碱性玄武岩
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碱性玄武岩(Alkali basalt)或碱性橄榄石玄武岩(alkali olivine basalt)是一种深色斑状喷出岩 ( 火成岩的一种 ) [2],常发现于与火山活动有关的海洋和大陆地区,如海岛、大陆裂谷和火山场等[3]。碱性玄武岩的特点是相对于其他玄武岩而言,含碱(氧化钠和氧化钾)量相对较高,并且基质和斑晶中存在橄榄石和富钛普通辉石以及符合 CIPW标准的霞石[4][5]。
地球化学特征
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碱性玄武岩在化学上被归类为总体碱与二氧化硅(TAS)示意图B区(玄武岩)中的岩石,它的CIPW标准中含有霞石。不含标准霞石的玄武岩特征为亚碱性玄武岩,包括拉斑玄武岩和钙碱性玄武岩[6]。
岩相
碱性玄武岩基质主要由橄榄石、富钛辉石和斜长石长石组成,可能有碱性长石或似长石间隙,但缺乏二氧化硅矿物,如紫苏辉石和石英[4]。
斑晶普遍存在于碱性玄武岩中,与基质类似,通常由橄榄石和富钛辉石组成,但也可能含有斜长石和出现率较低的氧化铁[3][4]。
地质背景
碱性玄武岩可发现于与火山活动相关的地区,如海洋岛屿(夏威夷、马德拉群岛[7]、圣赫勒拿[8]、阿森松岛)等以及大陆裂谷和火山区[3]。大陆碱性玄武岩可在各大洲发现,突出的例子是美国格兰德河裂谷(Rio Grande Rift)、东非裂谷和帕里埃克火山区[9]。
前苏联金星8号上的伽马射线光谱仪测量结果表明,它降落在了金星碱性玄武岩上[10]。
参考资料
- ^ Skewes, Milka Alexandra; Stern, Charles R. 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. 1979, 6 (1–2): 3–25. Bibcode:1979JVGR....6....3S. doi:10.1016/0377-0273(79)90044-1 (英语).
- ^ Basalt | Definition, Properties, & Facts. Encyclopedia Britannica. [2021-11-03]. (原始内容存档于2021-12-02).
- ^ 3.0 3.1 3.2 Haldar, S. K. Platinum-Nickel-Chromium Deposits. Elsevier. 2017: 45. ISBN 9780128020418.
- ^ 4.0 4.1 4.2 Winter, John DuNann. An Introduction to Igneous and Metamorphic Petrology. Upper Saddle River, New Jersey: Prentice Hall. 2001: 148, 182. ISBN 0132403420.
- ^ Irvine, T. N.; Baragar, W. R. A. A Guide to the Chemical Classification of the Common Volcanic Rocks. Canadian Journal of Earth Sciences. 1971, 8 (5): 523–548. Bibcode:1971CaJES...8..523I. doi:10.1139/e71-055.
- ^ 6.0 6.1 Le Maitre, R. W.; Streckeisen, A.; Zanettin, B.; Le Bas, M. J.; Bonin, B.; Bateman, P. (编). Igneous Rocks: A Classification and Glossary of Terms
. Cambridge University Press. 2002: 36–37. ISBN 9780521662154.
- ^ Hughes, D. J.; Brown, G. C. Basalts from Madeira: A petrochemical contribution to the genesis of oceanic alkali rock series. Contributions to Mineralogy and Petrology. 1972, 37 (2): 91–109. Bibcode:1972CoMP...37...91H. ISSN 1432-0967. doi:10.1007/BF00371069 (英语).
- ^ Baker, Ian. Petrology of the Volcanic Rocks of Saint Helena Island, South Atlantic. GSA Bulletin. 1969, 80 (7): 1283–1310. Bibcode:1969GSAB...80.1283B. ISSN 0016-7606. doi:10.1130/0016-7606(1969)80[1283:POTVRO]2.0.CO;2 (英语).
- ^ Farmer, G.L. Rudnick, R.L. , 编. Treatise on Geochemistry: The crust. Gulf Professional Publishing. 2005: 97. ISBN 9780080448473.
- ^ Ulivi, Paolo; Harland, David M. Robotic Exploration of the Solar System Part I: The Golden Age 1957-1982. Springer. 2007: 159–160. ISBN 9780387493268.