Late Quaternary sedimentation and permafrost development in a Svalbard fjord-valley, Norwegian high Arctic

Graham L. Gilbert*, Hugh B. O'Neill, Wojciech Nemec, Christine Thiel, Hanne H. Christiansen, Jan-Pieter Buylaert

*Corresponding author for this work

    Research output: Contribution to journalJournal articleResearchpeer-review

    Abstract

    The infilling history of the Adventdalen fjord-valley in central Spitsbergen is reconstructed, with a focus on permafrost development, based on sedimentological and cryostratigraphic evidence from drilling cores. The techniques of optically stimulated luminescence and radiocarbon accelerator mass-spectrometry dating were used to establish sediment chronology. The fjord-fill sedimentary succession includes the fjord-bottom late Weichselian subglacial till of the Last Glacial Maximum, the early Holocene muddy glaciomarine deposits with ice-rafted debris formed during the fjord deglaciation, and the younger Holocene deposits of a fjord-head Gilbert-type delta of which the fluvial distributary plain shows raised alluvial terraces hosting aeolian sedimentation. This sedimentary record of the last glaciation/deglaciation cycle is interpreted in terms of sequence stratigraphy. Zones of epigenetic and syngenetic permafrost are recognized from the vertical distribution of cryofacies, with a conclusion that the formation of permafrost commenced and extended down-fjord as the fluvio-deltaic fjord-fill was gradually reaching subaerial exposure. The upwards-grown syngenetic permafrost and the top part of downwards-grown epigenetic permafrost below contain excess ice in a suite of cryofacies indicating ground-ice segregation and segregative intrusion. The deeper epigenetic permafrost is ice-poor and contains cryofacies formed solely by segregation processes. This case study may serve as an analogue for other similar Arctic fjord-valleys where the fjord-head shoreline was established during the post-Weichselian deglaciation.
    Original languageEnglish
    JournalSedimentology
    Volume65
    Issue number7
    Pages (from-to)2531-2558
    ISSN0037-0746
    DOIs
    Publication statusPublished - 2018

    Keywords

    • Adventdalen
    • Cryofacies
    • Cryostratigraphy
    • Fjord-head delta
    • Ground ice
    • Sedimentary facies
    • Spitsbergen

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