Reconstruction of sedimentation rates based on the chronological framework of Lake Pykara, Tamil Nadu, India

This work presents a piece of initial information about the estimation of the sedimentation rate for Lake Pykara. In this investigation, a chronological sequence of sediment core was set up dependent on 137 Cs and 210 Pb ex analysis to study sediment accumulation rates in Lake Pykara. Caesium-137 (Cs) is an artificial radionuclide and is regularly utilized in building up the chronology of lake sediments in the Anthropocene period. The unsupported 210 Pb profile shows a non-exponential decline of 210 Pb activity with sediment depth. Sedimentation rates dependent on global atmospheric nuclear weapon maximum fallout of 137 Cs (1963) bolster the utilization of the consistent rate of 210 Pb supply (CRS) model in core sediments. The geochronology studies of the core were performed using the 137 Cs method, to evaluate the model of time changes in the sediment. The 137 Cs radioactivity was resolved directly by gamma spectrometry and fluctuated from 13.11 ± 1.3 Bq kg −1 for top layers to 1.21 ± 0.1 Bq kg −1 for the bottom of the core. Two trademark peaks of 137 Cs radioactivity identified with the global fallouts after atomic weapons testing and the Chernobyl mishap were observed and used to affirm the 210 Pb dating method. Radioactivity of 210 Pb ex ranged from 8.00 ± 1.0 to 1.40 ± 0.1 Bq kg −1 . The mean sedimentation rate evaluated from both models was 0.71 ± 0.06 cm year −1 , while the estimated age of Lake Pykara was 514.08 years ( 137 Cs) and 521.43 years ( 210 Pb ex ), respectively.