Dr S Bohaty, Dr CD Hillenbrand, Assoc Prof Richard Levy, Prof P Wilson
No more applications being accepted
Competition Funded PhD Project (European/UK Students Only)
About the Project
Project Rationale:
During the extremely warm global ’greenhouse’ period 50 million years ago, Antarctica was mostly ice free and hosted temperate forests in coastal regions of the continent. Subsequent cooling over many millions of years resulted in a steady deterioration of Antarctic climate, eventually culminating in widespread glaciation approximately 34 million years ago. The degree of climate variability prior to ice-sheet development and possible existence of glaciers, or even small ice sheets, during greenhouse intervals are intensely debated. Recent studies support glacial activity in the lead up to major glaciation [1, 2], but, controversially, more substantial ice cover in East Antarctica during earlier (and warmer) time intervals has also been interpreted [3].
The primary aim of this project is to document Antarctic climate behavior during ‘greenhouse’ periods of the past 50 million years in the lead-up to large-scale ice-sheet development. Fundamental questions need to be answered about both long- and short-term Antarctic climate variability in time intervals with higher-than-present CO2 levels. Were there phases of cooling and extensive ice accumulation in Antarctica during hypothesized warm ‘greenhouse’ periods? If so, did small ice sheets or coastal glaciers persist for long periods of time or were they ephemeral?
Methodology:
You will utilize sediment cores from around the Antarctic margin to gain new insight into the early climate history of Antarctica through application of established sedimentological, mineralogical, and geochemical methods, along with development and application of novel proxy methods. The primary focus will be on drillcore sequences obtained from scientific drilling campaigns in Antarctic shelf areas of Prydz Bay, the Ross Sea, and on the Adélie Land margin. You will also study pelagic Southern Ocean drillcore sequences located on Maud Rise and the Kerguelen Plateau and precisely correlate time-equivalent records between the shelf and pelagic realms.
A diverse methodological approach will be taken in order to gain information on changes in weathering states, climatic variations, and glacial activity on Antarctica. Planned analyses include: (i) identification and characterization of sand- and pebble-sized ice-rafted debris, (ii) geochemical and mineralogical analysis of the detrital silt fraction in shelf sequences, (iii) oxygen and carbon stable isotope analysis of foraminifers in pelagic sequences, and (iv) mineralogical and stable isotope analysis of clay minerals through X-ray diffraction (XRD) and elemental analyser–isotope ratio mass spectrometry (EA-IRMS).
Training:
The INSPIRE DTP programme provides comprehensive personal and professional development training alongside extensive opportunities for students to expand their multi-disciplinary outlook through interactions with a wide network of academic, research and industrial/policy partners. The student will be registered at the University of Southampton and hosted in the School of Ocean and Earth Science. Regular collaborative visits will be made to British Antarctic Survey (BAS). Specific training will include:
● Characterisation and age dating of Antarctic sediment cores
● Sedimentological, mineralogical, and geochemical analysis of sediments
● Oxygen and carbon stable isotope analysis of foraminifers
● Oxygen and hydrogen isotope analysis of clay minerals
● Correlation, integration, and interpretation of multi-proxy datasets for Antarctic palaeoclimatic reconstructions
In addition to the training opportunities and exchanges associated with the INSPIRE DTP, there will be opportunities to travel to Wellington, New Zealand, for collaborative work with Co-supervisor Levy and to International Ocean Discovery Program core repositories in Bremen, Germany, and Texas, USA. Travel to international scientific meetings to present project results will also be encouraged and supported.
References
[1] Carter, A., Riley, T.R., Hillenbrand, C.-D., and Rittner, M., 2017. Widespread Antarctic glaciation during the Late Eocene. Earth and Planetary Science Letters, 458: 49–57, doi:10.1016/j.epsl.2016.10.045.
[2] Passchier, S., Ciarletta, D.J., Miriagos, T.E., Bijl, P.K., and Bohaty, S.M., 2016. An Antarctic stratigraphic record of step-wise ice growth through the Eocene-Oligocene transition. GSA Bulletin, doi: 10.1130/B31482.1.
[3] Gulick, S.P.S., Shevenell, A.E., Montelli, A., Fernandez, R., Smith, C., Warny, S., Bohaty, S.M., Sjunneskog, C., Leventer, A., Frederick, B., and Blankenship, D.D., 2017. Initiation and long-term instability of the East Antarctic Ice Sheet. Nature, 552: 225-229, doi:10.1038/nature25026.