Australia: The Land Where Time Began

A biography of the Australian continent 

East Antarctica - Relative Sea-Level Rise During Oligocene Glaciation

The climate of the Earth cooled about 48-34 Ma during the Middle and Late Eocene (Zachos, Dickens & Zeebe, 2008; Liu et. al., 2009) with the result that an ice sheet accumulated on Antarctica. Crustal deformation and gravitational perturbations were induced by this accumulation of ice, which occurred in a stepwise manner (Coxall & Wilson, 2011). Sea level rose close to the ice sheet (Woodward, 1888; Raymo et al., 2011), in spite of the overall reduced mass of ocean as water from the ocean was transferred to the terrestrial ice sheet. The authors1 have identified the crustal response to the growth of the ice sheet by the forcing of a glacial-hydroisostatic adjustment model (Kendall et al., 2003) with an Antarctic ice sheet model. Their results indicate that the first response of the shelf areas around East Antarctica was shoaling as the upper mantle material upwelled with the development of a peripheral forebulge. As flexure of the lithosphere extended outwards from the margins of the ice sheet the inner shelf subsequently subsided, and the coasts experienced a progressive rise of sea level. Sediment cores from the vicinity of the Antarctic ice sheet agree with the spatial patterns of relative sea level change that is indicated by the analysis of the sediment cores by the authors1. The authors1 suggest their results are consistent with the proposal (Gomez et al., 2012) that the near-field processes, such as local changes in sea level, influence the equilibrium state obtained by an ice-sheet grounding line. 


Sources & Further reading

  1. Stocchi, Paolo, Carlota Escutia, Alexander J. P. Houben, Bert L. A. Vermeersen, Peter K. Bijl, Henk Brinkhuis, Robert M. DeConto, et al. "Relative Sea-Level Rise around East Antarctica During Oligocene Glaciation." Nature Geosci 6, no. 5 (05//print 2013): 380-84.
Author: M. H. Monroe
Last updated 15/05/2013
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