Ministry of Energy, Northern Development and Mines
Permanent Link to this Record: MDI000000002328| Deposit Name(s) | Bergman Intrusion - 1953 |
|---|---|
| Deposit Status | occurrence |
| Date Created | 2019-Aug-27 |
| Date Last Modified | 2019-Aug-27 |
| Created By | T Pettigrew |
| Revised By | T Pettigrew |
Primary Commodities: copper
Secondary Commodities: nickel, platinum, palladium
Township or Area: Pickerel Lake Area
Latitude: 48° 42' 9.59" Longitude: -91° 29' 7.53"
UTM Zone: 15 Easting: 611436 Northing: 5395510 UTM Datum: NAD83
Resident Geologist District: Thunder Bay South
NTS Grid: 52B11NW
Point Location Description: Figure 1.6 in OFR5997
Location Method: data compilation
Access Description: On an island in the northwestern bay of Nym Lake
1953-54: The island and its vicinity were staked by W. Bergman. 1954: The island was examined by Steeprock Iron Mines Ltd. A small grid was established, and a super dip needle survey was completed. One trench exists on the island, but it is not known by whom it was excavated. No assessment records were found on file.
Province: Southern
Subprovince: Quetico
Intrusion: Quetico Batholith
Geological Age: Archean
| Rock Type | Rank | Composition | Texture | Relationship |
|---|---|---|---|---|
| ultramafic intrusive | 1 | hornblendite | host | |
| felsic intrusive | 2 | quartz monzonite |
08/27/2019 (T Pettigrew) - The Bergman Intrusion is composed of massive, altered, locally biotitic, coarse--grained, hornblendite and feldspathic hornblendite. Common alteration products are actinolite and chlorite. Field evidence suggests that the intrusion is a rafted block or large xenolith contained within the varitextured to pegmatitic, quartz monzonitic border regions of the Quetico Batholithic Complex. Evidence to support this is the presence of a thin wedge of clastic metasediments in contact with the hornblendite. This contact is sharp, undulatory, and weakly chilled and has, in turn, been cross--cut by the quartz monzonite country rocks. Additional supporting evidence is the lack of a pronounced, coincident, airborne magnetic anomaly (ODM Map 1122G, 1961) characteristic of the other intrusions previously described (MacTavish, 1999).
| Rank | Mineral Name | Class | Economic Mineral Type | Alteration Mineral Type | Alteration Ranking | Alteration Intensity | Habit Description |
|---|---|---|---|---|---|---|---|
| 1 | pyrrhotite | economic | ore | ||||
| 2 | chalcopyrite | economic | ore |
08/27/2019 (T Pettigrew) - Finely disseminated pyrrhotite and chalcopyrite occur throughout. The average sulphide content is 1 to 2%. A diffuse, poorly exposed, strongly weathered, 3 to 6 m thick zone containing 2 to 10% disseminated to blebby pyrrhotite and minor chalcopyrite occurs near the southern contact and contained up to 0.28% Cu, 0.07% Ni, 180 ppb Pt, and 75 ppb Pd (MacTavish, 1999).
Publication - The Mafic-Ultramafic Intrusions of the Atikokan–Quetico Area, Northwestern Ontario
Publication Number: OFR5997 Date: 1999
Author: MacTavish, A.D.
Publisher Name: OGS
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