Mark Hannington

Polymetallic seafloor massive sulfide (SMS) deposits were first found in oceanic crust in 1977 and more than 300 sites of seafloor hydrothermal activity are now known in a variety of tectonic settings. About 200 are confirmed sites of high-temperature venting and polymetallic sulfide deposition with 65% located at midocean ridges. More detailed work about the distribution, size and nature of SMS deposits is crucial now that they are being evaluated as potential future resources for critical minerals. This project will utilize known deposits to understand geometallurgical properties of mid-ocean ridge SMS, including the mineralogy, physical rock properties, geochemistry, trace elements, isotopic systematics and their relationship to volcanic and tectonic settings in the oceans to understand the range of conditions impacting future exploration and exploitation. State-of-the-art analytical facilities, including conventional and multi-collector ICP-MS will be utilized to explore the application of trace elements (and heavy metal isotopes) in the interpretation of metal fluxes, mass accumulation rates and biogeochemical interactions. Recent advances in laser ablation ICP-MS now permit comprehensive characterization and “fingerprinting” of different ore-forming systems, and this technique will be used to better constrain the origins of metal-rich brine and metal concentrations in the reaction zones of mid-ocean ridge seafloor hydrothermal systems. It is essential for future sustainable seafloor resource exploitation that quantifiable models of resource formation are available and that the targeted resources are fully characterized before they are exploited. This is necessary for development of mineral processing technologies and mitigating environmental impacts and possible future trace metal contamination.