Petrogenesis of the Labrieville alkalic anorthosite massif, Grenville Province, Quebec

Saved in:
Online Access: Get full text
doi: 10.1093/petrology/42.8.1519
Authors:Owens, Brent E.; Dymek, Robert F.
Author Affiliations:Primary:
College of William and Mary, Department of Geology, Williamsburg, VA, United States
Other:
Washington University, United States
Volume Title:Journal of Petrology
Source:Journal of Petrology, 42(8), p.1519-1546. Publisher: Oxford University Press, Oxford, United Kingdom. ISSN: 0022-3530
Publication Date:2001
Note:In English. 92 refs.; illus., incl. 6 tables, geol. sketch maps
Summary:The 1010 m.y. old Labrieville anorthosite has three zones with antiperthitic plagioclase, orthopyroxene, hemoilmenite and a little biotite throughout: 1) a foliated inner core of pink anorthosite (An30Or13), 2) a foliated outer core of pink anorthosite (An35Or10) with more abundant leucogabbro than (1), and 3) a border of foliated to massive green leucogabbro which also has clinopyroxene, magnetite and apatite. The body is more alkalic, Sr and Ba-rich, oxidized and water-bearing than most other massif anorthosites and therefore was not derived from a typical tholeiite magma. All the rocks are mixtures of cumulus minerals with negligible trapped melt. Differentiation was from the core outwards (i.e. upwards before doming of the body) with increase in plagioclase An% outward due to decline in P during crystallization. Major, trace and REE analyses of anorthosites, oxide anorthosites, leuconorites and leucogabbros are given plus EPMA of clinopyroxene, orthopyroxene, ilmenite and hematite in hemoilmenite, magnetite, plagioclase and K feldspar in antiperthite. [B.E.L.]
Sections:Petrology
Subsections:Igneous petrology
Subjects:Alkali gabbros; Anorthosite; Crystallization; Cumulates; Feldspar group; Framework silicates; Gabbros; Igneous rocks; Magmas; Plagioclase; Plutonic rocks; Silicates; Canada; Canadian Shield; Eastern Canada; Grenville Province; North America; Quebec; Labrieville Massif
Coordinates:N492000 N492000 W0700000 W0700000
Abstract Numbers:02M/2103
Record ID:2001072898
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
Tags: Add Tag
No Tags, Be the first to tag this record!