Occurrence of Thaumasite in a Seawater-Basalt Interaction, Mururoa Atoll (French Polynesia, South Pacific)

Y. Noack
Lab. de Pétrologie de la Surface, 40 Avenue du Recteur Pineau, 86022 Poitiers Cédex, France

Abstract: The first occurrence of thaumasite resulting from seawater-basalt interaction has been discovered in a drill hole on Mururoa atoll (French Polynesia, South Pacific). This sulphate-carbonate-silicate is associated with zeolites (phillipsite, chabazite, gmelinite), apophyllite, analcime, and gyrolite. In this environment thaumasite can be considered as the last mineral of an alteration sequence. It crystallized from a Ca-SO3-CO2-rich and Al-Na-K-poor fluid. The temperature of this solution is unknown, but was probably not greater than 100°C.

Mineralogical Magazine; March 1983 v. 47; no. 342; p. 47-50; DOI: 10.1180/minmag.1983.047.342.08
© 1983, The Mineralogical Society
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