Textural and compositional variations of beach sands along the coast of South Andaman Island: Implications for provenance and depositional history

Abstract

The study of petrography is a primary step in provenance research of beach sand sediments. The data set needs to be analyzed for this study is based on their mineralogical compositions and structure. The study of sediments in the present-day depositional environment is important to find out the nature of sediments to reconstruct the history of rock including information about the origin of its constituent particles, the method and distance of sediment transport and the nature of the place where the grains eventually came to rest i.e. the environment of deposition. In the present study the beach sand sediments of five beaches viz Corbyn’s cove, Chiriyatapu, Wandoor, Radhanagar beach, Havelock and Lakshmanpur beach, Neil Island were analyzed to throw some light on to the sediment characteristics of the South Andaman Island. For the present study 40 Sand samples were collected, eight from each beach and thin section slides were prepared. The slides were studied under the petrographic microscope to study the textural and compositional characteristics of the sediments. It was found that the beaches are composed of sediments of two different types, viz silisiclastic and carbonate nature. The sediments are deposited under shallow marine environment which is influenced by tidal, river, wave and oceanic currents, which play a role in the dispersion of sediments. The sedimentation in this environment can be dominated by alternating episodes of siliciclastic and carbonate deposition.