Geochemical Characteristics and Environmental Significance of Muttom Coastal Teri Formation, Kanyakumari District, Southern India

The Teri sands along coastal regions are distinguished by their unique red coloring. This study aims to investigate geochemical characteristics and mineralogical composition of these sediments, assess the degree of weathering in the source area, and determine the environmental factors influencing their formation. The well-sorted, finely skewed sediments reflect a fluvio-marine environment and are classified as lithic arenites or wackes. Petrographic and X-ray diffraction analyses highlight the dominance of quartz and feldspar, with accessory minerals such as rutile, ilmenite, zircon, garnet, diopside, magnetite, hematite, hypersthene, and biotite. The Chemical Index of Alteration (CIA) values suggest moderate to high weathering in the source area. The red coloration is attributed to the oxidation and leaching of iron-bearing minerals, driven by high rainfall and fluctuating groundwater levels in arid to semi-arid climates. Major oxides like SiO₂, Al₂O₃, and Fe₂O₃ are abundant, while MnO, CaO, MgO, K₂O, TiO₂, P₂O₅, and Na₂O occur in lower concentrations. Trace elements, including Cu, Cr, Ni, Zn, Sr, Ga, Rb, Ba, Y, Nb, and Pb, are present in >10 ppm, with gallium being the most concentrated. The rare earth elements (REEs) patterns show enrichment in light REEs, with a flat trend for heavy REEs, featuring a negative europium anomaly and a positive cerium anomaly. These findings suggest that the sediments originated from felsic sources, likely dating to the Post-Archean or Proterozoic era. The study provides valuable insights into the Teri sands provenance, weathering processes, and environmental conditions.