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Zoning of chloritoid from kyanite-facies metapsammites, Alpi Apuane, Italy

Published online by Cambridge University Press:  05 July 2018

M. Franceschelli  and
I. Memmi
M. Franceschelli
Affiliation:
Dipartimento di Scienze della Terra, Università di Cagliari, via Trentino, 51, 09127 Cagliari, Italy
I. Memmi
Affiliation:
Dipartimento di Scienze della Terra, Università di Siena, via delle Cerchia, 1, 53100 Siena, Italy
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Abstract

Chloritoid with significant Mg-Fe zoning occurs as lath-shaped porphyroblasts and as clusters of subradiating crystals in the Triassic Verrucano metapsammite (quartz + muscovite + chlorite + chloritoid ± kyanite) of the Massa Unit, Alpi Apuane. Two main types of chloritoid zoning profiles were found. The first type is characterised by gradual increase in Mg from core to rim of the porphyroblasts. In the second type the Mg content is constant from the core to the inner rim, but sharply decreases in the outer rim. Both types of zoning have been interpreted as the result of prograde growth during the Alpine metamorphism. The temperature, estimated using the chlorite-chloritoid thermometer, ranges from 467 to 560°C.

Keywords

chloritoidMg-Fe zoningchloritekyanite facies rocksAlpi Apuane
Type
Research Article
Information
Mineralogical Magazine , Volume 63 , Issue 1 , February 1999 , pp. 105 - 110
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1999

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