The Sulphurets-Mitchell Creek area is underlain by rocks of the Lower Jurassic Unuk River Formation, Hazelton Group. These include green to grey volcanic epiclastics, and a sequence of dominantly fine- grained marine sediments. A third sequence of massive red and green volcanic sandstones and conglomerates form the highest peaks capping the stratigraphic sections.

The Kerr F mineral occurrence is reported to lie entirely within a "tectonic shear zone". This zone contains all of the significant gold anomalies. This zone covers an elongated northern trending area, 800 to 900 metres wide and 2 kilometres long. The zone is flanked by comparitively unaltered or weakly altered, fine-grained, brownish green clastic sediments and submarine volcanic rocks on the east, and by a thick unit of basaltic andesite on the west. The tectonic zone is typically composed of moderately to strongly altered and sheared rocks, interpreted to be of volcanic, subvolcanic or plutonic origin. Most of the altered zone can be described as a sericite schist, how- ever, andesitic tuffs and flows, and feldspar porphyry dykes, and possibly flows, can be recognized in the less altered zone. A later formed "swarm" of fine-grained, weakly altered andesite dykes cuts across the schistosity. Both the altered zone and dykes have been cut by faults. Minor sections of silty shale and siltstone occur on the western and eastern margin of the altered zone.

The F Zone mineralization is exposed on the south flank of the Kerr Ridge, just above the ice surface of the West Sulphurets Glacier.

Mineralization is reported to occur in quartz veins and is simi- lar to the Kerr C occurrence (104B 188). The host rock is a sericite schist or an andesitic tuff. The alteration assemblage includes sericite, quartz, pyrite and carbonate. A sample taken from here in 1985 assayed 46.5 grams per tonne gold (Assessment Report 14614).

The F Zone was outlined as an area of anomalous gold values during the 1985 reconnaissance geochemical survey. Follow-up detailed soil geochemical survey and rock sampling work in 1986 showed that the gold values were high, but distribution was erratic and discontinuous. Given the steep terrane and access problems in this area, no addi- tional work has been undertaken to date.