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Calcium-free pumpellyite, a new synthetic hydrous Mg–Al-silicate formed at high pressures

Naturevolume 321pages510511 (1986) | Download Citation



The mineral pumpellyite, W4X2Y4Z6O(20+t) (OH)(8−t) where W = Ca, Mn; X = (Mg, Fe2+, Mn)2−t (Fe3+, Al)t; Y = Fe3+, Al; Z = Si (ref. 1) is a well-known constituent of very low-grade metamorphic rocks, especially of metabasic compositions. Schiffmann and Liou2 have synthesized the ideal Fe-free endmember ‘Mg–-Al’ pumpellyite', Ca4MgAl5Si6O21(OH)7, and found its upper thermal stability to lie near 375–400 °C in the range of 5–8 kbar water pressure. Here we report the high-pressure synthesis of a pumpellyite-type phase in which the position W of the above formula is solely occupied by magnesium. This ‘Mg–Mg–Al pumpellyite’, which is chemically nearly equivalent to pyrope+H2O, crystallizes at 40–55 kbar, 700–850 °C. Therefore, it qualifies as a potential hydrous mantle phase in a subduction zone regime.

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  1. 1

    Coombs, D. S., Nakamura, Y. & Vuagnat, M. J. Petrol. 17, 440–471 (1976).

  2. 2

    Schiffman, P. & Liou, J. G. J. Petrol. 21, 441–474 (1980).

  3. 3

    Schreyer, W., Baller, T. & Chopin, C. Terra cognita 5, 327 (1985).

  4. 4

    Galli, E. & Alberti, A. Acta crystallogr. B25, 2276–2281 (1969).

  5. 5

    Yoshiasa, A. & Matsumoto, T. Am. Miner. 70, 1011–1019 (1985).

  6. 6

    Hölscher, A., Schreyer, W. & Lattard, D. Contr. Miner. Petrol. 92, 113–127 (1986).

  7. 7

    Chopin, C. Contr. Miner. Petrol. 86, 107–118 (1984).

  8. 8

    Ringwood, A. & Major, A. Earth planet. Sci. Lett. 2, 130–133 (1967).

  9. 9

    Yamamoto, K. & Akimoto, S. Am. J. Sci. 277, 288–312 (1977).

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  1. Institut für Mineralogie, Ruhr-Universität Bochum, D-4630, Bochum, FRG

    • W. Schreyer
    • , W. V. Maresch
    • , O. Medenbach
    •  & T. Baller


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