Sepiolita férrica en rellenos hidrotermales en las series del Triásico-Jurásico del Atlas Medio (Marruecos)características e hipótesis genética
- Enrique Arranz Yagüe 1
- M. Lago 1
- Joaquín Bastida Cuairan 2
- Carlos Galé Bornao 1
- Teresa Ubide 1
- Jesús Soriano Carrillo 3
- 1 Departamento de Ciencias de la Tierra, Área de Petrología y Geoquímica. Facultad de Ciencias Universidad de Zaragoza
- 2 Departamento de Geología, Universidad de Valencia
- 3 Laboratorio Central de Estructuras y Materiales, CEDEX
ISSN: 1576-5172
Year of publication: 2008
Issue Title: VII Congreso Geológico de España
Issue: 10
Pages: 1381-1384
Type: Article
More publications in: Geotemas (Madrid)
Abstract
Fe-sepiolite macroscopic fiber-bundles are part of the mineral assemblage of hydrothermal veins crosscutting the Triassic-Jurassic series of the Oujda Mounts (Middle Atlas, Morocco). The crystallographic parameters (obtained by X-ray diffraction) and the composition of this mineral (analysed by SEM-EDX and electron microprobe) are presented. The sedimentary series includes two basaltic flow units, partially altered and affected by palaeosoil development atop each basaltic unit. The analysed fiber bundles have a Fe-rich composition (1.01-1.40 octahedral cations); the substitution 2Mg2+→R3++ controls the stoichiometric input of trivalent cations in the sepiolite structure. Genesis of this mineral in veins is interpreted as the result of hydrothermal processes, described in the area during the Jurassic, with temperature and fluid compositions suitable for sepiolite development. Interaction of these fluids with the altered basaltic units would have set the appropriate conditions for the precipitation of sepiolite with an uncommon Fe content.