Volume : VIII, Issue : VI, June - 2018

REDISTRIBUTION AND MASS CHANGE GEOCHEMISTRY DURING WEATHERING OF LATERITES FROM THE SWARNAGADDE PLATEAU, UTTAR KANNADA DISTRICT, KARNATAKA, INDIA

Rajendrakumar Budihal, Ganapathi Pujar

Abstract :

The granite/granitic gneiss weathering in Swarnagadde plateau occurs in Uttar Kannada district of Karnataka state, forming low altitude flat topped laterite hills and plateaus adjoining part of Central Western Ghats, in the western continental margin of India. The laterite samples were highly weathered with chemical index of alteration ca.98.92%, nearly complete loss of Na, Ca, Mg and K in the ferruginous/aluminous zone. The alumina content mainly occurs as gibbsite, boehmite, diaspore and secondary clay minerals (kaolinite), where as iron content mainly occurs as goethite, and hematite in aluminous and scares amount in ferruginous and lithomarge zone. Mineralogy and geochemistry study is the basis for the classification of these deposits, as aluminous laterites, ferruginous laterites and lithomargic clay. The major, trace elements, and mineralogical characteristics of laterites, these were formed in situ by the alteration of parents rocks of granite/granitic gneiss compositions. Significant depletion of base cations and Si, coupled with enrichment of Fe and Al, reveal that intense leaching of cations, kaolinization, desilication and ferruginization took place in lateritic deposits during weathering and lateritization. The study uses the geochemistry of immobile elements to trace the precursor rock of the laterite deposits and calculate the mass changes that took place during the weathering and lateritization processes. Plot of chemical data and calculation of correlation coefficients show that Al and Zr were immobile during the lateritization process and were used for mass change calculations. Mass changes were calculated from the concentration ratio of immobile elements for the different lateritic rocks and the granitic gneiss (parent). As only one linear trend is evident in the Al–Zr binary diagram and granitic gneiss coincides with this trend, on the basis of mass change and correlation coefficients analysis that the source of the Swarnagadde lateritic deposit was the underlying granitic gneiss. 

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Article: Download PDF   DOI : 10.36106/ijar  

Cite This Article:

Rajendrakumar Budihal, Ganapathi Pujar, REDISTRIBUTION AND MASS CHANGE GEOCHEMISTRY DURING WEATHERING OF LATERITES FROM THE SWARNAGADDE PLATEAU, UTTAR KANNADA DISTRICT, KARNATAKA, INDIA, INDIAN JOURNAL OF APPLIED RESEARCH : Volume-8 | Issue-6 | June-2018


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