Occurrence of nacrite in the Lodève Permian basin (France)
Buatier, Martine D.; Potdevin, Jean-Luc; Lopez, Michel; Petit, Sabine
European Journal of Mineralogy Volume 8 Number 4 (1996), p. 847 - 852
published: Jul 29, 1996
manuscript accepted: Mar 22, 1996
manuscript received: Jun 20, 1995
ArtNo. ESP147050804015, Price: 29.00 €
Abstract Authigenic euhedral kaolins of nano-to-millimetre size were found in dolomite cavities in the Cambrian basement of the Lodève Basin, France. X-ray diffraction, DTA and infrared-spectroscopy data demonstrate that nacrite is the only kaolin phase present in the cavities. Nacrite is associated with authigenic quartz, barite, dolomite and calcite. Petrographic data indicate a contemporaneous growth of nacrite and quartz after dolomite. In some cavities, barite and nacrite crystallized together. The crystallization of quartz, nacrite and barite could be the result of fluid influx and trapping in a karstified basement during the Late Permian extensional tectonic regime that affected the Lodève Basin.