An Account of the Bottom Sediments off Andaman Islands, India

The sediments comprise sand, sandy silt, silty sand and clayey silt. Variation in their distribution with depth is discernible. Studies on the grain size parameters of the sediments reveal that the inclusive graphic mean vary from 2.3 to 7.0, inclusive graphic standard deviation 1.2 to 2.9 phi, inclusive graphic skewness -.07 to +.71 and kurtosis 0.6 to 5.4. Generally sand is extremely leptokurtic, positively skewed and better sorted than the rest of the sediments. Presence of two energy environments has been noticed.</P><P>The phosphate content in the sediments varies from 0.12 to 0.47% and calcium oxide from 3.0 to 27.15%. It is observed that, unlike CaO, a higher percentage of P₂O₅ is prevalent in the near shore sediments than those of the deep offshore.