Environmental impact on coastal wetlands since 4 ka in Cauvery Delta: Palynology and thecamoebian study |
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Authors: | Jyoti Srivastava Anjum Farooqui |
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Institution: | 1. Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow, 226 007, India
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Abstract: | Palaeoclimate and Palaeoecological study was carried out in ~2 m sediment core deposited since 4 ka in an estuarine environment along Uppanar River mouth, Cauvery Delta. Palynological and thecamoebian evidences indicate (1) a basal fluvial lacustrine depositional environment (~4–3 ka) characterized by sandy sediment, with low salinity and dominance of non-pollen forms like foraminiferal linings and thecamoebians with a low percentage of pollen and spores and (2) an estuarine environment (since 3 ka) characterized by clayey sediment with high salinity and a good percentage of mangrove and terrestrial pollen along with non-pollen forms. A shift in the depositional environment since ~3 ka indicates monsoonal and geomorphological changes in the coastal wetland. During this period dominance of Avicennia and Cheno/Ams indicate low freshwater runoff from land suggesting a weakened monsoon condition enhanced by anthropogenic activity. |
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