DEPOSITIONAL-ENVIRONMENTS - INFERRED FROM GRAIN-SIZE ALONG THE COAST OF TAMIL-NADU

Between north of Pondicherry and Ennore (12 degrees 03' to 13 degrees 12' N - 79 degrees 53' to 80 degrees 15' E) two geomorphic units such as beach and beach ridges and their associated units (Low Water Mark ( LWM), Foreshore (FS), Berm (BM), Backshore (BS), Dune (DU) and Beach R idge (SL)) are selected for the present study to understand the micro level variation in the depositional environment The samples mostly sho w medium to fine size, well sorted to moderately sorted, very coarse s kewed to fine skewed and platykurtic to leptokurtic nature. Graphic me an, standard deviation, skewness and kurtosis confirm that the sedimen ts are of typical beach origin. Frequency curves indicate that the dun e samples represent unimodal and others show bimodal to polymodal sour ce of influence. Based on bivariant plots the samples of dune, berm, b ackshore, foreshore and low water mark with strandline deposits are cl assified.