Page 248 - Microtectonics

8.2 · Primary Structures in Rocks of Igneous Origin or in Migmatites 239

Fig. 8.1. Igneous foliation originated by magmatic flow. The large subhorizontal crystals are K-feldspar (some with Karlsbad twins) with
some plagioclase and interstitial quartz along the contacts. Equidimensional relatively high relief grains are hornblende. Quartz syenite
from southern Brazil. Width of view 2 mm. CPL

Fig. 8.2. Subophitic microstructure typical for magmatic crystallisation. Note the elongated plagioclase crystals penetrating pyroxene.
Some plagioclase crystals are included within the pyroxenes, characterising ophitic microstructure locally. Gabbro from Angra dos Reis,
SE Brazil. Width of view 5 mm. CPL