| Summary: | A garnet-bearing schist from the southernmost such exposure along the Himalaya in east central Nepal records prograde metamorphism at 32.4 ± 0.3 Ma. Phase equilibria modelling, combined with Ti-in-biotite and quartz c-axis thermometry, outline a tight-to-hairpin pressure-temperature (P-T) path extending from ~515 °C and 5.5 kbar to peak conditions at ~575 °C and 7 kbar followed by deformation during the retrograde phase at 480–515 °C and 6–7 kbar. The new geochronology data place an upper bound on the evolution of metamorphism and deformation in the frontal-most part of the Himalaya, which lasted until 17.5 Ma, as indicated by previously published 40Ar/39Ar data. The P-T-time data from this part of the Himalaya, as well as that from more hinterland-ward portions of the orogen, outline a progressive, stepwise, commonly out-of-sequence evolution. Further data from along the orogen indicates that this evolution is not a local phenomenon, but instead characterizes the tectonics of this system as a whole.
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