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Publication - Dr Byron Adams

    Tectonic controls of Holocene erosion in a glaciated orogen

    Citation

    Adams, B & Ehlers, T, 2018, ‘Tectonic controls of Holocene erosion in a glaciated orogen’. Earth Surface Dynamics, vol 6., pp. 595-610

    Abstract

    Recent work has highlighted a strong, worldwide, alpine glacial impact on orogen erosion rates over the last 2Ma.
    While it may be assumed that glaciers increased erosion rates when
    active, the degree to which past glaciations influence Holocene erosion
    rates through the adjustment of topography is not known. In this study,
    we investigate the influence of long-term tectonic and post-glacial
    topographic controls on erosion in a glaciated orogen: the Olympic
    Mountains, USA. We present 14 new 10Be and 26Al
    analyses which constrain Holocene erosion rates across the Olympic
    Mountains. Basin-averaged erosion rates scale with basin-averaged values
    of 5km local relief, channel steepness,
    and hillslope angle throughout the range, similar to observations from
    non-glaciated orogens. These erosion rates are not related to mean
    annual precipitation or the marked change in Pleistocene alpine glacier
    size across the range, implying that glacier modification of topography
    and modern precipitation parameters do not exert strong controls on
    these rates. Rather, we find that despite spatial variations in glacial
    modification of topography, patterns of recent erosion are similar to
    those from estimates of long-term tectonic rock uplift. This is
    consistent with a tectonic model where erosion and rock uplift patterns
    are controlled by the deformation of the Cascadia subduction zone.

    Full details in the University publications repository