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The University of Southampton
Ocean and Earth Science, National Oceanography Centre Southampton

Research project: Rare earth elements as geochemical tracers of hydrothermal processes in the Southern Ocean

Currently Active: 

The East Scotia Sea, in the Atlantic sector of the Southern Ocean, hosts a chemically diverse range of high temperature (>380oC) and diffuse hydrothermal vents in back-arc and island-arc settings. Located on segments E2 and E9 of the East Scotia Ridge (ESR) and within the Kemp Caldera, these vents were detected from plume signals in 1998 and sampled for the first time in 2010 by ROV ISIS. Phase separation, subduction influence and magmatic gas injection generate end-member fluids with divers compositions. My research focuses on the rare earth element (REE) geochemistry of hydrothermal fluids and minerals in this region, and the potential of the REEs as tracers of fluid constituents and subsurface processes.

Location map with ESR segments E2 and E9, and the Kemp Caldera (after Frezdorff et al., 2002)
Location map

Rare earth elements

Hydrothermal fluids are highly enriched in REEs compared with seawater. Fractionation of the REEs in fluids and associated minerals typically reflects systematic variations in atomic radius across the group with the exception of Ce and Eu, which are more redox sensitive.

In back-arc and island-arc environments, the injection of volatile species released from the subducting slab and degassed from water-rich magmas generate hydrothermal fluids with unusual chemical compositions. REEs can be strongly influenced by fluid speciation, and the East Scotia Sea provides an ideal natural laboratory for studying the behaviour of REEs in geologically and chemically diverse hydrothermal vent systems.

High-temperature 'black smoker'  and diffuse vent sites on the East Scotia Ridge and Kemp Caldera, East Scotia Sea (after ChEsSO)
'Black smoker' and diffuse vents

Key Contacts

Catherine Cole (Postgraduate Research Student)

Prof Rachael James (Principal Investigator)

Dr Doug Connelly (Collaborator)






Ti syringes inserted into chimney orifice for high temperature fluid sampling; chimney samples with mineral zonation; CTD Niskin bottles for plume sampling throughout water column

Scientific Aims

The primary aim of my research is to enhance the understanding of subsurface hydrothermal processes using REEs as geochemical tracers. Working with a suite of hydrothermal fluids, anhydrite, and plume seawater samples from the ESR and Kemp Caldera, I am investigating:

  • The influence of fluid chemistry on REE fractionation patterns in hydrothermal fluids and minerals.
  • The mechanisms of fluid evolution through magmatic and subduction influence, phase separation and mineral deposition.
  • Temperature and redox conditions of mineral deposition from both contemporary and past fluids.
  • Transport and fate of plume material in dissolved and particulate phases.

PhDs and Other Opportunities


Associated research themes

Hydrothermal Processes and Mineral Deposits

Related research groups

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