Oxygen and hydrogen isotope study of minerals from metapelitic rocks, staurolite to sillimanite zones, Mica Creek, British Columbia

摘要: Oxygen and hydrogen isotope analyses have been made of coexisting quartz, ilmenite, muscovite, biotite from Late Precambrian metapelitic rocks, staurolite-kyanite to K-feldspar-muscovite-sillimanite zones, Mica Creek, British Columbia. The δ18O †D values these minerals are generally uniform do not decrease significantly with increasing metamorphic grade. This implies that there has significant infiltration deep crustal, possibly magmatic, fluids into the metapelites suggested for other high-grade terranes. uniformity oxygen compositions Creek metapelite rocks may reflect isotopic in sedimentary protolith rather than widespread exchange an isotopically homogeneous pore fluid. Temperature estimates based upon 18O thermometry samples below sillimanite zone reasonable agreement results garnet-biotite Fe–Mg thermometry. In higher grade yield which disagree by about 100°C. highest temperatures recorded thermometry, 595°C, at least 60°C minimum required phase equilibria. These discrepancies appear result pervasive equilibrium retrograde isotopes between minerals. addition, problems calibration temperatures. Retrograde be a general characteristic usually record peak if they exceed 600°C.