Above are photos of granophyric texture (and features therein) found within granitic blocks ejected as part of pyroclastic flows at the Alid volcanic center. These rock textures were formed during relatively rapid growth of silicate melt at shallow depths beneath Alid. Information below clarifies how the photos were taken and what they represent. See Lowenstern et al. (December 1997; Journal of Petrology) for further details.

Photomicrographs of areas within granophyric block found as a lithic in the "pf unit" at Alid volcanic center. Figure parts a-e with crossed nichols. (a) Micrographic groundmass surrounds feldspar phenocryst fragment. (b) Micrographic groundmass around clinopyroxene phenocryst. Quartz is white and feldspar is at extinction. (c, d) Radiating fringe of feldspar in groundmass is in optical continuity with phenocryst, from which it nucleated. (e) Quartz phenocryst is surrounded by feldspar groundmass. Quartz in groundmass does not appear to have nucleated directly on phenocryst, but is in optical continuity with it. (f) Primary vapor-rich fluid inclusion in phenocrystic quartz. Liquid (l) is seen at the bottom right, the rest being vapor (v). (g) Primary vapor-rich inclusion at the tip of a quartz stringer (outlined for clarity) in the granophyric groundmass.


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