Axial Plane Schistosity Research Articles

Development of Schistosity in Flexural Folds

AbstractAn example of the development of axial plane schistosity close to a buckled competent band is described. There is a difference in the degree of development of the schistosity on the convex and the concave sides of the fold arch. This is explained as due to variation in contact strain. A similar pattern has been produced experimentally and it is concluded that the axial plane schistosity in the example under consideration is a mechanical phenomenon and has developed perpendicular to the direction of maximum compressive strain.

Regional Structural Framework of the Lead-Zinc Deposits at Zawar, Rajasthan, India

Abstract The structural elements in rocks around the Zawar area have developed during three successive stages. Movements at the earliest stage are registered by northerly plunging folds-upright to 'reclined'-with steeply dipping overturned axial-plane schistosity (S2) and attendant a- and b-lineations. Striations on bedding, tension cracks in fold-arches, and occasional disharmonic character of the minor folds point to a flexure-slip origin. On these was superposed a generation of folds with contrasted style in profile and accompanying axial-plane cleavage (S8) and lineations. Off-setting of all other S-planes by the mineralized shear planes, their discordant attitude, and the incongruency of their direction of slip (recorded on their surface by striations and mineral lineations) with the regional movement plan indicate that these were the youngest structure to develop. Since the development of these structural elements (the mineralized shear zone) was broadly concurrent with metallization, these 'active' structural traps are believed to have been preferred to the earlier, relatively 'inactive' ones. Future prospecting in this mining district should, therefore, be intensified in those dolomites where this youngest set of structures have developed.