The occurrence is on Cracroft Island near the boundary of the Coast Crystalline Belt and the Insular Belt. Volcanic rocks in the area have undergone regional greenschist facies alteration.

The Tidewater-Copper Queen occurrence consists of massive chalco- pyrite, and disseminated pyrite, cuprite and bornite in andesite and volcanic breccia of the Upper Triassic Vancouver Group, Karmutsen Formation.

Malachite and azurite are present. Carbonate alteration is evi- dent as lenses, veinlets and stringers of calcite. Selected samples returned values in copper ranging from 4.11 to 9.3 per cent. Associated silver values are between 2.4 and 112.81 grams per tonne and gold ranges from up to 2.61 grams per tonne (Assessment Report 14230, page 8).