Influence Of Mineralogical Composition and Diagenesis an The Engineering Properties of Sedimentary Rocks In The Western Ghats, India

Abstract

The engineering behavior of sedimentary rocks is significantly influenced by their mineralogical composition and diagenetic alterations, especially in tectonically stable yet lithologically diverse terrains like the Western Ghats of India. This study investigates the interrelationship between mineralogical constituents, diagenetic features, and fundamental engineering properties of representative sedimentary rocks—primarily sandstones and limestones—collected from selected outcrops across the Western Ghats region.

A multi-analytical approach involving X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) was employed to characterize the mineral phases, textural attributes, and diagenetic imprints such as compaction, cementation, and recrystallization. Concurrently, rock samples were subjected to porosity and density measurements, ultrasonic pulse velocity (UPV) tests, and laboratory-based permeability assessments to quantify their geomechanical response.

The results revealed that quartz-dominated sandstones exhibited higher P-wave velocities and lower porosity values, indicating enhanced elastic moduli, while clay-rich limestones with complex diagenetic signatures displayed pronounced anisotropy and reduced wave propagation characteristics. Statistical correlation analyses highlighted strong inverse relationships between porosity and P-wave velocity (R² > 0.85), and positive associations between mineralogical maturity and mechanical integrity.

These findings underscore the significance of integrating microstructural and geochemical analysis with conventional geotechnical testing for better prediction of rock performance in excavation, tunneling, and foundation engineering. The study also establishes a baseline for region-specific rock classification and performance modeling, contributing to safer and more sustainable infrastructure development in Western Ghats.