Earth:Latite
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Latite is an igneous, volcanic rock, with aphanitic-aphyric to aphyric-porphyritic texture. Its mineral assemblage is usually alkali feldspar and plagioclase in approximately equal amounts. Quartz is less than five percent and is absent in a feldspathoid-bearing latite, and olivine is absent in a quartz-bearing latite. When quartz content is greater than five percent the rock is classified as quartz latite.[1] Biotite, hornblende, pyroxene and scarce olivine or quartz are common accessory minerals. Feldspathoid-bearing latite is sometimes referred to as tristanite.[2]
Rhomb porphyries are an unusual variety with gray-white porphyritic rhomb shaped phenocrysts embedded in a very fine grained red-brown matrix. The composition of rhomb porphyry places it in the trachyte - latite classification of the QAPF diagram.
Latite is found, for example, as lavas in Bulgaria[3] and as intrusive laccoliths and sills in South Dakota, USA.[4]
See also
References
- ↑ Classification of Igneous Rocks
- ↑ Philpotts, Anthony R.; Ague, Jay J. (2009). Principles of igneous and metamorphic petrology (2nd ed.). Cambridge University Press. p. 140-141. ISBN 9780521880060.
- ↑ Georgiev, V.; Milovanov, P. (2001). "Volcanism in the Momchilgrad Volcanotectonic Depression". Comptes rendus de l'Académie bulgare des Sciences 54 (3): 63–66. Bibcode: 2001CRABS..54c..63G. http://adsabs.harvard.edu/full/2001CRABS..54c..63G. Retrieved on 5 July 2015.
- ↑ "Latitic Intrusive Rocks". USGS. http://mrdata.usgs.gov/geology/state/sgmc-unit.php?unit=SDTl%3B0. Retrieved 5 July 2015.
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