Abstract

[1] New structural, microstructural, and 40Ar/39Ar data from the NW Massif Central (France) provide additional constraints on the timing and tectonic setting of late Variscan granite magmatism. Previous studies had emphasized the role of late orogenic extension in the emplacement of granite plutons in the Limousin region. In contrast, the new data set is consistent with syntectonic emplacement of magma in a dextral simple shear active from 350 to 300 Ma in a transpressional regime. As an alternative hypothesis to late orogenic extension, we propose that magmas migrated into tensional bridges between active P shears associated with a lithospheric shear zone comparable to a pop-up structure. The Galician region, in the western end of the Ibero-Armorican tectonic arc, exhibits major left-lateral ductile shear zones which can be interpreted as conjugate structures to the Limousin and Armorican shear zones.

DOI

10.1029/2005tc001822

Publication Date

2007-04-01

Publication Title

Tectonics

Volume

26

Issue

2

Publisher

American Geophysical Union (AGU)

ISSN

1944-9194

Embargo Period

2024-11-25

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