The distribution and characterization of minerals in Ponnaiyar River sediments are carried out using Fourier Transform Infrared (FTIR) spectroscopic technique. The minerals such as quartz, feldspar in different structure, kaolinite, calcite, gibbsite, montmorillonite, smectite, organic carbon and palygorskite are identified. The relative distribution of major minerals such as quartz, feldspar (orthoclase and microcline) and kaolinite are determined by calculating extinction co-efficient. From this calculation, the amount of kaolinite is very much lesser than quartz and lesser than orthoclase and microcline feldspar. The naturally occurring radionuclides (²³⁸U, ²³²Th and ⁴⁰K) and associated absorbed dose rate are determined by Gamma ray spectroscopic technique. The determined activity concentrations and average absorbed dose rate of all sites are fall within the typical world and Indian average values. Correlation analysis is carried out for distributions of quartz, feldspar (orthoclase and microcline) and kaolinite and naturally occurring radionuclides, with associated absorbed dose rate. Correlation analysis shows that the kaolinite (clay mineral) may act as a booster of level of natural radioactivity.