Ontario Mineral Inventory

Ontario Geological Survey
Permanent Link to this Record: MDI53B09NW00004

Record: MDI53B09NW00004

General

Commodities

Primary Commodities: Gold

Location

Township or Area: Skinner Lake Area

Latitude: 52° 39' 42.21"    Longitude: -90° 23' 56.25"

UTM Zone: 15    Easting: 675902.18   Northing: 5837816.88    UTM Datum: NAD83

Resident Geologist District: Thunder Bay North

NTS Grid: 53B09NW

Point Location Description: Transfer

Location Method: Conversion from MDI

Exploration History

1981-82: Geophysical, geological and geochemical surveys, trenching and prospecting by 493217 Ontario Ltd. 1985-88: Geological mapping, prospecting, trenching and diamond drilling by Van Horne Gold Explorations Inc., Oracle Resources Ltd. and Power Explorations Inc. 1994-1995: Pangea Goldfield -Geological mapping, magnetic survey and sampling. 1997: Placer dome - Diamond drilling. 2001: Placer dome - geological mapping. 2002: Placer dome - geophysical survey. 2007: Goldcorp - Diamond drilling. 2008: Premier Gold - Aeromagnetic survey. 2009: Premier Gold - Diamond Drilling. 2009: Goldcorp - Magnetometric survey, prospecting. 2010-11: Premier - 21 DDH totalling 20701.5 m.

Assessment Work on File

Geology

Province: Superior

Subprovince: Berens River

Terrane: North Caribou

Domain: North Caribou Core

Belt: North Caribou

Geological Age: Mesoarchean  

Geology Comments

Mar 18, 2008 (Mark Puumala) - Elliott and Corkery (1988) described the geology in the area of this prospect as being dominated by a large north-northwest-trending syncline. The core of this syncline consists largely of clastic metasedimentary rocks of the Eyapamikama metasedimentary assemblage (Thurston, Osmani and Stone 1991). The metasedimentary rocks are flanked to the east and west by the mafic metavolcanic rock dominated North Rim and South Rim units of the McGruer assemblage (Thurston, Osmani and Stone 1991). The mafic metavolcanic-dominated units contain local horizons of clastic metasediments, felsic and ultramafic metavolcanics and oxide facies iron formation (Elliot and Corkery 1988). The supracrustal rocks are reported by Elliott and Corkery (1988) to be intruded by lamprophyre dikes, sub-concordant to concordant quartz-feldspar porphyry dikes, ultramafic sills and at least one large Proterozoic-age diabase dike. A large granodiorite intrusion is located on the eastern margin of the greenstone belt to the east of the North Rim metavolcanic unit. The western limb of the major syncline is complicated by the presence of a smaller north-northwest-plunging anticline (Elliott and Corkery 1988). This structure contains two bands of oxide facies iron formation that have a close spatial association with gold mineralization in the North Opapimiskan Zone Anticline deposit. The core of the anticline is comprised of mafic metavolcanic rocks that are overlain by a thin lower banded iron formation. This iron formation is in turn overlain by mafic to ultramafic metavolcanics that are overlain by the main band of iron formation. This iron formation grades into a pelitic metasedimentary horizon that is overlain by a sequence of intercalated mafic flows, pelitic sediments, wackes and arenites (Elliott and Corkery 1988). Elliott and Corkery (1988) reported that the nose of the gold-mineralized anticline was mechanically stripped, mapped and sampled by Power Explorations in 1987. The stripped outcrop in this area consists of highly-contorted chert-grunerite-magnetite banded iron formation. Minor folds are reported by Elliott and Corkery (1988) to have trends between azimuth 321 to 329, with plunges ranging from 25 to 28 degrees. The average orientation of the fold axial planes is reported to be 147/80. Anomalous gold mineralization in this surface exposure is associated with weakly limonitic banded iron formation containing no visible sulphide mineralization (Elliott and Corkery 1988). Channel sample assays of up to 4940 ppb Au over 1.28 m were reported.

Lithology

Mineralization

Mineralization Comments

Mar 05, 2014 (Mark Puumala) - Between 1985 and 1988, three diamond drilling programs consisting of 89 drill holes were carried out by Van Horne Gold Exploration, Oracle Resources and Power Explorations to test the North Opapimiskan Lake Anticline Zone (Adams 1985, Corkery 1987, Corkery and Elliott 1988). Based on the results of the 49 diamond drill hole 1987-88 Power Explorations exploration program, Corkery and Elliott (1988) subdivided this prospect into three zones (Zones A, B and C). Zone A is described as a sheet-like and gently warped body at the contact between mafic metavolcanics and pelitic metasedimentary rocks on the west limb of the anticline. The zone is described as a sheet-like body that dips 20 to 25 degrees to the west-southwest, plunges 26 to 28 degrees to the northwest and is 1.22 to 4.57 m thick. The zone has been traced for 200 m down-dip and 230 m down-plunge. Mineralization in the mafic metavolcanics consists of minor sulphide and quartz-calcite veinlets containing occasional visible gold, while mineralization in the pelitic metasedimentary rocks consists of abundant quartz-carbonate veinlets and up to 7% pyrrhotite, pyrite and minor chalcopyrite (Corkery and Elliott 1988). The most notable assay reported from this zone by Corkery and Elliott (1988) was 0.837 oz/ton Au over 4.39 m. Corkery and Elliott (1988) indicated that Zone B is located in the apex of the main anticline, and has a shape similar to a flattened rod that plunges 28 degrees to the north-northwest. The zone has an average width of 53 m, covers a minimum strike length of 122 m, and has been intersected to a vertical depth of 218 m. Gold mineralization typically occurs in quartz-pyrrhotite-pyrite veins and in areas of the iron formation containing pyrrhotite +/- pyrite mineralization. The mineralized quartz veins are typically oriented near-parallel to the axial planar cleavage, while sulphides generally occur as an alteration product of magnetite, as fracture-fillings, and in pressure shadows in garnets (Corkery and Elliott 1988). The most notable assay from this zone reported by Corkery and Elliott (1988) was 0.218 oz/ton Au over 1.19 m. Corkery and Elliott (1988) indicated that Zone C is hosted by a 1.52 to 1.83 m thick unit of wacke and pelite on the west limb of the anticline, in close proximity to the fold axis. The zone is greater than 122 m long, up to 61 m wide, and has been intersected to a depth of 105 m. The mineralized zone plunges 31 to 35 degrees to the north-northwest and dips gently to the southwest (Corkery and Elliott 1988). This zone is reported to be mineralized with 1 to 3% pyrrhotite and contains quartz veinlets containing rare visible gold. The most notable assay form this zone reported by Corkery and Elliott (1988) was 0.221 oz/ton over 1.40 m. Numerous significant assays have been reported by Adams (1985), Corkery (1987), and Corkery and Elliott (1988) from other areas of the North Opapimiskan Lake Anticline. 2010-2011 drill program by Premier Gold - assays ranged from 5.10 g/t up to 58.44 g/t, all across 1 m.

Mineral Record Details

References

Article - Northwestern Superior province: review and terrane analysis

Publication Number: SV04-01.005 Date: 1997

Author: Thurston P.C., Osmani I.A., Stone D.

Publisher Name: Ontario Geological Survey

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