HR: 17:15h
AN: PP32D-06 INVITED     [PDF]
TI: Internal ice sheet layer distortions in interior West Antarctica
AU: * Siegert, M J
EM: m.j.siegert@bristol.ac.uk
AF: Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, BS8 1SS United Kingdom
AU: Payne, A J
EM: a.j.payne@bristol.ac.uk
AF: Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, BS8 1SS United Kingdom
AU: Vieli, A
EM: a.vieli@bristol.ac.uk
AF: Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, BS8 1SS United Kingdom
AU: Leysinger Vieli, G J
EM: g.leysinger-vieli@bristol.ac.uk
AF: Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, BS8 1SS United Kingdom
AU: King, E
EM: ecki@bas.ac.uk
AF: British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET United Kingdom
AB: Upstream of Ice Stream D in West Antarctica, ice penetrating radio-echo sounding (RES) data reveal a major and distinctive englacial structure, where internal layers are located at an ice depth up to 1 km deeper than their surrounding elevations. The linear englacial `fold' that is formed by the layer pattern can be traced well across 10 km, and less well for much longer. The long-axis of the structure is located at a 30 degree angle to the current ice flow direction. We examine a number of ways in which this layer pattern may have formed and show that it is more easily explained if the ice flow direction were along the line of the fold's axis than under the current glaciological setting. Using ice flow modelling, we interpret the englacial feature to have been caused by ice-sheet downdraw and/or basal melting at a time when the ice flow direction was different to today. Current ice dynamics may account for subsequent deformation of the internal layer patterns in the last few thousand years.
DE: 1827 Glaciology (1863)
DE: 4267 Paleoceanography
DE: 9310 Antarctica
DE: 9604 Cenozoic
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2003 Fall Meeting