Fig. 8.

Photomicrographs illustrating the correspondence between phase-equilibrium predictions and rock textures. a Group of biotite–quartz pseudomorphs after orthopyroxene in S-type monzogranite sample 06MD1 from the Mount Disappointment pluton in southeastern Australia (plane light, colour version of Fig. 5a of Clemens and Benn 2010). Note the delicate texture of the fine-grained, near-solidus quartz–biotite aggregates in the centres of the pseudomorphs and the rings of coarser red–brown biotite crystals that represent earlier, higher temperature reaction with the magma. b Quartz–biotite pseudomorph after orthopyroxene in a granodiorite from the I-type Budduso pluton in Sardinia, Italy. The texture is similar to the pseudomorphs in a, but a little coarser-grained. The biotite crystals are olive-coloured and the pseudomorph lies within a magmatic segregation of larger biotite crystals. c Euhedral quartz phenocryst (Qz) in porphyritic micromonzogranite sample 06MD8 from the Mount Disappointment pluton (crossed polars). Note the lack of recrystallisation of the quartz and the narrow marginal zone with near-solidus outgrowths of tiny quartz grains. d Late-crystallised, anhedral and interstitial K-feldspar crystal (Kfs) in I-type monzogranite sample HAR1 from the Harcourt batholith in southeastern Australia. This texture is in stark contrast with the euhedral phenocrysts of K-feldspar shown in Figs. 4 and 7. Note also that the main textural skeleton of the rock is formed by plagioclase (Pl) subhedra. Crossed polars