Mineralogical Characterization of Lithomargic Clay Deposits along the Coastal Belt of Udupi Region of South India

Abstract

Lithomargic clay is generally found below the lateritic soil along the coastal belt of Karnataka. It is rich in silt content and dispersive in nature. This type of soil is liable to erosion and landslides. The lithomargic clay is largely found in the western coast of South India. At present, coastal belt of Udupi district is witnessing a lot of developments in terms of industry, infrastructures, and other activities. Lithomargic clay is a type of problematic soil, which needs a thorough study to make it suitable to sustain any engineering structure such as buildings, pavements, railways, dams. A characterization and mineralogical study is conducted to identify the presence of minerals and compounds for the various soil samples collected along the coastal belt of Udupi regions using X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM) analysis. The primary minerals observed in majority of the regions are quartz, feldspar such as orthoclase, muscovite, and the secondary minerals formed by the decomposition and chemical alteration of primary minerals include sheet minerals such as kaolinite, halloysite, dickite, gibbsite, and illite in high proportions. The study also shows the presence of iron compounds such as fayalite, goethite, and siderite. The majority of the elements observed are oxygen, silicates, aluminum, potassium, and iron which confirms the presence of the compounds identified through XRD analysis.