Lateglacial rock slope failures in north-west Ireland: age, causes and implications

Colin Ballantyne, Peter Wilson, Christoph Schnabel, Sheng Xu

    Research output: Contribution to journalArticlepeer-review

    29 Citations (Scopus)

    Abstract

    Nine postglacial quartzite rock slope failures (RSFs) in north-west Ireland were dated using cosmogenic 10Be. Weighted mean RSF ages range from 17.7 ± 0.9 to 12.5 ± 0.7 ka or 16.6 ± 0.7 to 11.7 ± 0.5 ka, depending on assumed 10Be
    production rate. All dated RSFs occurred within ∼5000 years following
    ice-sheet deglaciation at ∼17.4ka (∼16.3 ka) and all but two occurred
    within 2000 years after deglaciation. The timing of RSFs rules out
    glacial ‘debuttressing’, permafrost degradation and enhanced deglacial
    cleft-water pressures as triggers of failure in most cases. We infer
    that paraglacial stress release and associated fracture propagation were
    critical in reducing rock masses to critical stability, although
    earthquakes caused by Lateglacial glacio-isostatic rebound and/or
    release of stored tectonic stresses may have triggered failure in some
    or all cases. In conjunction with data from related studies, our results
    imply that most undated RSFs outside the limit of Younger Dryas
    glaciation in the British Isles are of Lateglacial age, and that
    numerous Lateglacial RSFs occurred inside these limits, with subsequent
    removal of debris by glaciers. They support the view that paraglacial
    RSF activity in tectonically stable intraplate terrains was concentrated
    within a few millennia following deglaciation.

    Original languageEnglish
    Pages (from-to)789-802
    Number of pages14
    JournalJournal of Quaternary Science
    Volume28
    Issue number8
    Early online date28 Nov 2013
    DOIs
    Publication statusPublished - Nov 2013

    Keywords

    • 10Be exposure dating
    • palaeoseismicity
    • paraglacial
    • rock slope failure
    • stress release

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