Geochemical and isotopic studies Of the swarna - madisal river and Its estuary, southwest coast of India

Tripti, M (2014) Geochemical and isotopic studies Of the swarna - madisal river and Its estuary, southwest coast of India. Phd. Thesis thesis, Manipal Institute of Technology, Manipal.

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The thesis on ‘Geochemical and isotopic studies of the Swarna-Madisal River and its estuary, Southwest coast of India’ investigates the chemical weathering aspects, working of hydrological cycle and biogeochemical cycling of trace elements in the riverine and estuarine environment of the small tropical river basin, Swarna-Madisal basin, Southwest coast of India. The Swarna-Madisal river basin lies on the western part of the Western Ghats and receives higher rainfall mainly during the south-westerly summer monsoon season. The river basin is dominated by the silicate rock lithology with the Peninsular Gneiss covering the major part and the Dharwar Schists in the eastern edge of the basin. The short river length with the steep gradient particularly at the initial stage near the Ghats and higher surface runoff in the basin could support rapid transport of water and sediments to the nearby Arabian Sea. These characteristics feature the Swarna-Madisal river basin as an ideal setting to carry out chemical weathering and biogeochemical studies using advanced geochemical and isotopic tracers. Moreover, no geochemical and isotopic studies have been carried out earlier in the Swarna-Madisal river basin, even as half a million people of Udupi district use it for domestic and irrigational purposes. As large community in this region depends on freshwater of the Swarna River, the study on the geochemistry of this west flowing river becomes essential for better water management and sustainable development. With these views, the geochemical and isotopic studies have been carried out in the Swarna-Madisal river basin. Chemical weathering in river basin forms the key process to study the global climate change on a long term scale due to its association with the carbon sequestration. Water samples from the surface and sub-surface regions were collected for a period of two years to study the chemical weathering process and to quantify silicate weathering and associated carbon-dioxide consumption rates in the Swarna river basin. Physico-chemical aspects, major ion composition and radiogenic strontium isotopic ratio measured in the Swarna river water reflect the dominance of silicate rocks in the river basin. The river water chemistry is found to be least affected by the anthropogenic impact; however, the effect of evaporation is observed on few samples during the pre-monsoon. The delineation of percentage contribution from different sources shows that the dissolved major ion is mainly from the weathering sources. The chemical weathering rate (CWR), silicate weathering rate (SWR) and carbon-dioxide consumption rate (CCR) in the Swarna river

Item Type: Thesis (Phd. Thesis)
Subjects: Engineering > MIT Manipal > Civil Engineering
Depositing User: MIT Library
Date Deposited: 28 Jun 2016 14:48
Last Modified: 28 Jun 2016 14:48

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