Integrated Remote Sensing and Petrographic Guide to Delineate the Hydrothermal Alteration Zones Along the Phyllites of the Main Zawar Fold, Rajasthan, India

This study integrates Remote Sensing data, field investigation, and petrography to analyze the Zawar Pb–Zn sulfide deposits, in the Paleoproterozoic Aravalli Supergroup rocks of NW India. Structural features of the study area are delineated using Remote Sensing and Shuttle Radar Topography Mission (SRTM) data. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data, is used to distinguish the major rock types and alteration zones. Our findings reveal that the Zawar belt is composed of phyllite, quartzite, carbonate, and, greywacke. Phyllites from the hinge of the Main Zawar Fold (MZF) provide critical insights into the distribution of monazite veins, and, support the evidence of hydrothermal alteration over the hinge area of the MZF. Textural evidence investigated by Scanning Electron Microscopic study (SEM) suggests that the monazite is of epigenetic hydrothermal origin, formed subsequently after the formation of the primary host rock. Energy Dispersive X-ray spectroscopic (EDS) study indicates that these monazites have an average composition, P₂O₅(17.85 wt.%), Ce₂O₃ 14.49, La₂O₃ 6.98, Nd₂O₃ 5.39 and ThO₂ 1.60 wt.%, suggesting its hydrothermal origin.