Annual Geography Lecture 2019

Series Name School of Geography, Geology and the Environment
Speaker Professor Tavi Murray from Swansea University
Type Lectures & Talks
When 20 Nov 2019, 05:30PM - 06:30PM
Venue Rattray
Open To Public
Ticket Price Free
For Bookings Contact Gail Andrews on ga16@le.ac.uk
We regret to announce that this event has been postponed (date TBC). Hot-water drilling on Rutford Ice Sheet, West Antarctica Abstract Fast flowing ice streams and outlet glaciers are the volume regulators for the polar ice sheets of Greenland and Antarctica. Thus, the flow speed of ice streams is one of the key controls on the ice sheet’s contribution to sea-level rise. The fast flow of ice steams is controlled and facilitated at their base, making it important to understand processes and conditions beneath them. The Rutford Ice Stream is a fast-flowing glacier that drains ice from the West Antarctic Ice Sheet into the Ronne Ice Shelf. In austral summer 2004-5 with colleagues from the British Antarctic Survey we attempted to drill over 2 km through the ice stream to the bed. Unfortunately, the drill hose broke and we were forced to concentrate on surface experiments. We used data from a network of GPS receivers to show the flow of ice streams varies: near the grounding line the flow is modulated accelerating and decelerating at various tidal frequencies. Seismic reflection data were acquired and comparison between surveys in different years shows an period of rapid subglacial erosion (6 m in 6 years). This erosion was followed the deposition of a new drumlin, at the ice stream bed. The drumlin is 10 m high and 100m wide and formed in a period of no more than 7 years. Then in January this year, 2019, we returned to Rutford Ice Stream with a new hot-water drill and for the first time we successfully drilled three holes to the bed. We used these boreholes to undertake experiments at the bed, and to install instrumentation, as well as retrieving the first samples of basal sediments. I will report on both drilling attempts and report on the first scientific results interpreting results from this year’s successful boreholes. The lecture will be proceeded at 5pm by a reception and opportunity to meet the speaker in the Foyer of the Bennett Building

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