Deconstructing the Falkland sediment drift – Implications for Patagonian Ice Sheet and Antarctic Circumpolar Current evolution during the Plio-Pleistocene. PhD in Geology (NERC GW4 + DTP)

Lead Supervisor
Dr. Ian Bailey, Camborne School of Mines, College of Engineering, Mathematics and Physical Sciences, University of Exeter

Additional Supervisors
Dr. Sev Kender, Camborne School of Mines, College of Engineering, Mathematics and Physical Sciences, University of Exeter
Dr. Vicky Peck, British Antarctic Survey
Prof. Emrys Phillips, British Geological Survey
Dr. Dave McCarthy, British Geological Survey

Location: Penryn Campus, University of Exeter, Penryn, Cornwall, TR10 9FE

This project is one of a number that are in competition for funding from the NERC GW4+ Doctoral Training Partnership (GW4+ DTP). For further details about the programme please see http://nercgw4plus.ac.uk/

For eligible successful applicants, the studentships comprises:

- An stipend for 3.5 years (currently £15,009 p.a. for 2019/20) in line with UK Research and Innovation rates
- Payment of university tuition fees;
- A research budget of £11,000 for an international conference, lab, field and research expenses;
- A training budget of £3,250 for specialist training courses and expenses.
- Travel and accomodation is covered for all compulsory DTP cohort events.
- No course fees for courses run by the DTP

We are currently advertising projects for a total of 10 studentships at the University of Exeter


Project Background

The Southern Hemisphere plays an important role in Earth’s climate system. However, our understanding of the geological history of environmental change in this region remains notably incomplete. Situated in the Falkland Trough, the South Falkland Slope Drift (SFSD) is well placed to record past variations in two key, but poorly constrained, components of the climate system in this part of the world – the southern Patagonian Ice Sheet (PIS) and the largest current in the world, the Antarctic Circumpolar Current (ACC). Downstream of one of the largest glacial outwash plains in South America, SFSD accumulation is sensitive to both the evolution of the PIS and reworking of fine-grained sediments beneath the ACC. Sediment cores collected in March 2019 from the SFSD during International Ocean Discovery Program (IODP) Expedition 382, the first long records recovered from this region, provide an unparalleled opportunity to reconstruct the evolution of these two important variables over the past ~3 million years using the geochemistry and sedimentology of these new high-resolution (~10-40 cm/kyr) marine sequences.

Project Aims and Methods

The consensus based on terrestrial tills is that the PIS was more laterally extensive prior to the late Pleistocene. Yet, glacial erosion and dating issues make this geological archive incomplete and challenging to interpret. The more continuous marine record of the SFSD can therefore provide new insights into the timing of PIS advance into southernmost South America over this time. Are PIS advances into this region more frequent during the “41 kyr world” of the late Pliocene and early Pleistocene than during the “100 kyr world” of the late Pleistocene? How does the history of PIS expansion at this time compare to that observed in the Northern Hemisphere? The SFSD is ideally placed to determine past variability in ACC strength. What does it reveal about ACC history during key past intervals such as the late Pliocene onset of Northern Hemisphere glaciation and recent warm interglacials (MIS 5e and 11) of the late Pleistocene?

This studentship will address these key questions and more by analysing sediments from IODP Sites U1534 and U1535 to determine the drift’s evolution over the past ~3 million years in terms of sediment delivery to the Falkland Trough and the strength of the ACC. The student will do this by deconstructing the drift from two perspectives: sediment supply and sediment reworking. A variety of provenance tools (including clay mineralogy, Sr, Pb and Nd isotopes and trace metals) will be used on the silt-sized terrigenous component of its sediments to provide the first marine perspective on how PIS variability controls the nature and supply rate of glaciogenic outwash sediment to the Falkland Trough. Grain size analysis of the sortable silt fraction (10-63 microns) will be used to reconstruct past variability in the strength of the current sorting the drift sediment. Benthic foraminiferal assemblages will also be determined to assess whether changes in benthic community structure can be used to evaluate bottom current speed. In taking on this project, the successful candidate will also work closely with the internationally leading Expedition 382 scientific team. The supervisors are happy to adapt or change the project to match the interests of the student better.