Formation and Distribution of Beachrock

Formation and Distribution of Beachrock Beachrock is defined by Scoffin and Stoddart (1987, 401) as "the consolidated deposit that results from lithification by calcium carbonate of sediment in the intertidal and spray zones of mainly tropical coasts." Beachrock units form under a thin cover of sediment and generally overlie unconsolidated sand, although they may rest on any type of foundation. Maximum rates of subsurface beachrock cementation are thought to occur in the area of the beach that experiences the most wetting and drying below the foreshore in the area of water table excursion between the neap low and high tide levels (Amieux et al, 1989; Higgins, 1994). Figure B49 shows a beachrock formation displaying typical attributes.