ESTIMATION OF CHEMICAL WEATHERING OF SOURCE ROCK OF NARMADA RIVER

Abstract

Riverwater chemistry is a major sink for chemical weathering of provenance rocks and most importantly gives a feedback between dissolved load characteristics of a particular river and atmospheric water cycle. The nature of this feedback mechanism and particularly the extent upto which each component is contributing - gives a true glimpse of local lithology and general Geology there. Pre-monsoon, monsoon and post-monsoon watersamples from 20 points had been collected from the river Narmada - one of the major river in South-Western India by Gupta et al.(2010). That multiannual data has been taken and tried to make out the general trend on how the nature of the bedrock exerts a dominant control over dissolved riverine fluxes. This is carried out by using some definite parameters given by Gibbs (1970) and further calculation on already analysed riverwater samples on the basis of the method given by Garrels and Mackenzie (1997) and Harris et al.(1998). The result of the study shows that, major contribution is coming acted upon by the process of rock weathering and the percentage of carbonate dissolution that adds to the river water chemistry relative to those of the silicates and the evaporates is much greater.