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File Created: 25-Mar-1992 by Ron McMillan (RHM)
Last Edit:  09-Apr-2021 by George Owsiacki (GO)

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NMI
Name RAVEN Mining Division Omineca
BCGS Map 094C051
Status Showing NTS Map 094C05W, 094C12W
Latitude 056º 30' 14'' UTM 10 (NAD 83)
Longitude 125º 57' 06'' Northing 6266069
Easting 318352
Commodities Copper, Gold, Lead, Zinc Deposit Types L03 : Alkalic porphyry Cu-Au
Tectonic Belt Intermontane Terrane Quesnel, Plutonic Rocks
Capsule Geology

The Raven occurrence is located near the headwaters of Raven Creek, about 6 kilometres north of Kliyul Creek, approximately 110 kilometres northwest of the community of Germansen Landing.

The showing area is underlain by Middle to Upper Triassic volcaniclastic and volcanic rocks of the Takla Group, which have been intruded by the Croydon Creek ultramafic stock, the Croydon Creek pluton, the Kliyul Creek pluton and a host of related dikes. These intrusive bodies comprise the northern end of the Hogem batholith, a multiphase intrusive complex with latest Triassic to Middle Jurassic alkaline phases and Cretaceous calc-alkaline bodies. Compositional similarities, subvolcanic phases and heterolithic volcanic-subvolcanic intrusive assemblages are thought to be in part, coeval with the ultramafic stock and Croydon Creek pluton. Coarsely recrystallized hornfelsed rocks or an intrusive breccia commonly marks the contact between Takla volcano-sedimentary rocks and Hogem intrusive bodies.

Prominent and widespread copper and gold geochemical anomalies have been defined in the area (Assessment Reports 3197, 21521) and chalcopyrite has been found disseminated in monzonite porphyry dikes, as well as with magnetite, pyrrhotite and pyrite as fracture-controlled blebs and pods in tuff. Minor galena and sphalerite mineralization is also present.

In 1990-91, Teck Explorations Ltd., in joint venture with Total Energold Corp., evaluated base and precious metal and alkalic porphyry copper-gold potential of the property. The initial program involved contour soil sampling, prospecting and mapping over the entire claim block. Favourable geochemical response over the broadly gossanous Raven area prompted construction of a 25 line kilometre grid and collection of 1005 soil samples, and also geological mapping and an induced polarization survey. The work defined large copper-gold anomalies at the Raven showing (this description) and in the Bloom Cirque (094C 039) area. Three holes (totalling 450 metres) were drilled at Raven where two of the holes intersected weak copper and gold mineralization.

In 2002, Northgate Minerals flew an airborne magnetic/radiometric/electromagnetic survey and conducted limited rock and core sampling. In 2008, Newcrest Mining BC Ltd. and Serengeti Resources Inc. drilled a total of 2472.88 metres of NQ2 core in four surface holes on their Croy-Bloom/Davie Creek project. One of the four holes (CBR001) totalling 547.7 metres was drilled on the Raven prospect. Drillhole CBR001 tested a northwest break in the chargeability coincident with a less than 0.6 parts per million (ppm) gold anomaly. The gold anomaly is associated with an apophysis of moderately K-feldspar-silica altered hornblende-phyric diorite that has intruded pyroxene-phyric andesite porphyry. The andesite porphyry is similar to other andesite porphyries described in the district belonging to the Upper Triassic Takla Group volcanics. CBR001 was drilled towards 270 degrees at -60 degrees, approximately 200 metres north of three shallow diamond-drill holes drilled by Teck Exploration in 1991.

CBR001 intersected strongly vein controlled gold-copper mineralization; 3.0 metres at 1.9 grams per tonne gold, 2.0 metres at 0.7 gram per tonne gold, and 2.0 metres at 0.4 gram per tonne gold. Hostrocks include medium grained diorite porphyry and lesser pyroxene-rich andesite porphyry from surface to 292 metres. Below 292 metres, pyroxene andesite porphyry and lesser andesite are dominant. Alteration consists of weak to moderate chlorite plus/minue secondary biotite plus epidote alteration, and zones of sericite plus silica alteration as vein selvages. Rare and localized secondary K-feldspar also occurs as vein selvages. Albite plus silica alteration is common below 360 metres in andesite porphyry and is occasionally associated with sulphide-poor, monomictic, hydrothermal brecciation. Disseminated and vein pyrite is abundant (3 to 10 per cent) in andesite and andesite porphyry, and to a lesser extent in diorite porphyry from the surface to 335 metres. This is likely responsible for the Raven chargeability anomaly.

Copper sulphide mineralization consists of trace disseminated and vein-hosted chalcopyrite associated with epidote plus calcite or sericite plus silica alteration. Several approximately 1 metre vein-like structures with abundant pyrite, magnetite and chalcopyrite (up to 3 per cent) occur between 327 and 351 metres. Overall, alteration appears to increase downhole, from propylitic near surface, to albite plus silica and sericite plus silica with depth. Strong pyrite mineralization seen in the upper part of the hole may represent a barren pyrite shell peripheral to a zone of stronger copper mineralization further to the west of CBR001. Drillhole CBR001 ended in strong silica-sericite altered pyroxene andesite porphyry at 547.73 metres (Assessment Report 30937).

Bibliography
EMPR ASS RPT 3197, *21521, 27869, *30937
EMPR FIELDWORK 1991, pp. 127-145; 1992, pp. 109-134
EMPR OF 1989-17; 1990-13; 1992-11; 1993-2; 1995-6; 1996-19
EMPR GF 2000-1
EMPR GEOS MAP 2001-10
EMPR PFD 672094, 673269, 673270
GSC MEM 274
GSC MAP 1030A
GSC OF 864
PR REL Serengeti Resources Inc. Nov.18, 2004, Jan.21, 2009

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