Primary magnetic fabric in an ultramafic body (Moldanubian Zone, European Variscides) survives exhumation-related granulite-amphibolite facies metamorphism
Abstract
Serpentinized peridotite-clinopyroxenite, approximately 11 x 5 m in size, enclosed in high-pressure felsic granulite. occurs in a quarry near the village of Bory (Gfohl Unit of the Moldanubian Zone of Western Moravia, Czech Republic). The anisotropy of magnetic susceptibility (AMS) was used to investigate the fabrics of both the ultramafic body and the host granulite.
The granulite shows a PT path from above 2 GPa/850-900 degrees C following nearly isothermal decompression to sillimanite stability field with subsequent cooling. Two foliations (S-1-preserved only in isoclinal folds and the dominant S-2 foliation parallel to leucocratic bands) are visible in granulite.
Through investigating low-field variation of the AMS, one could resolve the AMS into the field-independent and field-dependent components.