Tafoni along the east coast, Chennai to Mamallapuram, Tamil Nadu

A study on weathering pits called tafoni was carried out on rock surfaces that age from a few hundreds to millions of years along the east coast between Chennai and Mamallapuram. Tafoni of varying sizes and shapes such as simple circular dots to oblate to prolate, hemispherical to spherical are formed on the granite, granite gneiss, charnockites (acid and mafic) and sandstone both on exposed and inner wall surfaces. In this study, their formation is related to not only tropical weathering processes, but also to sea salt water splays causing salt mineral etching, weathering processes, besides microbial activity, algal and lichen growth accentuating their formation.