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    Irish Ice Sheet dynamics during deglaciation of the central Irish Midlands: Evidence of ice streaming and surging from airborne LiDAR


    Delaney, Catherine A. and McCarron, Stephen and Davis, Stephen (2018) Irish Ice Sheet dynamics during deglaciation of the central Irish Midlands: Evidence of ice streaming and surging from airborne LiDAR. Geomorphology, 306. pp. 235-253. ISSN 0169-555X

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    Abstract

    High resolution digital terrain models (DTMs) generated from airborne LiDAR data and supplemented by field evidence are used to map glacial landform assemblages dating from the last glaciation (Midlandian glaciation; OI stages 2–3) in the central Irish Midlands. The DTMs reveal previously unrecognised low-amplitude landforms, including crevasse-squeeze ridges and mega-scale glacial lineations overprinted by conduit fills leading to ice-marginal subaqueous deposits. We interpret this landform assemblage as evidence for surging behaviour during ice recession. The data indicate that two separate phases of accelerated ice flow were followed by ice sheet stagnation during overall deglaciation. The second surge event was followed by a subglacial outburst flood, forming an intricate esker and crevasse-fill network. The data provide the first clear evidence that ice flow direction was eastward along the eastern watershed of the Shannon River basin, at odds with previous models, and raise the possibility that an ice stream existed in this area. Our work demonstrates the potential for airborne LiDAR surveys to produce detailed paleoglaciological reconstructions and to enhance our understanding of complex palaeo-ice sheet dynamics.

    Item Type: Article
    Keywords: LiDAR; Ireland; Crevasse-squeeze ridges; Ice surging;
    Academic Unit: Faculty of Social Sciences > Geography
    Item ID: 13127
    Identification Number: https://doi.org/10.1016/j.geomorph.2018.01.011 0169-555
    Depositing User: Dr. Stephen McCarron
    Date Deposited: 21 Jul 2020 14:27
    Journal or Publication Title: Geomorphology
    Publisher: Elsevier
    Refereed: Yes
    URI:

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