Mineral resource assessment of the Pacific Margin sponge reef areas of interest

Abstract

Glass sponge reefs (Hexactinellida, Hexactinosida) off the Pacific Margin of Canada are both geologically and ecologically unique and represent the only global occurrence. In order to provide protection to these unique living cold-water reefs, the Department of Fisheries and Oceans under the Oceans Act have made the four large reefs within the Pacific North Coast Integrated Management Area (PNCIMA) designates for protection as Marine Protected Areas (MPA). The federal government's process for evaluation of a MPA of Interest requires an assessment of the non-renewable resource potential, including marine minerals. Based on the limited knowledge of the offshore British Columbia surficial mineral potential, two settings that may contain mineral placers of gold and titanium include drowned beach and reworked shelf deposits at water depths of 150 m to the modern beach. In addition, extensive areas of construction aggregate and calcium carbonate occur on the shelf. The deep water sponge reefs within the Areas of Interest occur in depths below 150 m within glacial sediments and, therefore, outside the potential setting for mineral placers or industrial minerals. Consequently, the enactment of the sponge reef Marine Protected Areas will not include any surficial mineral deposits of economic potential.