Summary
The field trip allows participants to explore the following aspects of Kathmandu Nappe geology: (1) the right-way-up metamorphic field gradient that dominates the Kathmandu synform; (2) the deformation along the Galchi shear zone separating the Sheopuri gneiss from the Bhimphedi Group, which has opposite sense of shear vs. the Main Central thrust / Mahabharat thrust; and (3) the presence of kyanite-bearing gneiss between the Galchi shear zone and the Main Central thrust / Mahabharat thrust near Galchi vs. the absence of both gneiss and the Galchi shear zone in the Main Central thrust / Mahabharat thrust hanging wall near Malekhu. These features are discussed at length in Webb et al. (2011), who use them to support a tectonic wedging model for the emplacement of the Greater Himalayan Crystalline complex (Figure 5D), with the Galchi shear zone interpreted as the South Tibet detachment. In this model, the Sheopuri gneiss is interpreted as Greater Himalayan Crystalline complex rocks, and the Bhimphedi and Phulchauki Groups are interpreted as the lower sections of the Tethyan Himalayan Sequence. We hope that the field trip provides an opportunity for happy, spirited discussion and meaningful insights on questions such as the Lesser Himalayan Crystalline Nappe problem, the development of the South Tibet detachment, and the emplacement of the Greater Himalayan Crystalline complex.