Ontario Mineral Inventory

Ontario Geological Survey
Permanent Link to this Record: MDI52F07SW00027

Record: MDI52F07SW00027

General

Commodities

Primary Commodities: Gold

Location

Township or Area: Harper Lake Area

Latitude: 49° 24' 49.73"    Longitude: -92° 45' 13.84"

UTM Zone: 15    Easting: 517854.805   Northing: 5473488.293    UTM Datum: NAD83

Resident Geologist District: Kenora

NTS Grid: 52F07SW

Point Location Description: General

Location Method: Conversion from MDI

Access Description: The Rochon Island claims are situated in the Manitou Lakes area, Kenora Mining Division, Ontario, and occupy portions of claim map-areas G-2683 (Lower Manitou Lake), G-2572 (Boyer Lake), and G-2584 (Harper Lake) in N.T.S. map-area 52-F-7. Winter access into the area from Highway 502 is via a 5 km long skidoo trail into the settlement of Gold Rock. The trail leaves Highway #502 approximately 50 km south of Dryden, Ontario. Summer access is via float plane or by boat from Cedar Narrows, approximately 80 km to the south. The skidoo trail into Gold Rock is passable using ATC's but is not suitable for hauling boats. (Assessment File 52F07SW X-4, Cochrane Oil and Gas Ltd, Kenora Resident Geologist Office)

Assessment Work on File

Geology

Province: Superior

Subprovince: Wabigoon

Terrane: Western Wabigoon

Belt: Eagle-Wabigoon-Manitou

Geological Age: Precambrian  

Geology Comments

Feb 23, 2010 (D Scholtz) - During the period December 10, 1984 to March 29, 1985, a total of approximately 270 line kilometres of ground CEM, VLF-EM, and magnetic surveying was carried out over a 10m by 25m grid. Cross lines and base lines were slashed, blazed, chained, and flagged at 25m intervals. CEM and VLF-EM readings were taken at 25m intervals; magnetometer readings were taken at 12.5m intervals. Geological mapping of Map Sheets 1, 2, 3, 7, 8 and 9 was carried out under winter field conditions. Map Sheets 4, 5 and 6 were subsequently mapped under summer field conditions. Approximately 700 rock samples were collected and geochemically analyzed for Au. This work was performed by personnel of Cordilleran Resource Management Ltd. of Calgary, Alberta. Previous work by Cochrane Oil and Gas consisted of a number of small reconnaissance geophysical, geological, and geochemical surveys at various points within the present survey area, plus a number of Winkie drill holes at widespread locations within the present survey area. None of the reconnaissance grids exceeded a total of 2.5 line km. The total footage of the Winkie drill holes was 1,520'. The most significant results of this drilling were the intersection of a massive sulphides zone at the west end of Mosher Bay, and an intersection running up to 0.7 oz/ton gold in a hole at the south end of Leuiller Island. This work has been described in detail in an earlier report by the present writer. Archean volcanic and sedimentary stratigraphy in the Manitou Lakes area is typical of the greenstone belts of Wabigoon Sub-province. In broad terms, a lower mafic volcanic unit is succeeded by a sequence of intermediate to felsic flows and related tuffs, which is in turn overlain by a package of clastic and chemical metasediments consisting of conglomerate, sandstone, siltstone-argillite, chert, and derived schists. In some areas there is evidence of a younger mafic volcanic unit capping the metasediments. These 'upper' mafic volcanics are probably related to numerous late stage gabbroic intrusions which occur as small stocks and elongated dykes or sills. These rocks have been folded, faulted, and metamorphosed to green schist facies metamorphic grade, and are preserved in a northeasterly to easterly trending synclinorium herein referred to as the Manitou Lakes Synclinorium. This volcanic 'trough' is bounded on the southeast by the Irene-Eltrut Lakes batholithic complex and on the northwest by the Atikwa batholithic complex. Felsic metavolcanics and metasediments occur along the core of the synclinorium and are flanked by broad belts of mafic volcanics. Major schist zones related to folding and faulting parallel the trend of the synclinorium. These zones of weakness have been the focus of late stage (Kenoran) felsic dyking, further transcurrent faulting, and have acted as conduits for hydrothermal fluids which have produced intense hydrothermal alteration. Gold deposits in the Manitou lakes area are closely related to these major structures. The schist zones may be the result of penetrative deformation fabrics along major isoclinal (?) fold axes and/or may have been produced by transcurrent and vertical movements along a "mobile" zone separating the major crustal blocks represented by the Atikwa and Irene-Eltrut lakes batholithic complexes.

Lithology Comments

Feb 23, 2010 (C Ravnaas) - BEST ASSAY: UP TO 0.50 OPT AU FROM GRAB. The Leuiller Island and Rochon Island area is underlain by a northeasterly striking, vertically dipping sequence of interbedded mafic and intermediate flows and tuffs. Regional (1:31,680) mapping indicates that the island is transected by the axis of the Manitou Anticline. The only field evidence observed in support of this was the more or less synwnetrical distribution of lithologies about the projected axial plane of the fold. The meta-volcanic rocks are intruded by a series of subconcordant quartz porphyry dykes and felsite bodies. At the southern end of Leuiller Island a narrow zone of gabbro intrudes the mafic and intermediate volcanics. First pass mapping of Leuiller Island has partially delineated a brecciated and carbonatized pyroxenite at the core of the above-described gabbroic intrusion. This spectacular quartz-carbonate - pyrite +/- fuchsite +/- sericite alteration zone hosts gold values of up to 0.532 oz/ton (semi-reconnaissance sampling carried out to date). It has been traced intermittently along strike for 200m and geophysical data (VLF-EM and CEM surveys) indicate a further strike extension of 600m. The high assays occur in a pyrite-rich section of the zone cut by quartz veins. The alteration zone is only partially exposed in outcrop and a good deal of stripping, trenching and blasting will be necessary to "open it up" across strike for detailed sampling. At Rochon Island, first pass mapping and sampling has partially defined a 5m to &n wide zone of quartz veining consisting partly of massive quartz and partly of a quartz-pyrite stringer stockwork hosted in a quartz porphyry to felsitic intrusive. Sulphide rich sections of the zone have assayed up to 0.500 oz/ton gold. A small amount of blasting on available exposures will facilitate detailed channel sampling across the full width of the zone. On Map Sheet 5, two separate zones, one at Leuiller Island and one at Rochon Island, carry potentially economic gold values, ranging up to 0.532 oz/ton. Further evaluation of the Rochon Island zone will be straightforward, but considerable stripping and blasting will be required to prepare the Leuiller Island zone for channel sampling. (Assessment File 52F07SW X-4, Cochrane Oil and Gas Ltd, Kenora Resident Geologist Office) SEE DEPOSIT COMMENT GEOLOGY

Mineralization

Mineralization Comments

Feb 23, 2010 (C Ravnaas) - BEST ASSAY: UP TO 0.50 OPT AU FROM GRAB. The Leuiller Island and Rochon Island area is underlain by a northeasterly striking, vertically dipping sequence of interbedded mafic and intermediate flows and tuffs. Regional (1:31,680) mapping indicates that the island is transected by the axis of the Manitou Anticline. The only field evidence observed in support of this was the more or less synwnetrical distribution of lithologies about the projected axial plane of the fold. The meta-volcanic rocks are intruded by a series of subconcordant quartz porphyry dykes and felsite bodies. At the southern end of Leuiller Island a narrow zone of gabbro intrudes the mafic and intermediate volcanics. First pass mapping of Leuiller Island has partially delineated a brecciated and carbonatized pyroxenite at the core of the above-described gabbroic intrusion. This spectacular quartz-carbonate - pyrite +/- fuchsite +/- sericite alteration zone hosts gold values of up to 0.532 oz/ton (semi-reconnaissance sampling carried out to date). It has been traced intermittently along strike for 200m and geophysical data (VLF-EM and CEM surveys) indicate a further strike extension of 600m. The high assays occur in a pyrite-rich section of the zone cut by quartz veins. The alteration zone is only partially exposed in outcrop and a good deal of stripping, trenching and blasting will be necessary to "open it up" across strike for detailed sampling. At Rochon Island, first pass mapping and sampling has partially defined a 5m to &n wide zone of quartz veining consisting partly of massive quartz and partly of a quartz-pyrite stringer stockwork hosted in a quartz porphyry to felsitic intrusive. Sulphide rich sections of the zone have assayed up to 0.500 oz/ton gold. A small amount of blasting on available exposures will facilitate detailed channel sampling across the full width of the zone. On Map Sheet 5, two separate zones, one at Leuiller Island and one at Rochon Island, carry potentially economic gold values, ranging up to 0.532 oz/ton. Further evaluation of the Rochon Island zone will be straightforward, but considerable stripping and blasting will be required to prepare the Leuiller Island zone for channel sampling. (Assessment File 52F07SW X-4, Cochrane Oil and Gas Ltd, Kenora Resident Geologist Office) SEE DEPOSIT COMMENT GEOLOGY

Mineral Record Details

Report an Error

We are continuously updating our assessment file / technical report information. If you notice errors in the data, please contact us.

Terms of Use

Please review our Terms of Use agreement for this data product.

Ministry Contact Information

For detailed information regarding this mineral record please contact the Kenora Resident Geologist District Office