...Brent E. Owens; Robert F. Dymek Abstract Newly discovered orthopyroxene and clinopyroxene megacrysts (OPMs and CPMs) in the Labrieville massif provide additional constraints on megacryst origins and their significance in massif anorthosite petrogenesis. Pyroxene megacrysts (~ 1–15 cm across) occur...

...Alfred T. Anderson, Jr. Abstract The Labrieville anorthosite massif is an example of crystallization differentiation in a plutonic environment. As in other St. Urbain-type anorthosites (characterized in particular by andesine anti-perthite and hemo-ilmenite), the lithologic sequence is: anorthosite...

... subcontinental lithosphere. The lamprophyres are only slightly younger than ∼1010 Ma Labrieville massif, which is also alkalic and enriched in Sr and Ba relative to most other anorthosites. The lamprophyres provide unequivocal evidence for a Sr- and Ba-rich component in the lithospheric mantle that may have...

...Fig. 3. Total intensity aeromagnetic map of the region shown in Fig.  2 . Warm colors (red, purple) indicate high intensity; cool colors (pale green, blue) indicate lower intensity. c and b, core and border zones at Mattawa, respectively; LBV, Labrieville Anorthosite Massif; MAT, Mattawa...

... at Roseland, Virginia, and from the anorthosite massifs at Labrieville and St. Urbain, Quebec. We also present new data on oxide-apatite gabbronorites from the anorthosites at Château-Richer, Quebec, and Carthage, New York. This contribution supercedes earlier findings presented only in abstract form ( Dymek...

...) . Also shown for comparison is a field for anorthosites from the Labrieville, Québec massif ( Owens & Dymek 2001 ). Normalizing values from Boynton (1984) . The REE patterns for all samples are approximately parallel, strongly fractionated (La N /Lu N ∼ 50), and have large positive Eu...

... 1045±5 1 1020–1008 Ma: Valin Anorthositic Suite (AMCG) St. Ambroise Pluton 7 Farmer Monzonite 6 Mattawa Anorthosite 1016±3 10 Gouin Charnockite 1010±2 10 La Hache Monzonite 1010±3 10 Labrieville Alkalic Anorthositic Massif 1010–1008 11 a 1, Hébert...

... and labradorite anorthosites ( Anderson & Morin 1969 ). Massif anorthosites also differ in their silica activity and oxygen fugacity ( Hébert et al. 2005 , Morse 2006 ). Andesine anorthosites, such as Labrieville ( Owens & Dymek 2001 ), are commonly quartz-saturated, contain exsolved ferrian ilmenite...

...F ig . 1. Massif anorthosites in the Grenville and adjacent Provinces, after Davidson (2008) . Dark grey is the parautochthon, bounded to the NW by the Grenville Front, white is the Allochthonous Polycyclic Belt (APB), and light grey is the Allochthonous Monocyclic Belt (AMB). Anorthosite...

... – Saint-Urbain – Mattawa – Labrieville (CRUML) belt, Fig. 1 ] extending from Quebec City to the northeastern margin of the Lac-Saint-Jean massif. The ca. 1080–1010 Ma anorthosites of the CRUML Belt and the central Appalachians differ from the large massifs of the Adirondacks and Grenville Province...

...C. Casquet; R.J. Pankhurst; C.W. Rapela; C. Galindo; J. Dahlquist; E. Baldo; J. Saavedra; J.M. González Casado; C.M. Fanning Abstract We report the discovery of massif-type anorthosites in the Andean basement of the Western Sierras Pampeanas of Argentina. U–Pb zircon dating (by sensitive high...

.... OAGNs have been observed along the margins of the Labrieville and St. Urbain anorthosite massifs in Quebec ( Owens and Dymek, 1992 ), as well as along the margins of the Adirondack anorthosites ( Buddington, 1939 ), and as dikes and sheets in the Adirondacks ( Ashwal, 1982 ; McLelland et al., 1994...