Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite.[1] Phenocrysts are sodic sanidine with minor albite and bipyramidal quartz.[2] The blue colour is caused by very small crystals of riebeckite or arfvedsonite.[3] The 1903 eruption of Changbaishan volcano in northeast China erupted comendite pumice.[4]
Comendite derives its name from the area of Le Commende on San Pietro Island in Italy, where the rock type is found.[5] Comendite also occurs in the Glass House Mountains of southeast Queensland, Australia, as well as in Sardinia, Corsica, Ascension Island, Ethiopia, Somalia and other areas of East Africa.[2]
References
edit- ^ Troll, Valentin R.; Schmincke, Hans-Ulrich (2002-02-01). "Magma Mixing and Crustal Recycling Recorded in Ternary Feldspar from Compositionally Zoned Peralkaline Ignimbrite 'A', Gran Canaria, Canary Islands". Journal of Petrology. 43 (2): 243–270. doi:10.1093/petrology/43.2.243. ISSN 0022-3530.
- ^ a b Iddings, Joseph Paxson, 1913, Igneous rocks: composition, texture and classification, v. 2, pp. 94-96
- ^ Rocks and landscapes of the Sunshine Coast by Warwick Willmott, Brisbane: Geological Society of Australia Queensland Division, 2007
- ^ Changbaishan volcano, China - facts and information. Retrieved 2013-07-24.
- ^ Cioni, R. and Funedda, A., (2005) Structural geology of crystal-rich, silicic lava flows: A case study from San Pietro Island (Sardinia, Italy) in Manga, M. and Ventura, G. (editors) (2005) Kinematics and Dynamics of Lava Flows, Geological Society of America Special Paper 396, pages 1 to 14.
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