Ankaramite

Ankaramite, first described in 1916 in Ankaramy (Madagascar), is a pyroxene-rich basalt or basanite in which pyroxene is considerably more abundant than olivine. It is the pyroxene-rich alkaline equivalent of a picrite. Ankaramites may form as cumulates during high temperature clinopyroxene crystallisation, they might also evolve by partial melting of pyroxene-rich mantle wehrlite. Ankaramite is found in ocean islands and island arcs.

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Green-yellow olivine and black pyroxene crystals. Ankaramite from Port Louis, Mauritius. From (Hunterian Museum).




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Yellow-orange olivine (altered) and black pyroxene crystals. Ankaramite from La Palma, Canary Islands. From (Sand atlas).



Sample kindly given to me by F.Stoppa (University of Chieti, Italy).

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


Photo Foto
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Pyroxene and leucite crystals set in a fine-grained groundmass. Ankaramite from Fuerta ventura. PPL image, 10x (Field of view = 2mm)
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Pyroxene and leucite crystals set in a fine-grained groundmass. Ankaramite from Fuerta ventura. XPL image, 10x (Field of view = 2mm)
ankaramite(3).jpg

Pyroxene and leucite crystals set in a fine-grained groundmass. Ankaramite from Fuerta ventura. PPL image, 10x (Field of view = 2mm)
ankaramite(4).jpg

Pyroxene and leucite crystals set in a fine-grained groundmass. Ankaramite from Fuerta ventura. XPL image, 10x (Field of view = 2mm)
ankaramite(5).jpg

Pyroxene and leucite crystals set in a fine-grained groundmass. Ankaramite from Fuerta ventura. PPL image, 10x (Field of view = 2mm)
ankaramite(6).jpg

Pyroxene and leucite crystals set in a fine-grained groundmass. Ankaramite from Fuerta ventura. PPL image, 10x (Field of view = 2mm)
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Pyroxene and leucite crystals set in a fine-grained groundmass. Ankaramite from Fuerta ventura. PPL image, 10x (Field of view = 2mm)
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Pyroxene, leucite and altered olivine crystals set in a fine-grained groundmass. Ankaramite from Fuerta ventura. PPL image, 10x (Field of view = 2mm)
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Pyroxene, leucite and altered olivine crystals set in a fine-grained groundmass. Ankaramite from Fuerta ventura. XPL image, 10x (Field of view = 2mm)
ankaramite(10).jpg

Pyroxene and leucite crystals set in a fine-grained groundmass. Ankaramite from Fuerta ventura. PPL image, 10x (Field of view = 2mm)
ankaramite(11).jpg

Pyroxene and leucite crystals set in a fine-grained groundmass. Ankaramite from Fuerta ventura. XPL image, 10x (Field of view = 2mm)
ankaramite(12).jpg

Pyroxene and leucite crystals set in a fine-grained groundmass. Ankaramite from Fuerta ventura. XPL image, 10x (Field of view = 2mm)
ankaramite(13).jpg

Pyroxene and leucite crystals set in a fine-grained groundmass. Ankaramite from Fuerta ventura. XPL image, 10x (Field of view = 2mm)
ankaramite(14).jpg

Pyroxene and leucite crystals set in a fine-grained groundmass. Ankaramite from Fuerta ventura. PPL image, 10x (Field of view = 2mm)
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Pyroxene and leucite crystals set in a fine-grained groundmass. Ankaramite from Fuerta ventura. PPL image, 10x (Field of view = 2mm)
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Pyroxene, leucite and altered olivine crystals set in a fine-grained groundmass. Ankaramite from Fuerta ventura. PPL image, 10x (Field of view = 2mm)
ankaramite(17).jpg

Pyroxene, leucite and altered olivine crystals set in a fine-grained groundmass. Ankaramite from Fuerta ventura. PPL image, 10x (Field of view = 2mm)
ankaramite(18).jpg

Pyroxene, leucite and altered olivine crystals set in a fine-grained groundmass. Ankaramite from Fuerta ventura. PPL image, 10x (Field of view = 2mm)