HR: 0830h
AN: C31B-0402    [PDF]
TI: Aerogeophysical evidence for complex subglacial geology below the Rutford drainage basin,WestAntarctica
AU: Jones, P
EM: pcj@bas.ac.uk
AF: British Antarctic vSurvey, High Cross, Madingley Road,, Cambridge, CB3 0ET United Kingdom
AU: Ferraccioli, F
EM: ffe@bas.ac.uk
AF: British Antarctic vSurvey, High Cross, Madingley Road,, Cambridge, CB3 0ET United Kingdom
AU: Corr, H
EM: hfjc@bas.ac.uk
AF: British Antarctic vSurvey, High Cross, Madingley Road,, Cambridge, CB3 0ET United Kingdom
AU: * Smith, A M
EM: amsm@bas.ac.uk
AF: British Antarctic vSurvey, High Cross, Madingley Road,, Cambridge, CB3 0ET United Kingdom
AU: King, E
EM: ecki@bas.ac.uk
AF: British Antarctic vSurvey, High Cross, Madingley Road,, Cambridge, CB3 0ET United Kingdom
AU: Vaughan, D
EM: dgv@bas.ac.uk
AF: British Antarctic vSurvey, High Cross, Madingley Road,, Cambridge, CB3 0ET United Kingdom
AB: A significant part of the West Antarctic Ice Sheet appears to be imposed upon a complex and still largely unknown continental rift system, perhaps featuring sedimentary basins, thin crust and high heat flow. Subglacial geology has been postulated to strongly modulate the dynamics and stability of the ice sheet itself. Specifically, recent aerogeophysics collected over central West Antarctica at edge of the Whitmore Mountains crustal block show that narrow subglacial rift basins with thick sedimentary infill may control the onsets and lateral margins of ice streams. The British Antarctic Survey flew an aerogeophysical survey during the 2001-02 field season: the main aim was to investigate what factors control the location and dynamics of the onset region of the Rutford Ice stream. Airborne radar, aerogravity and aeromagnetic data were simultaneously collected over the drainage basin of the Rutford Ice Stream. The new bedrock elevation grid for the area shows that the Rutford Ice Stream is constrained by a deep bedrock trough with a N-S to NE-SW trend. The onset region appears however to lie within an E-W bedrock trough at the edge of the Ellsworth Mountains crustal block. Bouguer gravity maps do not reveal typical signatures for a coincident deep rift basin at this location. However, a sharp NE-SW trending gradient, likely separating crustal blocks with contrasting crustal thickness is revealed. Aeromagnetic data image NE-SW trends north of the Rutford Ice Stream. In the onset region, these trends appear to be truncated by a NNW-SSE trend, lying on strike with the Ellsworth Mountains. Hence, the new aerogeophysical data suggests greater complexity in the subglacial geology and structure of an onset region of an ice stream compared to previous investigations.
DE: 1234 Regional and global gravity anomalies and Earth structure
DE: 1517 Magnetic anomaly modeling
DE: 1640 Remote sensing
DE: 1827 Glaciology (1863)
SC: Cryosphere [C]
MN: 2003 Fall Meeting