Location: University of Exeter, Penryn Campus, Penryn, Cornwall TR10 9FE
This project is one of a number that are in competition for funding from the NERC Great Western Four+ Doctoral Training Partnership (GW4+ DTP). The GW4+ DTP consists of the Great Western Four alliance of the University of Bath, University of Bristol, Cardiff University and the University of Exeter plus five Research Organisation partners: British Antarctic Survey, British Geological Survey, Centre for Ecology and Hydrology, the Natural History Museum and Plymouth Marine Laboratory. The partnership aims to provide a broad training in earth and environmental sciences, designed to train tomorrow’s leaders in earth and environmental science. For further details about the programme please see http://nercgw4plus.ac.uk/
The retreat of marine-terminating glaciers can be recognized within the sedimentary record by the transition from subglacial to proximal glaciomarine sediments marking the decoupling of the ice sheet from the sea floor. Determining the accurate timing of such deglaciations and their particular environmental context is critical for reconstructing past ice sheet behavior and, consequently, constraining numerical ice sheet models (www.britice-chrono.org). Paleoenvironmental data, such as ocean temperature and salinity, can be extracted from marine sediments to identify mechanisms driving past deglaciations. However, within the glaciomarine setting, the interpretation of proxy records can be challenging due to physical disturbance of sediments during ice retreat or local salinity fluctuations that alter the local ecosystem or overprint salinity or temperature records. To improve our interpretation of past ice sheet sensitivity and response to ocean drivers, and refine ice sheet models, new calibration and process studies are necessary at the margins of marine terminating glaciers.
Project Aims and Methods
This PhD will exploit unrivalled opportunities to sample transects in front of three actively retreating glaciers on the West Antarctic Peninsula. As part of an upcoming joint UK-Chile ICEBERGS project, the RRV James Clark Ross will repeat sample transects at Rothera, William Glacier and King George Island from 2017 to 2020. Data generated from these transects will be used to identify the proxies that are most useful for determining key environmental gradients in deglaciating environments. Although we cannot guarantee participation in fieldwork, the intention is that the student will participate in the 2019 research cruise when surface sediment and seawater samples will be collected. Samples collected during the 2017 and 2018 field seasons will also be made available. Proxies conventionally used in these settings include microfossils (foraminifera, diatoms, dinoflagellate cysts), carbonate stable isotopes and organic biomarkers (open water and sea ice diatom-based). Data generated from these proxies will be analysed using multivariate statistics and calibrated using instrumental series to identify those that most successfully reconstruct 1. ocean temperature, 2. sea ice cover, and 3. distance from the ice front.
CASE or Collaborative Partner
This is a collaborative proposal with British Antarctic Survey (BAS). Dr Vicky Peck at BAS will be the BAS supervisor and the studentship involves a 4-month secondment at BAS. The student will work with several BAS personnel involved in the UK-Chile ICEBERGS project and will therefore be fully integrated into the project management.
Although BAS CASE studentships cannot be dependent on fieldwork the intention is that this project will provide an excellent opportunity for the student to participate in a research cruise and fieldwork in Antarctica. The research cruise element will provide practical training and participation in CTD deployment, water sampling and treatment, and bottom sediment sampling (grabs, multi-corer), and laboratory analyses at Rothera, as well as experience of Antarctic science more generally. Depending on the direction of research, the student will receive training in (1) laboratory preparation of samples for foraminiferal, diatom and dinoflagellate cyst analyses and their taxonomic identification, (2) preparation of samples for stable oxygen and carbon isotopic analyses.