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 Cs-137 and Pb-210(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 Pb-210 profile shows a non-exponential decline of Pb-210 activity with sediment depth. Sedimentation rates dependent on global atmospheric nuclear weapon maximum fallout of Cs-137 (1963) bolster the utilization of the consistent rate of Pb-210 supply (CRS) model in core sediments. The geochronology studies of the core were performed using the Cs-137 method, to evaluate the model of time changes in the sediment. The Cs-137 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 Cs-137 radioactivity identified with the global fallouts after atomic weapons testing and the Chernobyl mishap were observed and used to affirm the Pb-210 dating method. Radioactivity of Pb-210(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 (Cs-137) and 521.43 years (Pb-210(ex)), respectively.

Automated summary

This study presents initial information on the sedimentation rate estimation for Lake Pykara. It utilized Cs-137 and Pb-210(ex) analysis to establish a chronological sequence of sediment core, determining an average sedimentation rate of 0.71 cm year(-1) and estimated the age of the lake to be around 514.08 years to 521.43 years.