Luminescence chronology of Paleoflood deposits in lower Cauvery Basin, Tamil Nadu

Behera, Diptimayee (2018) Luminescence chronology of Paleoflood deposits in lower Cauvery Basin, Tamil Nadu. Masters thesis, Indian Institute of Science Education and Research Kolkata.

PDF (MS dissertation of Diptimayee Behera (13MS021)) 13MS021.pdf - Submitted Version Restricted to Repository staff only Download (6MB)

Abstract

The study relates the fluvial system developed around the Kaveri Basin to the past climatic events. Many flood units were observed during the study carried out in the Lower Kaveri River and its major tributary, River Amravati in the form of slack water deposits and natural levees deposits. The river is a monsoon fed river and Indian Winter Monsoon (IWM) is the major contributor of precipitation in this region. Studying these paleoflood deposits can help us reconstruct the past climatic conditions and variability and relate it to the recent conditions. Luminescence dating is a very widely used technique for dating quaternary deposits. This method was applied in our study to obtain the chronological information of the paleoflood records. This dating technique might suffer from partial bleaching for very young sediments, especially for fluvial deposits because of the depositional environment and the transportation distance. Various age models were applied to get the closest estimation of depositional age for samples with such phenomenon of partial bleaching. Findings suggest that a major shift in the global climatic events left behind a remarkable signature on the fluvial deposits, especially for river systems whose discharge is majorly dependent on the amount of precipitation for a particular period of time. Studies suggest that flood frequency was higher during the 100 to 200 years, 600 to 800years and 2000 to 3000 years before present suggesting an increased frequency of flood during the transition from Medival Warm Period( MWP) to Little Ice Age (LIA) and retreating of the Inter Tropical Convergence Zone (ITCZ) southward of the equator.

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