Jokulhlaup-related ice fracture and supraglacial water release during the November 1996 Jokulhlaup, Skeidararjokull, Iceland

During the initial stages of the November 1996 jokulhlaup at Skeioararjokul l, Iceland, floodwaters burst onto the glacier surface via a series of frac tures. This supraglacial drainage led to the formation of a number of disti nct ice surface depressions, one of which is investigated in detail. The mo rphology and structural characteristics of this feature are described, as w ell as the sedimentology of an associated assemblage of debris-filled fract ures. This work suggests that debris-charged subglacial floodwaters travell ed up to the glacier surface, where supraglacial flow occurred initially vi a an extensive network of fractures, orientated parallel to the glacier mar gin. Supraglacial discharge became progressively more focused into a series of discrete outlets, leading to the mechanical erosion of a number of depr essions on the glacier surface. The associated transfer of subglacially der ived floodwaters to high levels within the glacier resulted in the rapid en trainment of large volumes of sediment which may influence the patterns, pr ocesses and products of ice-marginal sedimentation in the future.