In the Variscan Batholith of Corsica large-scale, variably trending magmatic flow patterns are developed with steep magmatic foliation. This pattern is intensified by magmatic layering, mainly km-long lenses and layers of mafic and intermediate intrusions in the granitoids. Fabrics on the macro- to micro-scale indicate magma mingling and mixing. This reflects the complex intrusion history and the compositional variability of the Corsica Batholith on various scales.
At Abbartello, north of Golfe de Valinco (southern Corsica) in an area of at least 100 km2 diorite, tonalite and granite form alternating layers and lenses from several hundred meter down to millimeter thickness. Together with aligned platy feldspars, amphibole and biotite, these layers represent a flow foliation that results from several pulses of fragmentation, magma injection and mingling. Deformation of magma is indicated by boudinage, melt-injected micro shear zones, fragmenting and pseudo-folding with axial-plane parallel alignment of amphibole and biotite. The intensity of grain alignment roughly correlates with the thicknesses of layers. Weak sub-solidus deformation is indicated by chessboard subgrain patterns in magmatic quartz and by rare, up to 1 mm large, recrystallized plagioclase and amphibole grains.
Anisotropy and variable intensity of crystal alignment, together with melt-present fragmentation are interpreted as variations of flow intensity and strain-rate. The repeated injections of mafic to felsic magma and crystallization in the presence of a regional stress field reflect large-scale movements during late-Variscan crustal reorganization and represent an excellent example of localization of deformation into magma-enriched parts of the continental crust.