest. Geophysical data (Britton 1965) suggest the same dike has also intruded along this lineament in the vicinity of the Beavercross Lake (South) copper occurrence.

Lithology

Lithology Comments

Dec 07, 2005 (D McKay) - The occurrence is located within the Quetico Subprovince and is underlain primarily by migmatitic, coarse-grained, moderately foliated, garnet-biotite-quartz-feldspar paragneiss and diabase. The paragneiss commonly displays a well-developed lit-par-lit structure. Garnet porphyroblasts, up to 5 mm in diameter, locally comprise up to 5% of the paragneiss. The diabase is generally massive and locally porphyritic containing up to 10% pale-green plagioclase phenocrysts varying in size up to 8 mm in diameter. The contacts between the diabase and the host paragneiss are locally sheared, brecciated, and mineralized with copper-bearing quartz-carbonate veins.

Mineralization

Mineralization Comments

Apr 26, 2011 (N Bennett) - Condon (1965, p.1) described the copper mineralization comprising the Beavercross Lake (South) copper occurrence as follows: The copper mineralization is chalcopyrite in sheared quartz veins which trend parallel to the major diabase fault zone. On page 3 of his report, Condon (1965) provides the following additional comments regarding mineralization in the area: A second copper showing is located on line 92 south at 18+50 feet of the main grid. This occurrence is very minor although similar in nature to the copper showing on line 4 north. Outcrop is very scarce in this area. The showing consists of 3 or 4 blebs of chalcopyrite up to 3/16 inch in 2 vuggy quartz veins. One vein is 4 inches wide, the other is 3/4 inch wide. No assay data for the Beavercross Lake (South) copper occurrence is presented in the report filed for assessment credit by the Mining Corporation of Canada (1964), Limited. A chip sample taken across the width of 0.61m by Mining Corporation of Canada Ltd returned assay values of 5.61% Cu, 1.05 Ounces Ag per ton, 0.005 ounce Au per ton, trace Ni, and nil Pb and Zn.

Alteration Comments

Dec 07, 2005 (D McKay) - The contacts between the diabase and the host paragneiss are locally sheared, brecciated, and mineralized with copper-bearing quartz-carbonate veins.

Mineral Record Details

References

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 - Geology of the Manitouwadge-Hornepayne area

Publication Number: OFM0142 Scale: 1:50,000    Date: 1990

Author: Williams H.R., Breaks F.W.

Publisher Name: Ontario Geological Survey

Location:

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

Publication Number: OFR5906 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 RGP

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