Ontario Mineral Inventory

Ontario Geological Survey
Permanent Link to this Record: MDI52A11NW00003

Record: MDI52A11NW00003

General

Commodities

Primary Commodities: Granite

Location

Township or Area: Jacques

Latitude: 48° 38' 50.17"    Longitude: -89° 16' 30.22"

UTM Zone: 16    Easting: 332429.919   Northing: 5390743.507    UTM Datum: NAD83

Resident Geologist District: Thunder Bay South

NTS Grid: 52A11NW

Point Location Description: Outcrop

Location Method: Data Compilation

Access Description: GENERAL LOCATION: The pluton is located approximately 25 km north of Thunder Bay. It is in Jacques Township, Lots 1 to 6, Conc. I and II. ACCESS: Access to the pluton is gained via Highway 589 (Figure 10). Starting at Highway 102, drive north on Highway 589 approximately 13 km. to the village of Lappe. Drive 11 km. past Lappe to where the highway forks, take the right fork. The road enters the pluton 1.6 km. past the fork. Access to a large portion of the pluton is gained via private roads off Highway 589.

Exploration History

This pluton has had minimal prospecting and exploration activity within it. 1994 The whole of the Barnum Lake Pluton is patented land with both surface and mining rights reserved.

Geology

Province: Superior

Geological Age: Archean  

Geology Comments

Dec 07, 2005 (W Bellinger) - 6) GENERAL GEOLOGY AND STRUCTURE: The surrounding rocks are Archean pelitic to semipelitic mica schists and gneisses. The pluton itself is oval and covers an area of 6.5 km2. The major rock-type is quartz monzonite with lesser amounts of feldspar-megacrystic quartz syenite and quartz monzodiorite. Outcrop exposure is fair to good. The terrain is generally rolling hills with minor areas of swamp and bog.

Lithology

Lithology Comments

Dec 07, 2005 (W Bellinger) - JOINTING: Many of the outcrops observed, especially areas of large exposure, show widely spaced joint sets (1 to 3 m) that are well developed and orthogonal. There are some outcrops in the area that lack these joints. The sheeting is roughly 1.2 m except for surface spalling due to weathering. COLOUR: The colour throughout the pluton is generally pink. In places near the contact with the country rocks the colour varies from light pink to grey. Towards the centre the colour becomes consistent. TEXTURE: Kehlenbeck (1977) described the texture: A typical outcrop contains, buff to salmon coloured potash feldspar megacrysts ranging in size up to 3 cm. These are set in a coarse- to medium-grained, hypidiomorphic, granular matrix composed of pink plagioclase, quartz, biotite, and amphibole. OTHER FEATURES: Weathering of the outcrops is minimal except for spalling (0.5 to 1 m) thick near Warnica Lake. Inclusions of grey granitic material are commonly found within the outcrops. The xenoliths range in size from 3 to 30 cm, with the smaller inclusions being more common. There are rare aplitic dykes and hematite staining of the fractures.

Mineralization

Mineralization Comments

Dec 07, 2005 (W Bellinger) - Kehlenbeck (1977) described the mineralogy of the pluton: In general, the microcline megacrysts normally contain numerous inclusions of quartz and plagioclase. Amphibole and biotite also occur as inclusions in the megacrysts, although these are less common. The matrix of the rocks from the intrusion is composed of plagioclase, quartz, amphibole, and biotite. Accessory minerals include sphene, apatite, epidote, zircon and opaques. PHYSICAL PROPERTIES: Barnum Lake Granite Compressive Strength: 22,619 psi (155.79 MPa). Modulus of Rupture: 1,762 psi (12.19 MPa). Absorption: 0.15%. Bulk Specific Gravity: 2.68. Testing conducted by Geoscience Laboratories, Ontario Geological Survey, Toronto CHEMICAL ANALYSIS SAMPLE NO. B58: 67.35 Al2O3, 0.36 FeO, 15.41 MgO, 1.53 MnO

Mineral Record Details

References

Map - Gorham Township and vicinity, District of Thunder Bay, Ontario

Publication Number: ARM48C Scale: 1:63,360    Date: 1997

Author: Macdonald R.D.

Publisher Name: Ontario Dept. of Mines

Location:

Mono - Dimensional Stone Occurrences and Deposits in Northwest Ontario

Publication Number: OFR5890 Date: 1994

Author: Hinz P., Landry R.M., Gerow M.C.

Publisher Name: Ontario Geological Survey

Location:

Book - Geology and Mineral Potential of Ware Township, District of Thunder Bay

Publication Number: MP162.052 Date: 1993

Author: Brown G.H., Fogal R.I.

Publisher Name: Ontario Geological Survey

Location:

Map - Geological compilation series, Lakehead-Shebandowan sheet, District of Thunder Bay

Publication Number: P0177 Scale: 1:126,720    Date: 1997

Author: Pye E.G., Fenwick K.G.

Publisher Name: Ontario Dept. of Mines

Location:

Thesis - Magnetic Survey of the Barnum Lake Pluton, Thunder Bay, Ontario

Publication Number: BSc Thesis Date: 1979

Author: Cheadle, S.

Publisher Name: Lakehead University

Location: Thunder Bay RGP Office

File - Industrial minerals geologist files

Publication Number: IMF Date: 1996

Author:

Publisher Name:

Location: Thunder Bay RGP

Book - TECTONIC SIGN. OF BARNUM LK. AND TROUT LK INTRUSIVE,GEOTRAVERSE CONF.

Publication Number: CONF Date: 1976

Author: Kehlenbeck, M.M.

Publisher Name:

Location: UNIV. OF TORONTO

Book - THE BARNUM LK. PLUTON,TH. BAY,ONT,NRC OF CANADA

Publication Number: JOUR Date: 1977

Author: Kehlenbeck, M.M.

Publisher Name:

Location: CAN JOUR OF EARTH SCIENCES

Part - Geology of Gorham Township and vicinity

Publication Number: ARV48-03 Date: 1998

Author: Macdonald R.D.

Publisher Name: Ontario Dept. of Mines

Location:

Thesis - Structure and Petrology of the Barnum Lake Intrusive

Publication Number: BSc Thesis Date: 1975

Author: Steinert, G.L.

Publisher Name: Lakehead University

Location: Thunder Bay RGP Office

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