The γ-ray spectroscopic technique has been effectively utilized to know the activity concentrations of238U,232Th and40K in different depths of north-east coast beaches of Tamilnadu state of India. The measured activity concentrations were different while compare from surface to second feet depth. FTIR exhibits the presence of eleven minerals such as quartz, feldspar in different phases, kaolinite, gibbsite, calcite, organic carbon, aragonite, palygorskite and hematite in all feet sediments. Extinction coefficient calculation shows that the amount major minerals is in the order of kaolinite < microcline feldspar < quartz. Different minerals were identified through XRD analysis. Multivariate statistical was also adopted well and the results confirm that the magnetic susceptibility play a major role in controlling the present radioactivity values. The activity concentration of238U,232Th and40K for >125 µm grain sized samples are significantly lowered when compared with the respective values of the bulk samples. © 2023 Elsevier B.V., All rights reserved.