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Ontario Geological Survey
Permanent Link to this Record:
MDI000000000412
Record Name(s) | Green Mica Zone - 1989 |
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Related Record Type | |
Related Record(s) | |
Record Status | Prospect |
Date Created | 2007-Oct-31 |
Date Last Modified | 2022-Mar-03 |
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Revised By |
Primary Commodities: Gold, Zinc
Township or Area: Setting Net Lake Area
Latitude: 52° 50' 7.11" Longitude: -93° 34' 49.56"
UTM Zone: 15 Easting: 460899 Northing: 5854108 UTM Datum: NAD83
Resident Geologist District: Red Lake
NTS Grid: 53C13SE
Point Location Description: ddh database
Location Method: Data Compilation
1987-89: Prospecting, geological mapping, geophysics and diamond drilling by Greystar Resources and Noramco Explorations. 1990: Diamond drilling by Echo Bay Mines.
Office File Number | Online Assessment File Identifier | Online Assessment File Directory |
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2.13664 | 53C13SE0053 | 53C13SE0053 |
Province: Superior
Subprovince: Sachigo
Terrane: North Caribou
Belt: Favourable Lake
Geological Age: Neoarchean
Oct 31, 2007 (Mark Puumala) - This prospect is located in the southeastern portion of a major Northwest-striking deformation zone (Green Mica Zone) that extends 3 km to the northwest to the Gold Hill area (Whittaker 1989). Anomalous gold mineralization that appears to be associated with this structure has been reported by Greystar Resources and Echo Bay Mines from numerous diamond drill hole intersections over an approximate strike-length of 1250 m. The eastern end of the Green Mica Zone is located at the intersection with an east-west-striking structure referred to by Whittaker (1989) as the Rathouse Bay shear or lineament. Whitakker (1989) has interpreted each of these structures to have displaced stratigraphy dextrally. Whittaker (1989) indicates that rocks to the north of the Rathouse Bay shear are dominated by felsic metavolcanics (flows and tuffs), while the rocks to the south are dominated by a sequence of mafic metavolcanic flows with intercalated metasedimentary rocks. Whittaker (1989b) reports that foliation has a regional average orientation of west-northwest to northwest. The Green Mica Zone is indicated by Whittaker (1989) to be hosted largely within felsic ash tuff or siliceous metasediments of the northern felsic metavolcanic-dominated sequence. The altered felsic rocks within this zone are reported to be fissile, intermittently carbonatized, contain bottle-green mica (fuchsite) and are mineralized with weakly disseminated pyrite. Significant gold mineralization has also been noted in units of sulphidized iron formation that occur within this deformation zone.
Rock Type | Rank | Composition | Texture | Relationship | Felsic lava flow-unsubdivided | 1 | Contains |
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Mafic lava flow-unsubdivided | 2 | Adjacent | ||
Terrigenous-Clastic-Unsubdivided | 3 | Near | ||
Ironstone-unsubdivided | 4 | Contains |
Rank | Mineral Name | Class | Economic Mineral Type | Alteration Mineral Type | Alteration Ranking | Alteration Intensity | Alteration Style |
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1 | Pyrite | Economic | Ore | ||||
2 | Chalcopyrite | Economic | Ore | ||||
3 | Pyrrhotite | Economic | Ore | ||||
4 | Sphalerite | Economic | Ore | ||||
Silica | Alteration | Silicification | 1 | ||||
Fuchsite | Alteration | 2 |
Oct 31, 2007 (Mark Puumala) - Four diamond drill holes (NBE-88-04 and 14, and BRE-90-09 and 10) advanced by Greystar Minerals in 1988 (Whitakker 1989), and Echo Bay Mines in 1990 (AFRI# 53C13SE0053) appear to have intersected the Green Mica Zone, which is reported on drill logs as silicified felsic metavolcanics. Anomalous gold assays ranging from (130 to 1740 ppb Au) were reported from each of these intersections. Whittaker (1989) describes the mineralization at NBE-88-04 as consisting of green mica-bearing siliceous schist with minor carbonate. However, the most significant gold values reported from this hole (Chute 1988) came from an intersection of sulphidized iron formation. Echo Bay Mines drill hole log BRE-90-09 reports that mineralization within the silicified felsic metavolcanics includes finely-disseminated pyrrhotite and chalcopyrite. Similar alteration and mineralization was reported farther to the northwest in silicified felsic metavolcanics encountered in Greystar drill hole NBE-88-02, and to the west of NBE-88-14 in BRE-90-10. The anomalous gold assay in NBE-88-02 was reported by Chute (1988) to have been obtained from quartz vein material containing trace arsenopyrite, while mineralization at BRE-90-10 is reported to consist of 2-3% pyrite, 1% pyrrhotite and trace arsenopyrite. Anomalous gold values were reported from other horizons found in close proximity to the sheared and silicified felsic metavolcanic. These include an intersection of sulphidized iron formation reported in BRE-90-05 which produced the highest gold assay (5470 ppb) that has been reported from this prospect. Anomalous zinc assays (>1%) were also reported from drill hole BRE-90-06 in a section logged as intermediate to felsic tuff mineralized with up to 10% sphalerite. Chute (1988) also reported surface polymetallic showings consisting of pyrite + pyrrhotite + chalcopyrite + sphalerite in the vicinity of drill hole NBE-88-04. Whittaker (1989) reported that the stratigraphy in this area is likely to have been offset by late north-northeast-striking faults. Displacement along one of these structures may explain the apparent displacement of the silicified felsic metavolcanic horizon noted between drill holes NBE-88-14 and BRE-90-10. The most notable assays reported from diamond drill intersectons of this zone include the following: 1885 ppb Au over 1.5 m in NBE-88-04, 1049 ppb over 1.5 m in NBE-88-14, 1740 ppb over 1 m in BRE-90-09, and 5470 ppb Au over 0.5 m in BRE-90-05.
Rank | Classification |
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1 | Vein (Polymetallic) |
Rank | Characteristic |
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1 | Sheared |
Book - Exploration Report for the Berens River East Property for Greystar Resources Inc.
Publication Number: AF RL53C13SE 50 Scale: Date:
Author: Chute, M. 1988.
Publisher Name:
Location: Red Lake RGP
Book - Geological Report on the Berens River East Property (Greystar Resources), District of Kenora (Patricia Portion), 53C/13 for Noramco Explorations Inc.
Publication Number: AF RL53C13SE 54 Scale: Date:
Author: Whittaker, P.J. 1989.
Publisher Name:
Location: Red Lake RGP
Book - diamond drill hole logs for BRE-90-05, 06, 09 and 10
Publication Number: AFRI53C13SE0053 Scale: Date:
Author: Echo Bay Mines
Publisher Name:
Location: Red Lake RGP
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