Time: 6:00 pm - 7:30 pm
Free public event: Auckland Antarctic Science MeetUp, supported by the NZAS.
How to locate the grounding line, where the West Antarctic Ice Sheet starts to float, and become the Ross Ice Shelf? – explosives and hot-water drilling at the Siple Coast!
Speaker:
Professor Gary Wilson, Geologist, GNS Science
When: 6pm, Wednesday, 14 August, 2019
Where: BLT100 lecture theatre, Building 106, Old Biology Building, University of Auckland, 5 Symonds Street, Auckland city
Understanding the West Antarctic Ice Sheet is key to understanding potential sea level rise. It is stabilised, at least for the time being, by a phalanx of floating ice shelves, that hang off its outer edges—of which the Ross Ice Shelf is by far the largest.
However, previous drilling as part of the ANDRILL project and our best computer generated models imply that the area now covered by 800m thick ice was open sea in past warm intervals in Earth’s history. This suggests that the entire Ross Ice Shelf, and much of the West Antarctic Ice Sheet behind it, had collapsed.
The Ross Ice Shelf Programme is a major NZ scientific initiative to determine what conditions lead to Ross Ice Shelf and West Antarctic Ice Sheet retreat. Through NZARI and the new Antarctic Science Platform, scientist are determining the conditions beneath the ice shelf and what controls the grounding line to advance or retreat. Armed with this information they hope to forecast how the ice sheet and ice shelf will respond as the planet warms over the next decades and centuries.
To access the ocean cavity and the sea floor beneath, the team will drill through the ice shelf using hot water and then deploy instruments to measure the water conditions and a sediment drill to recover the record of response to past warm intervals. A number of important sites have been identified for study between the middle of the ice shelf and the grounding line on the remote Siple Coast, 850km from Scott Base.
In November and December last year, Professor Gary Wilson led the science team on the Siple Coast, conducting a seismic (by detonating explosives) and gravity surveys. The team spent a month camping in sub-zero temperatures to undertake the surveys. The results will help to identify a hot water drilling target for this coming summer, in order to drill through the shelf to collect a core of the sedimentary record from beneath the sea floor.
More information on:
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When: 6pm, Wednesday 14 August 2019
Where: BLT100 lecture theatre, Building 106, Old Biology Building, University of Auckland, 5 Symonds Street, Auckland city
photo credits: Ross Ice Shelf Programme: Antarctica NZ, University of Otago, GNS Science
