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"Early partial melting" in annealed natural cordierites

Gian Carlo Capitani, Jean Claude Doukhan, Thomas Malcherek and Michael Carpenter
"Early partial melting" in annealed natural cordierites
European Journal of Mineralogy (October 2002) 14 (5): 879-890


Natural cordierite crystals with a range of Fe/Mg ratios have been annealed over a range of T between 1200 and 1430 degrees C (under controlled fO (sub 2) ), after previously being annealed at 900 degrees C to drive off any volatiles contained within their channels. TEM showed no evidence of an orthorhombic to hexagonal transformation, but all the heat-treated samples contained pervasive glassy needles [001], each including a small bubble. These became larger and less regular in shape with increase in annealing T, and are interpreted in terms of early partial melting of cordierite at T well below the macroscopic melting point. Larger glassy veins contain crystals of mullite, and in two samples annealed at approximately 1400 degrees C or below, pockets of glass with prismatic spinel crystals were seen. Chemical analysis showed that the glass phase was generally enriched in SiO (sub 2) and depleted in Al (sub 2) O (sub 3) with respect to the cordierite matrix. It is thought that these areas of more extensive melting probably occurred in regions of altered cordierite or around inclusions.

ISSN: 0935-1221
EISSN: 1617-4011
Serial Title: European Journal of Mineralogy
Serial Volume: 14
Serial Issue: 5
Title: "Early partial melting" in annealed natural cordierites
Affiliation: Universita degli Studi di Siena, Dipartimento di Scienze della Terra, Siena, Italy
Pages: 879-890
Published: 200210
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Federal Republic of Germany
References: 50
Accession Number: 2002-071650
Categories: Mineralogy of silicates
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 4 tables
Secondary Affiliation: Universite Sciences et Technologies de Lille, FRA, FranceUniversitaet Muenster, DEU, Federal Republic of GermanyUniversity of Cambridge, GBR, United Kingdom
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United KingdomTwickenhamUKUnited Kingdom
Update Code: 200222
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