xrd investigation on clay minerals of the tertiary formations around panruti, cuddalore district, tamilnadu

Subramanian, P., Prabhakaran, R., Selvaraj, B., Babu. K and Kumar, R.S

The sedimentary formations of Cuddalore district are chiefly composed of tertiary and recent alluvial deposits. The Cuddalore sandstones of the tertiaries are well developed in this district and occur in two discontinuous patches in extensive areas. The formation consists of clays, sands, sandy clays and unconsolidated sandstone mottled in colour with lignite seams. Representative clay samples were collected from the tertiary formation Panruti both from the surface outcrops, nallas and working mine sites. Mineralogy was determined by XRD. The Cay mineral assemblages are present in the formations Kaolinite, Montimorillonite, Chlorite, Muscovite and illite. The non-clay minerals identified are quartz, orthoclase and siderite. The dominance of Kaolinite indicating the sediments are mostly derived from weathering of igneous rocks like Granites, Charnockites and gnessis etc. and deposited in a fresh water Continental basin.