Eocene Metamorphism and Anatexis in the Kathmandu Klippe, Central Nepal: Implications for Early Crustal Thickening and Initial Rise of the Himalaya

The continental collision between India and Asia has been ongoing since early Eocene time, but the orogenic record is typically dominated by Miocene younger deformation metamorphism that largely overprinted earlier Eocene-Oligocene events. This hinders our understanding of how crustal thickening responds to initial when Himalayan mountains initially rise. advancement spatially precise petrochronology techniques, however, provided means see through overprint enabled characterization in different parts Himalaya. current study presents new monazite paired thermobarometry from Kathmandu klippe central Nepalese These data reveal prograde (44-38 Ma) partial melting (38-35 under peak P-T conditions 730 °C–760 °C up 10.5 kbar. migmatites within equivalent Upper or Uppermost Greater Crystallines should have exhumed during Eocene-Oligocene. evidence anatexis presented herein adds a growing body detailing continent collision. mid-Eocene event indicates felsic crust was thickened depth ?35 km shortly 10–20 Myr collision, which probably responsible for topographic rise proto-mountains. Characterizing effects this orogenesis critical architecture prior better-preserved orogen may preconditioned stage.