%0 Journal Article
%A Ancochea Soto, Eumenio
%A Muñoz García, Mercedes
%A Sagredo Ruiz, Juana
%T Las rocas volcánicas neógenas de Nuévalos (provincia de Zaragoza)
%D 1987
%@ 0213-683X
%U https://hdl.handle.net/20.500.14352/58269
%X 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.
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