Beachrocks reveal blueprint for coastal sustainability: an attempt to explore natural cementation characteristics

Abstract

Beachrocks may look like just hardened sand on the shoreline, but globally, they tell a fascinating story about how nature turns sand into stone. Beachrocks are found along tropical and subtropical coastlines worldwide, exhibiting strong variation in composition and cementation characteristics [1]. In Okinawa, Japan, beachrocks exhibit extremely high calcium carbonate (CaCO3) content, indicating that cementation is dominated by precipitation from seawater [2]. In contrast, locations such as Ishikawa in Japan, St. Martin’s Island in Bangladesh, and Bozcaada in Turkey contain higher silica (SiO2) content, suggesting a combination of processes influenced by varying local sediment supply and limited carbonate cementation [2],[3]. These compositional differences indicate that beachrock formation cannot be explained by a single process but instead involves complex interactions among seawater chemistry, freshwater mixing dynamics, biological processes, climate, and geological conditions.