Poikilitic Texture

Poikilitic texture refers to crystals, typically phenocrysts, in an igneous rock which contain small grains of other minerals. In igneous rocks Poikilitic texture is widely used to determine order of crystallization; if one mineral is enclosed by another then the enclosed grain must have been the first to crystallize. This may sometime be true , but it is certainly not always so.

McBirney and Noyes (1979) show that this texture may be originated as a result of differing nucleation and growth rates, so that a single crystal (like pyroxene) nucleate and growth to a large size (low nucleation rate) in contrast to several other minerals (like feldspars) with higher nucleation rate which necessarily remain relatively small and became successively entrapped in the pyroxene.

poikilitic.jpg

Devolopment of Poikilitic texture by simultaneous growth but different nucleation rates of Pyroxene (green) and Plagioclase (pale-blue).


In many Poikilitic texture the enclosed crystals are randomly arranged, in other may be concentrated In zone and in some case crystals have a specific crystallographic relationship to the host. One of the best known is the arrangement of plagioclase and mica enclosed in K-feldspar.
Most commonly the (010) faces of plagioclase and the (001) faces of mica are aligned parallel to the principal faces of K-feldspar.

Bibliography



• Deer, W.A., Howie, R.A., Zussman, J. (1998) Rock-forming Minerals.
• Optical Mineralogy : The Nonopaque Minerals by Phillips / Griffen
• Eric A.K.Middlemost (1985): Magmas and Magmatic Rocks. Longman, London
• Ron H. Vernon (2004): A pratical guide to rock microstructure. Cambridge editore
• David Shelley (1983): Igneous and metamorphic rocks under the microscope. Campman & Hall editori


Photo
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Poikilitic Orthoclase with Biotite and Plagioclase inclusions. XPL image. 10x (Field of view = 2mm)
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Poikilitic Orthoclase with Biotite and Plagioclase inclusions. XPL image. 10x (Field of view = 2mm)
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Poikilitic Amphibole with pyroxene inclusions. PPL image. 10x (Field of view = 2mm)
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Poikilitic Augite with plagioclase inclusions in a Orthocumulate rock. PPL image. 2x (Field of view = 7mm)
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Poikilitic Augite with plagioclase inclusions in a Orthocumulate rock. XPL image. 2x (Field of view = 7mm)
augitepecilitica2012(4).jpg

Poikilitic Augite with plagioclase inclusions in a Orthocumulate rock. PPL image. 2x (Field of view = 7mm)
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Poikilitic Augite with plagioclase inclusions in a Orthocumulate rock. XPL image. 2x (Field of view = 7mm)
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Poikilitic Augite with plagioclase inclusions in a Orthocumulate rock. PPL image. 2x (Field of view = 7mm)
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Poikilitic Augite with plagioclase inclusions in a Orthocumulate rock. XPL image. 2x (Field of view = 7mm)
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Poikilitic Augite with plagioclase inclusions in a Orthocumulate rock. XPL image. 2x (Field of view = 7mm)
augitepecilitica2012(9).jpg

Poikilitic Augite with plagioclase inclusions in a Orthocumulate rock. XPL image. 2x (Field of view = 7mm)
augitepecilitica2012(10).jpg

Poikilitic Augite with plagioclase inclusions in a Orthocumulate rock. XPL image. 2x (Field of view = 7mm)
cy4(2018).jpg

Poikilitic augite (blue birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 1x (Field of view = 9mm)
cy4(2019).jpg

Poikilitic augite (blue birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 1x (Field of view = 9mm)
cy4(2020).jpg

Poikilitic augite with rounded serpentinized olivine inclusions. Wherlite from Cyprus. PPL image. 1x (Field of view = 9mm)
cy4(2023).jpg

Poikilitic augite with rounded serpentinized olivine inclusions. Wherlite from Cyprus. PPL image. 2x (Field of view = 7mm)
cy4(2024).jpg

Poikilitic augite (yellow birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 2x (Field of view = 7mm)
cy4(2025).jpg

Poikilitic augite (yellow birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 2x (Field of view = 7mm)
cy4(2034).jpg

Poikilitic augite with rounded serpentinized olivine inclusions (colorless and highly fractured). Wherlite from Cyprus. PPL image. 1x (Field of view = 9mm)
cy4(2035).jpg

Poikilitic augite (gray birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 1x (Field of view = 9mm)
cy4(2036).jpg

Poikilitic augite (blue-violet birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 1x (Field of view = 9mm)
cy4(2037).jpg

Poikilitic augite (gray birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 1x (Field of view = 9mm)
cy4(2038).jpg

Poikilitic augite (gray birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 1x (Field of view = 9mm)
cy4(2039).jpg

Poikilitic augite with rounded serpentinized olivine inclusions (colorless and highly fractured). Wherlite from Cyprus. PPL image. 1x (Field of view = 9mm)
cy4(2040).jpg

Poikilitic augite (gray birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 1x (Field of view = 9mm)
cy4(2041).jpg

Poikilitic augite (gray birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 1x (Field of view = 9mm)
cy4(2042).jpg

Poikilitic augite with rounded serpentinized olivine inclusions (beige, pale green due to alterartion). Wherlite from Cyprus. PPL image. 1x (Field of view = 9mm)
cy4(2043).jpg

Poikilitic augite (gray birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 1x (Field of view = 9mm)
cy4(2044).jpg

Poikilitic augite with rounded serpentinized olivine inclusions (beige, pale green due to alterartion). Wherlite from Cyprus. PPL image. 1x (Field of view = 9mm)
cy4(2045).jpg

Poikilitic augite (gray birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 1x (Field of view = 9mm)
cy4(2048).jpg

Poikilitic augite (gray birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 1x (Field of view = 9mm)
cy4(2049).jpg

Poikilitic augite (yellow birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 1x (Field of view = 9mm)
cy4(2050).jpg

Poikilitic augite (blue birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 1x (Field of view = 9mm)
cy4(2053).jpg

Poikilitic augite (blue-violet birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 1x (Field of view = 9mm)
cy4(2054).jpg

Poikilitic augite (yellow birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 1x (Field of view = 9mm)
cy4(2055).jpg

Poikilitic augite (yellow birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 1x (Field of view = 9mm)
cy4(2056).jpg

Poikilitic augite (gray birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 1x (Field of view = 9mm)
cy4(2057).jpg

Poikilitic augite (yellow birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 1x (Field of view = 9mm)
cy4(2061).jpg

Poikilitic augite with rounded serpentinized olivine inclusions (colorless and highly fractured). Wherlite from Cyprus. PPL image. 1x (Field of view = 9mm)
cy4(2062).jpg

Poikilitic augite (blue-violet birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 1x (Field of view = 9mm)
cy4(2069).jpg

Poikilitic augite with rounded serpentinized olivine inclusions (beige, pale green due to alterartion). Wherlite from Cyprus. PPL image. 1x (Field of view = 9mm)
cy4(2070).jpg

Poikilitic augite (blue-violet birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 1x (Field of view = 9mm)
cy4(2071).jpg

Poikilitic augite with rounded serpentinized olivine inclusions (beige, pale green due to alterartion). Wherlite from Cyprus. PPL image. 1x (Field of view = 9mm)
cy4(2072).jpg

Poikilitic augite (blue-violet birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 1x (Field of view = 9mm)
cy4(2031).jpg

Poikilitic augite (gray birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 1x (Field of view = 9mm)
cy4(2052).jpg

Poikilitic augite (gray birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 2x (Field of view = 7mm)
cy4(2053).jpg

Poikilitic augite (blu-violet birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 2x (Field of view = 7mm)
cy4(2075).jpg

Poikilitic augite (gray birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 2x (Field of view = 7mm)
cy4(2059).jpg

Poikilitic augite with rounded serpentinized olivine inclusions. Wherlite from Cyprus. PPL image. 2x (Field of view = 7mm)
cy4(2060).jpg

Poikilitic augite (yellow birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 2x (Field of view = 7mm)
cy4(2063).jpg

Poikilitic augite (yellow birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 2x (Field of view = 7mm)
cy4(2064).jpg

Poikilitic augite with rounded serpentinized olivine inclusions. Wherlite from Cyprus. PPL image. 10x (Field of view = 2mm)
cy4(2065).jpg

Poikilitic augite (yellow birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 10x (Field of view = 2mm)
cy4(2066).jpg

Poikilitic augite with rounded serpentinized olivine inclusions. Wherlite from Cyprus. PPL image. 10x (Field of view = 2mm)
cy4(2067).jpg

Poikilitic augite (yellow birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 10x (Field of view = 2mm)
cy4(2068).jpg

Poikilitic augite (yellow birefringence) with rounded serpentinized olivine inclusions. Wherlite from Cyprus. XPL image. 10x (Field of view = 2mm)
cy4(2073).jpg

Poikilitic augite with rounded serpentinized olivine inclusions. Wherlite from Cyprus. PPL image. 10x (Field of view = 2mm)
cy4(2074).jpg

Poikilitic augite with rounded serpentinized olivine inclusion. Wherlite from Cyprus. XPL image. 10x (Field of view = 2mm)