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

The Kerr A 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 north 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. This 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, feldspar porphyry dykes and possibly flows, can be recognized in the less altered zones. A later formed "swarm" of fine-grained, weakly altered andesite dykes cut 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.

Mineralization consists of quartz-sulphide veins, stockworks, and disseminated sulphides. Veining has accompanied the development of sericitization and silicification to the extent that disseminated and vein material are an integral part of the alteration assemblage. Veins range in width from a few millimetres to several centimetres. Pyrite is the most common sulphide and is ubiquitous within the shear zone. Chlorite and carbonate alteration are also observed. Chalco- pyrite occurs with pyrite, in a few locations in small quartz-pyrite stockworks. Minor malachite is visible at the margins of some chal- copyrite bearing veins. Silicification is common where stockwork veining is intense and clay alteration also occurs adjacent to some large quartz-pyrite veins. Calcite occurs in minor amounts.

Sphalerite, galena, and hematite were reported in polished thin sections. Gold mineralization is primarily associated with quartz- pyrite veins, with residual gold in the strongly weathered and leached zones.

Diamond drilling on the A Zone has shown that the gold distribu- tion is erratically high but discontinuous. The best drill hole intersection from 1987 assayed 19.65 grams per tonne gold, 1303.21 grams per tonne silver and 4.81 per cent copper over 2.0 metres (Assessment Report 16616). Trench samples taken in 1988 assayed 23.66 grams per tonne gold, 36.00 grams per tonne silver over 2.0 metres and 144 grams per tonne gold and 507 grams per tonne silver over 1 metre (Northern Miner, Sept.19, 1988).