Ontario Mineral Inventory

Ontario Geological Survey
Permanent Link to this Record: MDI000000000255

Record: MDI000000000255

General

Commodities

Primary Commodities: Zinc, Copper

Location

Township or Area: Gerry Lake Area

Latitude: 50° 55' 27.39"    Longitude: -93° 7' 14.04"

UTM Zone: 15    Easting: 491526.001   Northing: 5641411.003    UTM Datum: NAD83

Resident Geologist District: Red Lake

NTS Grid: 52K14NE

Point Location Description: Point taken from centre of "New Zone" on Geology and Alteration plan (p. 39) in AFRI# 52K14NE0028

Location Method: Data Compilation

Exploration History

1969-1970: Caravelle Mines drilled 5 holes totalling 693.7 m as a follow up to a regional airborne survey on the eastern portion of the property. 1978-1985: Selco carried out ground Mag, HLEM and UTEM geophysical surveys on the property. A total of 11 DDH totalling 1145 m were drilled to test targets generated. 1990-1992: Noranda acquired the Joy property and completed ground Mag and HLEM geophysical surveys. 1992: 4-hole DDH program totalling 968.3 m was completed. 1994: Cumberland Resources Ltd. carried out line cutting, geological mapping, prospecting, and sampling, resulting in the discovery of the zone.

Assessment Work on File

Geology

Province: Superior

Subprovince: Uchi

Terrane: North Caribou

Domain: Uchi

Belt: Birch-Uchi

Geological Age: Archean  

Lithology

Lithology Comments

Oct 03, 2022 (Therese Pettigrew) - During the course of the June and September 1994 mapping survey, four major rock types were recognized on the Big Falls property: North mafic flow (andesite), Joy pyroclastic tuff. Power Line ash tuff. South mafic flow, and a dioritic intrusive. The Joy pyroclastic flow and the Power-line ash tuff are part of the same stratigraphic succession that have been dilated by a large diorite sill. From west to east in the direction of younging these stratigraphic units are as follows: The North Mafic Flow(NMF) is exposed in two closely located outcrops immediately south of Trout Lake River. Both exposures were moderate to well foliated, dark green to black in colour with local speckled and patchy 10-15% feldspar porphyroblast. Numerous pink felsite/granitic veinlets are randomly distributed through-out the outcrop exposures. The Joy Ash Flow tuff (JAFT), which hosts the Joy, Caravelle and the South base metal occurrences, is knowingly exposed in one lone location on line 5900-E. This unit is medium grey in colour, is aphyric and has a medium grained sugary texture. Crude banding is evident with a 74 degree bearing. The weathered surfaces has a rusty coloration due to the presence of pervasive biotite and muscovite. The whole-rock analysis indicates intermediate composition. A unit of similar chemical composition exist as a xenolith within the southern felsic intrusive near the southeast corner of the property. The latter exposures differ in appearance from the JAFT in its alteration style. This alteration manifest itself as pervasive biotite, locally observed coarse-grained anthophyllite, and rare garnet porphyroblast. The Power Line Ash Flow Tuff (PLAFT) is exposed east from the South Bay mine road to the eastern boundary of claim 1144365 where the unit obtains a thickness of at least 400 meters. The unaltered and altered equivalents of the PLAFT are substantially different in appearance. The unaltered PLAFT is finely banded, medium grained , light to a dark grey in colour and contains up to 5% sub 2 mm size pink garnet. The altered variety, which is exposed in a number of outcrops over an open-ended strike length of 1.5 kms, is comprised of massive to coarsely bedded, coarse grained anthophyllite, biotite, cordierite, garnet, +/- chlorite. Garnets occur as pervasive sub 2cm porphyroblasts and heavily concentrated (50%) sub 20 cm beds and palm-size aggregates or clusters. Coarse-grained anthophyllite exists as heavily concentrated tabular to lath-like and radial (half bow-tie) crystals generally in an off-white to grey cordierite-rich matrix. Garnet and anthophyllite mineral assemblage results in an extremely rough and knobby appearance on outcrop surfaces. The South Mafic flow (SMF) overlies the PLAFT and is mainly exposed along the southern portion of claims 114365 and 1209260. This unit ranges from dark green, fine grained and massive to a more dioritic appearance from west to east. The more easterly exposures display a typical salt and pepper dioritic texture composed of mainly hornblende and feldspar. Intrusive rocks occur in the form of a diorite sill which extend along the entire 7.0 km strike length of the property. This sill appears to be rather consistent in thickness (approx 300 m) and separated Northern Mafic Flow from the felsic ash flow tuffs to the south. Texturally the intrusive is typically dioritic consisting of a characteristic salt and pepper -like appearance and is composed of 50% feldspar and 50% hornblende. The unit is generally massive with minor locally observed foliation (Assessment report) 52K14NE0028).

Mineralization

Mineralization Comments

Oct 03, 2022 (Therese Pettigrew) - With the exception of minor pyrite no other known mineralization exist on the Big Falls property. The highest assays returned 43 ppm Cu and 300 ppm Zn (Assessment report 52K14NE0028).

Alteration Comments

Oct 03, 2022 (Therese Pettigrew) - The alteration zone, which is 300 meters wide, and 1.5 km long, is characterized by a coarse anthophyllite-cordierite, garnet, biotite and chlorite mineral assemblage (Assessment report 52K14NE0028).

Mineral Record Details

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For detailed information regarding this mineral record please contact the Red Lake Resident Geologist District Office