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.

Correlation of Geotechnical and Mineralogical Properties of Lithomargic Clays in Uttara Kannada Region of South India

“…The investigation also revealed the existence of iron compounds, including siderite, goethite and fayalite. Oxygen, aluminum, silicon, potassium and iron comprised most of the elements found, indicating the presence of the compounds found via XRD analysis [2]. A correlation study conducted by Bhagyashree et al [3] on lateritic soil overlying lithomargic clay layer showed that the liquid limit decreases with quartz, magnetite and hematite, whereas the plastic limit increases with corundum and anatase, remains constant with quartz and decreases with magnetite and hematite.…”

Mineralogical Analysis of Lithomargic Clay Deposits along the Coastal Belt of Uttara Kannada Region in South India

“…It also has an amorphous blend of Al2Si2O5(OH)4 [3]. The investigation into lithomargic clay along the Udupi region's coastal belt revealed abundant minerals, including quartz, feldspar (such as orthoclase), muscovite, kaolinite, dickite, gibbsite, halloysite and illite in substantial proportions [4]. This distinctive residual soil, known as lithomargic clay, displays a pinkish and whitish coloration and is predominantly composed of illite and kaolinite.…”