...R. A. Frith; K. L. Currie Abstract An ancient tonalitic complex becomes migmatitic around the Lac St. Jean massif, ultimately losing its identity in the high grade metamorphic rocks surrounding the anorthosite. Field relations suggest extreme metamorphism and anatexis of tonalitic rocks...

... distinct from the closely associated, but older and much larger Lac St. Jean Complex has gone unrecognized until this time. In his compilation of worldwide occurrences of massif anorthosites, Anderson ( 1969 ) described the “Mattawa” massif (named for a prominent lake) as a small (∼200 km 2 ) pluton...

... plagioclase crystals with long dimensions of 15–30 cm and, rarely, up to 45 cm. These occur in subophitic intergrowths with both ortho- and clinopyroxene, some crystals of which qualify as “giant pyroxenes.” Emslie (1975) discussed similar giant pyroxenes from the Lac St-Jean and Morin massifs and reported...

...Manfred M. Kehlenbeck Abstract The Lac Rouvray anorthosite mass forms a part of the Lac St. Jean massif. Attempts to subdivide the Lac Rouvray mass into mappable types based on mafic mineral content and total rock textures failed. Although distinctive types can be discerned locally...

... gabbronorite, or a jotunite. The Lac St. Jean Anorthositic Suite, a term first used by ( Hébert 1997 ), encloses the Lac St. Jean Anorthosite and other felsic to intermediate intrusive rocks. This huge anorthositic massif (20 000 km 2 ) consists of several lobes formed as a result of multiple magma...

.... Cumming Magnetite-apatite intrusions and calc-alkaline magmatism, Camsell River, N.W.T .J. P. N. Badham and R. D. Morton A model for the origin of the Lac St. Jean anorthosite massif . R. A. Frith and K. L. Currie Contrasting types of bladed olivine in ultramafic rocks from the Archaean of Labrador.. K. D...

.... 1974 . Petrogenesis of metamorphic rocks . Springer Verlag , New York . Woussen G. Dimroth E. Corriveau L. Archer P. 1981 . Crystallization and emplacement of the Lac-St-Jean anorthosite massif (Québec, Canada) . Contributions to Mineralogy and Petrology , 76 : 343 – 350 . ...

... with the tectonic model presented above. Figure 2 shows the major anorthosite massifs of the northeastern Grenville Province, as well as those situated north of the Grenville Front in Labrador. Of special importance to this discussion are the Morin (1153 ± 2 Ma, Doig 1991 ) and the Lac-Saint-Jean massifs...

... C.G. Stickney D.M. Cray E.J. Jr Crustal evolution and global tectonics: A petrogenetic view Geological Society of America Bulletin 1974 85 843 858 Frith R.A. Currie K.L. A model for the origin of the Lac St Jean anorthosite massif Canadian Journal of Earth Sciences...

... 1050 and 1020 Ma ( Higgins and van Breemen 1996 ). Recent work indicates that many of the granitoids in the southeast part of the LSJAS crystallized around 1020 Ma. 4 4 C. Hebert and O. van Breemen. Age of plutonism in the eastern part of the Lac-St-Jean anorthosite suite. In preparation...

... (2001) noted that the andesine-bearing Lac Allard massif has geochemical and mineralogical similarities with the smaller andesine-bearing 1.05–1.01 Ga anorthosite bodies to the west ( i.e. , Saint-Urbain, Labrieville, etc .). Dickin (2000) included the Saint-Jean domain in his region underlain...