Phonotephrite
Appearance
Phonotephrite is a strongly alkaline volcanic rock with a composition between phonolite and tephrite.[1] This unusual igneous rock contains 7 to 12% alkali content and 45 to 53% silica content (see TAS diagram). It can be described as a mafic phonolite or a potassic tephrite. Phonotephrite lava flows and volcanic cones have been identified in Antarctica, North America and Africa.[2][3][4]
References
- ^ "Unusual Lava Types". Strongly Alkaline Lavas. San Diego State University. Retrieved 2016-09-11.
- ^ P. Esser, Richard; R. Kyle, Philip; McIntosh, William C. (2004). "40Ar/39Ar dating of the eruptive history of Mount Erebus, Antarctica: volcano evolution". Bulletin of Volcanology. Springer.
- ^ Kuehn, Christian; Guest, Bernard; K. Russell, James; A. Benowitz, Jeff (2015). "The Satah Mountain and Baldface Mountain volcanic fields: Pleistocene hot spot volcanism in the Anahim Volcanic Belt, west-central British Columbia, Canada". Bulletin of Volcanology. Springer: 8.
- ^ Berger, J.; Ennih, N.; Mercier, J.-C. C.; Liégeois, J.-P.; Demaiffe, D. (2009). "The role of fractional crystallization and late-stage peralkaline melt segregation in the mineralogical evolution of Cenozoic nephelinites/phonolites from Saghro (SE Morocco)". Mineralogical Magazine. 73 (1). Mineralogical Society of Great Britain and Ireland. ISSN 1471-8022.