Potential for Subaqueous Hot-spring (Eskay Creek) Deposits in British Columbia

BCMEMPR Open File 1999-14

By N.W.D. Massey, D.J. Alldrick and D.V. Lefebure

The Eskay Creek property lies 80 km north of Stewart, near the western margin of the Intermontane tectonic belt. The property includes several deposits of polymetallic sulphide and sulphosalt mineralization as both exhalative massive sulphides and discordant veins. These deposits are very attractive because of their enhanced precious metal contents and polymetallic nature. Eskay Creek has a mineable reserve of 1.45 Mt grading 57.7 grams per tonne gold and 2493 grams per tonne silver as of January 1, 1999 and is the fifth largest silver producer in the world.

The Eskay Creek deposits are examples of shallow subaqueous hot spring deposits, an important new class of submarine mineral deposits that has only recently been recognized in modern geological environments. The deposit type is transitional between subaerial hot spring Au-Ag deposits and deeper water, volcanogenic massive sulphide exhalites (Kuroko or Besshi types) and shares mineralogical, geochemical and other characteristics of both. They are relatively underexplored and poorly recognized within the geological record.

This study documents relevant geological, mineral deposit and geochemical indicators for Eskay Creek-type deposits in British Columbia on two 1:2 000 000-scale maps. Twenty-two prospective areas with potential for hosting Eskay Creek-type deposits are outlined. MINFILE descriptions are included for 10 known and 20 possible Eskay Creek-type deposits in the province.

Deposits and Areas of Interest: Some deposits of interest Some areas of potential