Elsevier

Tectonophysics

Volume 129, Issues 1–4, 15 October 1986, Pages 275-290
Tectonophysics

Petrological and age relationship between emplacement of magmatic breccia, alkaline magmatism, and static metamorphism in the North Pyrenean Zone

https://doi.org/10.1016/0040-1951(86)90256-8Get rights and content

Abstract

A magmatic breccia showing peculiar structural and geochemical features has been found in the North Pyrenean Zone (Lherz area). The features (concentric zoning, “fluidal” structure, reaction rim at the matrix-clast interface, high Co, Sc and REE contents) indicate a genetic relationship between the breccia and fluids of deep origin which have infiltrated the Mesozoic series. These fluids, probably related to the alkaline magmatism commonly observed in the Pyrenees, could be locally responsible for the static Pyrenean metamorphism.

39Ar/40Ar age determinations have been made in order to compare (a) the age of the neoblastesis in the magmatic breccia matrix (95 ± 2 Ma), (b) the age of the unoriented metamorphic minerals in the surrounding marbles (98.5 ± 2.2 Ma) and (c) the age of the alkaline magmatism in the Corbières and Lherz areas (95.4 ± 2.3 Ma and 101.2 ± 2.5 Ma, respectively).

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