Sediment characteristics in iceberg dominated fjords, Kangerlussuaq region, East Greenland

Sediment cores from three East Greenland fjords contain sediment lithofacie s and depositional processes in an iceberg dominated glacial marine setting . Three major lithofacies, diamicton, fine-grained mud, and sand, are depos ited by two processes, sediment rain-out and sediment gravity flows. The se diments in Kangerlussuaq Fjord are predominately fine-grained muds deposite d by rain-out from icebergs and glacier meltwater, with sediment gravity fl ows acting as secondary agents of deposition. Miki Fjord records rain-out o f fine-grained muds from a river plume emanating from a proglacial delta at the fjord head. Alternating units of diamicton and fine-grained mud in Nan sen Fjord are deposited by sediment rain-out from icebergs; particle size i s governed by the oceanographic conditions in the fjord at the time of depo sition. Despite their proximity to each other, each fjord is distinguished by a distinct sedimentological signature: Kangerlussuaq Fjord has low total organic carbon contact, Miki Fjord has high mass magnetic susceptibility, and Nansen Fjord has high amounts of ice-rafted debris. Comparison of the E ast Greenland iceberg dominated and Alaska glacial meltwater dominated envi ronments indicates few major differences between sediments deposited in the se two settings, This similarity raises doubt as to how well glacial marine sedimentary sequences can be used to interpret and reconstruct differences between glacial marine environments in the past without knowledge of sedim ent accumulation rates, environmental conditions at the time of sediment de position, and comparable sedimentological data between studies. (C) 2000 El sevier Science B.V. All lights reserved.