DEBRIS ENTRAINMENT AT THE ICE-BEDROCK INTERFACE IN SUB-FREEZING TEMPERATURE CONDITIONS (TERRE-ADELIE, ANTARCTICA)

The debris-rich ice from the bottom 6 m of the 82 m deep CAROLINE (Coa stal Antarctic Record of Last Interglacial Natural Environment) ice co re reaching bedrock, and from five 2 m long surface cores at Moraine P rudhomme in Terre Adelie (Antarctica) is described and compared to deb ris-laden ice from the core-drilling site D10. Isotopic, total-gas con tent, CO2 concentration and SEM investigations of embedded particles, together with ice textures and fabrics, rule out ''pressure-melting'' regelation around bed obstacles or ''freezing-on'' as possible mechani sms for the debris entrainment at the ice-bedrock interface. It is sug gested that the debris entrapment by purely mechanical means (e.g. she aring) is an efficient process in forming basal ice layers (BIL) at su b-freezing temperatures. This process might be dominant at the margin of the Antarctic ice sheet where no ice shelf exists and where a ramp terminus or a buttressing coastal relief induces compressive flow.