Seasonal variations in textural characteristics and depositional environment of foreshore sediments along Kerala Coast, India

Abstract

The study investigates textural characteristics of foreshore sediment along the central Kerala coast. The selected beaches extend from Ponnani in the north to Alleppey in the south along the west coast of India. Samples were collected from foreshore zone at 22 selected locations to assess sediment grain size distribution and its seasonality. Statistical parameters such as mean (M), standard deviation (SD), skewness (Sk), and kurtosis (K) were used to evaluate the textural characteristics. The purpose of the present study was to examine the textural behaviour of coastal sediments in different seasons from November 2014 to October 2015. Textural characteristics show that the sediment samples are unimodal and bimodal with medium and fine grain sand. The standard deviation (sorting) reveals the sediment samples are very well sorted to moderately sorted with a range of 0.24 phi to 1.03 phi, while the skewness values of the sediment samples range from −0.55 phi to 0.32 phi. The CM plot depicts that the foreshore sediments are transported by tractive currents and transporting the sediments by rolling, bottom suspension with rolling. The analysis of Linear Discriminant Function (LDF) illustrates that the sediment samples are accumulated by aeolian or coastal and shallow turbulent environments.