The study of speech sounds in language or a language with reference to their distribution and patterning and to tacit rules governing pronunciation. 2. The sound system of a language: the phonology of English. phoÂ·noÂ·logâ²ic (fÅâ²nÉ-lÅjâ²Ä­k) , phoâ²noÂ·logâ²iÂ·cal (-Ä­-kÉl) adj.
What does a porphyritic texture indicate about the history of an igneous rock? the magma sat and cooled a bit below the Earth's surface, thus giving time for the large crystals to grow, before erupting onto the surface and cooling very quickly
Rhyolite Porphyry Some of the best-known examples of rhyolite can be found in the Yellowstone Park region and in the southwestern United States. Many of the rocks in those areas formed approximately 600,000 years ago through a series of massive volcanic eruptions. Rhyolite is a fine-grained extrusive igneous rock that is mineralogically similar to granite. It chiefly contains orthoclase feldspar and quartz, but may contain lesser amounts of plagioclase feldspar, pyroxenes, biotite, and amphiboles.