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.

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

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

• Cox et al. (1979): The Interpretation of Igneous Rocks, George Allen and Unwin, London.
• Howie, R. A., Zussman, J., & Deer, W. (1992). An introduction to the rock-forming minerals (p. 696). Longman.
• Le Maitre, R. W., Streckeisen, A., Zanettin, B., Le Bas, M. J., Bonin, B., Bateman, P., & Lameyre, J. (2002). Igneous rocks. A classification and glossary of terms, 2. Cambridge University Press.
• Middlemost, E. A. (1986). Magmas and magmatic rocks: an introduction to igneous petrology.
• Shelley, D. (1993). Igneous and metamorphic rocks under the microscope: classification, textures, microstructures and mineral preferred-orientations.
• Vernon, R. H. & Clarke, G. L. (2008): Principles of Metamorphic Petrology. Cambridge University Press.

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