Dispersal pattern of clay minerals in the sediments of Nizampatnam bay, east coast of India

Abstract

Constituent minerals of the clays were (from X-ray diffraction) montmorillonite, illite, kaolinite and chlorite. Montmorillonite is the predominant mineral which constitutes > 80% of the clay minerals in most of the sediments. Illite is the next abundant mineral varying from 5-22%. Kaolinite and chlorite are least abundant with concentrations well below 10%. Lateral distribution pattern of the clay minerals shows an increase in smectite with concomitant decrease in illite and kaolinite from the coast to the shelf. A greater contribution of the clay fraction appears to have been derived from the erosion of alkaline rich rocks in the upper reaches of Krishna drainage basin.