Studies on South Indian radioactive minerals. Part I. Samarskite from Nellore

Abstract

Samarskite, a radioactive niobotantalate occurring in the Nellore pegmatites, has been studied in detail. The investigations comprise the determination of physical and optical characters, chemical composition, autoradiographic studies, distribution pattern, calculation and interpretation of age. The available data on Nellore Samarskite has been critically examined and it has been shown that the controversy raised by Holmes concerning the age of the Eastern Ghats can be solved, if the samarskite specimen analysed by Sarkar and Sen Sarma is understood to belong to the Gaya group of minerals, as has been later suggested. A tentative Archaean succession table has also been suggested.