Initiation and growth of the East Antarctic ice sheet

Abstract

There appears to be little support for an initiation of continental glacierization in the Palaeogene. The palaeobiological evidence indicates warm–temperate climates in the Antarctic Peninsula and Wilkes Land coast of East Antarctica. Glacial marine sediments from JOIDES Leg 28, oxygen-isotope analyses from Leg 29, global sea level changes and palaeontological investigations favour the development of full-bodied ice sheets from local, longer lived icefields and glaciers only in the late Cenozoic (after the lower Miocene) with a possible maximum about 5 m.y. BP. Recent geophysical exploration has enabled a model for the evolution of the East Antarctic ice sheet to be developed. The Transantarctic Mountains, the north-eastern sector of the Gamburtsev Mountains and other, smaller subglacial mountain massifs within continental East Antarctica provided growth centres for the ice sheet. Extensive glacial erosion took place within these highland areas at this time. Many glacial valleys in the Transantarctic Mountains were subsequently utilized by outlet glaciers of the ice sheet. Tectonic implications of the growth model indicate that the Transantarctic Mountains were probably 1500–2000 m lower at the commencement of glaciation, and that the initial vertical movements of the Victoria Orogeny began in the Eocene in response to the crustal separation of the Australian and Antarctic lithospheric plates.