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Rémy, F.
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Rémy, F.
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- PublicationOpen AccessUn karst sous la glace de l'Antarctide ?(2003)
; ; ; ; ; ; ;Bini, A.; Università degli Studi di Milano, Sez. Geologia, Via Mangiagalli 34, I-20133 Milan, Italy ;Forieri, A.; Università degli Studi di Siena, Dip. Scienze della Terra, Via del Laterino 8, I-53100 Siena, Italy ;Remy, F.; Laboratoire d’Etudes en Géophysique et Océanographie Spatiales, 18 av. Edouard Belin, 31055 Toulouse Cedex, France ;Tabacco, I. E.; Università degli Studi di Milano, Sez. Geofisica, Via Cicognara 7, I-20129 Milan, Italy ;Zirizzotti, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Zuccoli, L.; Università degli Studi di Milano, Sez. Geologia, Via Mangiagalli 34, I-20133 Milan, Italy; ; ; ; ; A new bedrock map of the Dome C area based on all radar data collected during Italian Antarctic Expeditions in 1995, 1997, 1999 and 2001 is presented. The map can clearly distinguish the Dome C plateau, along with some valleys and ridges develop. The plateau develops at three different altimetric levels and its morphology is characterized by hills and closed depressions. There are no visible features which can be ascribed to glacial erosion or deposition. The major valley is 15km wide and 500m deep; its axis is parallel to that of other valleys and ridges in the plateau. The valley bottom is not flat, but contains a saddle in its centre. The morphology of the major valley could be considered as a relict one which was not modified by the overlying ice cap. Two big ridges, characterized by hills, saddles and depressions, lie near the boundaries of the area. The hill and depression landscape may be the results of two different processes the weathering of granitic rocks, with the development of a "Wemi-oranges" and inselberg landscape, or the karstification of limestones, and development of a cone karst. The karstic hypothesis should be the more suitable, but it is impossible to exclude the granitic rock weathering. Both proposed genetic hypotheses call for a warm humide climate and a long period of stability in a continental environment. Consequently, the ice cap did not largely modified the landscape.14278 117 - PublicationRestrictedGeophysical survey at Talos Dome, East Antarctica: the search for a new deep-drilling site(2004)
; ; ; ; ; ; ; ; ; ; ; ; ; ;Frezzotti, M.; ENEA, Centro Ricerche Casaccia, P.O. Box 2400, I-00100 Rome, Italy ;Bitelli, G.; DISTART, University of Bologna, Viale Risorgimento 2, I-40136 Bologna, Italy ;De Michelis, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Deponti, A.; Department of Environmental Sciences, University of Milano–Bicocca, Piazza della Scienza 1, I-20126 Milan, Italy ;Forieri, A.; Department of Earth Sciences, University of Milan, Via Cicognara 7, I-20129 Milan, Italy and Department of Earth Sciences, University of Siena, Via del Laterino 8, I-53100 Siena, Italy ;Gandolfi, S.; DISTART, University of Bologna, Viale Risorgimento 2, I-40136 Bologna, Italy ;Maggi, V.; Department of Environmental Sciences, University of Milano–Bicocca, Piazza della Scienza 1, I-20126 Milan, Italy ;Mancini, F.; DISTART, University of Bologna, Viale Risorgimento 2, I-40136 Bologna, Italy ;Remy, F.; Legos, CNRS-CNES-UPS, 18 av. Edouard Belin, 31055 Toulouse Cedex, France ;Tabacco, I. E.; Department of Earth Sciences, University of Milan, Via Cicognara 7, I-20129 Milan, Italy ;Urbini, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Vittuari, L.; DISTART, University of Bologna, Viale Risorgimento 2, I-40136 Bologna, Italy ;Zirizzotti, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; ; ; ; ; ; ; ; ; ; ; ; 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; 2318.5m 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 cma–1. The other stakes, located 8 km away, move up to 0.33ma–1. Airborne radar measurements indicate that the bedrock at the Talos Dome summit is about 400m in elevation, and that it is covered by about 1900m 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 one-dimensional steady-state model was formulated. This model predicts that the ice 100m above the bedrock may cover one glacial–interglacial period.485 33 - PublicationRestrictedNew bedrock map of Dome C, Antarctica, and morphostructural interpretation of the area(2004)
; ; ; ; ; ; ;Forieri, A.; Università degli Studi di Milano, Sez. Geofisica, Via Cicognara 7, I-20129 Milan, Italy and Università degli Studi di Siena, Dip. Scienze della Terra, Via del Laterino 8, I-53100 Siena, Italy ;Zuccoli, L.; Università degli Studi di Milano, Sez. Geologia, Via Mangiagalli 34, I-20133 Milan, Italy ;Bini, A.; Università degli Studi di Milano, Sez. Geologia, Via Mangiagalli 34, I-20133 Milan, Italy ;Zirizzotti, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Remy, F.; Laboratoire d’Etudes en Géophysique et Océanographie Spatiales, 18 av. Edouard Belin, 31055 Toulouse Cedex, France ;Tabacco, I. E.; Università degli Studi di Milano, Sez. Geofisica, Via Cicognara 7, I-20129 Milan, Italy; ; ; ; ; A new bedrock map of the Dome C area is presented, based on all radar data collected during Italian Antarctic Expeditions in 1995, 1997, 1999 and 2001. The map clearly distinguishes the Dome C plateau, along with valleys and ridges. The plateau develops at three different altimetric levels, and its morphology is characterized by hills and closed depressions. There are no visible features which can be ascribed to glacial erosion or deposition. The major valley is 15km wide and 500m deep; its axis is parallel to that of other valleys and ridges in the plateau. The valley bottom is not flat, but contains a saddle at its centre. The morphology of the major valley may be considered a relict one which was not modified by the overlying ice cap. Two large ridges, characterized by hills, saddles and depressions, lie near the boundaries of the area. The map is used to recalculate ice thickness below the European Project for Ice Coring in Antarctica (EPICA) borehole. The new thickness is 3300 m, 50m greater than before, implying that the expected palaeoclimate record from the ice core could extend back >800 kyr.14205 80 - PublicationRestrictedLakes and subglacial hydrological networks around Dome C, East Antarctica(2003)
; ; ; ; ; ; ;Rémy, F.; Laboratoire d’Etudes en Géophysique et Océanographie Spatiale, 18 avenue Edouard Belin, 31055 Toulouse Cedex, France ;Testut, L.; Laboratoire d’Etudes en Géophysique et Océanographie Spatiale, 18 avenue Edouard Belin, 31055 Toulouse Cedex, France ;Legrésy, B.; Laboratoire d’Etudes en Géophysique et Océanographie Spatiale, 18 avenue Edouard Belin, 31055 Toulouse Cedex, France ;Forieri, A.; Dipartimento di Scienze della Terra, Università degli Studi di Milano, Via Cicognara 7, I-20129 Milan, Italy ;Bianchi, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Tabacco, I. E.; Dipartimento di Scienze della Terra, Università degli Studi di Milano, Via Cicognara 7, I-20129 Milan, Italy; ; ; ; ; Precise topography from European Remote-sensing Satellite radar altimetry and high density of airborne radio-echo sounding in the area surrounding Dome C, Antarctica, show a link between surface features and subglacial lakes. In this paper, we extend the study to fine structures by computing a curvature-based coefficient (cy) related to surface undulations. These coefficient variations reveal many surface undulations, and some elongated features of this parameter seem to link known subglacial lakes. A population of high values of this coefficient, assumed to correspond to transitions between sliding and non-sliding flow regime, strengthen the appearance of a network which would link most of the lakes in the area. The existence of such a network impacts on ice-flow dynamics and on subglacial-lake studies.510 103 - PublicationRestrictedInfluence of geometrical boundary conditions on the estimation of rheological parameters(2000)
; ; ; ; ;Testut, L.; UMR5566, Groupe de Recherche de Géodésie Spatiale, CNES-CNRS, Toulouse Cedex 31055, France ;Tabacco, I. E.; Dipartimento di Scienze della Terra, Università degli Studi di Milano, I-20129 Milan, Italy ;Bianchi, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Rémy, F.; UMR5566, Groupe de Recherche de Géodésie Spatiale, CNES-CNRS, Toulouse Cedex 31055, France; ; ; Improved knowledge of geometrical boundary conditions, such as bedrock geometry and surface topography, can contribute significantly to glaciological studies including ice-sheet-flow modelling. Precise thickness and altimetric data allow an estimation of ice-flow direction, the balance velocity and the basal shear stress. These parameters are calculated along a 1160 km profile in East Antarctica using a relationship between shear stress, basal temperature, the Glen flow exponent and a parameter related to strain rate. Strong variations of the flow-law parameters and basal conditions are found to play a major role in the ice-flow pattern. Sliding, anisotropy and longitudinal stress strongly perturb the validity of the law, but their signature can be identified.463 62