Structural Studies Around Kathar, Udaipur Rajasthan

Abstract The deceptively simple map pattern of quartzite, marble, and phyllite and mica schist, with nearly NS 'generalized strike' and steep dips of beds around Kathar in the Udaipur district, Rajasthan, conceals folds of two generations in large scale and structures of two additional phases in smaller scales. The folds of the first set (F1) are isoclinal with a pervasive axial plane cleavage (S1), which has largely blurred stratification in the more schistose rocks. These are buckle folds modified extensively by flattening. The S1 cleavage and F1 axial planes have been involved in tight to isoclinal upright folding on nearly NS-striking axial planes (F2). These folds have extensively reoriented the F1 axes and axial planes, but because of the style and orientation of the folds of the two systems, both the sets of axial planes have subparallel strikes in a major part of the area. Hook-shaped folds with double closures and orthogonal relation of stratification and S1 cleavage point to the presence of F1 folds. The F2 folds are also flattened parallel folds formed by a maximum compressive strain in a horizontal EW direction. Rare F3 folds with subhorizontal axial planes are gravity-induced. The F4 kinks with WNW-striking axial planes may represent structures formed by longitudinal shortening in the last stage of deformation.