Interpretation of airborne geophysical data acquired during PCMEGA
Metadata record for data from ASAC Project 2561
See the link below for public details on this project.
The project aims to investigate the multidimensional sub-surface structures in the southern Prince Charles Mountains using the airborne geophysical data acquired during Prince Charles Mountains Expedition of Germany-Australia (PCMEGA). This will be of national significance as it will identify ... continental geological processes occurring in Australia-Antarctica, prior to and during their separation ~120 million years ago, and relate them to present day observations.
Taken from the abstracts of the referenced papers:
Geological exposures in the Lambert Rift region of East Antarctica comprise scattered coastal outcrops and inland nunataks sporadically protruding through the Antarctic ice sheet from Prydz Bay to the southernmost end of the Prince Charles Mountains. This study utilised airborne magnetic, gravity, and ice radar data to interpret the distribution and architecture of tectonic terranes that are largely buried beneath the thick ice sheet. Free-air and Bouger gravity data are highly influenced by the subice and mantle topography, respectively. Gravity stripping facilitated the removal of the effect of ice and Moho, and the residual gravity data set thus obtained for the intermediate crustal level allowed a direct comparison with magnetic data. Interpretation of geophysical data also provided insight into the distribution and geometry of four tectonic blocks: namely, the Vestfold, Beaver, Mawson, and Gamburtsev domains. These tectonic domains are supported by surface observations such as rock descriptions, isotopic data sets, and structural mapping.
Three dimensional modelling of airborne magnetic data acquired in the Prince Charles Mountains, East Antarctica, provides an insight into the sub-ice distribution, and three-dimensional geometry of a Neoproterozoic sedimentary basin. A three-dimensional starting model was created from two two-dimensional GM-SYS modelling and our current geological understanding of the study area. Three-dimensional VPmg inversion modelling was performed on the aeromagnetic data to obtain an acceptable fit between the observed response collected in the field, and the calculated response of the three dimensional model. Modelling suggests that the base of the basin undulates and is relatively unstructured, however the margins of the basin thicken from north (~4 km) to south (~11 km). The volume of the Sodruzhestvo Group that in-fills the sedimentary basin has been calculated at approximately 35,000 cubic kilometres. Modelling of Banded Iron Formations at the southern margin of the basin and a sharp magnetic contrast in the north, reveal that both contacts dip toward the south. We interpret this asymmetric geometry of the sedimentary basin as having began as a set of half grabens, bounded by an underlying listric fault that flattened at depth below the sedimentary basin. Subsequent Early Palaeozoic inversion of this structure resulted in reactivation along the low-angle basal detachment, but rather than taking its original course underneath the sedimentary basin, the fault ramped up along the southern margin. This process caused exhumation of the underlying Banded Iron Formations, which are now juxtaposed at similar crustal levels to the Neoproterozoic cover rocks.
(Click for Interactive Map)
The Dates provided in temporal coverage are approximate only, and represent the beginning and end of the 2004 - 2006 Antarctic seasons.
The latitudes and longitudes provided in spatial coverage are approximate only.
See the referenced papers for further information.
Data Set Progress
+64 3 479 8786
+64 3 479 9037
sjf at geography.otago.ac.nz
Department of Geography
University of Otago
PO BOX 59
+64 3 358 0200
+64 3 358 0211
c.poirot at antarcticanz.govt.nz
Antarctica New Zealand
Private Bag 4745
+64 3 358 0200
+64 3 358 0211
s.gordon at antarcticanz.govt.nz
Antarctica New Zealand
Private Bag 4745
Filmer, V. 2000. The basal ice layer of the Taylor Glacier, Antarctica. Unpublished BSc (hons) dissertation, in Geography, at the University of Otago, Dunedin, New Zealand. 84 pp.
Fitzsimons, S. The state of the Ross Sea region terrestrial environment: Glaciers. In: Ross Sea Region 2001: A state of the environment report for the Ross Sea region of Antarctica. Waterhouse, ... E. (Ed). Christchurch: New Zealand Antarctic Institute. 2001. pp. 4.2-4.14.
Hooker, B.L. Chemical signatures of clear basal ice facies at the margins of dry-based glaciers, South Victoria Land, Antarctica. M.Sc., University of Otago, 1998.
Hooker, B.L., Fitzsimons, S.J. And Morgan, R.K. 1999. Chemical characteristics and origin of clear basal ice facies in dry-based glaciers, south Victoria Land, Antarctica. Global and Planetary Change 22: 29-38.
Lambourne, A. 1998. Physical and chemical composition of basal ice from the Suess Glacier, Antarctica. Unpublished BSc (hons) dissertation, in Geography, at the University of Otago, Dunedin, New Zealand. 84 pp.
Larking, R. 1997. The composition, structure and dynamics of a dry-based glacier apron. Unpublished BSc (hons) dissertation, in Geography, at the University of Otago, Dunedin, New Zealand. 68pp.
MacDonell, S. 2003. Cold-based glacier behaviour: Victoria Upper Glacier, Antarctica. Unpublished BSc (hons) dissertation, in Geography, at the University of Otago, Dunedin, New Zealand. 102 pp.
Mager, S. 1996. Sediment transport in dry-based glaciers : an assessment of sedimentary signatures imprinted by glacial transportation. Unpublished BSc (hons) dissertation, in Geography, at the University of Otago, Dunedin, New Zealand. 78 pp.
Mager, S. 2005. A compositional approach to understanding the formation of basal ice in cold Antarctic glaciers. Unpublished PhD thesis in Geography and Chemistry, University of Otago, Dunedin, New Zealand. 220 pp.
Morgan, T. 1999. Chemical and physical characteristics of ice from the basal zone, Taylor Glacier, Antarctica. Unpublished BSc (hons) dissertation, in Geography, at the University of Otago, Dunedin, New Zealand. 93 pp.
Sirota, P. 1999. The structure and strength of basal ice in the Suess Glacier, Antarctica. Unpublished BSc (hons) dissertation, in Geography, at the University of Otago, Dunedin, New Zealand. 92 pp.
Mager, S. and Fitzsimons, S. 2001. Sediment transport in dry-based glaciers: an assessment of the sedimentary signatures imprinted by glacial modification [Abstract]. Presented at: 2001 Geography A Spatial Odyssey, Joint Conference of the New Zealand Geographical Society and the Institute of Australian Geographers in Dunedin, in February 2001
Webb, N. 2003. Cold-based glacier apron morphology, structure, and composition : a multifaceted approach to testing basal ice formation by apron incorporation. Unpublished BSc (hons) dissertation, in Geography, at the University of Otago, Dunedin, New Zealand. 86 pp.
Samyn, D. 2003. Equifinality of basal ice facies at the base of an Antarctic cold glacier. MSc, Université Libre de Bruxelles, Belgium
Samyn, D. 2005. Structural and geochemical analysis of basal ice from Taylor Glacier, Dry Valleys, Antarctica. PhD dissertation, Université Libre de Bruxelles, Belgium.
Sleewaegen, S. Samyn, D. Fitzsimons, S.J. Lorrain, R.D. Equifinality of basal ice facies from an Antarctic cold-based glacier. Annals of glaciology 37: 257-262, 2003.
Fitzsimons, S.J. McManus, K.J. Sirota, P. Lorrain, R. Direct shear tests of materials from a cold glacier: implications for landform development. Quaternary international 86(1): 129-137, 2001.
Fitzsimons, S.J. McManus, K.J. Lorrain, R. Structure and strength of basal ice and substrate of a dry-based glacier: evidence for substrate deformation at sub-freezing temperatures. Annals of glaciology 28: 236-240, 1999.
Samyn, D., Svensson, A. And Fitzsimons, S.J. 2008. Dynamic implications of discontinuous recrystallisation in cold basal ice: Taylor Glacier, Antarctica. Journal of Geophysical Research 113, FO3S90, doi: 10.1029/2006JF000600, 2008
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