Dr Michelle Harris (University of Plymouth, School of Geography, Earth and Environmental Sciences) – Contact me
Dr Rebecca Greenberger, California Institute of Technology
Professor Antony Morris, School of Geography, Earth and Environmental Sciences, University of Plymouth
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 budgets, we need higher resolution characterisation of the distribution and composition of hydrothermal alteration 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 geochemical budgets by using preserved hydrothermal alteration sampled by drill cores from the Oman Drilling Project and from the International Ocean Discovery Program to calculate geologically robust estimates of hydrothermal geochemical 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 (major and trace elements and isotopic compositions) variability, and (3) integrate the abundance of alteration types with their geochemical variability to calculate geologically robust geochemical fluxes.
The individual will develop a range of industry and academia relevant skills, with specialist training in micro-imaging spectroscopy and a range of analytical geochemistry (including XRF, ICP-MS and isotopic analysis). The successful candidate will join an international team of researchers including the broader Oman Drilling Project Science team and the ocean drilling community.
This PhD is suitable for individuals with degrees in Geology/Earth Sciences with interests in petrology, geochemistry and big-picture Earth Science questions.