Beachrock: A chronological benchmark for Late Holocene build-up on the coast of Israel

Beachrock formations are proxies of coastal morphodynamics, and are thus commonly utilized for paleoenvironment interpretations. Linear beachrock outcrops parallel to the shoreline are typical of the Mediterranean coastline of Israel. A new geomorphic and sedimentological analysis of beachrock, integrated with relative and absolute geochronology, characterizes their clastic composition and determines their ages. In-situ beachrock outcrops in the sandy beaches of the Sharon coast of central Israel are composed of quartz sand, shells and shell fragments, and show a significant contribution of fragmented rocks from the coastal cliff. Sections of beachrocks analyzed using portable Optically Stimulated Luminescence (pOSL) provided a relative chronological framework within and between the sections. The results show a moderate optic signal accumulation, indicating a gradual beach build-up during initial beachrock formation stages. Optically Stimulated Luminescence (OSL) ages indicate deposition of unconsolidated beach sediments dated to about 1600–800 years before present (BP). The sediment burial at the former foreshore enabled rapid consolidation in the intertidal zone.