Ontario Mineral Inventory

Ontario Geological Survey
Permanent Link to this Record: MDI42C13NW00003

Record: MDI42C13NW00003

General

Commodities

Primary Commodities: Zinc

Secondary Commodities: Copper, Gold

Location

Township or Area: Black River Area

Latitude: 48° 53' 54.97"    Longitude: -85° 45' 53.33"

UTM Zone: 16    Easting: 590526.85   Northing: 5416919.54    UTM Datum: NAD83

Resident Geologist District: Thunder Bay South

NTS Grid: 42C13NW

Point Location Description: Several small pits exposing zinc-mineralized rock occur 250 m west of the dam on Dotted Lake.

Location Method: Field Visit

Access Description: The occurrence is accessible via motor vehicle followed by travel in boat and then on foot. From Manitouwadge, travel south along Hwy 614 for approximately 40 km to the Twist Lake logging road. Proceed northeast along the Twist Lake logging road for approximately 4 km to the Dead Otter Lake road. Proceed northeast along the Dead Otter Lake road for approximately 3.5 km to the boat launch on Dead Otter lake. Proceed, via boat, northeast across Dead Otter and Dotted lakes for approximately 5.5 km to the dam on the northwest arm of Dotted Lake. The occurrence is situated on level ground approximately 250 m west of the dam and 100 m southeast of a large (100 m high) northeast-trending ridge.

Exploration History

1957: Prospecting and sampling; prospector B. Fairservice. The occurrence was discovered at this time. Geological mapping; M. Bartley and T. Page (C.P.R.). 1964-1965: Geological mapping; V.G. Milne (ODM). 1965: Airborne geophysical survey (EM, MAG); Irish Copper Mines Ltd. The survey indicated one good conductor and a few minor ones in the surrounding area but none over the Fairservice zinc occurrence. 1966: Trenching; prospector B. Fairservice. 1970: Ground geophysical survey (EM, MAG); Clear Mines Ltd. This survey identified several weak to moderate conductors in the general vicinity of the occurrence. 1978-1979: Regional lake sediment and water geochemical survey: GSC-MNR. Samples collected from lakes in the vicinity of the occurrence contained anomalous amounts of Cu and Zn. 1983: Geological mapping, prospecting and soil geochemical sampling; Clear Mines Ltd. Airborne geophysical survey; Aerodat Ltd. 1984: Ground geophysical survey (VLF-EM, MAG; Clear Mines Ltd. 1985: Geological mapping; G.M. Siragusa and K.M. Chivers (OGS). 1989: Dighem airborne geophysical survey; Noranda Exploration Co., Ltd., and Noranda Minerals Inc. 1990: Lithogeochemical sampling; M. Smyk (OGS). 1991:Line cutting, geological mapping, ground geophysical surveys (VLF-EM, MAG and HLEM) and diamond drilling (3 holes totalling 502 m); Noranda Exploration Co., Ltd. 1991-1992: Reconnaissance till sampling program; I. M. Kettles (GSC). Samples collected in the vicinity of the occurrence contained anomalous amounts of Cu and Zn. 1992: Lithogeochemical sampling; D.B. McKay (OGS).

Assessment Work on File

Geology

Province: Superior

Subprovince: Wawa

Terrane: Wawa-Abitibi

Belt: Schreiber-Hemlo

Geological Age: Archean  

Metamorphism Type: Regional

Metamorphism Grade: Amphibolite

Geology Comments

Dec 07, 2005 (D McKay) - The occurrence is underlain primarily by an east-northeast-trending sequence of amphibolitic, mafic metavolcanic schists and gneisses, quartz- and feldspar-phyric felsic dikes, and banded iron formation. These rocks are moderately to strongly foliated (078 degrees/85 degrees SE) , have undergone intense complex folding, and have experienced upper amphibolite facies-grade regional metamorphism. The occurrence is hosted within a narrow (up to 80 cm wide) iron formation within the mafic volcanic seqence. In the vicinity of the occurrence, the supracrustal sequence is approximately 800 m wide and is bounded to the north and south by biotite leuco-granodiorite of the Dotted Lake batholith. A small (2 km long by 300 m wide) body of gabbroic rock is located approximately 1.25 km southeast of the occurrence. The axis of a southwest-trending and south-west plunging syncline is believed to lie approximately 400 m northwest of the occurrence . A northeast-trending topographic lineament is located approximately 100 m west of the occurrence. Two north-northeast-trending faults are inferred to occur approximately 50 and 500 m east of the occurrence, respectively. The occurrence is exposed in 3 pits varying in size up to 1.3 m long by 1.0 m wide by 0.5 m deep. These pits are largely rubble-filled and are partially overgrown with vegetation. The iron formation hosting the sulphides outcrops intermittently for at least 300 m along strike to the east of the pits. The sulphides and garnetiferous alteration however, appear to be confined to the immediate vicinity of the pits. Where exposed in the bed of a small creek approximately 250 m east of the pits, the iron formation is unaltered and only weakly mineralized (containing <1% py and rare cpy as disseminated grains).

Mar 16, 2016 (A Mitchell) - GENERAL GEOLOGY AND STRUCTURE: The Fairservice zinc occurrence is located within the Wawa Subprovince along the north limb of the Schreiber-Hemlo greenstone belt approximately 25 km north-northeast of the Hemlo mining camp. The occurrence is underlain primarily by an east-northeast-trending sequence of amphibolitic, mafic metavolcanic schists and gneisses, quartz- and feldspar-phyric, felsic dikes, and banded iron formation (Milne 1968b; Schnieders et al. 1991; Walmsley 1991). These rocks are moderately to strongly foliated (078+/85+SE), have undergone intense complex folding, and have experienced upper amphibolite facies-grade regional metamorphism (Milne 1968b; Schnieders et al. 1991). The occurrence is hosted within a narrow (up to 80 cm wide) iron formation within the mafic volcanic sequence. In the vicinity of the occurrence, the supracrustal sequence is approximately 800 m wide and is bounded to the north and south by biotite leuco-granodiorite of the Dotted Lake batholith (Milne 1968b, Map 2146). A small (2 km long by 300 m wide) body of gabbroic rock is located approximately 1.25 km southeast of the occurrence. The axis of a southwest-trending and southwest-plunging syncline is believed to lie approximately 400 m northwest of the occurrence (Milne 1968b, Map 2146). A northeast-trending topographic lineament is located approximately 100 m west of the occurrence. Two north-northeast-trending faults are inferred to occur approximately 50 and 500 m east of the occurrence, respectively (Milne 1968b, Map 2146).

Lithology

Lithology Comments

Dec 07, 2005 (D McKay) - The mafic metavolcanic rocks are dark gray-green, medium-grained, moderately to locally strongly foliated plagioclase-hornblende gneisses and schists. Highly strained pillow structures are preserved locally. The pillows have aspect ratios of approximately 4:1 and posses recessive-weathered, chloritic selvages. Py occurs as mgr. disseminated anhedra within the mafic metavolcanic rocks and generally constitutes <1% of this unit. Malachite staining occurs locally along fractures within the mafic metavolcanic rocks located immediately south of the occurrence. Several narrow, felsic dikes have intruded the mafic metavolcanic rocks in the vicinity of the occurrence. One of these dikes, located approximately 5 m north of the occurrence, contains a prominent minor fold. The axis of this fold trends 236 degrees and plunges 58 degrees. The iron formation, were exposed, varies i width from approximately 50 to 80 cm and has developed a marked rusty gossan. The iron formation is crudely laminated (on a cm scale), medium to dark greenish-brown, moderately foliated, moderately to locally strongly magnetic and is locally strongly altered containing up to 50% red-brown, subhedral to euhedral garnet porphyroblasts (5 to 10 mm across). Magnetite constitutes up to 10% of the iron formation and occurs as medium-to coarse-grained, black disseminated anhedral grains and octahedra. A quartz- and feldspar-phyric felsic dike has intruded along the southern contact between the iron formation and the surrounding mafic metavolcanic rocks. This dike varies in width from <1 m to 2m, is fine- to medium-grained, buff, weakly to locally strongly magnetic and contains 1 to 2% rounded quartz eyes up to 3 mm in diameter. The dike contains <1% pyrite as fine-grained to medium-grained disseminated subhedral grains.

Mineralization

Mineralization Comments

Dec 07, 2005 (D McKay) - The occurrence consists of disseminated grains to stringers and small pods of semi-massive to massive sphalerite, magnetite, minor pyrite and rare chalcopyrite hosted primarily in a narrow, banded iron formation within a mafic volcanic flow sequence. The sulphides, exosed within and adjacent to the pits, define a mineralized zone approximately 65 cm wide (width varies from 50 to 80 cm) and 2.5 m long which parallels the foliation of the surrounding rocks (078 degrees/85 degrees SE). The sulphides are confined primarily to the iron formation and locally constitute up to 25% of this unit. The sulphides consist primarily of fine- to coarse-grained, brown-black sphalerite which occurs as disseminated grains, narrow (up to 2cm wide) stringers and small, irregulary-shaped pods. Pyrite occurs in minor amounts as fine-grained disseminated subhedral grains and as irregularly shaped fine- to medium-grained masses (up to 5 mm across). Chalcopyrite is present as rare blebs (up to 3 mm across and as isolated, fine- to medium-grained anhedra. Grab samples collected from the occurrence by M. Symk in 1990 for the OGS returned assay values of up to 12.00% Zn, 0.024% Cu, trace Ag and 0.074 ounce Au/ton. Grab samples collected from the occurrence by D. McKay in 1991 for the OGS returned assay values of up to 9.44% Zn, 0.012% Cu, trace Ag and 0.006 ounce Au/ton.

Alteration Comments

Mar 16, 2016 (A Mitchell) - The mineralized zone occurs in the mafic metavolcanics and is oriented approximately parallel to both the host rock foliation and the elongation direction of the pillows. The host metavolcanics become noticeably altered within 1 m of the mineralized zone. Garnet porphyroblasts, up to several millimetres in diameter, may compose 50 percent of this altered rock. X-ray diffraction analysis has confirmed the presence of (edenitic?) hornblende in the alteration assemblage (H. DeSouza, Ontario Geological Survey, personal communication, 1990). The mineralized zone is 50 to 80 cm wide and has developed a considerable gossan. According to Milne (1968), the mineralization and the garnetiferous alteration are exposed over lengths of less than 3 m and 20 m, respectively. Mineralization consists of disseminated grains to stringers of massive, red sphalerite with minor pyrite and hydrozincite in altered mafic metavolcanics. The mineralized zone is moderately to strongly magnetic; subhedral grains to euhedral octahedra of magnetite are disseminated throughout the zone and may locally compose up to 10 percent of the rock. The southern contact of the zone is occupied by a fine-grained felsic dike which varies from being weakly foliated near the easternmost pit to becoming a very fissile rusty sericite schist in the westernmost pit, where it is strongly magnetic.

Assay Samples

Mineral Record Details

References

Map - Geophysical Series, White Lake, Thunder Bay District, Ontario

Publication Number: Map 2168G Scale: 1:63,360    Date: 1963

Author: Geological Survey of Canada

Publisher Name: Geological Survey of Canada

Location: https://doi.org/10.4095/116493

Map - Dotted Lake sheet, Thunder Bay District

Publication Number: M2146 Scale: 1:31,680    Date: 1968

Author: Milne V.G.

Publisher Name: Ontario Dept. of Mines

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:

Map - Manitouwadge-Wawa sheet, geological compilation series, Algoma, Cochrane, Sudbury and Thunder Bay districts

Publication Number: M2220 Scale: 1:253,440    Date: 1972

Author: Milne V.G., Giblin P.E., Bennett G., Thurston P.C., Wolfe W.J., Giguere J.F., Leahy E.J., Rupert R.J.

Publisher Name: Ontario Division of Mines

Location:

MonoMap - Geology of the Black River area, District of Thunder Bay

Publication Number: R072 Date: 1968

Author: Milne V.G.

Publisher Name: Ontario Dept. of Mines

Location:

Map - Geological series, Precambrian geology, White Lake (Hemlo) area, Dotted Lake and Black River sections, District of Thunder Bay

Publication Number: P3046 Scale: 1:15,840    Date: 1986

Author: Siragusa G.M., Chivers K.M.

Publisher Name: Ontario Geological Survey

Location:

Publication - Regional Lake Sediment and Water Geochemical Reconnaissance Data, Ontario Eastern Shore, Lake Superior; Geological Survey of Canada, Open File 555

Publication Number: GSC OF 555 Date: 1979

Author: Hornbrook, E.H.W., Coker, W.B., Lynch, J.J.

Publisher Name: Geological Survey of Canada

Location: https://doi.org/10.4095/129524

Publication - Regional Lake Sediment and Water Geochemical Reconnaissance Data, Northwestern Ontario; Geological Survey of Canada, Open File 2362

Publication Number: GSC OF 2362 Date: 1991

Author: Friske, P W B; Hornbrook, E H W; Lynch, J J; McCurdy, M; Gross, H; Galletta, A C; Durham, C C

Publisher Name: Geological Survey of Canada

Location: https://doi.org/10.4095/132202

Article - Schreiber-Hemlo Resident Geologist's District - 1990

Publication Number: MP152.007 Page: 141-171  Date: 1997

Author: Schnieders B.R., Smyk M.C., Hinz P.

Publisher Name: Ontario Geological Survey

Location:

Book - Reconnaissance Geochemical Data for Till Samples from the Manitouwadge Area, Ontario

Publication Number: GSC OF 2616 Date: 1993

Author: Kettles, I.M.

Publisher Name: Geological Survey of Canada

Location: https://doi.org/10.4095/183942

Map - Black River area, southeast part, District of Thunder Bay

Publication Number: P0335 Scale: 1:31,680    Date: 1997

Author: Milne V.G.

Publisher Name: Ontario Dept. of Mines

Location:

Map - Manitouwadge sheet, districts of Thunder Bay and Algoma, geological compilation series

Publication Number: P0494 Scale: 1:126,720    Date: 1997

Author: Milne V.G.

Publisher Name: Ontario Dept. of Mines

Location:

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