Ontario Mineral Inventory

Ontario Geological Survey
Permanent Link to this Record: MDI000000001916

Record: MDI000000001916

General

Commodities

Primary Commodities: Gold, Zinc, Silver

Secondary Commodities: Copper, Lead

Location

Township or Area: Brothers

Latitude: 48° 38' 14.36"    Longitude: -85° 43' 45.88"

UTM Zone: 16    Easting: 593606   Northing: 5387919    UTM Datum: NAD83

Resident Geologist District: Thunder Bay South

NTS Grid: 42C12NW

Point Location Description: Map in Assessment file 20000007421

Location Method: Based on Assessment

Access Description: The property is situated south of Highway 17 (TransCanada Highway) between the towns of Marathon (40 km west) and White River (20 km east). Road access to the Gouda Lake area is good and is accomplished by means of the well-maintained Domtar 700 logging road system, which runs west-southwest to the Gouda Lake area from the community of White River.

Exploration History

1981-82: Lac Minerals Ltd. conducted reconnaissance mapping, soil sampling, and airborne EM and magnetometer geophysical surveys. 1983: Lac Minerals conducted detailed mapping, grid cutting, geochemical soil sampling, and geophysical surveys (VLF, IP and magnetometer). 1984: Lac Minerals conducted detailed mapping. 1985: Lac Minerals conducted a drill program in the Gouda Lake area. 1988: Lac Minerals drilled 3 DDH, including the discovery hole (N-12-1). 1989: Lac Minerals drilled 19 DDH. 1994: Lac Minerals became a subsidiary of Barrick Gold Corp. Barrick optioned the property to Placer Dome, who conducted geological mapping. 1999: Teck Exploration optioned the property from Barrick. 1999-2001: Teck conducted geological mapping, prospecting, lithogeochemical sampling, humus and soil geochemistry, trenching, drilling, relogging and resampling of historic core, and drilled 11 DDH. 2007: MetalCorp Ltd. staked the property. 2009: A. Fage completed a geological study for a Master’s thesis, partially by MetalCorp. 2010: MetalCorp drilled 29 DDH totaling 3650 m. 2012: MetalCorp and Cava Resources Ltd. signed a joint venture agreement and drilled 5 DDH totaling 1056 m. 2013: Joint venture agreement terminated by Cava, property reverted completely to MetalCorp.

Assessment Work on File

Geology

Province: Superior

Subprovince: Wawa

Terrane: Wawa-Abitibi

Belt: Schreiber-Hemlo

Geological Age: Archean  

Lithology

Lithology Comments

Apr 21, 2016 (Therese Pettigrew) - In the Gouda Lake area, both bedding and foliation in the rocks generally dip moderately steeply (35-55 degrees) northward. The stratified rocks in the grid area are bound on the south by granitoid rocks of the Pukaskwa batholith. Immediately north of the batholith, the southernmost and structurally lowest stratified rocks are biotite amphibolite, a unit which has also been termed a mafic metavolcanic, which is a reasonable protolith for these metamorphic rocks. The amphibolite is overlain by a package of schistose to gneissose biotite quartzofeldspathic rocks, most likely metamorphosed intermediate to felsic volcanic and derived sedimentary rocks. The schistose rocks commonly host a relatively thin layer of pyrite biotite white mica schist (the white mica may be muscovite, phlogopite or “sericite”) which contains local quartz eyes and which also hosts the gold-mineralized Gouda Lake zone. According to Fage (2011), the quartz eye-bearing schistose rocks of the Gouda Lake horizon are a metamorphosed primary felsic volcanic rock; they yielded a 2704.8 +/- 1.1 Ma U-Pb zircon date (Fage 2011). The biotite-bearing quartzofeldspathic schist-gneiss in the Gouda Lake grid area and its interpreted protoliths have been termed differently by previous mappers. For example, Guthrie (1985), described the rocks as gneissic quartzofeldspathic metasedimentary rocks. In contrast, McIlveen et al.(1984), also mapping for Lac Minerals, subdivided these rocks into two units: metasedimentary rocks (fine-grained siliceous rocks, pelitic schists or biotite-rich sedimentary rocks) and “intermediate” volcaniclastic rocks (fine-grained tuffs). Mappers for Placer Dome also subdivided the rocks into two map units: one termed a wacke and the other an arkosic wacke. Both were described as being feldspar dominant rocks containing <50% quartz, but the “wackes” containing greater than 15% biotite and the “arkosic wackes” containing <5% mafic minerals. Subunits within this sequence were all described as fine-grained gneissic rocks, with mm-scale compositional layers outlined by varying amounts of biotite, amphibole, quartz, and feldspar (Shevchenko 1995). In the Teck Exploration mapping, the Gouda Lake zone host sequence is described as clastic sedimentary rocks (biotite and hornblende wackes and derived gneisses) but they also included mafic and intermediate volcanic schists and gneisses within the same stratigraphic package (Thompson et al. 1999). To the north, the host biotite schist-gneiss to the Gouda Lake horizon and its contained mineralization are overlain by another more mafic sequence, also dominated by biotite amphibolite, which in this case includes a well-defined and distinctive “marker” layer, known locally as the Poker Chip horizon, which has previously been interpreted to represent a metamorphosed lapilli tuff. Near the northernmost limits of MetalCorp’s Gouda Lake area cut grid, another package of biotite quartzofeldspathic schist-gneiss outcrops and contains a number of layers of white mica schist which are at least outwardly similar in appearance to the Gouda Lake horizon rocks. This northern belt of schist-gneiss rocks also hosts discontinuous layers of amphibolite that have been interpreted as mafic coarse-grained flows and tuff; they thicken to the east and pinch out to the west. Within the bounds of the Gouda Lake area grid, and elsewhere on the Hemlo East property, stratified rocks also host common feldspar porphyry and granite pegmatite intrusions. The felsic intrusions in most cases lie parallel to the foliation common to the stratified rocks and are themselves commonly foliated, although the intrusions are typically less well-foliated than their hosts. Finally, all of the stratified and intrusive rocks on the Gouda Lake grid, including the porphyries and pegmatites, have been cut by Proterozoic diabase dykes (AFRO 2.48501)

Mineralization

Mineralization Comments

Apr 21, 2016 (Therese Pettigrew) - Anomalous gold was sampled from a quartz eye muscovite schist unit. Mo/Bi veining is seen associated with pegmatite dykes and quartz veins in the Pukaskwa gneissic complex (AFRI 20000004912). The 2010 drill program successfully outlined a north-northwesterly plunging higher-grade core to the Gouda Lake zone which averages 2.8 g/t Au, 87 g/t Ag, 0.17% Pb, and 1.01% Zn (5.74 g/t Au eq) over an average thickness of 3.5 m. The core zone rakes to the north-northwest within the Gouda Lake horizon, an extensive (greater than 3 km along strike, and greater than 600 m down-dip) 10 to 20 m thick horizon of metamorphosed felsic volcanic and derived sedimentary rocks that is characterized by the presence of white mica, quartz, and pyrite. Mineralization in the core zone consists of disseminated to semi-massive and local massive sulphides (principally pyrite, but with subordinate pyrrhotite, sphalerite, galena, and chalcopyrite). In general the highest precious metals grades are spatially associated with the highest abundances of sulphides, although there is not necessarily a one-to-one correspondence between gold grades and sulphide abundance. Molybdenite mineralization also occurs in the Gouda Lake area. Occurrences have been noted near Duck Lake, where Fage (2011) described molybdenite occurring locally within quartz-feldspar porphyry dykes in amounts up to 20% , and where Guthrie (1985) reported trace to 5% molybdenite associated with pyrite in pegmatite dykes, metasedimentary rocks, and within mafic metavolcanics (amphibolite). These occurrences have certainly sparked some interest, as molybdenite is commonly associated with gold at Hemlo. Unfortunately, there appears to be little direct association between the molybdenite in the Gouda Lake area and the gold mineralization in the Gouda Lake zone. The gold-bearing part of the Gouda Lake horizon is without exception located in the lower 1 to 6 metres of the schist. The mineralized zone, referred to herein as the Gouda Lake mineralized zone or Gouda Lake gold mineralized zone, is also host to associated Ag and Zn, with lesser Pb and Cu. The grades and thicknesses of the zone are highly variable, even across short distances. When present, mineralization occurs as fine- to medium-grained disseminated pyrite and sphalerite or coarse-grained massive pyrite with associated sphalerite, galena, pyrrhotite, and chalcopyrite. The disseminated mineralization is typically foliated and occurs in layers which alternate with layers of massive to semi-massive sulphide on a dcm-scale. Etched and stained sections of the foliated, disseminated pyrite zones indicate that the main constituents, aside from the sulphides, are quartz and muscovite, while potassium-feldspar and plagioclase are only locally present, with local abundances of each ranging up to 5%. Petrography reveals that minor mineral phases include tremolite, sericite, chlorite, and rutile. Commonly located between the upper homogeneous and more mica-rich layer and the Gouda Lake mineralized zone near the base of the Gouda Lake horizon, is a 2 to 3 metre thick, light grey, fine-grained, white mica and talc(?)-bearing layer which contains 1-2% pyrite and local medium-grained quartz grains (quartz eyes). There were some significant gold intercepts during the 2010 drilling program, including: HEGZ10-10-16: 76.5-77.75 m with 19.70 ppm Au, 155.0 ppm Ag, 0.15% Cu, 0.08% Pb and 1.05% Zn; HEGZ10-20: 122.4-123.9 m with 11.40 ppm Au, 253.0 ppm Ag, 0.02% Cu, 0.045% Pb, and 0.829% Zn; HEGZ10-24: 152.0-153.5 m with 11.15 ppm Au, 200.0 ppm Ag, 0.03% Cu, 0.236% Pb, and 0.934% Zn (AFRO 2.48501).

Mineral Record Details

References

Mono - Report of Activities 2013, Resident Geologist Program, Thunder Bay South Regional Resident Geologist Report: Thunder Bay South District

Publication Number: OFR6293 Date: 2014

Author: Puumala M.A., Campbell D.A., Tuomi R.D., Debicki R.L., Wilson A.C., Moses P., Brunelle M.R.

Publisher Name: Ontario Geological Survey

Location:

Map - Geological Compilation of the Eastern Half of the Schreiber-Hemlo Greenstone Belt

Publication Number: M2614 Scale: 1:50,000    Date: 2000

Author: Muir T.L.

Publisher Name: Ontario Geological Survey

Location:

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