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Keywords:

  • depositional environments;
  • fjord stratigraphy;
  • fjords;
  • sedimentary processes;
  • sedimentation rates

ABSTRACT

Fjords commonly hold sediment basins with high temporal resolution that mirror land- and marine-based processes and depositional environments during a glacial–interglacial cycle. Here, we present TOPAS seismic profiles, with a vertical resolution of <30 cm, bathymetric records and a gravity core from Fensfjorden, west Norway, which allow a detailed study of sedimentary processes and depositional environments in a NE Atlantic fjord system. Fensfjorden hosts a sediment volume of 0.70 km3 and the sediment basins evolved reach a maximum thickness of 100 m. The basins are characterized by a lower acoustically well-laminated glacimarine unit, of Allerød and Younger Dryas age. This unit is overlain by several acoustically transparent lenses, interpreted to be slide debrites. We suggest these slide debrites to be a result of recurrent mass failures that occurred between 11 500 and 2100 cal a BP. A thin late Holocene hemipelagic unit drapes the slide debrites. During the late Holocene the sedimentation rates in Fensfjorden decreased from 0.110 to 0.040 cm a−1 and two turbidity currents occurred in the 2040–1190 cal a BP time period. This ability to map fjord processes in more detail has, furthermore, made it possible to revise the established stratigraphical framework for NE Atlantic fjords. Copyright © 2013 John Wiley & Sons, Ltd.