An Aerogeophysical Survey South of the Prince Charles Mountains, East Antarctica

D. Damaske¹* & M. McLean²

¹Bundesanstalt für Geowissenschaften und Rohstoffe, Postfach 510153, 30631 Hannover - Germany
²The University of Melbourne, Melbourne 3001 – Australia

Received 31 January 2005; accepted in revised form 9 November 2005

 

Abstract - Previous interpretations of existing Russian data have allowed distinction of major geological blocks and magnetic trends in the Prince Charles Mountains (PCMs), which can be correlated with the known geology. However, there is extremely poor outcrop south of the PCMs region. The objective of our investigation was to extend the magnetic coverage to the south to assist in understanding the Lambert / Amery rift system in its most southerly part and to look for its possible extension beneath the East Antarctic Ice Sheet.
This paper presents the methodology, data and preliminary interpretations of the airborne magnetic data acquired as part of the Prince Charles Mountains Expedition of Germany and Australia 2002/03 (PCMEGA). It also explains the specific survey design with respect to the integration of simultaneously collected airborne magnetics, gravity and ice radar. The study area covered part of the southern PCMs, from ca. 72º 45’S to 77º 30’S latitude and 62º E to 72º E longitude. The main grid extended over 350 km, from the southern most PCM outcrop (Wilson Bluff). Within a month of field work a total of 20 515 km of survey lines at 5 km line spacing and 25km tie-line spacing was acquired over an area of approximately 81 000 km2. An additional 9150 km was flown without gravity, over an area of 20 000 km2 in transit from Mt Cresswell to the main grid.
Magnetic base stations were located at the base camp (Mt Cresswell), approximately 160 km north of the main survey area, and at Wilson Bluff located at the northern perimeter of the main grid. Data acquisition was carried out during the most magnetically quiet periods. Magnetic data were subject to de-spiking, followed by the application of diurnal, IGRF, levelling and micro-levelling corrections. A low-pass filter of length 50 s was then applied.
The southern region of the aeromagnetic image is dominated by alternating high-low magnetic bands trending northeast. These anomalies are truncated by a northwest trending lineament suggesting separation of major blocks by crustal scale faults / shear zones. South of the Mawson Escarpment, a magnetic low suggests the landward extension of the Lambert Graben system. The gravity and ice thickness features correlate with this magnetic low.


*Corresponding author (d.damakse@bgr.de)