Granites built by sheeting in a fault stepover (the Sanabria Massifs, Variscan Orogen, NW Spain)

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doi: 10.1046/j.1365-3121.2001.00343.x
Authors:Vegas, N.; Aranguren, A.; Tubía, J. M.
Author Affiliations:Primary:
Universidad del País Vasco, Departamento de Geodinámica, Bilbao, Spain
Volume Title:Terra Nova
Source:Terra Nova, 13(3), p.180-187. Publisher: Blackwell, Oxford, United Kingdom. ISSN: 0954-4879
Publication Date:2001
Note:In English. 36 refs.; illus., incl. geol. sketch maps
Summary:An asymmetrical thermal dome within the Sanabria region contains the small Ribadelago and Sotillo plutons, and associated migmatites. The mineralogically diverse plutons mainly comprise biotite granodiorites and tonalites, but granites and gabbros are also common. The plutons are confined by the releasing stepover of a transpressional shear zone of strike 120°E, and dip 70°SW. The igneous rocks mostly form sheets parallel to the shear zone and their magnetic foliations and lineations are parallel to the shear bands and stretching lineations respectively. The fault-valve behaviour of the shear zone, and the power of overpressured melt to open and ascend through previously formed planar structures (S- or C-planes), explains how these igneous sheets formed at high angles to the stress field's main axis. [J.F.]
Subsections:Igneous petrology
Subjects:Biotite; Dikes; Emplacement; Fabric; Foliation; Granites; Igneous rocks; Intrusions; Laccoliths; Lineation; Metamorphic rocks; Mica group; Migmatites; Models; Orogeny; Petrology; Plutonic rocks; Plutons; Sheet silicates; Silicates; Structural analysis; Variscan Orogeny; Europe; Iberian Peninsula; Southern Europe; Spain; Northwestern Spain; Sanabria Massif
Abstract Numbers:02M/3452
Record ID:2003084739
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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