Earth’s network of mid-ocean ridges represents the world’s largest magmatic system, which is responsible for the creation of oceanic crust covering >60% of the Earth’s surface. At slow-spreading mid-ocean ridges, fault systems known as Oceanic Core Complexes (OCCs) exhume mantle and lower crustal rocks to the seafloor, creating hydrothermal systems that directly impact ocean and seafloor chemistry. These hydrothermal systems create unique natural laboratories for understanding geochemical processes vital to net-zero ambitions, including hydrogen production, carbon sequestration, and metal-sulphide mineralization. However, to understand these geochemical and hydrothermal processes, we must first constrain the conditions of deformation and fluid-flow that control the development of hydrothermal systems in OCCs.

This ARIES REP project will address this problem through high-resolution insitu analyses of deformation and hydrothermal processes recorded in new rock core samples from the Atlantis Massif OCC situated on the Mid-Atlantic Ridge. These samples were collected during International Ocean Discovery Program (IODP) Expedition 399 in 2023 and provide a unique grain-scale record of OCC processes with unprecedented detail and structural continuity. To understand how hydrothermal systems develop and evolve in OCCs, the successful candidate will use cutting-edge facilities at the University of Plymouth’s Microscopy Laboratory and Plymouth Electron Microscopy Centre (PEMC) to constrain the thermal evolution of deformation and fluid-flow recorded in the Exp 399 samples:

(1)  The successful candidate will be trained in the use of research-grade petrographic microscopes to characterise different styles of microstructural deformation in a suite of deformed gabbroic samples from the Exp 399 core. From these analyses, representative samples of distinct “deformation facies” will be selected for electron microscopy analyses

(2)  The successful candidate will be trained in a range of electron microscopy techniques to determine the conditions of deformation within their selected samples. High-resolution electron imaging will constrain grain-scale deformation mechanisms and identify sites for quantitative electron dispersive spectroscopy (QEDS) analyses of element compositions. QEDS analyses will measure elemental compositions of key minerals formed and/or deformed during deformation and fluid-flow. These data will be used to constrain temperatures of deformation.

(3)  The successful candidate will be trained to processes and interpret the QEDS data and calculate precise temperatures of deformation and fluid-flow and interpret their impacts on hydrothermal systems in an OCC.

Training in petrographic analyses and electron microscopy will be provided by Dr Parsons and Dr Berry. Training in microstructural analyses of deformation and hydrothermal processes, geochemical data processing and interpretation will be provided by Dr Parsons and Dr Harris. The successful candidate will join our vibrant and active research group of postgraduate students and faculty from the University of Plymouth. They will get hands on experience of what its like to work in the research sector, with opportunities to develop key professional skills in scientific analysis, research management, science communication and networking. It is hoped that the results of this project will feed into a peer-reviewed publication, to which the successful candidate will be offered the opportunity to contribute to.

For further information, interested students can contact Dr Andy Parsons (andy.parsons@plymouth.ac.uk).