A geological journey through the deepest gorge on Earth: the Kali Gandaki valley section, central Nepal

Rodolfo Carosi, L. Gemignanni, L. Godin, S. Iaccarino, K. P. Larson, C. Montomoli, and Santa Man Rai

The Kali Gandaki valley in Central Himalaya is the deepest canyon in the world bounded by the eight thousands Annapurna and Dhaulagiri massifs. It offers an invaluable opportunity to directly observe a cross section of the continental crust involved in the Himalayan orogeny. Moreover the North-South trend of the valley cross cuts the major tectonic units of the Himlayas from the Lesser Himalaya, the Greater Himalayan Sequence (GHS) and the Tibetan Sedimentary Sequence. The valley is easily accessible compared to many other sections throught the belt. We propose a one week itinerary starting from the very-low grade Proterozoic quartzites of the Lesser Himalaya to the South, reaching the Cretaceous sequence of the Tibetan Sedimentary Sequence to the North, crossing all the crystalline unit (GHS) with evidence of repeated partial melting both as the meso- and the nano-scale. The major tectonic faults/shear zones such as the Main Central Thrust and the South Tibetan Detachment are well-observable along the section as well as some other important shear zone within the GHS (i.e. Kalopani shear zone). The section offers also a spectacular view both mesoscopic and large-scale deformation affecting the three main tectonic units with particular emphasis to the km-scale north-verging folds in the Tibetan Sedimentary Sequence.

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