Fábricas constrictivas de ejes-c de cuarzo en arcosas deformadas por disolución por presión

• F.J. Fernández ^[1] ; D. Brown ^[2] ; J. Álvarez-Marrón ^[2] ; A. Pérez-Estaún ^[2] ; R. Menéndez-Duarte ^[1]
  1. [1] Universidad de Oviedo

     Universidad de Oviedo

     Oviedo, España

     
  2. [2] Instituto de Ciencias de la Tierra Jaume Almera

     Instituto de Ciencias de la Tierra Jaume Almera

     Barcelona, España

     
• Localización: Geotemas (Madrid), ISSN 1576-5172, Nº. 6, 3, 2004 (Ejemplar dedicado a: IV Congreso Geológico de España (Zaragoza, 12-15 julio, 2004)), págs. 37-40
• Idioma: español
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• Resumen

  • Arkosic sandstone interlayered within calcite mylonites at the base o f the southern Urals accretionary prism preserves their original sedimentary microstructure and presents only a weak shape and crystallographic preferred orientation (SPO and CPO, respectively). SPOs of XZ-sections show fabrics mainly formed by pressure solution, where quartz and feldspar grains have a characteristic bimodal shape and the mean axial ratio of the finite strain is c. 2. The unusual pattern described by the quartz c-axes fabrics formed during the acquisition o f their SPOs is characterised by girdles normal to Y At the light o f our results, and accordingly with the deformation conditions o f the calcite mylonites, the quartz c-axis preferred orientation may be formed by pressure solution under constrictional strain, and not as usually occurs by intracrystalline plasticity.