OSL Dating Reveals Vaigai Flood Buried Keezhadi Settlement 1,155 Years Ago

Key facts

• Researchers from Physical Research Laboratory (PRL) and Tamil Nadu’s Department of Archaeology used optically stimulated luminescence (OSL) dating on four sediment samples from Keezhadi pits KDI-1 and KDI-2.
• OSL ages span roughly the last 1,200 years and vary with depth, matching layered flood deposits.
• The study concludes that burial of the urbanesque structures at Keezhadi likely happened a little over a thousand years ago—around 1,155 years before present—due to a high-energy flood event that deposited sands and then finer silts and clays on the floodplain.
• Fine silty-clay layers sit over brick structures and coarse sand layers deeper down, with potsherd layers and fragments of roof tiles at some levels.