P–T–t–D paths of the North Himalayan metamorphic rocks: Implications for the Himalayan orogeny

摘要: Abstract Metamorphic P – T t D paths have been determined in the Yardoi gneiss dome of eastern Himalaya that place new constraints on genesis North Himalayan Gneiss Dome and tectonic evolution orogen. Our study shows schists from underwent at least three stages metamorphism deformation. The first stage prograde is represented by core porphyroblastic garnet, showing distinct growth compositional zoning, hosting mineral inclusions biotite, muscovite, quartz ilmenite; curved inclusion trails define deformation foliation (S1). second peak rim garnet aligned matrix minerals plagioclase, quartz, kyanite staurolite, which main (S2). third retrograde characterized occurrence muscovite sillimanite within distributed shear bands, late (S3). Phase equilibrium modeling reveals witnessed a upper amphibolite-facies under conditions 7–8 kbar 615–665 °C, records clockwise path with process both temperature pressure increase subsequent retrogression isothermal decompression. zircon U–Pb dating indicates occurred during Middle Eocene 48–36 Ma probably lasted to ca. 16 Ma. present result formation was related subduction exhumation Indian crust, initial collision Asian continents 50 Ma, northeastern margin continent shallowly underthrusted beneath continent, discontinuity Greater Sequence.