The Nature and Origin of a Jökulhlaup Near Casey Station, Antarctica

Abstract

Abstract A jökulhlaup event of 6 months duration occurred near Casey Station, Law Dome, Antarctica, in late March (austral autumn) 1985. This was followed by sporadic outbursts during the austral autumn and winter of 1986. The event is the first recorded outburst of water from beneath a cold ice-cap terminus on Law Dome and, to the author’s knowledge, in Antarctica. From the results of oxygen-isotope and solute analysis, the water was found to have originated as basal melt water. It contained a high total solute load with a dominant enrichment in alkalis, indicting that it had been squeezed through subglacial sediments for an extensive time period. Evidence from the subglacial topography, basal ice exposures, and the sedimentology of nearby supraglacial moraines supports the presence of an ice-marginal subglacial water reservoir as the jökulhlaup source.