phonolite
phonolite A fine-grained, porphyritic, extrusive, igneous rock consisting of essential alkali feldspar (sanidine or anorthoclase), nepheline, sodic pyroxene, and sodic amphibole (with or without iron-rich olivine), with accessory sphene, apatite, and zircon. Where present, phenocrysts can consist of alkali feldspar, sodic pyroxene, or sodic amphibole. Phonolites are the extrusive equivalent of nepheline syenites and are found on off-axis ocean islands and in continental regions subjected to anorogenic upwarping and rifting. The name, from the Greek phone meaning ‘sound’, refers to the fact that the rock rings like a bell when struck with a hammer.
More From encyclopedia.com
Pelite , pelite (adj. pelitic) An aluminium-rich, metamorphic rock formed by the metamorphism of clay-rich sedimentary rocks, e.g. shales and mudstones. The t… Skylight , skylight •halite • candlelight • fanlight •lamplight • gaslight • flashlight •starlight • headlight • penlight •daylight • tail light •Peelite, pelit… Searchlight , searchlight •halite • candlelight • fanlight •lamplight • gaslight • flashlight •starlight • headlight • penlight •daylight • tail light •Peelite, pe… sidelight , side·light / ˈsīdˌlīt/ • n. 1. a light placed at the side of something. ∎ (sidelights) a ship's port (red) and starboard (green) navigation lights. ∎… Mafic , Mafic
Igneous rocks are classified by geologists using various schemes. One of the several schemes based on chemical composition divides igneous rock… Dacite , dacite A light-coloured, fine-grained igneous rock containing 63–70 wt.% SiO2, as well as plagioclase feldspar, alkali feldspar, quartz, biotite, and…
About this article
phonolite
All Sources -
You Might Also Like
NEARBY TERMS
phonolite