Cordierite growth textures and the conditions of genesis and emplacement of crustal granitic magmas; the Velay granite complex (Massif Central, France)

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doi: 10.1093/petrology/40.9.1425
Authors:Barbey, P.; Marignac, C.; Montel, J. M.; Macaudière, J.; Gasquet, D.; Jabbori, J.
Author Affiliations:Primary:
Université Henri Poincare, Nancy, France
Other:
Institut National Polytechnique de Lorraine, France
Volume Title:Journal of Petrology
Source:Journal of Petrology, 40(9), p.1425-1441. Publisher: Clarendon Press, Oxford, United Kingdom. ISSN: 0022-3530
Publication Date:1999
Note:In English. 56 refs.; illus., incl. 1 table, geol. sketch map
Summary:The Velay migmatites and granites contain three types of cordierite, all grown above the granite solidus: 1) anhedral on older biotite-sillimanite melanosomes, 2) prismatic cordierite, 3) cordierite-quartz aggregates. Prismatic cordierite formed from equilibrium biotite dehydration under low-P (peritectic and possibly cotectic cordierite) as crustal melts formed from metamorphic rocks. Cordierite-quartz aggregates overprinting the fabric formed from earlier biotite-bearing assemblages. Phase relationships favour two coupled reactions, one breaking down biotite in the presence of melt and the other dissolving feldspars, releasing Al and producing quartz, the aggregates resulting from diffusion-controlled growth at the melt interface in granites and migmatites. Cordierite formation favours en masse ascent of the whole granite-migmatite complex which led to a diapir. Major, trace and REE analyses of cordierite-quartz aggregates and their host granites and EPMA results for cordierites are given. [B.E.L.]
Sections:Mineral data
Subsections:Silicates
Subjects:Cordierite; Crust; Crystal growth; Emplacement; Granites; Igneous rocks; Magmas; Metamorphic rocks; Migmatites; Plutonic rocks; Ring silicates; Silicates; Textures; Central Massif; Europe; France; Haute-Loire France; Velay; Western Europe; Velay Complex
Coordinates:N445500 N451500 E0043000 E0030000
Abstract Numbers:00M/1930
Record ID:1999055592
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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