Marine Geodynamics and Ore Deposits

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Metal mining is one of the largest sectors of the global economy, challenged by demand for resources that are increasingly difficult to find. Many of the world´s presently exploited metal deposits were originally formed in ancient oceans, by rifting of continental or thickened oceanic crust, where metal-enriched melts are produced. Research in today's oceans is revealing the complex architecture and compositional heterogeneity of the crust and mantle where ore deposits are formed and providing new clues to their possible locations in the geologic past. Some of the most richly endowed crust on Earth exists today in subduction zones of the Western Pacific, where intricate microplate dynamics regulate crustal growth and provide the pathways to the surface for melts and metal-bearing fluids. However, the large-scale magmatic and tectonic processes responsible for enrichment of the ore elements at these locations are still poorly understood. Students under my supervision at uOttawa are using state-of-the-art deep-sea technology to probe the oceanic crust where this enrichment is taking pace, and sophisticated analytical techniques to trace the ore elements and their isotopes back to their crustal sources. To carry out this research, the students are gathering samples and data on scientific expeditions to the Mariana arc, the Melanesian Archipelago (PNG, Solomons, Vanuatu), and the Tonga-Kermadec arc, as well as the Tyrrhenian and Aegean Seas in the Mediterranean and on continuing research cruises to the Mid-Atlantic Ridge and Iceland. Their goal is to test whether fertile crustal domains can be identified in the oceans in the same way that metallogenic provinces have been defined on land. This ambitious program is made possible by long-established and successful cooperation with German, US, NZ and Australian partners who are providing access to research vessels, sea-going infrastructure, and analytical facilities. The students are combining marine geology, geophysics, and geochemistry in a uniquely multidisciplinary approach to identify the sources and the pathways for ore elements through the crust and test new hypotheses about the relationship between crustal growth and ore formation. My group is one of the few scientific teams worldwide bridging modern marine research to the understanding of ancient ore deposits, with direct practical application to resource discovery on land.