Non-coaxial heterogeneous deformation in the Num orthogneiss (Arun valley, Mt. Makalu area, eastern Nepal)

In the Arun and Barun valleys the upper portion of the Lesser Himalayan section is made up by the Num orthogneiss. It is a 3-4 km thick unit of granitic augen gneiss with bands of kyaniteflogopite schists (Lombardo et al. 1993). It records a noncoaxial deformation related to its involvement within the Main Central Thrust zone that produced an heterogeneous mylonitic deformation with rotated feldspar porphyroclasts, bookshelf structures and localized shear bands with a prominent top-to-the SW sense of shear. The base of the Num orthogneiss is the Main Central Thrust I.