| Title | SHRIMP U-Pb zircon geochronology of the Bondy gneiss complex: evidence for circa 1.39 Ga arc magmatism and polyphase Grenvillian metamorphism in the Central Metasedimentary Belt, Grenville Province,
Québec |
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| Author | Wodicka, N ;
Corriveau, L; Stern, R A |
| Source | Proterozoic tectonic evolution of the Grenville orogen in North America; by Tollo, R P (ed.); Corriveau, L (ed.); McLelland, J (ed.); Bartholomew, M J (ed.); Geological Society of America, Memoir vol. 197, 2004 p. 243-266, https://doi.org/10.1130/0-8137-1197-5.243 |
| Year | 2004 |
| Alt Series | Geological Survey of Canada, Contribution Series 2002111 |
| Publisher | Geological Society of America |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Province | Quebec |
| NTS | 31F/01; 31F/08; 31F/09; 31F/16; 31G; 31J; 31K/01; 31K/08; 31K/09; 31K/16; 31N/01; 31N/08; 31O/01; 31O/02; 31O/03; 31O/04; 31O/05; 31O/06; 31O/07; 31O/08 |
| Area | western Quebec; Ottawa River; Hull-Gatineau |
| Lat/Long WENS | -76.5000 -74.0000 47.5000 45.0000 |
| Subjects | general geology; geochemistry; geochronology; igneous and metamorphic petrology; structural geology; gneisses; plutons; hydrothermal systems; metasedimentary rocks; zircon; Archean; tonalites;
metamorphism; magmatic arcs; volcanic rocks; volcanic-sedimentary belts; uranium lead dates; uranium lead dating; neodymium; Central Metasedimentary Belt |
| Illustrations | location maps; geological sketch maps; tables; photomicrographs; Concordia diagrams |
| Released | 2004 01 01 |
| Abstract | We report sensitive high-resolution ion microprobe (SHRIMP) U-Pb zircon ages from high-grade gneisses of the Bondy gneiss complex, a volcano-plutonic arc and back-arc edifice hosting a Cu-Au-Fe oxides
hydrothermal system in the Central Metasedimentary Belt, Grenville Province, Québec. Samples of quartzofeldspathic gneiss gave broadly similar results, with zircon cores indicating ages between 1.59 and 1.21 Ga and mantles or whole new zircon
crystals giving Grenvillian metamorphic ages. A few analyses indicate minor involvement of Paleoproterozoic and Archean crustal material. Zircon cores are interpreted to have grown during crystallization of the quartzofeldspathic gneiss protoliths,
but precise ages could not be determined for any of the samples. The spread of ages is attributed mainly to isotopic disturbance owing to hydrothermal alteration, high-pressure-temperature (P-T) metamorphism, and/or recent Pb loss. Only a sample of
tonalitic gneiss yielded a well-defined, igneous crystallization age of 1386 ± 10 Ma. Younger zircons from the dated lithologies provide evidence for two episodes of Grenvillian metamorphism: a period of high-P-T granulite-facies metamorphism and
partial melting at 1.21–1.18 Ga, and a younger, albeit localized, metamorphic overprint at ca. 1.15–1.13 Ga.
The new SHRIMP U-Pb data indicate that the composite volcano-plutonic edifice likely formed, at least in part, at ca. 1.39 Ga. Together
with recently published geochemical and Nd data, the new data (1) extend the known distribution of ca. 1.39 Ga arc-related magmatism in the Grenville Province, and (2) suggest that a major portion of the source region to the Bondy gneiss complex was
produced by the addition of voluminous juvenile Mesoproterozoic material. |
| GEOSCAN ID | 213636 |
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