Las rocas volcánicas neógenas de Nuévalos (provincia de Zaragoza)

• Eumenio Ancochea Soto ^[2] ; M. Muñoz ^[1] ; J. Sagredo ^[3]
  1. [1] Universidad de Granada

     Universidad de Granada

     Granada, España

     
  2. [2] Facultad de Ciencias Geológicas y Biológicas.Departamento de mineralogía y Petología
  3. [3] Instituto de Geología Económica CSIC-UCM. U.E.I. Petrologíade

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• Localización: Geogaceta, ISSN 0213-683X, Nº. 3, 1987, págs. 7-10
• Idioma: inglés
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• Resumen

  • On the basis of petrological data, the ultra-alkaline character of the volcanics from Nuévalos is clearly pointed out. This character rejects any type of relationship with Permian and Mesozoic volcanic events. Furthermore, analogies with plio-quaternary volcanics from Cofrentes suggest a similar episode related to a tensional regime that can be linked to the openning of the Valencia gulf. The volcanics are massive and look a porphyritic crystalline texture. Mineralogical composition define them as olivine-nephelinite rocks.

    They have a large amount of xenocrysts from mantle spinel-peridotite. The high xenocryst accumulation percentage has modified the original character of the primary melt. The whole geochemical data suggest a parental magma derived by a very low degree of melting (4,3%) from a peridotitic mantle source, strongly enriched in incompatible elements, and from a depth near to 100 km.