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Kyanite bearing micaschist, Bruncu Nieddu. About 0.5 km further north along the track we reach the kyanite+biotite isograd withmm- to cm-size bluish kyanite crystals in the matrix of the mylonites and in quartz-rich veins (Fig. 1). The kyanite+biotite isograd is marked by the first appearance ofkyanite crystals. The rocks consist of porphyroblasts of staurolite, kyanite,…

Kyanite bearing micaschist, Bruncu Nieddu.

About 0.5 km further north along the track we reach the kyanite+biotite isograd withmm- to cm-size bluish kyanite crystals in the matrix of the mylonites and in quartz-rich veins (Fig. 1). The kyanite+biotite isograd is marked by the first appearance ofkyanite crystals. The rocks consist of porphyroblasts of staurolite, kyanite, andplagioclase enveloped in a mylonitic matrix of muscovite, biotite, chlorite, and ilmenite. Temperatures up to 595 °C and pressures up to 0.67 GPa have been reported byFranceschelli et al. (1989), and pressures over 0.9 GPa by Carosi & Palmeri (2002) for the metamorphic peak.