Hostname: page-component-cd9895bd7-7cvxr Total loading time: 0 Render date: 2024-12-27T05:44:15.803Z Has data issue: false hasContentIssue false
  • English
  • Français

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
Get access Rights & Permissions [Opens in a new window]

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

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Ashworth, J.R. and Evirgen, M.M. (1984) Mineral chemistry of regional chloritoid assemblages in the chlorite zone, Lycian nappes, south west Turkey. Mineral. Mag., 48, 159–65.CrossRefGoogle Scholar
Berman, R.G. (1988) Internally consistent thermodynimic data for minerals in the system SiO2-K2O-Na2O- Fe2O3-TiO2-Al2O3-FeO-MgO-K2O-H2O-CO2 . J. Petrol., 2, 445–522.CrossRefGoogle Scholar
Cardaci, N. (1987) Metamorpfismo Alpino e Pre-Alpino nella Toscanide II (Unità di Massa). Thesis, University of Pisa, Italy.Google Scholar
Carmignani, L. and Kligfield, R. (1990) Crustal extension in the Northern Apennines: the transition from compression to extension in the Alpi Apuane core complex. Tectonics, 9, 1275–303.CrossRefGoogle Scholar
Chopin, C., Seidel, E., Theye, T., Ferraris, G., Ivaldi, G. and Catti, M. (1992) Magnesiochloritoid, and the Mg-Fe series in the chloritoid group. Eur. J. Mineral., 4, 67–5.CrossRefGoogle Scholar
Cruickshank, R.D. and Ghent, E.D. (1978) Chloritoid- bearing rocks of the Horsethief Creek Group, southeastern British Columbia. Contrib. Mineral. Petrol., 65, 333–9.CrossRefGoogle Scholar
Franceschelli, M., Leoni, L., Memmi, I. and Puxeddu, M. (1986 a) Regional distribution of Al-silicates and metamorphic zonation in the low-grade Verrucano metasediments from the Northern Apennines, Italy. J. Metam. Geol., 4, 309–21.CrossRefGoogle Scholar
Franceschelli, M., Mellini, M., Memmi, I. and Ricci, C.A. (1986 b) Fine-scale chlorite muscovite associa-tion in low grade metapelites from Nurra (SW Sardinia) and the possible misidentification of metamorphic vermiculite. Contrib. Mineral. Petrol., 93, 137–43.CrossRefGoogle Scholar
Franceschelli, M., Memmi, I., Carcangiu, G. and Gianelli, G. (1997) Prograde and retrograde chlor-itoid zoning in low temperature metamorphism, Alpi Apuane, Italy. Schweiz. Mineral. Petrog. Mitt., 77, 43–52.Google Scholar
Ghent, E.D., Stout, M.Z., Black, P.M. and Brothers, R.N. (1987) Chloritoid-bearing rocks associated with blueschists and eclogites, northern New Caledonia. J. Metam. Geol., 5, 239–54.CrossRefGoogle Scholar
Vidal, O., Goffé, B. and Theye, T. (1992) Experimental study of the stability of sudoite and magnesiocar-pholite of a new petrogenetic grid for the system FeO-MgO-Al2O3-SiO2-H2O. J. Metam. Geol., 10, 72–81.CrossRefGoogle Scholar
Vidal, O., Goffé, B., Bousquet, R. and Parra, T. (1998) Calibration and testing of an Empirical chloritoid- chlorite Mg-Fe exchange thermometer and thermodynamic data for daphnite. J. Metam. Geol., (in press).CrossRefGoogle Scholar