Exploration of Subsurface Antarctica: Uncovering Past Changes and Modern Processes
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Position and variability of complex structures in the central East Antarctic Ice Sheet
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Published:January 01, 2018
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CiteCitation
Thilo Wrona, Michael J. Wolovick, Fausto Ferraccioli, Hugh Corr, Tom Jordan, Martin J. Siegert, 2018. "Position and variability of complex structures in the central East Antarctic Ice Sheet", Exploration of Subsurface Antarctica: Uncovering Past Changes and Modern Processes, M. J. Siegert, S. S. R. Jamieson, D. A. White
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Abstract
Although the flow of the East Antarctic Ice Sheet is well constrained from surface measurements and altimetry, our knowledge of the dynamic processes within the ice sheet remains limited. Recent high-resolution radar data from the Gamburtsev Subglacial Mountains in central East Antarctica reveal a series of anomalous englacial reflectors in the lower half of the ice column that cannot be explained by conventional ice flow. Expanding on previous analyses, we describe the geometrical and morphological features of 12 of these anomalous reflectors. Our description reveals a previously unacknowledged diversity in size, geometry and internal structure of these reflectors. We are able to identify four distinct morphological features: (1) fingers; (2) inclusions; (3) sheets; and (4) folds. The ‘fingers’ and ‘inclusions’ probably form by shear instabilities at the boundary between the reflectors and the surrounding meteoric ice. The ‘sheets’ highlight that basal ice can be uplifted off of the bed and above surrounding meteoric ice, and the ‘folds’ may have formed in local regions of converging flow associated with subglacial topography. The study provides key insights into the rheology, stress and deformational regimes deep within the central East Antarctic Ice Sheet.
- Antarctic ice sheet
- Antarctica
- deformation
- dynamics
- East Antarctic ice sheet
- East Antarctica
- freezing
- geometry
- geophysical methods
- geophysical surveys
- glacial geology
- high-resolution methods
- ice
- ice movement
- ice sheets
- mechanics
- melting
- radar methods
- rheology
- size
- stress
- subglacial environment
- subglacial processes
- surveys
- topography
- internal structure
- Gamburtsev Mountains
- Dome A
- meteoric ice
- echo-free zone
- accreted ice
- englacial reflectors
- englacial features