Quartz grain microstructures and microscopic shear sense indicators in the outer Lesser Himalaya, Barahakshetra-Tribeni-Raighat area of Arun Valley, eastern Nepal

The outer Lesser Himalaya in eastern Nepal has gone through intense ductile shearing and recrystallization due to the emplacement of Higher Himalayan thrust sheet. It resulted formation various microstructures footwall rocks Himalaya. Present study focuses on quartz grain shear sense indicators metasedimentary interpret deformation characteristics area. Thin sections were prepared from oriented rock samples collected formations studied under petrographic microscope. occurrence diversity area manifests uneven distribution stress regime temperature conditions. Nevertheless, it suggests a progressive transition southern northern part. vicinity Dharapani Thrust represents mechanical higher strain lower Chimra Sheet exhibits mild- medium at basal section while high-temperature high-strain upper MCT.