phonolite

     

Phonolite is an evolve lava which is considered as forming in shallow magma chambers. Phonolite is an igneous, volcanic (extrusive) rock, of intermediate (between felsic and mafic) composition, with aphanitic to porphyritic texture. Mineral assemblage is usually abundant feldspathoids (nepheline, sodalite, hauyne, leucite and analcite) and alkali feldspar (sanidine, anorthoclase or orthoclase), and rare sodic plagioclase. Biotite, sodium rich amphiboles and pyroxenes along with iron rich olivine are common minor minerals. Accessory phases include titanite, apatite, corundum. zircon, magnetite and ilmenite. Phonolites are silica under-saturated, as illustrated by the position of phonolite in the TAS classification and QAPF diagrams.

Found pages about phonolite

Users that searched for phonolite