The glaciolacustrine landform-sediment assemblage at Heinabergsjokull, Iceland

Landform-sediment assemblages associated with two ice-dammed lakes, one act ive and one fossil, at Heinabergsjokull in southeast Iceland are described. The current ice-dammed lake (Vatnsdalur) is dominated by a large aggradati onal terrace, as well as an excellent suite of shorelines. The second fossi l ice-dammed lake dates from the Neoglacial maximum of Heinabergsjokull (c. 1887) and drained during the late 1920s. This lake is associated with a su ite or shorelines and ice-marginal glaciolacustrine fans. The sedimentology of one of these fans is described. Between 50 and 70% of the sediment succ ession is dominated by ice-rafted sediment, although rhythmites, matrix-ric h gravels, sands and graded sand-silt couplers are also present. A range of intra-formational, soft-sediment deformation structures are present, consi stent with liquefaction and deformation associated with lending, current sh ear, and iceberg calving. The landform-sediment assemblages described from Heinabergsjokull provide important data for the interpretation of Pleistoce ne ice-dammed lakes.