Table 2.

Compilation of Ottawan metamorphic conditions, U–Pb metamorphic ages, and 40Ar/39Ar hornblende and muscovite cooling ages in the aHP Belt

Location W→EAssemblagesEstimated P–T and time of metamorphismReferencesComments
Shawanaga domain [western HP segment]Cpx-Opx-Grt-Pl (retrograde Prg, Spl, Spr, Crn replacing Grt-Omp)U/Pb Zrn: Eclogite facies ≥1090 Ma? Granulite facies at c. 1080 Ma Amphibolite facies at c. 1020 Ma. Ar Hbl cooling age 970 MaDavidson 1990, 1998; Bussy et al. 1995; Ketchum & Krogh 1997, 1998; Ketchum et al. 1998; Reynolds et al. 1995Granulite-facies overprint associated with exhumation of HP Belt; amphibolite-facies overprint with extension on Shawanaga shear zone
Southern GFTZ and northern Britt domain [western HP segment]Grt-Hbl-Pl±Qtz±Cpx ± Opx±Bt± Ilm±MtHP granulite; 1380 MPa/870 °C. U–Pb Mnz: 1037±1, 1035±1 Ma. Ar Hbl c. 975–965 Ma; Ms c. 925–905 MaCorrigan et al. 1994; Jamieson et al. 1995Structurally beneath the ABT. Mnz dates are minimum ages for the granulite-facies metamorphism
Lac Dumoine terrane [western HP segment]Cpx-Opx-Grt-Pl (retrograde Prg, Spr, Crn replacing Grt-Omp)1350 MPa, 720 °C 1070 MaIndares & Martignole 1990a; Indares & Dunning 1997Retrograde P–T conditions
Manicouagan Imbricate Zone (Lelukuau and Tshenukutish terranes) [central HP segment]Cpx-Opx-Grt-Pl (Ky inclusions in Pl); Grt-Omp replacing igneous Ol, Px and Pl1700–1900 MPa, 750–920 °C U–Pb Zrn: 1060–1040 MaIndares 1997, 2003; Cox et al. 1998; Cox & Indares 1999a, b; Indares et al. 1998, 2000; Indares & Dunning 2004; Yang & Indares 2005Eclogite and HP granulite with coronitic and granoblastic textures. HP granulite in lithologies with low bulk Na2O. Steep retrograde dP/dT paths
Cape Caribou River Allochthon [eastern HP segment]Prg-Cpx-Opx-Grt-Pl1400 MPa, 875 °C c. 1050 Ma (U–Pb Zrn)Krauss & Rivers 2004; Cox et al. unpublishedHP granulite assemblages
  • ABT, Allochthon Boundary Thrust; Mineral abbreviations: Cpx, clinopyroxene; Crn, corundum; Grt, garnet; Hbl, hornblende; Ilm, ilmenite; Jd, jadeite; Ky, kyanite; Mnz, monazite; Ms, muscovite; Mt, magnetite; Ol, olivine; Omp, omphacite; Opx, orthopyroxene; Pl, plagioclase; Prg, pargasite; Px, pyroxene; Spl, spinel; Spr, sapphirine; Zrn, zircon.