IAP2-23-115

Impact of climate change on the northern Greenland Ice Sheet over the Late Cenozoic based on a novel geochemical technique

Recent studies have highlighted the sensitivity of the Greenland Ice Sheet (GrIS) to future climate warming with significant implications for global sea-level rise and impacts on the Atlantic Meridional Overturning Circulation. Understanding the past evolution of the GrIS and the interaction with broader climate changes is key to improving our understanding of the potential future response of the GrIS to ongoing climate change. Yet, there are significant gaps in our knowledge in respect to the evolution of the GrIS associated with past climate changes. For example, the detailed evolution and cycles of growth and decay of the GrIS during the time period covering the Pliocene through the Pleistocene (the last 4 – 5 million years) that encompasses numerous fluctuations between warmer and cooler climates.
To address these questions our proposal will build on ongoing research developing and applying a novel technique, osmium isotopes, to reconstructing ice sheet dynamics associated with development and growth of a Northern GrIS onto and across the continental shelf into the marine environment. Utilising seafloor sediment cores our recent research shows osmium isotopes can be used to track periods of increased delivery of continental material due to glacial erosion out to the Greenland continental margin and into Baffin Bay (Ownsworth et al., 2023). The osmium isotope signal in marine cores is, therefore, sensitive to the growth and expansion of the GrIS onto and across the continental shelf during colder intervals and subsequent retreat from the shelf during warmer intervals.
Overarching aim: To investigate the link between the development of major glaciation of the northern GrIS and the intensification of northern hemisphere glaciation at approximately 3 Ma, and the amplitude of variability of northern GrIS through the Pleistocene, particularly focussed on the Mid Pleistocene Transition (MPT). This project will benefit from the major international research effort and support associated with International Ocean Discovery Program Expedition 400 (IODP 400) ‘NW Greenland Glaciated Margin’. This will include access to core material and initial datasets collected during the IODP cruise in summer 2023.

This project will contribute to the IODP 400 to the northwest Greenland margin during summer 2023 and is supervised by global leaders in climate and isotope research. To achieve the above aim sediment cores from IODP 400 will be investigated. Research will principally involve geochemical analyses (osmium isotopes) but will also include additional sedimentological and microfossil analyses (e.g. foraminiferal analysis, total organic carbon (TOC), XRF scanning, x-rays and multi-sensor core logging). Osmium data will be compared to the well-established proxies collected from the same cores (in collaboration with international partners on IODP 400) and used to reconstruct environmental changes. Specifically the osmium isotopes will be used to investigate sediment delivery from the Greenland landmass via glacial erosion and track the development and evolution of the northern GrIS into a tidewater environment onto and across the continental shelf. The sensitivity of the osmium isotope signature to terrestrial-sourced vs open ocean sourced material will provide a detailed understanding of the more subtle changes in sediment provenance linked to past climate changes and, ultimately, the sensitivity of northern GrIS to climate change.

Year 1

Review existing literature on northern GrIS evolution together with recent developments of osmium isotope techniques. Engage in Faculty training programme and complete first year Progression Paper to detail project overview, research questions, and planned methodology.
Initial investigations of cores and sample selection for preliminary osmium isotope analysis and other microfossil, sedimentological and geochemical analyses.

Year 2

Main laboratory analysis phase – collection of osmium isotope data from all cores. Assessment of collected and available proxy data and identification of additional data to be collected. Collection of additional proxy data – foraminiferal fauna, TOC, XRF scanning, x-rays and MSCL. Include extended visit to GEUS. Preparation of preliminary review chapters. Presentation of initial results at national postgraduate conference.

Year 3

Completion of laboratory work. Data analysis and interpretation – comparison of osmium isotope data with traditional proxies to assess potential of osmium isotopes for environmental and relative sea-level reconstruction from marginal marine environments. Preparation of major data and interpretation chapters for thesis. Preparation of first research paper. Presentation of research at international conference (target EGU, Vienna, AGU, San Francisco, GSA).

Year 3.5

Preparation and completion of final chapters for thesis. Submission of papers for publication.

The student will receive training in core analysis and in sediment core description (Durham, Sterling, and GEUS).
Training in state-of-the-art osmium isotope geochemical analyses will be provided in a world leading laboratory in the Department of Earth Sciences, Durham. Training in additional proxy techniques (microfossil, sedimentological and geochemical teachniques) will be provided in state-of-the-art laboratories in the Department of Geography, Durham / Stirling and GEUS.
The student will be a member of the Geochemistry Research Group in Earth Sciences: (https://www.dur.ac.uk/research/institutes-and-centres/durham-geochemistry-centre/) and the Sea Level, Ice and Climate Research Cluster in Geography
(https://www.dur.ac.uk/departments/academic/geography/research/clusters/sea-level-ice-climate/)

The student will also have the opportunity provided by a broad range of skills training provided by the graduate training programme at Durham and through the IAPETUS2 Doctoral Training Partnership framework (e.g. thesis and paper writing, presentation skills etc.). The student will also attend and contribute to the programme of regular departmental seminars and discussion groups to support their general development as a scientist.