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TitleGeochemistry and petrogenesis of the Lapeyrère gabbronorite, south-central Grenville Province, Quebec
DownloadDownload (whole publication)
LicencePlease note the adoption of the Open Government Licence - Canada supersedes any previous licences.
AuthorNadeau, L; Brouillette, P; Bédard, J
SourceCanadian Shield/Bouclier canadien; by Geological Survey of Canada; Geological Survey of Canada, Current Research no. 1998-C, 1998 p. 179-188, https://doi.org/10.4095/209526 Open Access logo Open Access
Year1998
PublisherNatural Resources Canada
Documentserial
Lang.English
Mediapaper; on-line; digital
RelatedThis publication is contained in Geological Survey of Canada; (1998). Canadian shield, Geological Survey of Canada, Current Research no. 1998-C
File formatpdf
ProvinceQuebec
NTS31P/01SW; 31P/01NW; 31P/08SW; 31P/08NW
AreaPortneuf-Mauricie
Lat/Long WENS-72.5000 -72.2500 47.4000 47.1333
Subjectsgeochemistry; igneous and metamorphic petrology; lithology; gabbros; igneous rocks; petrographic analyses; major element analyses; trace element analyses; analyses; geochemical analyses; tectonic interpretations; Lapeyrère gabbronorite; Proterozoic
Illustrationssketch maps; analyses
Released1998 03 01
AbstractThe Lapeyrère gabbronorite is the largest of a number of post-collisional, mid-crustal gabbroic intrusions in Grenvillian terrain of the Portneuf-Mauricie region. These intrusions contain no significant amount of anorthosite and are 60-70 Ma younger than the much larger neighbouring Morin and Lac Saint-Jean anorthosite-mangerite-charnockite-granite complexes.
Whole-rock geochemistry shows unidirectional trends and large overlaps from þhornblende-free' gabbronorite to þpyroxene-free' hornblende-quartz-diorite and granodiorite, consistent with diversification from the same parent magma.
The flat distribution in heavy rare-earth elements and the low Ti/Y ratios of model liquids in equilibrium with the cumulate phases suggest extraction of gabbronorite parent magma from a shallow-mantle spinel-lherzolite reservoir, which contrasts with the deeper mantle-plume-related setting commonly invoked for anorthosite-mangerite-charnockite-granite magmatism. Partial melting in upper mantle reservoirs is consistent with intrusion of the Lapeyrère gabbronorite at the initial stage of orogenic collapse, following convective thinning of the lithospheric mantle.
GEOSCAN ID209526

 
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