Reconnaissance Survey of the Quaternary Geology of the Cauvery Delta

The exposed Quaternary geology of the Cauvery delta has been mapped from aerial photographs. The study has been complemented by a series of augerings in the northern part-of the delta. The grain size distribution of Holocene deposits, consisting of natural. levee complexes, backswamps, coastal ridges and low lying areas under tidal and back-water influences have been studied. With the aid of subsurface data it has been attempted to reconstruct the Post-Tertiary development of the delta. The relative chronology of the formations could be established.

Eustatic curves are discussed briefly in the context of their applicability to the Indian subcontinent and they have been used for a provisional dating of various Holocene deposits. A late Pleistocene to early Holocene transgression was followed by delta formation in the south. Subsequently the main fluvial deposition shifted towards the north. Since the Atlantic period, a series of beach ridges were formed along the coast. Transportation of sands and finer material by long shore currents has resulted in the formation of a cuspate foreland on the southern part of the delta. Three marine stages in the cuspate foreland have been correlated with fluvio-marine stages in the north.