Correlation of multiple deformation events in an area: Example from schistose rocks of Lesser Himalayas, NW Pakistan

Abstract

Integrated micro-, meso- and macro-structural investigations were carried out in the multiply deformed rocks of the Mula Gori area, northeastern Khyber Agency, Lesser Himalayas. These investigations revealed an intricate history of deformation events that have not been formerly recognised. These structural examinations show four successive deformations. These events were identified in the field as well as in oriented vertical thin sections. The first deformation event \(\hbox {D}_{1}\) is preserved in the form of inclusion trails in garnet porphyroblasts of foliation intersection axis 1 (FIA 1) and the fold axis of the macroscopic fold indicates NW–SE orogeny-oblique shortening. The \(\hbox {D}_{2 }\) event produced N–S trending foliations, fold axes and mineral lineations indicating E–W shortening. The \(\hbox {D}_{3}\) is preserved as FIA 2 in garnet porphyroblast and E–W trending foliations, mineral lineations and fold axes in the field representing N–S shortening. The \(\hbox {D}_{4}\) created NNW–SSE fabrics, which post-dates the main mantle thrust and the main boundary thrust, and likely resulted from the ENE–WSW bulk shortening related to development of the Hazara–Kashmir syntaxis.