Spectroscopic Studies (FTIR, XRD, EDX with SEM) and Elemental Analysis (XPS) on Sedimentary Rocks of Pachamalai Hills, Tamil Nadu, India

Objective: To investigate the presence of minerals and elements in sedimentary rocks of Pachamalai hills which is located in Tamil Nadu state, South India by suitable spectroscopic techniques such as FTIR, XRD, EDX with SEM and XPS. Methods: The FTIR technique has been carried out to identify the minerals and XRD analysis is made for confirmation of identified minerals. EDX with SEM used to determine the surface structure, internal morphology and superficial elemental profile. XPS technique could be used in line profiling of the elemental composition across the surface or in-depth profiling when paired with ion etching. Findings: The minerals such as Quartz, Calcite, Cristobalite, Gibbsite, Goethite, Halloysite, Hectorite, Illite, Kaolinite, Lepidocrocite, Microline Feldspar, Montmorillonite, Nacrite, Organic Compound, Palygorskite, Sepiolite, and Siderite are identified. The minerals were identified from the IR absorption band of the location of different peaks. This study demonstrates the Nature of Crystallinity, which was calculated by Crystalline Index of the Rock cementation in elevation wise from Top to Bottom are discussed. The EDX with SEM and XPS gives detailed availability of elements in the middle site of the hill. Novelty: The crystalline nature of the hills revealed in non-uniform pattern, this property randomly varies (0.63 – 1.39) in almost all the locations. Their elemental composition is measured in EDX and XPS as well. From EDX results the atomic weight percentage of elements are C – 23.43%, O – 52.24%, Na – 0.86%, Mg – 0.74%, Al – 7.29%, Si – 11.4%, S – 0.07%, K – 0.27%, Ca -1.4%, Ti – 0.11%, Fe – 2.12% and Cu – 0.08%. XPS results revealed O 1s - 58.2%, C 1s - 24.1%, Si 2p - 13.0%, Fe 2p3 – 4.8%, Mg 2s, Ca 2p, K 2p and S 2p are less than 1%. Keywords: FTIR, XRD, EDX with SEM, XPS, Nature of crystallinity