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SCAR Report No. 13, November 1996 

Appendix 6

A Proposal for a SCAR-GLOCHANT Initiative on the
Late Quaternary Evolution of the Antarctic Ice Margin (ANTIME)

Introduction

The physical and dynamical processes controlling the nature of the Antarctic ice sheet and the surrounding oceans have been found to be highly variable, both temporally, on interannual to interdecadal time-scales, and geographically. Because of this large background variability and because the instrumental records span such a short time span, it is difficult to predict the responses of the ice sheet and the ocean to future forcings such as global warming. Attempts to determine this variability on century to millennial time scales by medium depth ice core drilling and analysis have only been partially successful. Ice cores have provided detailed information on climate and temperature variability over periods covering just the last few hundred years to the last 10,000 years, at Law Dome and Taylor Dome, East Antarctica and Dyer Plateau, Antarctic Peninsula. The new Law Dome summit core may provide a detailed climate record over the Holocene and perhaps the Late Pleistocene transition. However, the ice coring projects to date have experienced significant difficulties in dating and in providing temporal data on changes in ice sheet elevation and fluctuations in ice dynamics during the Holocene and Late Pleistocene. This information is vital if we are to understand the response of the ice sheet to climate variability. This difficulty might be overcome by utilizing the geological record. The Antarctic sedimentary record in the marine, coastal, lacustrine and glacial environments has already yielded high resolution information on palaeoenvironmental changes, particularly in ice marginal and outlet glacier fluctuations. We believe that a coordinated SCAR initiative on palaeoenvironmental research focused on the Late Quaternary (last 200-250,000 years) Antarctic sedimentary record, particularly a detailed component on the last 20,000 years, including the very high resolution Holocene records, would provide a solid basis for the understanding of present and future variability in the Antarctic.

Proposed Antime Initiative

SCAR-GLOCHANT has developed a joint initiative with IGBP-PAGES on ice core drilling in Antarctica. This project is entitled, "An international strategy for ice-core drilling in Antarctica &emdash; Reducing uncertainty in global environmental change". This project will investigate ice sheet palaeoenvironments on the two time scales, Stream 1 (the last 2,000 years), and Stream 2 (the last 250,000 years). It was the original intention of SCAR-GLOCHANT in 1991 to also develop a sister project on Palaeoenvironments from the Antarctic sedimentary record. However, this has not been initiated to date, and this proposal outlines the need and context for such a project and probable linkages with other organisations such as the IGBP-PAGES.

At present, Quaternary and in particular Holocene research is conducted around the Antarctic ice margin by scientists from a number of nations. Quaternary sequences have been drilled on the continental shelf by marine geological programmes, and have been extensively recorded by seismic surveys conducted by the SCAR-ANTOSTRAT programme. However, most of the Late Quaternary and Holocene research has been focused on the inner continental shelf, in the coastal zone in fjords and beach sequences, and in the vicinity of the terrestrial ice margin and adjacent lakes. Similar to the GLOCHANT-PAGES programme on ice coring, there is a strong need to coordinate the international research on the variability and evolution of the Antarctic ice margin, to maximise the international resources and target the Antarctic areas of most mutual interest. A coordinated effort would allow international resources to be available for specific regional projects, and allow for efficient exchange and correlation of findings between the sedimentary and ice core science communities. The latter could be a major focus for the ANTIME initiative.

We propose that GLOCHANT and the Working Groups on Geology and Solid Earth Geophysics jointly develop a SCAR initiative to coordinate research on the Antarctic sedimentary record, which we refer to at this stage as ANTIME (Antarctic Ice Margin Evolution). We envisage that ANTIME together with the ice core project will form the SCAR contribution to PAGES, and that it will complement the IGBP/SCOR IMAGES transects in the circum-Antarctic regions. We are investigating a joint sponsorship of the initiative with the International Union for Quaternary Research (INQUA), and that some aspects may contribute to the International Geological Correlation Project (IGCP). It is also important for SCAR to produce a coordinated request to the Scientific Steering Committee of the Ocean Drilling Project (ODP) to publicise the importance of Antarctica in the global ocean-atmosphere system, and to encourage further targeted deep drilling sites in the Antarctic. A priority for ANTIME is the drilling and retrieval of a long core which spans the entire Quaternary sequence.

It is proposed to commence this initiative by organising a SCAR sponsored International Workshop, in late 1996 or early 1997 to discuss the planning of future multi-national fieldwork programmes and the coordination of technology and stratigraphic correlations. It is intended that representatives from all the marine and glacial geological programmes in SCAR countries should be invited to the proposed workshop, together with representatives from IGBP-PAGES. The key themes for the workshop are outlined below.

Some Key Questions for ANTIME to Answer or Contribute to include:

 Dr Ian D. Goodwin

SCAR Global Change Programme Coordinator

26 March, 1996