Clay mineralogy

The sedimentary rocks of Garudamangalam formation consisting two members viz., lower Kulakkanatham and upper Anaipadi are exposed around Perambalur town in Perambalur District, Tamilnadu. These rocks have been studied for petrofacies variation, geochemistry, clay mineralogy, sedimentology and reconstruction of depositional environment based on field and laboratory analyses. Based on lithological analysis an updated lithostratigraphy is worked out along ten systematic traverses. The detailed petrographic study resulted in identifying six clastic dominated petrographic types among arenites and wackes, and nineteen carbonate rich sub-types among wackestone, packstone, grainstone and mudstone of the Garudamangalam formation. The textural characteristics of sandstone have been studied by using the parameters like mean, standard deviation, skewness and kurtosis. The clay mineral studies were carried out by using XRD, IR-Spectra and DTA/TGA analyses. The major minerals identified in the study area clays are Kaolinite together with small amounts of illite and muscovite. The non-clay mineral impurities are identified as quartz and orthoclase.