Gravimetric Profiling in Central Dronning Maud Land, East Antarctica


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dfritsch [ at ] awi-potsdam.de

Abstract

Central Dronning Maud Land is a key area for reconstruction of the Gondwana supercontinent. The transition from continental to oceanic crust takes place in a 200 km wide zone, remarkably narrow in comparison with other parts of the Antarctic continent.The ground-based geophysical data presented here were obtained in three campaigns along profiles in the area of Schirmacheroase in 1991-95. Gravity measurements, radio-echo-sounding (RES) measurements of ice thickness, and magnetic measurements were made along three profiles. Geodetic and glaciological studies were made at the same time along these profiles.Gravity values were measured at about 350 stations. The Bouguer reductions were made for the 276 sites for which ice thickness data were available from the RES survey. Geomagnetic data were taken into consideration for the interpretation of the free-air and Bouguer anomaly data.Bouguer gravity values decrease southwards from the ice edge of the Nivlisen Ice Shelf to the Wohlthatmassiv by 220-240 mGal due to the increase in thickness of the Earth's crust, known from deep seismic soundings.A local maximum in the Bouguer anomaly data of approximately 60 mGal has been observed along a profile from Schirmacheroase to the ice shelf front. This zone starts south of the grounding line of the Nivlisen Ice Shelf at 70°24'S, 12°30'E in the area of a geomagnetic anomaly. The gradient south of this Bouguer anomaly maximum is much higher along the profile than on a comparable profile surveyed by the RV Polarstern in the marine area off the shelf ice front. This anomaly is also observed in both gravimetric and geomagnetic data and could be interpreted as a signal from the boundary between the continental and oceanic plates.



Item Type
Article
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Peer revision
Peer-reviewed
Publication Status
Published
Eprint ID
5492
Cite as
Fritzsche, D. (2005): Gravimetric Profiling in Central Dronning Maud Land, East Antarctica , Geologisches Jahrbuch, B97, pp. 165-176 .


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