Inclusion patterns within titanite indicate that the younger group formed following breakdown of rutile that originally coexisted with the older generation of titanite at pressures and temperatures similar to those determined from the garnet cores. 489 Ma) and breakdown to clinozoisite (c. Trace‐element systematics of the two titanite populations indicate varying co‐stability with allanite and are consistent with Th–Pb dates of allanite growth (c. Two generations of titanite are recognized on the basis of mineral morphology, chemical zoning, and U–Pb date (c. Major element thermobarometry of the garnet rims returns temperatures and pressures lower than those preserved by the garnet cores but are consistent with previous estimates of Cenozoic metamorphism in the frontal portion of Kathmandu thrust sheet. Estimation of the degree to which overstepping may have occurred, however, is complicated by uncertainty in the estimated reactive bulk compositions. Comparison of these temperatures and pressures with the results from phase equilibria modelling indicates that the garnet cores nucleated after overstepping the equilibrium garnet isograd. Combined titanium‐in‐quartz thermometry (TitaniQ) and quartz‐in‐garnet barometry (QuiG) of quartz inclusions in garnet cores yields temperatures and pressures (555–580☌, 0.89–0.91 GPa) statistically higher than those estimated for both garnet rims and secondary garnet neoblasts (535–545☌, 0.81–0.84 GPa). Quartz‐inclusion geothermobarometry of texturally and chemically zoned garnet, together with U–(Th)–Pb accessory phase petrochronology, phase equilibria modelling, and major element thermobarometry delineates two metamorphic events within the Kathmandu Complex in central Nepal. We distinguish short-time (≤14 days) from long-time (≥30 days) runs by the predominance of lozenge or prismatic crystal shapes. For run times up to 14 days, lozenge-shaped crystals dominate. (i) Number of titanite crystals per unit area with run time. (h) Etch-pits occur exclusively on planar features at the bottom and terraces in the cavities. (g) Cavities on the rutile surface (run RT14 and other long-time runs) are commonly terraced and show smaller etch-pits. (f) Prismatic crystal shape is imprinted on the rutile humps and cavities become more pronounced with run time. (e) Titanite grain coarsening with increasing run duration floral patterns are typical. No correlation between the dissolution pattern and the crystallographic orientation of the rutile is observed. Floral patterns are more pronounced, whereas linear patterns are inherited from the precursor rutile surface with striations and steps parallel to the c axis. (d) Small grain size of titanite is imprinted on the rutile surface. (c) Thirty-day run (RT14) grain shapes are dominantly prismatic due to coarsening floral patterns disappeared. (b) Seven-day run (ttn3) crystals are coarser and many are arranged in a floral pattern with several crystals radiating from a center. (a) One-day run (ttn6) the overgrowth is already complete with typical lozenge-shaped titanite crystals in random orientation. (a-c) SEM images of titanite overgrowth on rutile for different run durations (d-h) morphology of the corresponding rutile surfaces after removal of the titanite overgrowth, which mimics the titanite morphology with a hump-and-valley texture.
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