Nott, Jonathan (2011) Boulder beaches. In: Hopley, David, (ed.) Encyclopedia of Modern Coral Reefs: structure, form and process. Encyclopedia of Earth Science . Springer, Dordrecht, The Netherlands, pp. 165-167.
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[Extract] Boulder beaches occur along many of the world's coasts. Their presence and formation is a function of sediment availability and wave energy. Both storm waves and tsunami may be responsible for deposition of boulder beaches but differentiating which of the two may have been responsible, principally, at any one location can be difficult (Nott, 2004). It is common for boulder beaches to display sorting both alongshore but more often perpendicular to the shore with coarser clasts closer to the intertidal zone and progressively fining with distance landward (Figure 1). The shape of clasts varies depending upon the nature of the bedrock from which the clasts were derived and also the depositional processes. Joint spacing in the source bedrock will often limit clast size. Lithology along with the history of transportation and reworking will influence the degree of abrasion and eventual clast shape. Clasts that have experienced a high frequency of reworking and mobilization will theoretically be more rounded whereas clasts that have experienced only one transporting event after erosion from their bedrock source could be expected to be more angular. However, in this last instance the degree of angularity will depend upon the nature of that bedrock source i.e., whether it was composed of rounded core stones in a saprolitic profile or was unweathered jointed rock.
|Item Type:||Book Chapter (Reference)|
|Date Deposited:||18 Jan 2012 01:43|
|FoR Codes:||04 EARTH SCIENCES > 0406 Physical Geography and Environmental Geoscience > 040601 Geomorphology and Regolith and Landscape Evolution @ 100%|
|SEO Codes:||97 EXPANDING KNOWLEDGE > 970104 Expanding Knowledge in the Earth Sciences @ 100%|