Deerite from Ile de Groix, Brittany, France

K. Dudek and J. R. Kienast
Academy of Mining and Metallurgy, Institute of Geology and Mineral Deposits, Al. Mickiewicza 30, 30-059 Krakow, Poland
Laboratoire de Pétrologie Métamorphique, U.A.727, Universite P. et M. Curie, 4 place Jussieu, 75252 Paris Cedex 05, France

Abstract: Deerite has been found in layers of Fe-rich metasediments, metamorphosed under conditions of blueschist to eclogite facies (T = ca. 480°C). Geochemical comparisons with other deerites described in the literature show that the Ile de Groix deerites most closely resemble the Mn-poor, alpine type, and Sifnos deerites. The P-T conditions of the Ile de Groix metamorphism do not conform with the stability field of deerite. In the assemblages examined here deerite seems to be a relic from earlier stages of prograde metamorphism.

Keywords: deerite • metamorphism • Brittany • France

Mineralogical Magazine; December 1989 v. 53; no. 373; p. 603-612; DOI: 10.1180/minmag.1989.053.373.11
© 1989, The Mineralogical Society
Mineralogical Society (