komatiite
Sign in to savethumb|Komatiite lava at the type locality in the Komati Valley, Barberton Mountainland, South Africa, showing the distinctive "spinifex texture" formed by dendritic plates of olivine (scale shown by a hammer on the right edge of photo)
Article
15 sectionsContents
- Petrology
- Mineralogy
- Metamorphism
- Hydration vs. carbonation
- Mineralogic variations in komatiite flow facies
- Geochemistry
- Morphology and occurrence
- Textural features
- Volcanology
- Intrusive komatiites
- Economic importance
- See also
- References
- Bibliography
- External links
thumb|Komatiite lava at the type locality in the Komati Valley, Barberton Mountainland, South Africa, showing the distinctive "spinifex texture" formed by dendritic plates of olivine (scale shown by a hammer on the right edge of photo)
Komatiite is a type of ultramafic mantle-derived volcanic rock defined as having crystallised from a lava of at least 18 wt% magnesium oxide (MgO). It is classified as a 'picritic rock'. Komatiites have low silicon, potassium and aluminium, and high to extremely high magnesium content. Komatiite was named for its type locality along the Komati River in South Africa, and frequently displays spinifex texture composed of large dendritic plates of olivine and pyroxene.