Ontario Mineral Inventory

Ontario Geological Survey
Permanent Link to this Record: MDI000000001921

Record: MDI000000001921

General

Commodities

Primary Commodities: Palladium

Location

Township or Area: Lac Des Iles Area

Latitude: 49° 7' 46.16"    Longitude: -89° 31' 33.3"

UTM Zone: 16    Easting: 315736   Northing: 5444923.01    UTM Datum: NAD83

Resident Geologist District: Thunder Bay South

NTS Grid: 52H04NE

Point Location Description: GPS point from N. Pettigrew

Location Method: Field Visit with GPS

Access Description: Access to the Legris Lake Property is obtained by travelling approximately 20 km east on Highway 11/17 from Thunder Bay, then 81 km north along provincial highway 527. From there, Fensom Road (gravel) leads to the claim group 16 km to the west. From kilometers 16 and 17 of Fensom Rd, trench and drill sites can be reached via a network of secondary and tertiary roads and access trails

Exploration History

1999: prospector K. Fenwick discovered the Main Showing Zone. 1999-2002: Avalon Ventures Ltd. and Starcore Resources Ltd. optioned the property and conducted IP and magnetic geophysical surveys, geological mapping, geochemical surveys, trenching, sampling, and drilled 28 DDH totaling 4633 m. The Stonefish Lake Zone was discovered in 2000. 2004: North American Palladium Ltd. (NAP) optioned the property and conducted prospecting and trenching. 2005: NAP drilled 3 DDH totaling 465 m and conducted airborne magnetic and VLF-EM surveys. Option was dropped and property returned to K. Fenwick. 2006: property was optioned by Abitibi Mining Corp. who conducted a ground magnetometer survey. 2010: Lac des Iles Mines Ltd. optioned the property, drilled 7 DDH totaling 3942.6 m, and conducted trenching. 2011: Lac des Iles conducted trenching and drilled 4 DDH totaling 2168 m.

Assessment Work on File

Geology

Province: Superior

Subprovince: Wabigoon

Geological Age: Archean  

Geology Comments

May 20, 2016 (Therese Pettigrew) - The Legris Lake property is situated within the Archean Wabigoon Subprovince of the Superior Structural Province. The Legris Lake Complex is part of a series of PGE-bearing mafic-ultramafic intrusions that form a circular pattern approximately 30 km in diameter commonly referred to as the "Ring of Fire". The series primarily intrude metasediments and metabasalts near the Wabigoon-Quetico Subprovince boundary. The series include the Lac des Iles Complex, Tib Lake, Towle Lake, Wakinoo Lake, Demers Lake, Taman Lake, Buck Lake, and Dog River intrusions. The Legris Lake Complex is intruded by late granodiorite dykes and quartz feldspar pegmatites part of larger granodiorite plutons forming the sanukatoid suite of rocks. The Legris Lake Complex has later been intruded by Proterozoic-age diabase dykes and sills (AFRI 20000000847).

Lithology

Lithology Comments

May 20, 2016 (Therese Pettigrew) - The Stonefish Lake Zone is located near the northwestern tip of the northwestern border zone. It the most lithologically evolved and heterogeneous zone discovered thus far, consisting of a variety of leucocratic to mesocratic gabbroic rocks with lesser amounts of mottled anorthosite, numerous clinopyroxenite and metasedimentary clasts, and abundant igneous breccia. The Stonefish Lake Zone exhibits many lithological, mineralogical, and structural indications that it is a type of tilted gabbroic pegmatite sill or dyke. The highly evolved nature of the rocks, mottled anorthosite, magnetite-rich leucogabbro (up to 20 vol. % magnetite), and quartz-rich varitextured leucogabbro which locally grades into true quartz-albite + minor tourmaline pegmatites and micropegmatites indicate a highly evolved magmatic system. The highly variable grain size (varitextured), chaotic ductile and crystal mush flow textures, strong assimilation/alteration of metasedimentary clasts, and abundant igneous brecciation indicates an energetic water-rich system consistent with conditions under which pegmatites form. The zone occurs in conjunction with separate unmineralized mesogabbro lenses as well defined tilted sills or dykes hosted within clastic metasedimentary wall rocks. Its location, on the outer fringe of the northwestern border zone, is also where pegmatites radiating out from the Legris Lake Complex are most likely to occur.

Mineralization

Mineralization Comments

May 20, 2016 (Therese Pettigrew) - The zone is very sulphide-poor consisting of the Pd-rich, Cu-Ni-poor style of PGE mineralization. The zone is overall low grade (less than 1 g/t PGEs) but intervals of up to 2.04 g/t PGEs over 2.11 metres were intersected in hole L00-07. PGE mineralization is typically hosted within varitextured leucogabbro, typically forming the matrix of the leucogabbro breccia but it also occurs as clasts in a fine grained, magnetite rich leucogabbro matrix. The varitextured leucogabbro differs from the varitextured mesogabbro of the Main Showing Zone and the Lac des Iles Roby Zone, being slightly finer grained, more plagioclase-rich and differing in texture, however, they both share a highly variable grain size, thereby warranting the term varitextured. The magnetite-rich leucogabbro may also contain low-grade PGE mineralization (up to 95 ppb Pt, 426 ppb Pd, 56 ppb Au, 0.06% Cu, 0.02% Ni), and displays local layering. This fine-grained, magnetite-rich leucogabbro, which consists almost entirely of magnetite and plagioclase with minor mafics is identical to that intersected by holes L00-09, L01-14 and 16 under the Poplar Zone’s hole 8 mineralization, which also contains local low-grade PGE mineralization. The Stonefish Lake Zone has been tested to a depth of 65 metres by holes L00-07 and L01-13 and displays good vertical continuity with a dip of 55 to 60 degrees to the southeast, appearing to widen at depth. The zone, exposed over a strike length of ~50 metres in Trench 7, displays a rough southwest-northeast strike. However, hole L00-11 collared 100 metres southwest of hole L00-07 failed to intersect any mineralization or favourable gabbroic rocks. Hole L01-13 intersected three narrow (less than 1.5 metres) sills/dykes of weakly mineralized (up to 255 ppb PGEs) varitextured leucogabbro similar to that of the main body of the Stonefish Lake Zone. These sills/dykes were not intersected in hole L00-07, suggesting that they pinch out before reaching the surface. This observation, combined with the inferred high stratigraphic elevation of the zone and apparent widening at depth of the main body of the Stonefish Lake Zone, suggests that multiple, thick sills/dykes with similar style mineralization may exist at depth. The enrichment of PGEs occurs erratically in the varitextured leucogabbro breccia and mottled anorthosite. Copper-Ni sulphides are not common and they are not correlated with the enrichment of PGEs. This observation suggests that this style of PGE enrichment was the result of primarily hydrothermal processes caused by deuteric fluids derived from the parental magmas of the Legris Lake Complex (AFRI 52H03NW2008). Significant drill intercepts include: LL00-07 from 43.92-48.84 m: 0.96 ppm Pd, 0.15 ppm Pt, 0.10 ppm Au, 0.13% Cu, and 0.04% Ni including from 46.73-48.84 m: 1.60 ppm Pd, 0.25 ppm Pt, 0.19 ppm Au, 0.26% Cu, and 0.06% Ni (AFRI 20000007467)

Mineral Record Details

References

Map - Precambrian Geology of the Southwest Portion of the Nipigon Embayment, Northwestern Ontario

Publication Number: P3580 Scale: 1:100,000    Date: 2006

Author: Hart T.R.

Publisher Name: Ontario Geological Survey

Map - Precambrian Geology, Lac des Iles Area

Publication Number: P3532 Scale: 1:50,000    Date: 2003

Author: Stone D., Fell M., Daley A., Schnieders B.R., Scott J.F., Nielsen P., Wagner D.

Publisher Name: Ontario Geological Survey

Publication - Palladium-Copper-rich Platinum-Group Element Mineralization in Legris Lake Mafic-Ultramafic Complex, Western Superior Province

Publication Number: AppSci Scale:     Date: 2002

Author: Pettigrew, N.T., Hattori, K.H.

Publisher Name: Applied Earth Science, Volume 111, Issue 1, 2002

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