In the early 1980s, the Geological Survey of Canada began a program to assess the resource potential of the modern seafloor. This work was in support of Canadian claims of sovereignty over its offshore areas, with a particular focus on ongoing international boundary disputes with the United States. It led, in 1985, to the discovery by Survey scientists of an active hydrothermal system and massive base metal sulphide deposits in the Middle Valley area of the Juan de Fuca Ridge, about 300 kilometres off the shore of British Columbia.
This present-day hydrothermal system is similar to those that formed ancient base metal deposits in important mining districts such as Noranda in Quebec and Flin Flon in Manitoba. As a result, they provide a unique and rare opportunity to observe ore-forming processes in real time.
Middle Valley became the focus of a Canadian-led research program involving deep-sea submersibles and other advanced technologies, and it culminated in a large-scale program with the International Ocean Drilling Program in 1991.
Category: Science Advances
Davis, E.E., Goodfellow, W.D., Bornhold, B.D., Adshead, J., Blaise, B., Villinger, H., and Lecheminant, G.M., 1987. Massive Sulfides in a Sedimented Rift Valley, northern Juan De Fuca Ridge; Earth and Planetary Science Letters, v. 82, p. 49–61. doi:10.1016/0012-821X(87)90106-3