The Bergette porphyry copper-molybdenum occurrence is in an area underlain by the Jurassic Hazelton Group hornfelsed argillite and Cretaceous Kasalka Group porphyritic andesite. These have been intruded by the Late Cretaceous Sibola Stock (Bulkley Plutonic Suite) which consists of quartz diorite, aplite, granitic quartz porphyry, porphyritic quartz monzonite, breccia, and feldspar porphyry dikes. Biotite from porphyritic quartz monzonite yielded potassium-argon isotopic age of 76.7 plus or minus 2.5 million years.

One type of mineralization is associated with a breccia zone in the Sibola Stock where molybdenite bearing quartz occurs between breccia fragments and vugs contain calcite, pyrite, chalcopyrite, magnetite, epidote, biotite, chalcocite, and zeolites. The other type of mineralization is widespread on the west side of the stock and is comprised of pyrite, chalcopyrite, and minor molybdenite filling fractures with quartz and adularia. Sericitic alteration envelopes these fractures and the zone, approximately 6.5 square kilometres, is pervasively oxidized. Jarosite and azurite are abundant.

Work History

Kennco Explorations (western), Limited, was attracted to the area in the early 1960s by anomalous high copper and molybdenum concentrations in silt samples taken from local streams. A follow-up investigation led to the discovery of scattered copper and molybdenum bearing zones in a large gossan, after some additional investigations over a period of several years, Kennco abandoned the property.

The showings were restaked in July 1970 by G.O.M Stewart. By an agreement of December 1970 Frontier Exploration Limited optioned 27 claims and fractions in the Bergette and BS soups from G.O.M. Stewart and R.R. Blusson. This was superseded by an agreement of 1971 between Frontier, the Optioners, and Granges Exploration Aktiebolag, of Sweden. Further staking in the BF, FG, and LK groups expanded the property to some 190 claims and fractions. A joint exploration program during 1971 included geological mapping, a geochemical soil survey (1171 samples), a magnetometer survey over 8 kilometres, trenching, and diamond drilling in 6 holes totalling 1222.5 metres.

Berg Metals Limited Partnership is the owner of the Berg property which envelopes the Bergette occurrence area; however a small claim over the Bergette showing (in 2015) indicates ownership by John Billingsly. In 2010, Aeroquest International conducted a helicopter-borne geophysical survey on behalf of Terrane Metals Corp., over the Berg property in August 2010 (Assessment Report 32307). The total survey coverage is 754.35 line-kilometres, flown at 100 metre line spacing and appears to have covered the Bergette occurrence also.

See Berg (093E 046) for further details of the Berg property.