Palagonites of the Red Sea: A New Occurrence of Hydroxysulphate

E. Ramanaidou and Y. Noack*
Laboratoire de Pétrologie de la Surface, U.A. CNRS 721, 41 Avenue Recteur Pineau, 86022 Poitiers Cédex, France
*Present address: Lab. de Geologie Dynamique et Petrologie de la Surface, Université Aix Marseille III, F-13397 Marseille Cedex 13, France.

Abstract: Palagonites from the Red Sea consist of two zones: an orange palagonite which is a mixture of Mg-Al double hydroxide, Al-hydroxide and an undetermined Si-K phase, and a white palagonite, similar to motukoreaite, a Mg-Al hydroxy-sulphate-carbonate. This mineral, frequent in experimental alteration of glass by seawater, is discovered for the first time in natural palagonite. Hydroxysulphates and hydroxides are the precursors of phyllosilicates, generally found in palagonites. The very young palagonites of the Red Sea are the first link between the natural and experimental observations.

Keywords: palagonites • hydroxides • hydroxysulphates • Red Sea

Mineralogical Magazine; March 1987 v. 51; no. 359; p. 139-143; DOI: 10.1180/minmag.1987.051.359.15
© 1987, The Mineralogical Society
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