Beach rock from Goa Coast

Abstract

Beach rock is a common rock type in many parts of the southern hemisphere and also some areas north of the equator. Its distribution particularly in the Indian Ocean islands and atolls and coasts of India is reviewed. The mineralogic and faunal constituents of beach rock found along Goa coast is dealt with in detail. While discussing the various views on its origin, it is emphasized that the process of cementation is chiefly controlled by ground water evaporation, inorganic precipitation and optimum temperature under the beach and inland. However, the thickness depends upon variabilities of precipitation, hinterland, water table fluctuations, temperature changes, composition and changes in sea level. Since the beach rock is formed in the tidal or spray zone its occurrence at higher or lower levels is suggestive of eustatic movement. The physical setting of this rock along the west coast of India indicates a post-middle Miocene to Pleistocene age