Ontario Geological Survey
Permanent Link to this Record:
MDI52B11NE00001
| Record Name(s) | Eva Lake Stock - 1996 |
|---|---|
| Related Record Type | Simple |
| Record Status | Occurrence |
| Date Created | 1996-Dec-14 |
| Date Last Modified | 2022-Jan-05 |
| Created By | W Bellinger |
| Revised By | W Bellinger |
Primary Commodities: Granite
Township or Area: Eva Lake Area
Latitude: 48° 41' 29.7" Longitude: -91° 13' .3"
UTM Zone: 15 Easting: 631232.06 Northing: 5394705.63 UTM Datum: NAD83
Resident Geologist District: Thunder Bay South
NTS Grid: 52B11NE
Point Location Description: Outcrop
Location Method: Data Compilation
Access Description: GENERAL LOCATION: The pluton lies on Hwy. 11 approximately 55 km west of Kashabowie. This area is just southwest of Gateway Bay, Eva Lake. ACCESS: Highway 11 transects the northeast and southwest parts of the pluton. The southwest half of the intrusive is accessible by two bush roads off the TransCanada Hwy. Limited access to the northeast half of the area is available via the Eva Lake Resort Road.
No claims staked on ground; only activity in area is cottage lots on Marion and Eva Lakes and Hwy. construction 1994 The majority of the pluton is open.
Province: Superior
Subprovince: Quetico
Geological Age: Archean
Dec 07, 2005 (W Bellinger) - GENERAL GEOLOGY AND STRUCTURE: The Eva Lake Stock has intruded Archean gneissic-migmatite rocks of the Quetico Subprovince. The stock is oval and measures 1.6 km by 1.3 km. Outcrop exposure is poor due to the Eagle-Finlayson end moraine. The Eva Lake Stock has been identified as a diatextite with a composition that classifies it as a quartz monzonite. The rock exhibits weak foliation and ghost-like structures, termed nebulites, both of which are recognized by the concentrations of mafic minerals.
| Rock Type | Rank | Composition | Texture | Relationship | Quartz Monzonite | 1 | Uniform | Host |
|---|---|---|---|---|
| Diatexite Migmatite | 2 | Gneissic-Migmatite Rocks | Gneissic | Adjacent |
Dec 07, 2005 (W Bellinger) - MINERALOGY: Staining of a sample showed the rock to be composed of 40 to 50% potassium feldspar, 30 to 50% plagioclase, 15 to 20% quartz, and 5% hornblende and muscovite together. JOINTING: The jointing in the examined outcrops was well developed and regular. The best developed set has an orientation of 140 degrees with a near vertical dip, and a spacing of 2.5 to 3 m. A weaker developed joint set was noted trending 40 to 50, but it is irregular in its occurrence. Little or no fracturing was observed in the outcrops examined. Even the road outcrops that had been blasted show very little fracturing. Where outcrops allowed the measuring of sheeting, it was noted to be horizontal and 2 to 3 m thick. COLOUR: Near the centre of the intrusive the colour is a consistent light grey. Upon close examination, one can see the ghost structures defined by the concentration of mafic minerals. These structures sometimes outline assimilated xenoliths or are seen as streaks with irregular orientations. Close to the edge, the colour varies from pink to grey, and the ghost structures are still recognizable. TEXTURE: The texture of the rock is very uniform. The stone is a medium grained (1 to 5 mm) with rare phenocrysts up to 1 cm in length. OTHER FEATURES: In the outcrops examined, two small (2.5 to 5 cm wide) pegmatitic dikes that parallel joint sets, were noted. Other than the nebulites, no inclusions or xenoliths were identified. At one outcrop a small horizontal shear zone was observed.
| Rank | Mineral Name | Class | Economic Mineral Type | Alteration Mineral Type | Alteration Ranking | Alteration Intensity | Alteration Style |
|---|---|---|---|---|---|---|---|
| 1 | Microcline | Economic | Ore | ||||
| 2 | Quartz | Economic | Ore | ||||
| 3 | Plagioclase | Economic | Ore | ||||
| 1 | Hornblende | Economic | Gangue | ||||
| 2 | Muscovite | Economic | Gangue |
Dec 07, 2005 (W Bellinger) - MINERALOGY: Staining of a sample showed the rock to be composed of 40 to 50% potassium feldspar, 30 to 50% plagioclase, 15 to 20% quartz, and 5% hornblende and muscovite together. COLOUR: Near the centre of the intrusive the colour is a consistent light grey. Upon close examination, one can see the ghost structures defined by the concentration of mafic minerals. These structures sometimes outline assimilated xenoliths or are seen as streaks with irregular orientations. Close to the edge, the colour varies from pink to grey, and the ghost structures are still recognizable. TEXTURE: The texture of the rock is very uniform. The stone is a medium grained (1 to 5 mm) with rare phenocrysts up to 1 cm in length. OTHER FEATURES: In the outcrops examined, two small (2.5 to 5 cm wide) pegmatitic dikes that parallel joint sets, were noted. Other than the nebulites, no inclusions or xenoliths were identified. At one outcrop a small horizontal shear zone was observed.
Mono - Dimensional Stone Occurrences and Deposits in Northwest Ontario
Publication Number: OFR5890 Scale: Date: 1994
Author: Hinz P., Landry R.M., Gerow M.C.
Publisher Name: Ontario Geological Survey
MonoMap - Geology of the Crooked Pine Lake area, District of Rainy River
Publication Number: R179 Scale: Date: 1978
Author: Pirie J.
Publisher Name: Ontario Geological Survey
Book - GRANITIC PLUTONS OF THE SUPERIOR TRAVERSE,IN GEOTRAVERSE CONF 1977
Publication Number: CONF Scale: Date: 1977
Author: Goodwin, A.M. et al
Publisher Name:
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