D. S. Suresh Babu

Heavy mineral distribution and characterisation of ilmenite of Kayamkulam — thothapally Barrier Island, southwest coast of India

Mineral concentration and ilmenite characterization of the Thothapally — Kayamkulam Barrier Island of the southern Kerala has been studied. 96.86% concentrations of heavy minerals are recorded in the surficial and core samples (4 m) in the southern Kayamkulam and northern Thothapally areas. The total heavy mineral content decreases with depth. The primary heavy mineral suite of the surficial and core samples consists of ilmenite, sillimanite, zircon, garnets, rutile, monazite and magnetite. Longshore current and onshore-offshore movements of sediment during the southwest monsoon are primarily responsible in sorting of the heavy minerals. TiO2 content in ilmenite is significantly higher in the Kayamkulam core sediments than the surface samples. XRD analysis supports intensive weathering and alteration leading to the higher TiO2 concentration. Higher percentage of ferric iron than ferrous iron in the core samples reveals that considerable weathering occurred under burial condition. SEM examination of ilmenite grains reveal the presence of solution pit, chemical leaching, corrosion and replacement textures, supporting the intense epigenetic alteration and weathering under subaerial condition and post-depositional changes by water-table condition.

Textural Characteristics of Surface and Core Sediments of Ilmenite-Enriched Coasts of Southwest, India

Sediment samples from the foreshore and backshore regions between Thottappally and Kayamkulam, (Thottappally – Trikkunnapuzha = Northern; Trikkunnapuzha – Arattupuzha = Central; Arattupuzha – Kayamkulam = Southern), which are enriched with heavy minerals, were subjected to detailed textural evaluation. Through frequency curves, bivariate and CM pattern, the textual characteristics of black sand deposits have been brought out and their provenance has been discussed. Beach sands of the study area mainly comprise fine sand, moderately well- to well-sorted, with near symmetrical skewness in all three sectors. Kurtosis is platykurtic in the northern sector, whereas mesokuritic sediments in the central and southern sectors show a characteristic playtkuritc nature. In the Trikkunnapuzha – Arattupuzha and Aratupuzha – Kayamkulam sectors, sediments are mesokurtic to platykurtic, which shows that low energy conditions and high wave energy conditions must have prevailed. Sediment transportation is mainly by saltation. The bivariate textural plots indicate beach and inland involvement for these sediments. The CM pattern also indicates that the sources for the sediment deposition in the study area were beach with the influence of fluvial and high-energy waves.

A terrain evaluation using remote sensing and gis—case study of neyyar wild life sanctuary, Kerala

A multi-thematic analysis based on different physical factors has been adopted to generate integrated maps on erosion proneness as well as on critical slope under a GIS platform for terrain evaluation. This spatial data on erosion proneness has demonstrated that 17.62 km2 area, out of the 140 km2 in the catchment zone, needs careful attention for ecorestoration. In the critical slope map four land stability classes have been demarcated. The area represented as Unstable and Moderately-stable is found to be important for slope stability problems. Temporal change in the drainage network over a period of four decades as well as the extent of loss in the perennial status of tributaries have been recorded to evaluate the landform changes. A catchment treatment plan has also been suggested.

An assessment of the merits of remote sensing techniques for environmental mapping: A case study from Kerala

For a proper analysis of any ecosystem and the assessment of environment impact on it, the bearing of data on distribution properties and characteristics of land-form, water, vegetation, soil and rock and even of the typology of cultural pattern are to be evaluated on the basis of the everchanging anthropogenic involvement. The extent to which the techniques of Remote Sensing alone could attain this is yet to be ascertained. The direct method for this would be to conduct the resource surveys of specific regions exclusively and separately by remote sensing as well as by field-studies and then compare the results. An extract of a major study pursued in this line in the Coastal Zone of Kerala, India has indicated an authenticity of about seventy percent through remote sensing. Weighing on the comparative time factor involved, the procedure of mapping through remore sensing alone may be advocated.