Evaluation of the Holocene environmental changes of the southwest coast, India: Apalaeopalynological approach

Abstract

The climatic variability and the influence of temperature and sea level fluctuations on the earth's surface configuration during the Holocene are being discussed all over the world. The present study evaluates the palaeo-environmental conditions of western coast of India during this epoch through the analysis of pollen grains embedded in a carbonaceous clay formation (≅ 0.4-0.6 m) found sandwiched within the palaeodeposit of sand of Meenachil River basin. The carbon dating revealed that the clay formation has an age of 5786 ± 94 14C yr BP, while the embedded wood samples have the age varying in between 2888 ± 78 and 5780 ± 95 14C yr BP. The overall analysis suggests that the southwestern margin of India had experienced high intensity rainfall during the earlier part of the Atlantic chronozone due to then strengthened Asiatic monsoon, while water stagnation and hydrological modifications were observed during the later part. The dominance of weeds and lesser number of tree elements suggested a drier climate during the end of the Atlantic period. Besides, the morphometric rearrangement of the Meenachil River contemporaneous to the geomorphological modifications of the southwestern coast of India shall be classified into three categories: (1) Pre-Vembanad Lake formation, (2) Contemporaneous to lake formation and (3) Post-Lake formation. © Indian Academy of Sciences.