The Gulch East occurrence is located along the southwest ridge of Mount Gordonia at an elevation of 2065 metres and approximately 300 metres southwest of the summit. The showing is 290 kilometres north of Smithers. It lies within the Omineca-Cassiar mountains in the north-central portion of the Toodoggone gold camp.

The Gulch East showing is situated within a Mesozoic volcanic arc assemblage which lies along the eastern margin of the Intermontane Belt, a northwest-trending belt of Paleozoic to Tertiary sediments, volcanics and intrusions bounded to the east by the Omineca Belt and to the west and southwest by the Sustut and Bowser basins.

Permian Asitka Group crystalline limestones are the oldest rocks exposed in the region. They are commonly in thrust contact with Upper Triassic Takla Group andesite flows and pyroclastic rocks. These Takla rocks have been intruded by plutons and other bodies of the mainly granodiorite to quartz monzonite Early Jurassic Black Lake Suite and are in turn unconformably overlain by or faulted against Lower Jurassic calcalkaline volcanics of the Toodoggone Formation, Hazelton Group.

The dominant structures in the area are steeply dipping faults which define a prominent regional northwest structural fabric trending 140 to 170 degrees. In turn, high angle, northeast-striking faults (approximately 060 degrees) appear to truncate and displace northwest-striking faults. Collectively these faults form a boundary for variably rotated and tilted blocks underlain by monoclinal strata.

Toodoggone volcanics, observed at the Gulch East showing, are described as purple agglomerates, grey to purple tuffs, rhyolites and orange lithic to crystal tuffs (Assessment Report 20671). The oldest rocks are light to dark green porphyritic or massive andesitic flows and pyroclastics of the Takla Group (Assessment Report 20671). These have been summarized as basaltic and andesitic flows and breccia, with minor limestone and argillite (Bulletin 86).

Propylitic alteration is widespread throughout the area surrounding the Gulch East showing, predominantly affecting andesitic flows and tuffs. These zones are characterized by chlorite alteration of plagioclase, biotite and hornblende phenocrysts, accompanied by a strong increase in epidote and/or carbonate, pyrite and magnetite in the groundmass (Assessment Report 20671).

The west ridge of Mount Gordonia is crossed by numerous north and northwest-trending, steeply dipping faults, with which numerous quartz veins and zones of silicification are associated. The veins are commonly mineralized with gold, silver and copper. Individual veins are up to 50 centimetres width with strike lengths of 10 metres or less. They are often widely spaced (greater than 15 metres), generally striking north and dipping steeply east and west (Assessment Report 20671). One of these veins comprises the Gulch East showing. It is up to 10 centimetres wide, strikes 350 degrees and dips 65 to 90 degrees. Mineralization consists of up to 10 per cent blebs, stringers and disseminations of pyrite, chalcopyrite and possibly arsenopyrite. Malachite staining is also present. The host rock is quartz monzonite porphyry.

In 1989, a select chip sample (KR-1) from a 6-metre wide silicified zone in volcanics, located approximately 250 metres to the west, yielded 0.150 gram per tonne gold (Assessment Report 18763).

In 1990, a grab sample (DO-109) from the Gulch East vein assayed 1.195 grams per tonne gold, 56.7 grams per tonne silver and 2.93 per cent copper (Assessment Report 20671). Also a this time, a grab sample of quartz veining in volcanic tuff and porphyry with blebs and stringers of pyrite and chalcopyrite, located approximately 100 metres to the east, assayed 4.3 grams per tonne silver and 0.812 per cent copper, whereas a grab sample (DO-112) from a 0.3-metre wide sheared quartz-epidote vein with pyrite hosted in a silicified andesite, located approximately 200 metres to the southwest, yielded 3.750 grams per tonne gold, 4.6 grams per tonne silver, 0.164 per cent copper, 0.402 per cent lead and 0.583 per cent zinc (Assessment Report 20671).

In 1995, two samples (DB-3 and -4) from 5-centimetre wide quartz veins with pyrite, sphalerite and malachite, located approximately 250 metres to the east-northeast, assayed 1.05 and 0.67 grams per tonne gold, 1.7 and 9.0 grams per tonne silver with 1.28 and 0.404 per cent copper, respectively (Assessment Report 24284).

In 2005, a 0.1-metre chip sample (64637) from a quartz vein with malachite assayed 6.1 grams per tonne silver and 0.462 per cent copper, whereas a nearby float sample (646338) of quartz vein with pyrite assayed 6.31 grams per tonne gold and 8.8 grams per tonne silver (Assessment Report 28039).

Work History

Refer to the Joanna West showing (094E 175) for details of the Joanna work History.