THE NEOGENE EAST ANTARCTIC ICE-SHEET - A DYNAMIC OR STABLE FEATURE

This paper is a review of the history and behaviour of the East Antarctic ice sheet during the late Neogene and is a response to the publication of Sugden et al. (1993a), 'The Case for a Stable East Antarctic Ice Sheet', in Geografiska Annaler, 75A(4). The Antarctic ice sheet is a critical factor in the global climate and oceanographic system. Knowledge of its historical development is critical to understanding global palaeoceanographic and palaeoclimatic systems and their development. The 'Webb-Harwood hypothesis' proposes that the ice sheet, while being present in Antarctica for more than 40 Ma, was, until recently (ca. 2.5 Ma), a dynamic feature, waxing and waning under a more temperate climatic and glaciologic regime. The 'stabilistic hypothesis' proposes that the current ice sheet has existed in its present cold and polar form for at least the last 14 Ma. 'The Case for a Stable East Antarctic Ice Sheet' is the dearest statement of the stabilistic argument to date. The authors find support for their viewpoint by presenting evidence, from several geologic data bases, that does not support their own null 'meltdown hypothesis', which they deem to be equivalent to the 'Webb-Harwood hypothesis', thereby they conclude supporting the 'stabilistic hypothesis'. However, their conclusions are weakened by: failure to reject their null hypothesis, conflict between the 'meltdown' and 'Webb-Harwood' hypotheses, infraction of geological laws, and poor application of stratigraphic principles. Several issues are highlighted here as important for direction of future research and discussion concerning Late Cenozoic Antarctic glacio-climatic history.