Quantitative roundness analysis of coastal boulder deposits

The sedimentology of coastal boulder deposits (CBD) is little known. These deposits, and especially the largest clasts within them—which commonly weigh many 10s of tonnes—are of increasing interest because they attest to extreme energy wave events acting well above the high-tide mark (in some cases >40m above high water and >100m inland). Recent observations have made clear that storm waves (rather than tsunami) are important in both creating and activating these deposits; but beyond that we know little about their hydrodynamics, or the relative frequency of boulder movement, and how this might vary with topographic setting.