Why are there no volcanoes in the Himalayas? Is there any basaltic or granitic rock, indicative of volcanic activity or metamorphosis, respectively? Might just a deeper subduction plate ever be descriptive for Himalayan formation, even without volcanoes? Would lack of any suitable evidence be consistent with another model for orogeny?
Not just up thrust alone, as for N. American Rocky mountains, but perhaps also an alternative model and example. Perhaps one has an ‘accordion‘ model of folded weaker continental lithosphere crust; hence consistent with greater susceptibility to landslides. Might ancient collision of continents (~1 Byr ago?), represented by Ural mountains, also be consistent with such latter model? Hence no evidence of deeper subduction, nor of volcanoes, for Ural mountains?