Geology, Petrography and Structural Analysis of Precambrian Rocks near the village Maruwas, Northwest of Udaipur (Rajasthan)

ABSTRACT The Aravalli Supergroup in the Maruwas area, located to the northwest of Udaipur, preserves a comprehensive record of progressive structural changes and greenschist facies metamorphism. In-depth structural studies at both mesoscopic and microscopic levels identify three distinct deformation phases (AF1, AF2, AF3). A detailed analysis of the fold geometry in selected quartz-vein layers using arc-length, orthogonal-thickness, and dip-isogon methods suggests that both AF1 and AF2 folds were formed through buckle-initiated folding, which was later altered by flattening, resulting in Class 1B hinge shapes and Class 1C limb forms. Strain estimates, calculated using √(λ2/ λ1), vary between 0.1 and 0.6 for AF 1 folds and 0.1 to 1.0 for AF2 folds, indicating a heterogeneous distribution of strain influenced by viscosity differences between quartz veins and schist layers. Petrographic observations, including syn-tectonic garnet, biotite overgrowths and retrograde chlorite, indicate a polymetamorphic history under greenschist-facies conditions. The integration of structural geometry, strain data and metamorphic assemblages provides new insights into mechanical stratification and progressive deformation associated with the Aravalli Orogeny.