Expressions of Intent for IPY 2007-2008 Activities

Expression of Interest Details

PROPOSAL INFORMATION

Late Quaternary dynamics of the Antarctic Ice Sheet reconstructed from iceberg-rafted debris  (IRD and Antarctic Ice Sheet dynamics)

Outline
Episodic collapse of the largest (1,000,000 km2) drainage basin of the last North American ice sheet during the Quaternary is recorded in the North Atlantic by layers of iceberg-rafted debris (IRD) – the “Heinrich layers”. During these collapses, enormous armadas of icebergs were released into the North Atlantic. Melting of these icebergs released IRD and flooded the North Atlantic with fresh-water. This fresh-water ‘cap’ had a profound affect on oceanographic conditions and, thus, climate. Investigations of the Heinrich layers have resulted in major advances to our understanding of ice-ocean-climate interactions in the North Atlantic region. In contrast, there have been relatively few investigations of IRD in the seas around Antarctica and the potential of this approach for reconstructing Antarctic Ice Sheet dynamics remains underutilised. Most previous investigations have been based on a small number of cores and have proposed radically different interpretations, ranging from a stable Late Quaternary Antarctic Ice Sheet to repeated, millennial-scale, ice-sheet collapse. It is therefore timely to investigate the Late Quaternary Antarctic IRD record, and is also important, in order to determine if recent changes to the Antarctic Ice Sheet (e.g., catastrophic ice shelf collapse) are part of a natural cycle or are a response to human-induced climate change. This topic has socio-economic significance, as it is estimated that collapse of the modern West Antarctic Ice Sheet would raise global sea level by ~5 m. In this project we will investigate if IRD layers similar to the Heinrich layers are present in cores from the Weddell and Scotia seas and if large-scale collapse of the Late Quaternary Antarctic Ice Sheet has occurred. Our investigation will focus on “Iceberg Alley”, the major pathway of modern iceberg drift out of the Weddell Sea. This is the area where temporal changes in Antarctic iceberg delivery during the Quaternary are most likely to be recorded. Our approach is three-fold: first sampling of modern Antarctic icebergs to quantitatively constrain debris concentrations and sedimentology; second quantification and characterisation of modern IRD deposition on the floor of the Weddell Sea using box- and gravity-coring. This will provide a control for the third part of the study which will focus on coring investigations of longer-term changes in IRD delivery that are related to variations in ice-sheet stability. We will employ a combination of sedimentology and micropalaeontology. Results from this project will be of considerable interest to the Antarctic palaeoceanographic, glaciological and climate modelling communities.

What significant advance(s) in relation to the IPY themes and targets can be anticipated from this project?
This project aims to quantify and characterise the delivery of IRD to the deep sea around Antarctica and to understand the role of the Antarctic Ice Sheet in the wider global climate system, today and in the past (Themes 1-3). The project will investigate ice-sheet-ocean-climate interactions in the Weddell Embayment, an area which has seen relatively little investigation compared to the Antarctic Peninsula (Theme 4). The project pertains directly to the stability of the West Antarctic Ice Sheet and its impact on global sea level, and it is thus of socio-economic relevance (Themes 5 and 6).

What international collaboration is involved in this project?
Scientists from the UK (University of Durham and British Antarctic Survey, Cambridge), Germany (Alfred Wegener Institute) and the USA (Rice University, Texas) will cooperate closely in this project.

FIELD ACTIVITY DETAILS

Geographical location(s) for the proposed field activities:
The geographical areas for this research are the Weddell and Scotia seas.

Approximate timeframe(s) for proposed field activities:
Arctic: n/a
Antarctic: Field work associated with this project would take as a single cruise during the either the Antarctic summer of 2007/2008 or 2008/2009.            

Significant facilities will be required for this project:
An ice-strengthened research vessel will be required for coring and geophysical investigations. This resource could be shared with other projects that might wish to deploy or recover buoys or moorings for oceanographic, biological or geological purposes in these regions.

Will the project leave a legacy of infrastructure?
The legacy of this project will include the development of new international collaborative research links between participating members and institutions, intellectual advances and the training of the next generation of polar scientists.

How is it envisaged that the required logistic support will be secured?

Through applications to national funding agencies such as NERC and polar operators (e.g., British Antarctic Survey).

Has the project been "endorsed" at a national or international level?
This expression of intent has been submitted to the UK National IPY Committee.

PROJECT MANAGEMENT AND STRUCTURE

Is the project a short-term expansion (over the IPY 2007-2008 timeframe) of an existing plan, programme or initiative or is it a new autonomous proposal?
yes
This study builds on previous IRD investigations from the Antarctic Peninsula and terrestrial glacial geology investigations from the Weddell Embayment. It will be the most detailed study to date of modern IRD deposition in Iceberg Alley, and of the relationship between temporal changes in iceberg-rafting and Antarctic palaeo-ice sheet dynamics.

How will the project be organised and managed?
The main component of this project will be a marine geological cruise to the Weddell and Scotia seas during which deep-sea sediment cores (box-, gravity- and piston-cores) will be recovered. Subsequent core analysis (sedimentology, dating, micropalaeontology) will take place in the laboratory. Pre-existing available sediment cores from core repositories in the UK, Germany and the USA will also be analysed. The project will be organised jointly through the University of Durham and the British Antarctic Survey and it is anticipated that there will be regular project meetings involving all participants.

What are the initial plans of the project for addressing the education, outreach and communication issues outlined in the Framework document?
Given the importance of the Antarctic Ice Sheet to global sea level, the project should generate wide public interest. Key findings will be disseminated via the media and a project web-page, as well as lectures and publications. The project will include training of a PhD student in sedimentology and micropalaeontology.

What are the initial plans of the project to address data management issues (as outlined in the Framework document)?
Sediment cores will be archived at the British Ocean Core Repository (BOSCOR), Southampton Oceanography Centre. Marine geophysical data will be archived at the British Antarctic Survey, Cambridge. Marine geological data will be made available to the scientific community through the PANGAEA database of the Alfred Wegener Institute.

How is it proposed to fund the project?
Applications for funding will be made to the appropriate national funding agencies (e.g., NERC).

Is there additional information you wish to provide?
This project addresses a research problem of wide scientific and socio-economic importance (the past, present and future behaviour of the Antarctic Ice Sheet). It complements growing concerns regarding the response of this ice sheet to future climate change. The project involves investigations of both modern and Late Quaternary IRD, and will be the most comprehensive investigation of IRD delivery to the Weddell and Scotia seas to date. The work will provide a longer temporal context for the interpretation of short term satellite observations of current changes to modern Antarctic Ice Sheet mass balance.

PROPOSER DETAILS

Dr. Colm O’Cofaigh
Department of Geography, University of Durham
South Road
Durham
DH1 3LE
UK

Tel: 00-44-(0)191-3341890
Mobile:
Fax: 00-44-(0)191-3341801
Email:

Other project members and their affiliation

Other Information