Research

Understanding the kinematic evolution of a continent-continent collisional orogen such as the Himalaya remains challenging due to structural complexities across its length. Main Central Thrust (MCT) is one of those structure whose position, timing and deformation history is very crucial in terms of Himalayan orogenesis understanding. Although different criteria have been used to demarcate this contact, very little work has been done on structural based criteria. We are studying  a detailed rheological profiling of the major structures in the study area to resolve the strain complexities and assess whether the Main Central Thrust (MCT) comprises a broad shear zone or a varying number of narrow thrust planes. This information is crucial in developing a generalized tectonic model for the exhumation of the mid-crust of Himalaya. Our analysis focuses on the deformational microstructures of quartz using optical microscopy and crystallographic preferred orientations (CPO) from a fabric analyzer to constrain active slip systems, deformation temperatures, and strain geometries across the area. So far, our results show a comparatively strong fabric at the proximity of the shear zones, reflecting high strain localization in accordance with the deformation mechanism and temperature range from microstructure analysis. Combining these results with geochronology and metamorphism pressure-temperature data will enable us to construct a thermo-kinematic profile to understand the orogenic system better. Hence, this work offers new insight into one of the most prominent structures in the orogen and the role it played during convergence accommodation processes.