Boudinage in the Delhi Rocks Between Bhim and Todgarh, Rajasthan

Pegmatite veins of variable thickness occur in biotite schists and calc schists belonging to Delhi System between Bhim and Todgarh. Rectangular, barrel shaped, lozenge shaped, rotated and folded boudins have been observed in the pegmatite veins. The degree of competency contrast, the degree of strain and the direction of stresses seem to be the controlling factors in the development of boudinage. The thickness of the rock unit behaving homogeneously as a competent band in relation to degree of strain seems significant. Rotated and folded boudins have been attributed to later deformation. The development of boudinage has been shown to be a late feature of the deformation that resulted in F₂ folds of this area.