The Width of Shore Platforms in Britain, Canada, and Japan


  • Alan S. Trenhaile


Rock coasts, geomorphology, Canada, Wales, Japan


Variations in the width of shore platforms were investigated within southern Wales, Gaspe in eastern Canada, and southern Japan. The strong, positive linear relationship between platform gradient and tidal range implies that platform width may be largely independent of tidal range, although regional negative correlations between platform gradient and width suggest that platforms become narrower with increasing tidal range. Platform width increases with wave intensity, and the widest platforms are oriented toward the dominant waves. The width of the platforms also decreases with increasing rock dip. A structural classification, based upon combinations of rock dip and strike, relative to the orientation of the cliff face, helped to explain variations in platform width in Canada and Japan. Changes in structural class induced by variations in coastal orientation may partially account for differences in the width of platforms on headlands and in embayments. Platform width is also influenced by the presence and type of cliff-foot deposits.