Hornblende-olivine-bearing pyroxenite

A pyroxenite is a basic igneous rock dominated by pyroxene, with up to 40% olivine, accessory phases can include plagioclase, spinel, garnet, ilmenite, chromite and magnetite. Pyroxenites dominated by orthopyroxene are termed orthopyroxenites, those dominated by clinopyroxene are known as clinopyroxenites, those with similar abundances of orthopyroxene and clinopyroxene are known as websterites.

Pyroxenites are an important component of mantle rocks and are found within mantle xenoliths and within the mantle sequence of ophiolites, often occurring as veins and dykes. In the mantle pyroxenites are largely produced by crystallisation of partial melts. Pyroxenites also are found in layered intrusions where they form as cumulates.


Bibliography



• Ron H. Vernon (2004): A pratical guide to rock microstructure. Cambridge editore
• Eric A.K.Middlemost (1985): Magmas and Magmatic Rocks. Longman, London
• Ron H. Vernon (2004): A pratical guide to rock microstructure. Cambridge editore


Photo
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Hornblende, Clinopyroxene and Olivine crystals in a Hbl-Pyroxenite. Antarctica. PPL image. 2x (Field of view = 7mm)
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Hornblende, Clinopyroxene and Olivine crystals in a Hbl-Pyroxenite. Antarctica. PPL image. 2x (Field of view = 7mm)
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Hornblende, Clinopyroxene and Olivine crystals in a Hbl-Pyroxenite. Antarctica. PPL image. 2x (Field of view = 7mm)
pirosseniteaolivinaehblantartide(6).jpg

Hornblende, Clinopyroxene and Olivine crystals in a Hbl-Pyroxenite. Antarctica. PPL image. 2x (Field of view = 7mm)
pirosseniteaolivinaehblantartide(7).jpg

Hornblende, Clinopyroxene and Olivine crystals in a Hbl-Pyroxenite. Antarctica. XPL image. 2x (Field of view = 7mm)
pirosseniteaolivinaehblantartide(2).jpg

Hornblende, Clinopyroxene and Olivine crystals in a Hbl-Pyroxenite. Antarctica. XPL image. 2x (Field of view = 7mm)
pirosseniteaolivinaehblantartide(8).jpg

Hornblende, Clinopyroxene and Olivine crystals in a Hbl-Pyroxenite. Antarctica. PPL image. 2x (Field of view = 7mm)
pirosseniteaolivinaehblantartide(9).jpg

Hornblende, Clinopyroxene and Olivine crystals in a Hbl-Pyroxenite. Antarctica. XPL image. 2x (Field of view = 7mm)
pirosseniteaolivinaehblantartide(10).jpg

Hornblende, Clinopyroxene and Olivine crystals in a Hbl-Pyroxenite. Antarctica. PPL image. 2x (Field of view = 7mm)
pirosseniteaolivinaehblantartide(11).jpg

Hornblende, Clinopyroxene and Olivine crystals in a Hbl-Pyroxenite. Antarctica. PPL image. 2x (Field of view = 7mm)
pirosseniteaolivinaehblantartide(12).jpg

Hornblende, Clinopyroxene and Olivine crystals in a Hbl-Pyroxenite. Antarctica. PPL image. 2x (Field of view = 7mm)