Australia: The Land Where Time Began

A biography of the Australian continent 

East Antarctic Ice Sheet - Dynamic Behaviour During the Pliocene Warmth

Global temperatures that are comparable to those predicted for the end of this century (Haywood & Valdes, 2004) and atmospheric CO₂ concentrations similar to those of the present, characterised the warm intervals within the Pliocene epoch, (5.33-2.58 Ma) (Seki et al., 2010; Bartoli & Zeebe, 2011; Pagani, Liu, LaRivieri & Ravelo, 2010). Possible retreat of the East Antarctic Ice Sheet is implied by global sea level highstands at these times (Miller et al., 2012), though ice-proximal evidence from the Antarctic margin is scarce. In this paper the authors¹ present new data recovered from marine sediments of Pleistocene age offshore of Adèlie Land, East Antarctica that demonstrate dynamic behaviour of the East Antarctica ice sheet in the vicinity of the Wilkes Subglacial Basin, which is low-lying, at times of climatic warmth in the past. Increases in the productivity of the surface water of the Southern Ocean, associated with elevated circum-Antarctic temperatures are indicated by sedimentary sequences that were deposited between 5.3-3.3 Ma. Active erosion of continental bedrock from within the Wilkes Subglacial Basin, an area which at the present is covered by the East Antarctic ice sheet, is suggested by the geochemical provenance of detrital material that had been deposited during these warm intervals. The erosion was interpreted by the authors¹ to be associated with retreat of the margin of the ice sheet several hundred kilometres inland, concluding that during the Pliocene the East Antarctic sheet was sensitive to climatic warmth.

Sources & Further reading

1. Cook, Carys P., Tina van de Flierdt, Trevor Williams, Sidney R. Hemming, Masao Iwai, Munemasa Kobayashi, Francisco J. Jimenez-Espejo, et al. "Dynamic Behaviour of the East Antarctic Ice Sheet During Pliocene Warmth." Nature Geosci 6, no. 9 (09//print 2013): 765-69.