Ontario Geological Survey
Permanent Link to this Record:
MDI000000001038
| Record Name(s) | Powerline Zones - 2005 |
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| Related Record Type | |
| Related Record(s) | |
| Record Status | Occurrence |
| Date Created | 2011-Mar-04 |
| Date Last Modified | 2022-Jul-27 |
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| Revised By |
Primary Commodities: Copper
Secondary Commodities: Gold, Silver
Township or Area: Halkirk
Latitude: 48° 42' 34.55" Longitude: -93° 2' 48.34"
UTM Zone: 15 Easting: 496560.001 Northing: 5395174.996 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-8 AFRO 2.37249
Mar 04, 2011 (C Ravnaas) - There are a series of closely-spaced, apparently subparallel CU±PGE occurrences stung out along the powerline right-of-way that are group within this MDI record.. The Powerline 1 Zone was first sampled by MTC prospectors in 2003, with adjacent outcrops sampled in 2005, and presently exhibits a strike length of40 m. The mineralized zone is located -420 m northeast of the East Zone within the recently recognized basal ultramafic zone of the Grassy Portage Intrusion. Mineralization is hosted within fine- to medium-grained, locally coarse-grained, greenish-grey, rusty-weathering, ultramafic intrusive rocks, possibly pyroxenite, that contain 1 to 2% disseminated chalcopyrite and pyrrhotite. Sampling to date has obtained up to 3300ppm Cu, 318ppb Pd, 213 ppb Pt, and 87ppb Au from 4 surface grab samples. The Powerline 2 Zone was discovered by MTC prospecting during 2003 and is located 280 m west-northwest of the Powerline 1 Zone. The 2 surface grab samples taken in 2003 contained up to 9130ppm Cu but contained only slightly anomalous amounts of Ni, PGE's, or Au. Three samples taken during the 2005 prospecting program obtained up to 1.66% Cu. The 3rd in a is located 140 m east-southeast of the Powerline 1 Occurrence The single sample taken from the site consisted of coarse-grained gabbro containing an undisclosed amount of coarse blebby chalcopyrite and graded 3633ppm Cu, 91 ppb Au, and 98ppb Pd.. The Powerline 4 Zone is located 75 m east-southeast oft he Powerline 2 Occurrence and has been traced for -35 m along strike to the northeast, within a single large outcrop. It consists of fine-grained, greenish-grey, locally pillowed mafic metavolcanic flows containing between 1 and 10% disseminated chalcopyrite and pyrrhotite. The single 2003 surface grab sample contained 6131 ppm Cu and 271 ppb Au. The 4 samples taken in 2005 contained up to 1.34% Cu, 358ppb Au, and 1.8ppm Ag. The T1 Footwall Zone is located 120 m south-southeast of the Powerline 5SW Occurrence. The zone can be intermittently traced for at least 375 m to the southwest and may include the Powerline 1 Zone located 280 m to the northeast. The variably malachite-stained pyroxenite unit is quite variable in thickness, is host to 1 to 2% , locally 10 to 15%, disseminated chalcopyrite and some pyrrhotite, and can contain up 1.43% Cu, 9.5ppmAg, 145ppbAu, 555ppb Pt, and143ppb Pd. Reference MetalCORP, Kenora assessment file 52C11NE BBB-3 AFRO 2.32111.
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