Computer Science
Scientific paper
Dec 1993
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1993e%26psl.120..177m&link_type=abstract
Earth and Planetary Science Letters (ISSN 0012-821X), vol. 120, no. 3-4, p. 177-185
Computer Science
7
Abundance, Calcium, Garnets, Metamorphism (Geology), Sediments, Canada, Mineralogy, Pressure Effects, Temperature Effects
Scientific paper
In the central part of the Grenville Province, Proterozoic metasediments of the Reservoir Cabonga Terrane are underlain by gently dipping Archean migmatites. A major mylonite zone, located within the migmatites, is the base of a large thrust sheet made up of the Reservoir Cabonga Terrane and a migmatitic sole. Garnets from meta-aluminous assemblages in Proterozoic metasediments, mylonites and migmatites display contrasting types of Ca zoning patterns. Garnets with Ca-rich cores are found along the western edge of the Reservoir Cabonga Terrane, whereas garnets with flat Ca profiles are found in the remaining Proterozoic metapelites, in the mylonites and in the Archean migmatites. Considering samples in which an infinite reservoir of Ca ions is warranted by abundant plagioclase in the matrix, pressures well in excess of 1200 MPa, at temperatures between 700 and 800 C are indicated for a metamorphic event recorded in the cores of garnets from the western edge of the Reservoir Cabonga Terrane. The inner rim of garnet records pressures of around 1000 MPa for the same temperature range. In homogeneous garnets, a single P-T set, around 800 MPa and 750 C, is recorded in the migmatites. Some of the mylonites initiate their crystallization under relatively high pressures, which is continued during decompression, and record the lowest P-T values. These metamorphic signatures suggest that the Proterozoic metapelites were already metamorphosed under relatively high pressure when emplaced on to Archean migmatites and that the entire area was subsequently subjected to metamorphism at a lower pressure.
Martignole J.
Pouget P.
No associations
LandOfFree
Contrasting zoning profiles in high-grade garnets: Evidence for the allochthonous nature of a Grenville province terrane does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Contrasting zoning profiles in high-grade garnets: Evidence for the allochthonous nature of a Grenville province terrane, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Contrasting zoning profiles in high-grade garnets: Evidence for the allochthonous nature of a Grenville province terrane will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-786101