Hydrothermal inputs to global geochemical cycles: a novel high resolution approach to quantifying hydrothermal exchange

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To apply please use the online application form. Simply search for PhD Geological Sciences (and select the entry point of October 2023), then clearly state that you are applying for a PhD studentship and name the project at the top of your personal statement.

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Director of Studies: Dr Michelle Harris
2nd Supervisor: Dr Rebecca Greenberger (rgreenbe@caltech.edu) California Institute of Technology
3rd Supervisor: Professor Tony Morris 
Applications are invited for a 3.5 years PhD studentship. The studentship will start on 01 October 2023.

Project description

Scientific background
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 and reacts 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.
Research methodology
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.
Training
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. 
Person specification
This PhD is suitable for individuals with degrees in Geology/Earth Sciences with interests in petrology, geochemistry and big-picture Earth Science questions.
Funding notes
This project has been shortlisted for funding by the ARIES NERC DTP and will start on 1 October 2023.
Successful candidates who meet UKRI’s eligibility criteria will be awarded a NERC studentship for 3.5 years, covering fees, stipend (£17,668 p.a. for 2022-23 rate) and research funding. International applicants (EU and non-EU) are eligible for fully-funded UKRI studentships.
ARIES students benefit from bespoke graduate training and £2,500 for external training, travel and conferences.
ARIES is committed to equality, diversity, widening participation and inclusion. Academic qualifications are considered alongside non-academic experience. Our recruitment process considers potential with the same weighting as past experience.
For information and full eligibility visit https://www.aries-dtp.ac.uk/.
Apply
Please clearly state the name of the studentship project code HARRIS_P23ARIES that you are applying for on your personal statement.
If you wish to discuss this project further informally, please contact Dr Michelle Harris.
Please see our 'how to apply for a research degree' page for a list of supporting documents to upload with your application.
For more information on the admissions process generally, please contact research.degree.admissions@plymouth.ac.uk.
The closing date for applications is 23:59 (UK Time) 11 January 2023. 

References

1 Rebecca N. Greenberger, Michelle Harris, Bethany L.Ehlmann, Molly Crotteau, Peter B. Kelemen, Craig E. Manning, Damon A. H.Teagle, the Oman Drilling Project Science Team (inc. Tony Morris) (2021)Hydrothermal Alteration of the Ocean Crust and Patterns in Mineralization withDepth as Measured by Micro-Imaging Infrared Spectroscopy. JGR Solid Earth.doi.org/10.1029/2021JB021976

2 Michelle Harris, Rosalind M. Coggon, Martin Wood,Christopher Smith-Duque, Tim J Henstock, Damon A. H. Teagle (2017) Hydrothermal cooling of the ocean crust:Insights from ODP Hole 1256D. Earth and Planetary Science Letters, 462:110–121.https://doi.org/10.1016/j.epsl.2017.01.010

3 Rosalind M. Coggon, Damon A. H. Teagle, MichelleHarris, Gary J. Davidson, Jeffrey C. Alt, Tim S. Brewer (2016) Hydrothermalcontributions to global biogeochemical cycles: Insights from the MacquarieIsland ophiolite. Lithos, 264:329–347.https://doi.org/10.1016/j.lithos.2016.08.024

4 Molly A. Crotteau, Rebecca N. Greenberger, Bethany L.Ehlmann, George R. Rossman, Michelle Harris, Peter B. Kelemen, Damon A. H.Teagle, the Oman Drilling Project Phase 1 Science Party CharacterizingHydration of the Ocean Crust Using Shortwave Infrared Microimaging Spectroscopyof ICDP Oman Drilling Project Cores. JGR Solid Earth.https://doi.org/10.1029/2021JB022676