trachyte
Sign in to saveTrachyte () is an extrusive igneous rock composed mostly of alkali feldspar. It is usually light-colored and aphanitic (fine-grained), with minor amounts of mafic minerals, and is formed by the rapid cooling of lava (or shallow intrusions) enriched with silica and alkali metals. It is the volcanic equivalent of syenite.
Key facts
- Rock.name
- Trachyte
- Rock.type
- Igneous
- Rock.image
- Trachyt Herz Jesu Kirche Aachen.jpg
- Rock.caption
- A cut sample of trachyte, with phenocrysts of sanidine, in a wall in Germany
- Rock.composition
- Alkali feldspar
- Rock.composition_secondary
- Plagioclase, quartz, or feldspathoid
- Rock.class
- Felsic
- Rock.texture
- Aphanitic
- Rock.Equivalent
- Intrusive variant is syenite
via Wikipedia infobox
Article
6 sectionsContents
- Chemical composition
- Mineralogy
- Geographic distribution
- See also
- Notes
- External links
Trachyte () is an extrusive igneous rock composed mostly of alkali feldspar. It is usually light-colored and aphanitic (fine-grained), with minor amounts of mafic minerals, and is formed by the rapid cooling of lava (or shallow intrusions) enriched with silica and alkali metals. It is the volcanic equivalent of syenite.
Trachyte is common wherever alkali magma is erupted, including in late stages of ocean island volcanism and in continental rift valleys, above mantle plumes, and in areas of back-arc extension. Trachyte has also been found in Gale crater on Mars.