Geomorphic evolution and genesis of laterites around the east coast of Madras, Tamil Nadu, India

Laterites and lateritic soils (Red soils) of the east coast especially around Madras, Tamil Nadu have been formed in different geomorphic conditions and on various geological deposits. They occur as caprocks over recent alluvium, Upper Gondwana sandstones and shales, and Precambrian basement rocks. The laterite profiles studied around Madras are generally 2 to 5 m thick and exposed 5 to 45 km inland from the present-day shoreline. ed analysis (micromorphological and chemical) and the bore hole litho-log data reveal that lateritisation was not continuous but occurred in phases. Lateritisation could have taken place in humid to sub-humid conditions with a rich source of iron in the parent rock and sediment and efficient internal drainage. haeological investigations and Quaternary stratigraphical studies date the lateritic crust surface to the early late Neogene. Neotectonics have played a vital role in shaping the present landscape.