Latite

Latite is an igneous, volcanic rock intermediate between andesite and trachyte. Latite have aphyric to porphyritic texture. The term Latite derives from the Latin word "latium" (a region of central Italy) where Latites was found and classified for the first time.

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.

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QAPF Diagram Latite field in blue





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Latite sample. From "Mineralogischen Museum Bonn".




Bibliography



• David Shelley (1983): Igneous and metamorphic rocks under the microscope. Campman & Hall editori.
• Vernon, R. H. & Clarke, G. L. (2008): Principles of Metamorphic Petrology. Cambridge University Press
• Shelley D (1992): Igneous and Metamorphic Rocks under the Microscope: Classification, textures, microstructures and mineral preferred orientation
• Cox et al. (1979): The Interpretation of Igneous Rocks, George Allen and Unwin, London.
• Eric A.K. (1985): Middlemost Magmas and Magmatic Rocks. Longman, London
• D’Amico C., Innocenti F. & Sassi F.P. (1987): Magmatismo e metamorfismo. UTET
• Innocenti F., Rocchi S. & Triglia R. (1999:) La classificazione delle rocce vulcaniche e subvulcaniche: schema operativo per il progetto CARG.
• Carmichael I.S.E., Turner F.J. & Verghoogen J. (1974): Igneous Petrology. McGraw-Hill.

Photo
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Sanidine, plagioclase, pyroxene (green) and altered olivine crystals in a Latite from Bolsena lake (Latium, Italy). PPL image, 2x (Field of view = 7mm)
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Sanidine, plagioclase, pyroxene (green) and altered olivine crystals in a Latite from Bolsena lake (Latium, Italy). PPL image, 2x (Field of view = 7mm)
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Sanidine, plagioclase and altered olivine crystals in a Latite from Bolsena lake (Latium, Italy). PPL image, 2x (Field of view = 7mm)
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Sanidine, plagioclase and altered olivine crystals in a Latite from Bolsena lake (Latium, Italy). XPL image, 2x (Field of view = 7mm)
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Biotite, sanidine, plagioclase and pyroxene (green) in a Latite from Bolsena lake (Latium, Italy). PPL image, 2x (Field of view = 7mm)
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Biotite, sanidine, plagioclase and pyroxene (green) in a Latite from Bolsena lake (Latium, Italy). PPL image, 2x (Field of view = 7mm)
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Sanidine and pyroxene in a Latite from Bolsena lake (Latium, Italy). XPL image, 2x (Field of view = 7mm)
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Sanidine and pyroxene in a Latite from Bolsena lake (Latium, Italy). XPL image, 2x (Field of view = 7mm)
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Sanidine and pyroxene in a Latite from Bolsena lake (Latium, Italy). XPL image, 2x (Field of view = 7mm)
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Biotite, plagioclase and pyroxene + plagioclase cluster in a Latite from Bolsena lake (Latium, Italy). PPL image, 2x (Field of view = 7mm)
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Biotite, plagioclase and pyroxene + plagioclase cluster in a Latite from Bolsena lake (Latium, Italy). XPL image, 2x (Field of view = 7mm)
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Pyroxene + plagioclase cluster in a Latite from Bolsena lake (Latium, Italy). PPL image, 2x (Field of view = 7mm)
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Pyroxene + plagioclase cluster in a Latite from Bolsena lake (Latium, Italy). XPL image, 2x (Field of view = 7mm)
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Biotite, plagioclase and pyroxene + plagioclase cluster in a Latite from Bolsena lake (Latium, Italy). XPL image, 2x (Field of view = 7mm)
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Pyroxene + plagioclase cluster in a Latite from Bolsena lake (Latium, Italy). XPL image, 2x (Field of view = 7mm)