Dynamics of magma mixing and degassing recorded in plagioclase at Stromboli (Aeolian Archipelago, Italy)

Contrib Mineral Petrol (2004) 147:213–227

Figures 3 and 7 were given incorrect and are reproduced here.

Fig. 3a–f

Back-scattered electron images of plagioclase phenocrysts. Crystals are cut nearly parallel to (010) through the approximate geometric center. a) Zoned phenocryst consisting in alternating labradoritic (light gray) and bytownitic (dark gray) concentric layers. Large glass pockets are commonly present at the inner boundaries of the bytownitic layers; b) the labradoritic layers are characterized by small-scale, oscillatory zoned texture, the bytownitic by patchy-zoned, sieve textures, including micrometric glassy inclusions and voids; c) thin bytownitic layers and their compositions are shown. Thin layers have composition An74–79, whereas An contents >80 are typical of thick layers (>30 μm); d) dissolution surfaces at the inner boundary of the bytownitic layers are marked by angular discordances and gulfs cross-cutting the labradoritic, oscillatory-zoned layers. The outer boundary are crenulate surfaces (the crystal rim is on the top) (see also b and c); e) phenocryst showing an inner part with dominant bytownitic composition and remnants of labradoritic zones resulting from partial dissolution; f) coarse sieve-textured, patchy-zoned core rimmed by relicts of labradoritic layers

Fig. 7

Stability field of plagioclase in a HK-basaltic melt, within the range H2O 0.2–3 wt% and pressure between 0.1 and 1 kbars, according to MELTS calculations (Ghiorso and Sack 1995). Water saturation boundaries according to MELTS calculations (solid line) and to Papale (1997) (dotted line) are shown