It is conjectured that a rise in worldwide sea levels over the last 6,000–8,000 years occurred with a pause in the rise of sea level about 7,000 years ago, which could have resulted in the formation of a sandy beach near the coast at the Southern sector. With the rise in the sea level, the sand beach grew gradually, progressed seaward to the northeast and formed the spit of Chilika. A fossil unearthed from the southwestern edge of the spit indicates that the lake was formed about 3,500–4,000 years ago. The abrupt change in the direction of the coast north of the lake, strong winds shifting sand to the shore, longshore drift (littoral drift), the presence or absence of strong river and tidal currents in different areas are the reasons attributed for the growth of the spit.