Ontario Mineral Inventory

Ontario Geological Survey
Permanent Link to this Record: MDI52O12SE00006

Record: MDI52O12SE00006

General

Commodities

Primary Commodities: Gold

Location

Township or Area: Stoughton Lake Area

Latitude: 51° 33' 38.94"    Longitude: -91° 31' 14.47"

UTM Zone: 15    Easting: 602544.003   Northing: 5713230.002    UTM Datum: NAD83

Resident Geologist District: Thunder Bay North

NTS Grid: 52O12SE

Point Location Description: Transfer

Location Method: Conversion from MDI

Exploration History

1950: Chellow Gold Mines Ltd. Conducted geological mapping, trenching and diamond drilling in the Lower McVicar Lake area. 1959-1961: Kenlew Mines Ltd conducted geological mapping, stripping, trenching and diamond drilling in the lower McVicar Lake area and the area to the east of McVicar Lake. 1968-1969 New Jersey Zinc Exploration Company (Canada) Limited conducted geological mapping, geophysics, trenching and limited diamond drilling for VMS mineralization in the area north of north of McVicar Lake. 1971 Hoey Syndicate conducted geological mapping, trenching and geophysics for Cu-Ni-PGE mineralization in the lower half of the McVicar Lake area. 1977-1981, 1987, 1991 Cominco Ltd conducted extensive airborne geophysical surveys as well as diamond drilling over the McVicar Lake and Andy lake areas, well as limited diamond drilling in McVicar and Cannon Lake areas for gold and base metals. 1985-1994 Utah Mines, later BHP-Utah Mines, and then simply BHP conducted extensive grid mapping, geophysics and diamond drilling on the area surrounding McVicar Lake resulting in the discovery of the Altered Zone and Lower McVicar Lake structural zones and several associated gold showings. Utah Mines also conducted extensive work in the western Lang Lake area. 2001-2003 Prospector Consolidated Inc and Continuum Resources Ltd, conducted extensive trenching and limited diamond drilling for gold on the old BHP-Utah Mines property in the McVicar Lake area.

Assessment Work on File

Geology

Province: Superior

Subprovince: Uchi

Terrane: North Caribou

Domain: Uchi

Belt: Lang Lake

Geological Age: Neoarchean  

Geology Comments

Mar 27, 2007 (Mark Puumala) - Stott and Corfu (1991) describe the Lang Lake greenstone belt as being dominated by tholeiitic basalt flows and calc-alkalic pyroclastic deposits, with the eastern portion of the belt containing a significant clastic metasedimentary sequence that also includes iron formation horizons. The supracrustal rocks of this belt have been provisionally assigned to the Confederation Assemblage by Stott and Corfu (1991) based on a single age determination from a dacitic tuff in the lowermost (i.e., interpreted to be oldest) portion of the supracrustal rock sequence. The entire belt has been isoclinally folded into an east-trending and east-plunging syncline (Thomas 1988). Thomas (1988) also indicates that the belt contains two significant intrusions, including an east-west trending mafic stock in the Sor-McVicar Lakes area, and a later north-south trending felsic intrusion in the Shonia-McVicar Lakes area. The mafic intrusion has a number of Cu-Ni-PGE occurrences that have been documented near its northern contact, while the felsic intrusion hosts several gold occurrences. The dominant structural feature in the area is the Bear Head Fault Zone, which is located immediately to the southwest. This is an approximately northwest-southeast striking, regional-scale, dextral shear zone that has been classified by Stott and Corfu (1991) as a transcrustal megafault. This fault zone extends approximately 515 km from Lake Winnipeg to the northern boundary of the Meen-Dempster Greenstone Belt (Osmani and Stott 1988). Two additional WNW-ESE trending deformation zones referred to as the Lower McVicar Fault and Altered Zone Fault (McKay 2004) are also present in the area and are associated with a number of gold occurrences. Fumerton (1997) suggests a relationship between the Altered Zone Fault and the axial plane of the regional syncline. Fumerton (1997) indicates that supracrustal rocks between the Bear Head and Lower McVicar Faults have been folded into sigmoidal S-folds, and that a number of splay faults also exist in this area. The geometry of these structures has been interpreted as being consistent with a dextral sense of displacement.

Lithology

Mineralization

Mineralization Comments

Mar 27, 2007 (Mark Puumala) - The Sor Lake sill is a tonalite intrusion that hosts a number of gold occurrences within an area that is approximately 100 to 300 metres wide and up to 2 km long (McKay 2004). The locations of the five gold showings that make up this occurrence are provided on Figure 3 of McKay (2004). This map also indicates that a portion of the north contact of this intrusion coincides with the Lower McVicar Fault. Two styles of gold mineralization have been noted in the Sor Lake Sill by McKay (2004). The first type consists of the erratic distribution of gold in relatively narrow (1 cm to 2 m wide) quartz-carbonate veins. These veins typically strike northeasterly, are discontinuous, and cover a relatively short strike-length. The host tonalite intrusion is described by McKay (2004) as being variably altered and deformed, with alteration consisting of Ca- and Fe-carbonate, sericite and silicification. The tonalite also contains disseminated pyrite which may reach concentrations of up to 2-3% in localized areas. A number of late shear and fault zones have been noted in the area by McKay (2004). One of these shears, located in the vicinity of the most significant known vein (referred to by McKay (2004) as occurrence #6), is reported to strike between 104 and 111 and dips 85 degrees to the south. Shears with similar orientations are also shown by McKay (2004) on detailed maps of a trench (occurrence #10) located approximately 1 km to the east of occurrence #6. The large vein at occurrence #6 is described by McKay (2004) as a locally vuggy, white to smoky grey quartz +/- Fe-carbonate vein. The vein is up to 2 m wide, covers an exposed strike length of 35 m, and is oriented 060/80. The vein narrows and bifurcates to the east, and is reported to be truncated by the ESE-striking shear zone. Information provided on Map P of McKay (2004) indicates that some quartz veins are truncated by this shear zone, while others cross-cut and post-date it. Mineralization is reported by McKay (2004) to consist of disseminated pyrite, with occasional visible gold. Numerous smaller veins with similar orientations and mineralization were also mapped by McKay (2004) in the trench at occurrence #10. Gold values in these areas of quartz veining are reported to generally have a positive correlation with pyrite content. The most significant assay reported from occurrence # 6 by McKay (2004) was 3.20 g/t over 1.0 m in a channel sample collected from silicified tonalite adjacent to a disrupted portion of the large vein. A grab sample assay of vein material from a 9 cm wide vein at occurrence #10 was reported by McKay (2004) to have assayed 122.94 g/t. Fumerton (1997) reported an assay of 1.65 g/t Au over a true width of 1.75 m in McVicar Minerals ddh MV97-1. This drill hole targeted the large quartz vein at occurrence #6. The second type of mineralization described by McKay (2004) in the Sor Lake Sill consists of gold associated with 2 to 3% disseminated coarse to very coarse-grained euhedral pyrite. This mineralization is found at occurrence #10 of McKay (2004). The known extent of this mineralization is restricted to two irregular-shaped zones that cover a total area of approximately 70 m2 adjacent to the northern contact of the sill with intermediate to felsic metavolcanic rocks. A 1.0 m channel sample of this material is reported by McKay to have assayed 8.83 g/t.

Mineral Record Details

References

Article - Uchi subprovince

Publication Number: SV04-01.006 Page: 145-236  Date: 1997

Author: Stott G.M., Corfu F.

Publisher Name: Ontario Geological Survey

Location:

Article - Regional-scale shear zones in Sachigo Subprovince and their economic significance

Publication Number: MP141.006 Page: 53-67  Date: 1997

Author: Osmani I.A., Stott G.M.

Publisher Name: Ontario Geological Survey

Location:

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