The ages of the storm beaches of the Lakshadweep (Laccadives)

Most of the islands in the Lakshadweep are marked by storm beaches on the eastern seaward shores and sandy beaches on the western lagoonal shores. The storm beaches consist of up to 3–4 sets almost at the same level and extend up to a distance of 5–12 km on some of the islands. They largely comprise uncemented pebbles, shingles, cobbles and boulders. The tracks for cyclones (1891–1960) show that the islands are normally hit by post-monsoon (November) cyclones from the east. The waves generated by these cyclones have formed the storm beaches. Radiocarbon dates of the storm beaches range from modern to 2975 ± 100 BP and indicate clustering between 3000 to 2000 BP and present to 500 BP. The younger storm beaches towards the shore suggest that parts of the islands have grown by about 30 m in the last 2780 years (Chetlat), 120 m in 1620 years (Kiltan) and even 100 m in 470 years (Minicoy). The absence of the storm beaches on some of the islands, younger beaches towards the shore and the clustering of ages, and the lack of lateral and chronological continuity may be explained by periodic stormy conditions rather than by the changes in the sea level. The number of storms in the Arabian Sea has varied from a minimum of 1 in 1949 to 10 in 1893, 1926 and 1930. It is very likely that such changes would have occurred in the past also.