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Fe-Mg solid solution of sursassite, (Fe,Mg) (sub 4) (Mg,Fe,Al) (sub 2) Al (sub 4) [Si (sub 6) O (sub 21) /(OH) (sub 7) ]

Bernd Wunder and Matthias Gottschalk
Fe-Mg solid solution of sursassite, (Fe,Mg) (sub 4) (Mg,Fe,Al) (sub 2) Al (sub 4) [Si (sub 6) O (sub 21) /(OH) (sub 7) ]
European Journal of Mineralogy (June 2002) 14 (3): 575-580


Sursassites (Fe,Mg) (sub 4) (Mg,Al,Fe) (sub 2) Al (sub 4) [Si (sub 6) O (sub 21) /(OH) (sub 7) ] have been synthesized along the Mg-Fe join at 4.0-5.0 GPa, 600-650 degrees C and at f (sub O2) defined by the iron-wuestite buffer using gels as starting materials. (Fe,Mg)-sursassites have been investigated by scanning electron microscopy, X-ray powder diffraction, and electron microprobe. Pure Fe-sursassite of the composition (Fe) (sub 4) (Fe (sub 0.55) Al (sub 1.45) )Al (sub 4) [Si (sub 6) O (sub 21.45) /(OH) (sub 6.55) ] formed as an almost single-phase product at 4.0 GPa, 650 degrees C. The cell-dimensions of Fesursassite are a = 8.627(2) Aa, b = 5.736(1) Aa, c = 9.704(3) Aa, beta = 108.73(2) degrees , V = 454.8(2) Aa (super 3) . We assume that in comparison to Mg-sursassite, Fe-bearing sursassites might be stable towards lower pressures, indicating that Fe-bearing sursassite is probably more important as a host of water than the Mg-endmember within subducting slabs. This would provide a mechanism for the transport of water into the mantle for metapelitic and metabasaltic compositions. The assemblage Fe-chloritoid + ferrosilite + Fe-staurolite formed at 3.5 GPa, 600 degrees C from the Mg-free gel. Although not verified by equilibrium experiments, the stability of Fe-sursassite might be limited by this assemblage towards lower pressures.

ISSN: 0935-1221
EISSN: 1617-4011
Serial Title: European Journal of Mineralogy
Serial Volume: 14
Serial Issue: 3
Title: Fe-Mg solid solution of sursassite, (Fe,Mg) (sub 4) (Mg,Fe,Al) (sub 2) Al (sub 4) [Si (sub 6) O (sub 21) /(OH) (sub 7) ]
Affiliation: GeoForschungsZentrum Potsdam, Potsdam, Federal Republic of Germany
Pages: 575-580
Published: 200206
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Federal Republic of Germany
References: 18
Accession Number: 2002-047659
Categories: General geophysics
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 3 tables
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 200216
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