[1] Spatially coincident radar and seismic data collected two weeks apart on Rutford Ice Stream were analyzed to investigate the mechanical and hydrological characteristics of the ice-bed interface. Seismic data allow the differentiation of bed deformation from basal sliding. In radar data, sliding regions are characterised by highly variable permittivity values. We suggest these regions are characterized by small water bodies, possibly a cavity system. In contrast, deforming regions are characterised by consistent, low permittivity, which suggests intimate icesediment contact without a distinct interface. However, in deforming regions we identified three bright radar features $50 m wide, consistent in lateral location over distances of 5 -10 km up and downstream, and comprised of water less than $0.2 m deep. We interpret these as part of a water evacuation system, most likely canals. Our results emphasise the great potential of radar and seismic techniques in combination to infer basal conditions beneath ice streams. Citation: Murray, T., H. Corr, A. Forieri, and A. M. Smith (2008), Contrasts in hydrology between regions of basal deformation and sliding beneath Rutford Ice Stream, West Antarctica, mapped using radar and seismic data, Geophys. Res. Lett., 35, L12504,

ABSTRACT. Talos Dome is an ice dome on the edge of the East Antarctic plateau; because accumulation is higher here than in other domes of East Antarctica, the ice preserves a good geochemical and palaeoclimatic record. A new map of the Talos Dome area locates the dome summit using the global positioning system (GPS) (72˚47' 14''S, 159˚04' 2'' E; 2318.5 m elevation (WGS84)). A surface strain network of nine stakes was measured using GPS. Data indicate that the stake closest to the summit moves south-southeast at a few cm a Airborne radar measurements indicate that the bedrock at the Talos Dome summit is about 400 m in elevation, and that it is covered by about 1900 m of ice. Snow radar and GPS surveys show that internal layering is continuous and horizontal in the summit area (15 km radius). The depth distribution analysis of snow radar layers reveals that accumulation decreases downwind of the dome (north-northeast) and increases upwind (south-southwest).The palaeomorphology of the dome has changed during the past 500 years, probably due to variation in spatial distribution of snow accumulation, driven by wind sublimation. In order to calculate a preliminary age vs depth profile for Talos Dome, a simple onedimensional steady-state model was formulated. This model predicts that the ice 100 m above the bedrock may cover one glacial-interglacial period.

We present the interpretation of 11 radio echo-sounding (RES) missions carried out over the\ud Vostok–Dome Concordia region during the Italian Antarctic expeditions in the period 1995–\ud 2001. The extension and the density of the radar data in the surveyed area allowed to reconstruct\ud a reliable subglacial morphology and to identify four relevant morphological structures namely:\ud the Aurora trench, the Concordia trench, the Concordia ridge and the South Hills. These\ud structures show evidence compatible with the presence of tectonic features. Morphological\ud considerations indicate their development in Cenozoic time. Hybrid cellular automata (HCA)-\ud based numerical modelling allowed to justify a possible role played by the tectonics of the\ud Aurora and Concordia trench evolution. This was accomplished by matching the bed profiles\ud along opportunely projected sections with the modelled surfaces as derived by the activity of\ud normal faults with variable surfaces within the continental crust. The Vostok–Dome C region\ud is characterized by a large number of subglacial lakes. From the analysis of basal reflected\ud power echo, we identified 14 new lakes and obtained information about their physiography as\ud well as their possible relations with tectonics.We propose a grouping of subglacial lakes on the\ud base of their physiography and geological setting, namely relief lakes, basin lakes and trench\ud lakes. Relief lakes located in the Belgica subglacial highlands and are characterized by sharp\ud and steep symmetric edges, suggesting a maximum water depth of the order of 100 m. Their\ud origin may well relate to localized, positive geothermal flux anomalies. Basin lakes located\ud in the Vincennes subglacial basin and are characterized by wider dimension that allow the\ud development of well-defined, flat ice surface anomalies. Trench lakes characterize the Aurora\ud and Concordia trenches as the possible effect of normal fault activity

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Abstract. Ice thickness data over much of East Antarctica are sparse and irregularly distributed. This poses difficulties for reconstructing the homogeneous coverage needed to properly assess underlying sub-glacial morphology and fundamental geometric constraints on sea level rise. Here we introduce a new physically-based ice thickness interpolation scheme and apply this to existing ice thickness data in the Aurora Subglacial Basin region. The skill and robustness of the new reconstruction is demonstrated by comparison with new data from the ICECAP project. The interpolated morphology shows an extensive marine-based ice sheet, with considerably more area below sea-level than shown by prior studies. It also shows deep features connecting the coastal grounding zone with the deepest regions in the interior. This has implications for ice sheet response to a warming ocean and underscores the importance of obtaining additional high resolution data in these marginal zones for modelling ice sheet evolution.