As differences form between the heating of land and ocean, the characteristic monsoon climate of the Bay of Bengal is created. The formation, evolution and controlling factors of the monsoon in the studied district are analyzed in this paper. Results indicate that a strong salinity contrast is a direct response to the monsoonal climate regime which dominates the north Indian Ocean. The salinity changes reflected by delta (super 18) O values are analyzed. In the studied district, the south-west monsoon was stronger during the Holocene and Oxygen Isotope Stage 3 than during the last glacial maximum and Oxygen Isotope Stage 2. In contrast with the Arabian Sea, it seems the primary forcing factor of the South Asian monsoon is the changes in the distribution of solar radiation as determined by the procession of 23,000-year periodicity.