Ontario Mineral Inventory

Ontario Geological Survey
Permanent Link to this Record: MDI000000000494

Record: MDI000000000494

General

Commodities

Primary Commodities: Gold

Location

Township or Area: Neawagank Lake Area

Latitude: 52° 26' 57.95"    Longitude: -89° 54' 23.04"

UTM Zone: 16    Easting: 302499.997   Northing: 5815000.002    UTM Datum: NAD83

Resident Geologist District: Thunder Bay North

NTS Grid: 53A05NW

Point Location Description: Assessment file maps.

Location Method: Data Compilation

Exploration History

1987-89: Geological mapping and diamond drilling by Power Explorations and Santa Maria Resources. 1996: Geological mapping and prospecting by Placer Dome Canada.

Assessment Work on File

Geology

Province: Superior

Subprovince: Berens River

Terrane: North Caribou

Domain: North Caribou Core

Belt: North Caribou

Geological Age: Mesoarchean  

Lithology

Mineralization

Mineralization Comments

Mar 12, 2008 (Mark Puumala) - Burk (1988) indicates that the area of this occurrence is underlain by a steeply west-dipping sequence of unaltered to carbonatized metavolcanics, magnetiferous chert transitional to garnetiferous pelitic sediments, and numerous bands of oxide facies iron formation. Gold mineralization is reported to be associated with two bands of oxide-facies iron formation that were intersected during a diamond drilling program conducted in the area in 1987 by Power Explorations (Burk 1988). Timoshenko and Corkery (1989) reported that the iron formation horizons are sheared and brecciated, and that the mineralized zone covers an approximate northwest-southeast strike length of 100 m, with the possibility of additional mineralization to the southeast and at depth. The eastern iron formation horizon is approximately 3 to 4.5 m thick and consists of chert, magnetite and grunerite (Burk 1988). Secondary pyrrhotite mineralization (>1%) occurs throughout this unit in brecciated and recrystallized chert, with localized chalcopyrite and arsenopyrite mineralization, and rare visible gold. Burk (1988) reported that the best assay from this horizon was 0.26 oz/ton Au over 0.6 m. The second (western) gold mineralized iron formation is separated from the eastern horizon by 9 to 12 m of metavolcanic and clastic metasedimentary rock, and has an approximate thickness of 4.5 to 6 m (Burk 1988). This iron formation is described as oxide- transitional to sulphide-facies iron formation consisting predominantly of pyrrhotite-biotite-almandine-magnetite, and grunerite-chert assemblages. Consistently anomalous gold values are reported by Burk (1988) to occur in the garnetiferous oxide-facies iron formation. Mineralization at this location is also hosted within quartz veins (Burk 1988). A vein associated with the eastern iron formation horizon that assayed 0.21 oz/ton Au over 0.43 m is reported to contain 1% pyrite, and trace pyrrhotite, arsenopyrite and visible gold. A quartz-pyrrhotite vein containing visible gold was also reported to occur in a 4.45 m wide drill hole intersection that produced an average assay of 0.059 oz/ton Au. Timoshenko and Corkery (1989) reported that the iron formation horizons in this area are folded horizons that extend northwest from a large, west-southwest trending antiform. The major west-southwest trending fold is also reported to have a well-developed axial planar fabric (i.e., foliation) that is parallel to shear zones and quartz veins. A geological compilation map prepared by Talbot (1996c) indicates the presence of a late northwest-striking fault zone immediately northeast of the mineralized zone. The proximity of this structure to an approximately parallel zone of mineralization suggests that it may have a genetic relationship. Burk (1988) reported anomalous gold assays (i.e., >0.02 oz/ton) from seven diamond drill holes advanced at this location in 1987 by Power Explorations, including NK-87-03, 15, 16, 17, 20, 21 and 23. Later drilling of this prospect reported by Timoshenko and Corkery (1989) also included anomalous assays in drill holes NK-88-2 and 3. A re-evaluation of the 1987-88 Power Explorations diamond drilling results by Talbot (1996c) suggested that the data do not indicate the presence of a continuous zone of gold mineralization within the folded iron formation. Talbot (1996c), who interprets the gold mineralization to be associated with the axial planar cleavage, has suggested that the historic diamond drilling pattern may explain the apparent lack of continuity of gold mineralization. This is because the drill holes, which were drilled from west to east, are oriented subparallel to the axial planar cleavage.

Mineral Record Details

References

File - Resident Geologist files: Report on diamond drilling, Neawagank Lake property for Power Explorations Inc.

Publication Number: AFTB53A05NW0030 Date: 1988

Author: Burk, C.P.

Publisher Name:

Location: Thunder Bay RGP donated files

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Ministry Contact Information

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