Ontario Geological Survey
Permanent Link to this Record:
MDI52C12NW00007
| Record Name(s) | Shenston Township Diabase - 1954 |
|---|---|
| Related Record Type | Simple |
| Related Record(s) | |
| Record Status | Occurrence |
| Date Created | 1987-May-19 |
| Date Last Modified | 2022-Jan-28 |
| Created By | |
| Revised By |
Primary Commodities: Granite
Township or Area: Dobie
Latitude: 48° 40' 40.63" Longitude: -93° 58' 45.69"
UTM Zone: 15 Easting: 427907 Northing: 5392119 UTM Datum: NAD83
Resident Geologist District: Kenora
NTS Grid: 52C12NW
Point Location Description: From map in MDC027
Location Method: Data Compilation
Access Description: Located in Lot 12, concession II and III, the deposit is crossed by a township road.
There has been no recorded extraction of this rock. No assessment report were found on file.
Province: Superior
Subprovince: Wabigoon
Geological Age: Archean
| Rock Type | Rank | Composition | Texture | Relationship | Diabase | 1 | Diabase | Is |
|---|---|---|---|---|
| Mafic lava flow-unsubdivided | 2 | Adjacent |
Dec 19, 2019 (Therese Pettigrew) - The deposit is a Proterozoic (Keweenawan) diabase dyke hosted by Archean metavolcanics (Storey, 1986). The dikes, as indicated by the distribution of outcrops, have remarkable continuity at a bearing of N45W. Two are apparently continuous for distances of over 20 miles, and several others have been traced for about five miles. The major dikes range from 100 to 200 feet wide, but smaller dikes ranging from a few inches to 6 feet wide are also common. The dike rock is fine-grained along the margins of the intrusive, be coming medium- to coarse-grained in the central parts. It is dark greenish-grey in colour and weathers a distinctive brown. Microscopic examination shows it to be composed of labradorite, augite, interstitial quartz, and accessory magnetite and sulphides. The augite is partially uralitized. Diabasic or intergranular texture is well developed (Fletcher and Irvine, 1954). Where examined the diabase shows five distinct zones: a narrow porphyritic chilled margin on each side, a fine-grained porphyritic zone (presumably on each side) and a wide medium- to coarse-grained central zone. The porphyritic zones contain 2 to 5% feldspar phenocrysts 0.5 to 5 mm in length. The zones grade into each other over distances of 1 to 2 m. The combined chill margin and fine-grained porphyritic zone are 23 m in width at the point examined. The central zone is non-porphyritic and up to 5 mm in grain size. Traces of disseminated pyrite are present. Joint sets 055-070/80N, 350-000/85W and 100/90 are present, the latter is found in the central part of the dike. Joint spacing is 0.5 to 1.5 m with the central part of the dike having the widest spacing. The margins often have very close spaced joints (15 cm). The joint directions vary along the length of the dike. The rock polishes well to a dark green colour. A small amount of pyrite is visible on the polished surface but these did not appear as rusty spots on the weathered surface (Storey, 1986).
| Rank | Mineral Name | Class | Economic Mineral Type | Alteration Mineral Type | Alteration Ranking | Alteration Intensity | Alteration Style |
|---|---|---|---|---|---|---|---|
| 1 | Pyrite | Economic | Ore |
Mono - Building and ornamental stone inventory in the districts of Kenora and Rainy River
Publication Number: MDC027 Scale: Date: 1986
Author: Storey C.C.
Publisher Name: Ontario Geological Survey
Location:
Part - Geology of the Emo area
Publication Number: ARV63-05 Scale: Date: 1997
Author: Fletcher G.L., Irvine T.N.
Publisher Name: Ontario Dept. of Mines
Location:
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