... rocks and massif anorthosite: Problems of interpretation illustrated from the Labrieville and St-Urbain plutons, Quebec : Canadian Mineralogist , v. 30 , 163 – 190 . Owens , B.E. , and Dymek , R.F. , 1999 , A geochemical reconnaissance of the Roseland anorthosite complex, Virginia...

... ( Anderson 1963 b ) and then the Labrieville Anorthosite ( Anderson 1966 ). The Labrieville Anorthosite contains two contiguous lithological assemblages: the Lac Brûlé Dome and the Sault-aux-Cochons Complex, previously recognized and named by P.J. Goldsmith (cited in Anderson 1963 b ). This massif...

...Fig. 2. Simplified regional geologic map in the vicinity of the Mattawa and Labrieville anorthosites, based on the Carte des gîtes minéraux du Québec (Ministère de l’Énergie et des Resources de Québec 1981), Hébert et al. ( 1998 ), and our own field observations. LGC, Lac Gouin Complex; LHC, La...

... in similarly young, alkalic anorthosites in the Grenville Province of Québec ( e.g ., St-Urbain, Labrieville, Château-Richer, Mattawa). Such differences indicate that the Virginia anorthosites crystallized under low f O 2 conditions compared to their Québec counterparts, despite higher silica activity. We...

...Brent E. Owens; Paul B. Tomascak Abstract Mesoproterozoic lamprophyre dikes occur at four localities within the ∼1010 Ma Labrieville anorthosite in the Grenville Province of southern Quebec. All dikes are thin (<20 cm wide), oriented ∼N57 W, and steeply dipping. Three are biotite lamprophyres...

...F ig . 8. A) Δlog f (O 2 ) (relative to FMQ) versus fictive X Fe Opx diagram and B) silica activity versus fictive X Fe Opx showing the conditions of crystallization of anorthositic plutons in the Laramie Anorthosite Complex. Data from Frost & Lindsley (1992) , Lindsley et al...

...-à-Jack, 11. Saint Urbain, 12. Labrieville anorthosite, Havre-Saint-Pierre anorthosite suite: 13. Lac Allard massif, 14. Rivière-au-Tonnerre massif, 15. Morin anorthosite, 16. Marcy massif, 17. Lac-Bouchette gabbro-anorthosite, 18. Whitestone anorthosite. F ig . 2. Simplified geological...

... (1160–1140 Ma) de l’orogenèse Shawinigan, dans l’intervalle ca. 1200–1140 Ma. La mise en place de plusieurs autres suites de type AMCG (anorthosite – mangérite – charnockite – granite) semble associée aux stades finaux d’une orogenèse, par exemple ca. 1155 Ma pour les complexes de Morin et de Lac...

... role on the subsequent formation of AMCG (anorthosite–mangerite–charnockite–granite) complexes in that part of the province. The youngest crustal package, assembled between 1300 and 1220 Ma, is exposed in the southwestern Grenville in Ontario (Composite Arc Belt; Carr et al. 2000 ; Fig. 1...

... and van Breemen 1996 ). The outer part of this composite intrusion is chemically similar to the Astra granite. The Saint Ambroise intrusion, however, was not emplaced into an older shear zone, like the Astra granite. The post-tectonic Labrieville anorthosite complex, 50 km to the south, is slightly...

... dating of comagmatic anorthosite complexes, as shown here. Whereas no zircon was found in the anorthosites, the mafic dyke MAZ-7210 contains anhedral to globular grains and clusters of clear colourless zircon up to 250 μm in size. Cathodoluminescence (CL) imaging ( Fig. 3 ) reveals dark rims <30 μm...

... indicating a complex petrogenesis. The origin and relationship of massif anorthosite to associated rocks has been a major petrological problem despite decades of study. The Adirondack Mountains is one of the best areas to study these rocks because it contains one of the world's most abundant occurrences...