Exploring seafloor hydrothermal systems with novel high resolution mineral mapping

Global geochemical cycles are fundamental to the Earth system; where, when, and how much elements are cycled through the Earth underpins a broad range of science, including our understanding of ocean chemistry and how the oceans will be impacted by future climate change. Geochemical fluxes from deep sea hydrothermal systems, where seawater circulates through the seafloor and exits back into oceans via hydrothermal vents, are a key component of global geochemical cycles.

The ocean crust preserves this fluid/rock interaction ("hydrothermal alteration") and by analysing these crustal rocks we can estimate the hydrothermal geochemical flux. However, such studies are limited by poor core recovery by scientific ocean drilling and the time-limitations of mineralogical and geochemical studies.

To advance our understanding of hydrothermal processes and geochemical budgets, we need higher resolution characterisation of the distribution and composition of hydrothermal alteration, and the controls on these, throughout the ocean crust. To achieve this, micro-imaging infrared spectroscopy datasets can be collected on recovered drill core, where mineral specific spectral fingerprints can identify the minerals present at sub-mm resolution.

This novel project aims to redefine our hydrothermal budgets by using preserved hydrothermal alteration sampled by drill cores from the Oman Drilling Project and the International Ocean Discovery Program to calculate geologically robust estimates of hydrothermal fluxes.

The individual will (1) use micro-imaging spectroscopy datasets to define a set of hydrothermal alteration types in the drill-cores and interpret their abundance and distribution; (2) use representative samples of the different alteration types to characterise the geochemical and textural variability, and (3) integrate the abundance of alteration types with their geochemical variability to calculate geologically robust geochemical fluxes.