Boudin Types, Their Morphology and Significance in Interpreting Deformational History in Proterozoic Rocks of North Delhi Fold Belt, North Western India

Abstract

The boudins can be of symmetric as well as asymmetric type and can help in determining shear sense and help unfold the deformational history, hence are important structure for recognizing the history of deformation in an area; Once the rocks of an area undergo polyphase of deformation, the boudins get modified and can no longer help in determining the deformational evidences. The present study involves identification of various types of boudins their classification and morphology as per existing status of knowledge and their role in determining the type of deformation in Neem Ka Thana belt, Proterozoic rocks of North Delhi fold belt. The study of symmetric, asymmetric and modified boudins in the area enabled the author to deduce that the rocks in above belt have suffered a ployphase deformation marked with flattening type of progressive deformation during the first phase (DF1) of deformation and the second phase (DF2) with a time gap, has produced modified boudins and folded boudin structures with the largely same axis of deformation in both these deformations.