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Debris entrainment at the ice-bedrock interface in sub-freezing temperature conditions (Terre Adelie, Antarctica)

par Tison, Jean-Louis ;Petit, Jean-Robert;Barnola, Jean-Marc;Mahaney, William W.C.
Référence Journal of Glaciology, 39, 132, page (303-315)
Publication Publié, 1993

Article révisé par les pairs

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Résumé :

The debris-rich ice from the bottom 6 m of the 82 m deep CAROLINE (Coastal Antarctic Record of Last Interglacial Natural Environment) ice core reaching bedrock, and from five 2 m long surface cores at Moraine Prudhomme in Terre Adelie (Antarctica) is described and compared to debris-laden ice from the core-drilling site D10. Isotopic, total-gas content, CO2 concentration and SEM investigations of embedded particles, together with ice textures and fabrics, rule our "pressure-melting' regelation around bed obstacles or "freezing-on' as possible mechanisms for the debris entrainment at the ice-bedrock interface. It is suggested that the debris entrapment by purely mechanical means (e.g. shearing) is an efficient process in forming basal ice layers (BIL) at sub-freezing temperatures. -from Authors