Ontario Geological Survey
Permanent Link to this Record:
MDI000000001028
| Record Name(s) | East Zone - 2005 |
|---|---|
| Related Record Type | |
| Related Record(s) | |
| Record Status | Prospect |
| Date Created | 2011-Mar-04 |
| Date Last Modified | 2022-Jul-27 |
| Created By | |
| Revised By |
Primary Commodities: Copper, Nickel, Platinum, Palladium, Gold
Secondary Commodities: Silver, Cobalt, Molybdenum
Township or Area: Halkirk
Latitude: 48° 42' 20.3" Longitude: -93° 3' 2.12"
UTM Zone: 15 Easting: 496278 Northing: 5394734.995 UTM Datum: NAD83
Resident Geologist District: Kenora
NTS Grid: 52C11NE
Point Location Description: Taken from geology map with occurrences AFRO 2.32111
Location Method: Data Compilation
Access Description: The property is accessed from Highway 11 east of Fort Frances. There is a series of logging roads which provide access to the internal parts of the Grassy Portage intrusive rocks.
There is a long history of base metals exploration within the North Rock area, with the earliest recorded work occurring in 1918, with possible, unrecorded work as early as 1902. Research suggests that there has been little exploration for the platinum group elements (PGE's) and only minor interest in Au. Most of the exploration activity occurred between 1958 and 1978 and was sporadic before or since.2001, 2003 to 2006 as presented in MetalCORP, Kenora assessment file 52C11NE BBB-8 AFRO 2.37249 Two prospecting programs were completed during 2003 and 2004. The property was optioned to MetalCORP Ltd (MTC) during October 2004. During 2005 and 2006 MTC completed an AeroTEM IT helicopter-borne survey, Phase 1 and II diamond drill programs, linecutting, detailed prospecting, and geological mapping.
Mar 04, 2011 (C Ravnaas) - The North Rock Property is primarily underlain by the differentiated Grassy Portage Intrusion (GPI) with lesser amounts of the Grassy Portage ultramafic pyroclastic sequence (GUP); clastic metasedimentary rocks of the Couchiching Metasediments; granitoid rocks of the Bear Passage and Blind Bay plutons; sections of2 formational, composite, chemical/clastic metasedimtmtary sequences; two narrow mafic metavolcanic units; and a few, possibly subvolcanic gabbro sills. All observed rocks-types comprise the southern limb of a large-scale open, antiformal fold cored by the Rice Bay Dome located approximately 1.50 km north of the property (Figure 3). Most rock-types have been regionally metamorphosed to lower amphibolite-grade. The southwestern two-thirds of the Grassy Portage Intrusion underlies the core of the property (~75%). This large, sill-like, mafic complex intrudes all observed supracrustal rock-types, and is composed ofa well-differentiated, locally layered, cumulate sequence of medium- to coarse-grained, melagabbro, gabbro and leucogabbro; coarsely plagiophyric to glomero-plagiophyric gabbro to leucogabbro; localized intervals ofmedium- to coarse-grained anOlthosite; and a discontinuous, noncumulate, ophitic-textured, melagabbroic border phase that is present along both the upper and lower contacts ofthe complex. The intrusion is structurally overturned and stratigraphically south-facing. Cha1copyrite-dominated mineralization concentrates along both upper and lower contacts with the greatest sulphide abundances observed near the basal or northern contact. Reference MetalCORP, Kenora assessment file 52C11NE BBB-8 AFRO 2.37249
Mar 04, 2011 (C Ravnaas) - The mineralized corridor is fairly constant from the west extremity of Beaver Pond Zone to the east end of East Zone covering up to l.5km along this contact. Traversing from the south northward to the contact with the GPI is very poorly mineralized medium grained gabbro, which gabbro becomes melanocratic with an increase of sulphides (po-cpy mainly) when getting closer to the contact at an average distance of20 meters up to 5 meters to the contact where a coarse grained leucocratic pegmatitic horizon develop with a width of I to 5 meters before hitting the contact. The melanocratic gabbro contains 1races increasing to 8% of disseminated sulphides with local spots that can reach up to 15% mainly in pyrrhotite and chalcopyrite. The contact leuco gabbro contains less sulphide, with an average of I to 3% disseminated or blebby sulphides, but is regularly higher grade than the melanocratic gabbro. The sulphides are normally distributed as disseminated, blebs of wisps in the matrix. On the north side of the contact, considered to be the hanging wall as well as the host rock, a thin band of ultramafic rocks separate the gabbro from the meta-volcanic rocks to the north. This band is irregular, and sometimes disappears at the contact where it generally varies from I to 5 meters in thickness and consists in some basal mafic to ultramafic intrusive rock such as a fine grained mela-gabbro or fine to medium grained pyroxenite. Mineralization is found irregularly in these rocks as pods or patches mostly found along the local fracture paths, and consist of pyrrhotite and chalcopyrite. Some relatively high values of Platinum Group Minerals have been found preferentially in this horizon. Finally, passed this horizon is an environment of pillowed mafic meta volcanic rocks that occasionally contain remnant patches of mineralization also associated with two major fracture patterns running roughly at 340 and 020 azimuths. Reference MetalCORP, Kenora assessment file 52C11NE BBB-3 AFRO 2.32111
Mar 04, 2011 (C Ravnaas) - The East Zone is located ~875 m to the northeast of the Main South Zone and, as exposed on surface, is 500 m in length and 40 to 60 m in width. It is adjacent to the basal contact of the Grassy Portage Intrusion within spotted, variably altered, plagioclase-megacrystic to glomeroplagiophyric gabbro, leucogabbro, and melagabbro with a fine- to coarse-grained groundmass containing 1 to 5% disseminated chalcopyrite, pyrrhotite, and molybdenite. Two historic drill holes have tested the zone with one intersecting 0.233% Cu/70.0 m, including 0.425% Cu and 0.044% MoS;/20.0 m. MTC 2005 samples obtained up to 2.64% Cu, 3290ppm Ni, 4.30ppm Ag, 0.580ppm Pd, 0.813 ppm Pt, 0.579ppmAu, 434ppm Co, and 74ppm Mo. Reference MetalCORP, Kenora assessment file 52C11NE BBB-3 AFRO 2.32111. Twenty-one holes, totalling 4000 m, were drilled on the East zone in 2006. The drill program was to test high-priority airborne geophysical conductors. A 3.7 m core interval from this program graded 12.2 g/t Pt. This intercept included 2 half-metre intervals that averaged 22.4 g/t and 46.1 g/t Pt (MetalCORP Limited, press release, March 6, 2006). The East Footwall Zone is located north and northwest of the East Zone within the footwall volcanic sequence and forms a 450 to 500 m long, 100-175 m wide, diffuse zone of disseminated and stringered chalcopyrite and pyrrhotite mineralization that roughly subparallels the basal contact of the Grassy Portage Intrusion. The mineralization was initially sampled during 2003 MTC prospecting with assays of up to 6516ppm Cu and 72 ppb Au within finegrained, altered mafic, possibly locally ultramafic metavolcanic rocks. Most of the samples defining the zone were taken during 2005 from metavolcanic rocks that usually contained Cu with some anomalous Au and Ag. Assays of these samples obtained up to 2.64% Cu, 172ppb Au, and 4.3 ppm Ag. Two of the 2005 samples, however, consisted of fine- to medium-grained gabbro to melagabbro containing I to 2% disseminated chalcopyrite, pyrrhotite, and up to 7990 ppm Cu, 3290ppm Ni, 434ppm Co, 5040ppm As, 579 ppb Au, and 630 ppb Pd. These 2 samples are 200 m apart, apparently along strike from each other, may have been taken from the same gabbroic sill or dyke, and may constitute a separate mineralized zone, with distinct lithological and mineralization characteristics, that is flanked by the East Footwall Zone. Reference MetalCORP, Kenora assessment file 52C11NE BBB-3 AFRO 2.32111.
We are continuously updating our assessment file / technical report information. If you notice errors in the data, please contact us.
Please review our Terms of Use agreement for this data product.
For detailed information regarding this mineral record please contact the Kenora Resident Geologist District Office