0016-7622/2020-95-1-67/$ 1.00 © GEOL. SOC. INDIA | DOI: 10.1007/s12594-020-1387-2 JOURNAL GEOLOGICAL SOCIETY OF INDIA Vol.95, January 2020, pp.67-74 Textural Analysis of Coastal Sediments along East Coast of India U. K. Pradhan* 1 , R.K. Sahoo 2 , S. Pradhan 3 , P. K. Mohany 2 , and P. Mishra 1 1 National Centre for Coastal Research (NCCR), NIOT Campus, Narayanpuram, Chennai - 600 100, India 2 Department of Marine Sciences, Berhampur University, Berhampur -760 007, India 3 Chilika Development Authority, C-11, BJB Nagar, Bhubaneswar - 751 014, India *E-mail: uma22pradhan@gmail.com ABSTRACT The study investigates textural characteristics of sediment at selected tourist beaches extending from Rameswaram to Paradip along east coast of India. Samples were taken from backshore and foreshore at nine selected locations to evaluate sediment grain size distribution and its seasonality. Analysis of grain size distribution carried out to identify textural characteristics (mean size, standard deviation, skewness and kurtosis) and its variability in two different seasons (southwest and northeast monsoon). Results show that sediments lying in backshore regions are mostly medium sand, while its changes are relatively invariant against seasons. The percentage of fine sand is higher during January compared to September due to prevalence of calm wave conditions. The mean grain size trend decreases at backshore region while it increases at foreshore region from south to north along the coast indicating dominance of aeolian transport. Sediments are mostly moderately sorted at backshore and moderately well sorted at foreshore region. Mostly symmetrical and mesokurtic sediments are dominated along the coast indicating sediments are well sorted at central portion of sediment distribution. The CM diagram depicts sediment source are from beach environment during both the seasons and some of them transported by tractive current in September and transporting during September is by rolling, bottom suspension and rolling; and graded suspension no rolling. INTRODUCTION Sedimentology which includes characteristics and dynamics of sediments is an important area of research often provides valuable information on coastal environment. Many researchers in the field, work on coastal sediments on a seasonal scale to understand behavior of the coast viz. erosion, accretion and evolution of sand dune systems. Besides, sediment texture acts as instrument for fundamental analysis of origin of coastal sediments, prevalence of oceanographic conditions and sediment transport processes (Komar, 1998; Pentney and Dickson, 2012). The beach sediment moves both in cross-shore and alongshore direction under the action of wind, wave, tide, and extreme events such as storm, cyclone, tsunami and coastal/terrestrial flooding. In general, beach sediment transport occurs by wind at upper part of beach while oceanographic conditions such as tide, current and waves are accountable for uninterrupted transport of sediments at swash zone and nearshore region up to continental shelf. Textural analysis of sediments has fascinated coastal researchers around the globe and also these studies are made available worldwide to investigate the potential information about transport behavior and size-sorting processes of sediments in several environments (Folk and Ward, 1957; Friedman, 1961; Tairaand Scholle, 1979; Clark, 1981; Slyetal., 1982). The study has been carried out along the east coast of India whose sedimentology and transport mechanisms are essential for coastal management. Sediment along east coast of India is influenced by reversal wind and current pattern (Shetye et al.,1993; Schott and McCreary, 2001), which resulted in northerly sediment movement during southwest monsoon and southerly during northeast monsoon (Chandramohan and Nayak, 1991; Mishra et al., 2001). The aim of this work is to investigate the seasonality in textural characteristics of major selective sandy beaches along the east coast of India. The study explain the grain size characteristics and mode of transport at each location. Textural parameters for Tamil Nadu coast is studied by Chandrasekar (1992), for Andhra Pradesh (Karunakarudu et al., 2013; Bangaku Naidu et al., 2016; Suvarna et al., 2017) and for Odisha coast (Chauhan, 1986, 1992; Mohanty et al., 2012) have made significant contributions in differentiating the environments of beach and river sediments. However, information is lacking on the grain size characteristics of such sediments and on the processes operating along the east coast of India. The present study aims to fill this gap. STUDY AREA The study area lies along the east coast of India, which has an extensive coastline of about 3480km with diverse oceanographic conditions (Fig.1). The southern east coast of India (Tamil Nadu coast) is generally dominated by micro tidal pattern while the central east coast of India (Odisha coast) is dominated by the meso-tidal pattern. The east coast of India is characterized with various geomorphological features such as open beaches, rocky shores, sandy spits, estuaries, tidal inlets, bays, lagoons, marshy land & mangroves etc. The stations at which sediment samples were collected are experienced with reversal sediment transport as well as regional coastal processes which are influenced by a number of environmental drivers such as geological, meteorological and oceanographical factors. Besides, many river systems also discharge huge amount of sediments, which takes part in coastal evolution process. Therefore, east coast of India is much more dynamic compared to the Arabian coast due to huge propensity of sediment out flux to Bay of Bengal. The study sites along east coast of India is highly exposed to tropical cyclones (Dube et al., 1997; Singh et al., 2001; Monalisha and Panda, 2018; Baral et al., 2018) and tsunami like extreme catastrophic events are responsible to changes in the nearshore geomorphology drastically. On the other hand, anthropogenic activities like development of port, groyne field and breakwater along the coast acts as barrier for uninterrupted sediment transport along the Indian coast and noticed the changes in sediment distributions and budget (Rao et al., 2009; Mohanty et al., 2012). Study area has been fixed along east coast of India within four maritime states and one union territory. DATA AND METHODOLOGY Sediment sample from nine locations along east coast of India were collected during the month of September and January 2016 representing southwest and northeast monsoon at study locations.