Alkali basalt or alkali olivine basalt is a dark-colored, porphyritic volcanic rock[2] usually found in oceanic and continental areas associated with volcanic activity, such as oceanic islands, continental rifts and volcanic fields.[3] Alkali basalt is characterized by relatively high alkali (Na2O and K2O) content relative to other basalts and by the presence of olivine and titanium-rich augite in its groundmass and phenocrysts, and nepheline in its CIPW norm.[4][5]
- ^ Skewes, Milka Alexandra; Stern, Charles R. (1979). "Petrology and geochemistry of alkali basalts and ultramafic inclusions from the palei-aike volcanic field in Southern Chile and the origin of the patagonian plateau lavas". Journal of Volcanology and Geothermal Research. 6 (1–2): 3–25. Bibcode:1979JVGR....6....3S. doi:10.1016/0377-0273(79)90044-1.
- ^ "Basalt | Definition, Properties, & Facts". Encyclopedia Britannica.
- ^ Haldar, S. K. (2017). Platinum-Nickel-Chromium Deposits. Elsevier. p. 45. ISBN 9780128020418.
- ^ Winter, John DuNann (2001). An Introduction to Igneous and Metamorphic Petrology. Upper Saddle River, New Jersey: Prentice Hall. pp. 148, 182. ISBN 0132403420.
- ^ Irvine, T. N.; Baragar, W. R. A. (1971). "A Guide to the Chemical Classification of the Common Volcanic Rocks". Canadian Journal of Earth Sciences. 8 (5): 523–548. Bibcode:1971CaJES...8..523I. doi:10.1139/e71-055.