Glacio-isostasy and Glacial Ice Load at Law Dome, Wilkes Land, East Antarctica

• Published in: Quaternary research Vol. 53; no. 3; pp. 285 - 293
• Main Authors: Goodwin, Ian D., Zweck, Christopher
• Format: Journal Article
• Language: English
• Published: New York, USA Cambridge University Press 01.05.2000; Elsevier Inc; Elsevier
• Subjects: Antarctica; Bgi / Prodig; East Antarctica; glacio-isostasy; Holocene; ice sheet; Marine; Physical geography; Polar regions; sea level; Wilkes Land; Antarctica; PSE, Antarctica, Wilkes Land, Budd Coast, Windmill Is; ice sheet; Wilkes Land; East Antarctica; glacio-isostasy; Holocene; sea level; Glacial isostasy; Geochronology; Palaeogeography; C 14 dating; Sea level; Deglaciation
• ISSN: 0033-5894; 1096-0287
• DOI: 10.1006/qres.1999.2125

The Holocene sea-level high stand or “marine limit” in Wilkes Land, East Antarctica, reached ∼30 m above present sea level at a few dispersed sites. The most detailed marine limit data have been recorded for the Windmill Islands and Budd Coast at the margin of the Law Dome ice cap, a dome of the East Antarctic Ice Sheet (EAIS). Relative sea-level lowering of 30 m and the associated emergence of the Windmill Islands have occurred since 6900 14C (corr.) yr B.P. Numerical modeling of the Earth's rheology is used to determine the glacio-isostatic component of the observed relative sea-level lowering. Glaciological evidence suggests that most of EAIS thickening occurred around its margin, with expansion onto the continental shelf. Consequently, a regional ice history for the last glacial maximum (LGM) was applied in the glacio-isostatic modeling to test whether the observed relative sea-level lowering was primarily produced by regional ice-sheet changes. The results of the modeling indicate that the postglacial (13,000 to 8000 14C yr B.P) removal of an ice load of between 770 and 1000 m from around the margin of the Law Dome and adjacent EAIS have produced the observed relative sea-level lowering. Such an additional ice load would have been associated with a 40- to 65-km expansion of the Law Dome to near the continental shelf break, together with a few hundred meters of ice thickening on the adjoining coastal slope of the EAIS up to 2000 m elevation. Whereas the observed changes in relative sea level are shown to be strongly influenced by regional ice sheet changes, the glacio-isostatic response at the Windmill Islands results from a combination of regional and to a lesser extent, Antarctic-wide effects. The correspondence between the Holocene relative sea-level lowering interpreted at the margin of the Law Dome and the lowering interpreted along the remainder of the Wilkes Land and Oates Land coasts (105°–160° E) suggests that a similar ice load of up to 1000 m existed along the EAIS margin between Wilkes Land and Oates Land.