Variación de la textura y química mineral de rocas metabásicas en una zona de cizalla (Complejo de Cabo Ortegal, NW de España)

  1. M. L. Valín 1
  2. A. Pérez-Estaún 1
  3. A. Martín-Izard 1
  4. A. Marcos 1
  1. 1 Universidad de Oviedo
    info

    Universidad de Oviedo

    Oviedo, España

    ROR https://ror.org/006gksa02

Journal:
Revista de la Sociedad Geológica de España

ISSN: 0214-2708

Year of publication: 1994

Volume: 7

Issue: 1-2

Pages: 179-189

Type: Article

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Abstract

Narrow shear zones observed within lenses of metagabbro in the Candelaria Amphibolite Formation, are characterized by textural and mineralogical gradients. From undeformed metagabbros to the inner part of the shear zone, there is a progressive change in rock texture, from granoblastic to nematoblastic, a marked decrease in grain size and in the abundance of garnets, pyroxenes and amphiboles. Mineral chemistry variations in the same direction include a change in amphibole composition from tschermakitic to actinolitic, and transformation of garnets, pyroxenes and tschermakitic amphibol to actinolitic hornblende. The observed (mineral, textural and chemical) changes are interpreted to represent a decrease in metamorphic grade with increasing of the strain.

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