Geology and Mineral Occurrences of the Upper Iskut River Area: Tracking the Eskay Rift through Northern British Columbia

The Eskay Creek gold-silver mine, located in northwest British Columbia, is the highest-grade precious-metal volcanogenic massive sulphide deposit in the world. The mining industry continues to spend more than $2 million each year on exploration for similar deposits in the area. The geologic setting at the minesite is well studied, but large tracts in north-central British Columbia require more detailed surveys to determine if favourable sites exist for formation and preservation of additional deposits. In 2003, the British Columbia Geological Survey and the Geological Survey of Canada launched a two-year mapping program to delineate the ore horizon through the region north of the mine, and to assess potential for additional Eskay Creek type deposits. This horizon lies within Lower to Middle Jurassic, arc-related, rift sequence rocks along the northwest perimeter of the Bowser Basin, a large (48,000 km) Middle Jurassic to Early Cretaceous sedimentary basin (Fig. 1).