HR: 0800h
AN: T11A-1241    [Abstracts]
TI: An Aerogeophysical Transect South of the Prince Charles Mountains, East Antarctica
AU: * Damaske, D
EM: d.damaske@bgr.de
AF: Bundesanstalt fuer Geowissenschaften, Stilleweg 2, Hannover, 30655 Germany
AU: Damm, V
EM: volkmar.damm@bgr.de
AF: Bundesanstalt fuer Geowissenschaften, Stilleweg 2, Hannover, 30655 Germany
AU: McLean, M
EM: m.mclean@pgrad.unimelb.edu.au
AF: School Of Earth Sciences, University of Melbourne Victoria, Melbourne, 3010 Australia
AB: Interpretations of the existing magnetic data in the Lambert region raise questions about the nature of the southern Lambert Rift system. Preliminary interpretations of this data have allowed distinction of major geological blocks and magnetic trends, which can be correlated with the known geology of the Southern Prince Charles Mountains (PCMs). The objective of this investigation was to extend the magnetic data to the south and also acquire ice penetrating radar and gravity data to assist in understanding the Lambert / Amery rift system. This will provide a better understanding of the formation and breakup of Gondwana. Ice radar data will also contribute to ice mass balance analysis of this major ice drainage area in Antarctica. This research presents the methodology, data and preliminary interpretations of the airborne data acquired as part of the Prince Charles Mountains Expedition of Germany and Australia 2002/03 (PCMEGA). The area of study covered part of the southern PCMs and the adjacent polar ice cap, from approximately 72.5 to 77.5 South and 62 to 72 East. Within a month of field work more than 20000 km of survey lines at 5km line spacing and 25 km tie-line spacing was acquired over an area of approximately 81000 square kilometers. Transit flights between the base camp at Mt. Cresswell and the survey grid were utilized to collect ice radar data over the major ice tributaries feeding the Lambert Glacier. Increasing surface elevation towards the southern region of the survey grid made it necessary to divide the survey into three separate flying elevations of 2160 m, 2760 m and 3360 m (GPS height). The aeromagnetic image is characterized by long wavelength magnetic anomalies which display different trends. The southern region of the image is dominated by alternating high-low northeast-trending magnetic anomalies. These anomalies have been truncated by a northwest trending feature suggesting separation of major blocks by crustal scale faults / shear zones. The gravity data presented here is simply free-air gravity. The gravity image displays long wavelength anomalies which are contrasted by sharp gradients. North to north-north-east trending features are truncated in the northern region of the grid by a north-west trending gravitational low. The high gravitational response in the south-east region of the grid is interpreted as the `foothills' of the Gamburtsev Mountains. Detailed maps of sub-ice topography were produced that allow a 3-dimensional ice thickness correction of the gravity data and the production of crustal thickness maps. The PCMEGA airborne survey provided new elevation and ice thickness data of the upper Lambert glacier basin extending to 78 South. This data can be used to assess the state of balance by computed balance fluxes based on an improved DEM and fluxes derived from ice thickness and velocity. Maps illustrating the sub-ice topography are one of the major results of the PCMEGA project and the basis for a range of geological and glaciological interpretations.
DE: 9310 Antarctica
DE: 5475 Tectonics (8149)
DE: 1827 Glaciology (1863)
DE: 1219 Local gravity anomalies and crustal structure
DE: 1517 Magnetic anomaly modeling
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting