Geodynamic controls on hydrothermal ore formation in modern subduction zones

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Increasing demand for base and precious metals has encouraged the search for alternative resources, including mining of hydrothermal vents in the deep sea, known as seafloor massive sulphide (SMS) deposits. Since the discovery of the first vent in 1977, more than 340 active vent sites have been found diverse tectonic settings. Despite 41 years of research, scholars in this field have not adequately constrained the fundamental geologic processes that control where these deposits form, particularly in subduction zones. Seafloor mining may become a reality within the next decade; however, active vent sites host unique chemosynthetic ecosystems that should be protected. There is an urgent need to develop the tools to find inactive vent sites that cannot be detected using traditional techniques. The proposed research program will test the hypothesis that the formation of SMS deposits is directly linked to geodynamic processes on the ocean floor, and that this knowledge can be used to guide regional exploration for inactive deposits. In the next five years, we will focus on developing a robust understanding of the tectonic and volcanic controls on the size, distribution, and composition of newly-discovered active deposits in volcanic arcs, backarc rifts, and oceanic spreading centers. With this information, we will develop regional exploration criteria for inactive deposits that will form the basis of future shiptime proposals to test and refine our models. This program will focus on three subduction zones that represent a variety of structural and volcanic styles: Tonga-Kermadec, Vanuatu and Cascadia. Given the scale of this problem, we will adopt an integrated geological, geochemical and geophysical approach, taking advantage of established partnerships and participation in upcoming research cruises. On land, geological maps are essential for mineral exploration. We will develop new methods for remote-predictive geological mapping of the seafloor using innovative Machine-Learning Algorithms to improve the speed and repeatability of mapping, and We will also adapt land-based approaches to mineral potential mapping for exploration on the seafloor. Together with deposit-scale studies, this work will increase our understanding of geological processes in relatively unexplored areas and will enable more efficient exploration for new deposits on the seafloor. This knowledge will benefit Canadian seafloor mining companies, government regulators, and NGOs, and may inform the creation of Marine Protected Areas in W. Canada. This research also has important implications for exploration for ancient land-based deposits in the long-term. There is an urgent need to train skilled geoscientists who will face the challenge of supplying mineral resources to a growing global population. This program will train HQP in the application of field, laboratory, and remote sensing techniques that will provide them with the knowledge and skills necessary to meet this challenge.