dacite
Sign in to saveDacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. It is composed predominantly of plagioclase feldspar and quartz.
Key facts
- Rock.name
- Dacite
- Rock.type
- Igneous
- Rock.image
- Black porphyritic dacite (upper Holocene, 14 May 1915; Devastated Area, Lassen Volcano National Park, California, USA) 51.jpg
- Rock.caption
- Dacite from the Lassen Volcano National Park
- Rock.composition
- Plagioclase feldspar, quartz
- Rock.composition_secondary
- Hornblende, biotite, and pyroxene
- Rock.class
- Felsic
- Rock.texture
- Aphanitic or porphyritic
- Rock.Equivalent
- Intrusive variant is granodiorite
via Wikipedia infobox
Article
9 sectionsContents
- Etymology
- Composition
- Texture
- Geological context and formation
- Dacite's role in the formation of Archean continental crust
- Molten dacite magma at Kīlauea
- Distribution
- See also
- References
Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. It is composed predominantly of plagioclase feldspar and quartz.
Dacite is relatively common, occurring in many tectonic settings. It is associated with andesite and rhyolite as part of the subalkaline tholeiitic and calc-alkaline magma series.