Characterization of Secondary Laterite Profiles

Abstract

This section minutely analysed the profiles of low-level or ex situ laterites which separate the lithological formations of Archaean, Gondwana , and Tertiary gravels from the Sijua and Chuchura Formations (Quaternary Alluvium) deposited over the shelf zone of Bengal Basin between Pliocene and Pleistocene. The secondary laterites are specifically found as the dissected interfluves in Rampurhat, Illambazar, Bolpur, Kanksa, Ausgram, Bishnupur, Garhbeta, and Kharagpur through the variations of horizons are still observed. The presence of a subsurface layer of kaolinitic clay reddened from above by ferro-colloids and of rounded pebbles of different rocks, gravelly appearance of crust and the general absence of conventional horizons of laterite signify a detrital origin (ex situ) in Rarh Plain.