Notable Finding of Sediment Transport Mechanism of Rivers and Its Implications on Temporal Hydrodynamic Characteristics of Estuarine Core Sediments of East Coast of Tamil Nadu, India

A study investigates characteristics of sediment textures, magnetic susceptibility (χlf), frequency dependence (χfd%), and mineral assemblages at selected five core samples collected from Uppanar estuary, Cauvery estuary, Nandalar estuary, Arasalar estuary, and Vettar estuary along the east coast of Tamil Nadu, Bay of Bengal. To establish the textural characteristics, an analysis of grain size distribution was performed (mean size, sorting, skewness and kurtosis) and its hydrodynamic energy conditions; the magnetic susceptibility (χlf) profile quantifies the magnetic components; and mineral assemblage unveils the magnetic minerals of the sediment transport and accumulation characteristics at different depths of different river estuaries. The anticipated findings is worth to notice the hydrodynamic energy plots reveals the Uppanar, Cauvery, and Arasalar core profile shows an higher energy environment conditions, which is higher than the Nandalar and Vettar core sediment estuary, it suggests an higher composition of sand and silt content of the percentage of grains distribution in the sediments. The magnetic susceptibility of (χlf) profile shows Uppanar core samples showing 41.96 × 10–6 m3/kg to 94.34 × 10–6 m3/kg, with an average of 54.48 × 10–6 m3/kg; the Cauvery core samples displays 7.13 × 10–6 m3/kg to 157.39 × 10–6 m3/kg, with an average of 44.25 × 10–6 m3/kg; the Arasalar core displays 8.67 × 10–6 m3/kg to 196.57 × 10–6 m3/kg, with an average of 45.96 × 10–6 m3/kg. While the magnetic susceptibility value of Nandalar core is showing an 5.67 × 10–6 m3/kg to 33.67 × 10–6 m3/kg with an average of 13.01 × 10–6 m3/kg; and Vettar core indicates 15.77 × 10–6 m3/kg to 279.13 × 10–6 m3/kg with an average of 127.78 × 10–6 m3/kg, which is higher than that of Uppanar, Cauvery, and Arasalar estuary, it suggests an higher components of ferromagnetic minerals in the sediments. In five different cores, the sand, silt, and clay particles shows significant correlation with the low magnetic frequency (χlf), which infers that the size of the magnetic minerals are directly related to grain sizes. The magnetic mineral assemblages and sediment textures indicates the Uppanar, Cauvery core sediments having magnetite minerals, the Nandalar, and Vettar core sediments indicates maghemite, while Arasalar core sediments comprised of hematite minerals due to oxidization process, the magnetite converts to hematite in the estuarine river sediments accumulations. The χlf/fd value shows the magnetic sediment trap zones at a particular depth of all the core profile in the river estuaries. Therefore, the findings of this study suggest that relation of hydrodynamic characteristics and environmental magnetic studies can possibly applied as an efficient way for monitoring and assessing the sediments nature on a qualitative level.