El yacimiento de zeolitas de Los Murcianos (San José, Almería)

  1. Emilia García Romero 1
  2. María Mercedes Suárez Barrios 2
  3. María Victoria López-Acevedo Cornejo 1
  4. José Ángel López García 1
  5. Manuel Regueiro 3
  1. 1 Dpto. de Cristalografía y Mineralogía. Facultad de C. C. Geológicas. Universidad Complutense. Madrid
  2. 2 Dpto. de Geología. Universidad de Salamanca
  3. 3 Instituto Geológico y Minero de España
    info

    Instituto Geológico y Minero de España

    Madrid, España

    ROR https://ror.org/04cadha73

Journal:
Geotemas (Madrid)

ISSN: 1576-5172

Year of publication: 2008

Issue Title: VII Congreso Geológico de España

Issue: 10

Pages: 1559-1562

Type: Article

More publications in: Geotemas (Madrid)

Abstract

Los Murcianos is the only zeolite mine in Spain and is located near San José, in the province of Almería (SE Spain). The mine is located on the western side of the Los Frailes volcanic complex, and the mineral deposit is emplaced in Miocene dacitic ignimbrites and tuffs. These rocks have been hydrothermally altered and replaced by zeolites and smectites. The main conduits for hydrothermal fluids were NW and N-S trending faults that bound the economic mineralization. The zeolite is a silica-rich mordenite, with a mean formula of Na1.92 K0.52 Ca1.51 Fe0.17 Mg0.15 (Al7.43 Si40.92 O96) 28 H2O, whereas that of the smectite corresponds to montmorillonite: (Si7.97Al0.03) O20 (Al2.36Fe3+ 0.18Mg1.47) (OH)4 [Na0.21K0.13Ca0.13] with variable amounts of amorphous silica. The chemical composition of the zeolites resembles that of the ignimbrite, whereas the chemistry of the smectites is very different. This suggests that zeolite formation occurred under confined, isochemical conditions. In addition, the textural study indicates that devitrification and hydration, during hydrothermal alteration, played a major role in zeolite formation. On the other hand, movement of fluids along faults would have resulted in leaching of alkaline and alkaline earth elements with the exception of Mg which was introduced to the system. We further suggest the mineral deposit formed during at least two episodes of fluid circulation.