Phonolite is an uncommon shallow intrusive or extrusive rock, of intermediate chemical composition between felsic and mafic, with texture ranging from aphanitic (fine-grained) to porphyritic (mixed fine- and coarse-grained).

Phonolite, any member of a group of extrusive igneous rocks (lavas) that are rich in nepheline and potash feldspar. The typical phonolite is a fine-grained, compact igneous rock that splits into thin, tough plates which make a ringing sound when struck by a hammer, hence the rock’s name.

2019年12月5日 · We know that the Tower is formed of a rare igneous rock, phonolite porphyry, and is the largest example of columnar jointing in the world. To better understand processes which shaped the Tower, we look back through Earth's history to a time long before this unique feature took shape.

2023年11月20日 · Phonolite is a type of volcanic rock that belongs to the family of igneous rocks. It is characterized by its unique mineral composition and texture, which set it apart from other volcanic rocks. The name "phonolite" is derived from the Greek words "phōnē," meaning sound, and "lithos," meaning stone, highlighting one of its distinctive features.

5 photos of Phonolite associated with Titanite: CaTi(SiO 4)O: 5 photos of Phonolite associated with Sanidine: K(AlSi 3 O 8) 3 photos of Phonolite associated with Quartz: SiO 2: 2 photos of Phonolite associated with Sodalite: Na 4 (Si 3 Al 3)O 12 Cl: 2 photos of Phonolite associated with Arisite-(Ce) NaCe 2 (CO 3) 2 [F 2x (CO 3) 1-x]F: 2 photos ...

2017年9月18日 · Phonolite is an uncommon rock— “exotic and enigmatic.” Yet I encountered it again just recently, in the Rattlesnake Hills of central Wyoming only 175 miles southwest of Devils Tower. In both places the phonolite is estimated to be about 40 million years old, emplaced during the Eocene Epoch.

2024年6月17日 · Phonolite is a type of fine-grained igneous rock composed primarily of the mineral feldspar. A ‘porphyry’ is a rock that has coarse crystals surrounded by fine-grained material, or groundmass.

The common feldspathoid is nepheline (implied when the term “phonolite” is used unqualified), but leucite, nosean, haüyne, sodalite or analcime may be present and may be the only feldspathoid; melilite may be present.

Phonolite is a subvolcanic rock variety characterized by the presence of variable amounts of pyroxene and phenocrysts of sanidine, nepheline, diopside, nosean, kaersutite, and titanite, embedded in a groundmass of mainly nepheline and sanidine microlites.

Phonolite is a rare igneous, volcanic (extrusive) rock of intermediate composition, with aphanitic to porphyritic texture. Phonolite is unusual in that it forms from a highly silica undersaturated melt by low degrees of partial melting (less than 10%) of highly aluminous lower crustal rocks such as tonalite, monzonite and metamorphic rocks.