Spectroscopic Study of Hydrous Magnesium Minerals (Serpentine) from Ultramafic Rocks along the Rikhabhdev Lineament, Rajasthan, India

Abstract

Serpentine minerals, typically formed through the hydrothermal alteration of ultramafic rocks such as dunite, are commonly found in mid-ocean ridge environments and in ophiolitic complexes that have been uplifted onto continental crust, such as those present in mountain belts. This study focuses on the identification and characterization of serpentine and associated alteration products within the Rikhabdev ultramafic suite, located along the Rikhabdev lineament in the Aravalli Mountain Range, Rajasthan, India. The spectroscopic approach proves to be a powerful non-destructive tool for mineral mapping and enhances our understanding of alteration processes in ultramafic terrains. Spectral signatures of key minerals,including lizardite, chrysotile, antigorite, talc, tremolite, and dolomite,were collected and analyzed with the help of field-based reflectance spectroscopy. These spectral features were then compared with USGS reference spectra to confirm mineral identification. Serpentine has a characteristic absorption depth at 2.3µm. At the same time, other alteration products also have nearly similar wavelengths, but there is a differenceof nanometers that has been assessed through a spectroradiometer. So, this technique has the potential to detect the various serpentine minerals and alteration products. The presence of serpentine also has implications for methane release, contributing to broader geobiological and geochemical interpretations