Ontario Mineral Inventory

Ontario Geological Survey
Permanent Link to this Record: MDI52A03SW00013

Record: MDI52A03SW00013

General

Mineral Record Identification
Record Name(s) Naomi Island - 1935, L.K. Johnson - 1973
Related Record Type Simple
Related Record(s)
Record Status Occurrence
Date Created 1979-Jul-30
Date Last Modified 2022-Apr-27
Created By
Revised By

Commodities

Primary Commodities: Zinc

Secondary Commodities: Copper, Nickel, Silver, Lead



Location

Township or Area: Crooks

Latitude: 48° 1' 41.09"    Longitude: -89° 29' 55.06"

UTM Zone: 16    Easting: 313721   Northing: 5322442    UTM Datum: NAD83

Resident Geologist District: Thunder Bay South

NTS Grid: 52A03SW, 52A04SE

Point Location Description: Precise

Location Method: Conversion from MDI



Exploration History

Pre-1935: B. Renshaw first reported the vein. No assessment files have been located.


Geology

Province: Southern

Formation Group: Animikie Group

Geological Age: Paleoproterozoic  



Lithology

Lithology Data
Rock Type Rank Composition Texture Relationship
Gabbro 1 Gabbro Dyke Host
Vein 2 Carbonate

Mineralization

Mineralization and Alteration
Rank Mineral Name Class Economic Mineral Type Alteration Mineral Type Alteration Ranking Alteration Intensity Alteration Style
1ChalcopyriteEconomicOre
2SphaleriteEconomicOre
3PyrrhotiteEconomicOre
4GalenaEconomicOre

Mineralization Comments

Feb 26, 2018 (Therese Pettigrew) - The occurrence of copper-nickel mineralization on Naomi Island was first reported by B. Renshaw (Tanton, 1935). A grab sample collected by OGS staff J. Geul assayed 5% Zn in the form of sphalerite and trace silver. Weakly disseminated copper-nickel mineralization occurs in a sheared and fractured gabbro dyke, 5-15 feet in width, which follows the south shore of the island for a distance of 600 feet. The gabbro dyke is locally porphyritic in texture and is itself intruded by small, parallel, diabase dykelets. Associated with the gabbro dyke is granophyre that appears to have metamorphosed and altered the original mafic constituents of the gabbro dyke. A N-NW-striking, left-handed fault, cemented by calcite, cuts and offsets the mafic intrusions (Geul, 1973).



Mineral Record Details

References

Mono - Copper, nickel, lead and zinc deposits of Ontario

Publication Number: MDC012 Page: 346  Date: 1969

Author: Shklanka R.

Publisher Name: Ontario Dept. of Mines

Location:


MonoMap - Geology of Crooks Township, Jarvis and Prince locations, and offshore islands, District of Thunder Bay

Publication Number: R102 Page: 22, 28  Date: 1973

Author: Geul J.J.C.

Publisher Name: Ontario Division of Mines

Location:


Publication - Copper-Nickel Mineral Occurrences in Pigeon River Area, Ontario; Geological Survey of Canada, Paper no. 35-1

Publication Number: GSC Paper 35-1 Page: Date: 1935

Author: Tanton, T.L.

Publisher Name: Geological Survey of Canada

Location: https://doi.org/10.4095/101044


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