鹼性玄武岩

鹼性玄武岩（Alkali basalt）或鹼性橄欖石玄武岩（alkali olivine basalt）是一種深色斑狀噴出岩 ( 火成岩的一種 ) ^[2]，常發現於與火山活動有關的海洋和大陸地區，如海島、大陸裂谷和火山場等^[3]。鹼性玄武岩的特點是相對於其他玄武岩而言，含鹼（氧化鈉和氧化鉀）量相對較高，並且基質和斑晶中存在橄欖石和富鈦普通輝石以及符合 CIPW標準的霞石^[4]^[5]。

地球化學特徵

總體鹼-矽示意圖，鹼性玄武岩通常位於玄武岩區（B區）左上角^[6]。

鹼性玄武岩在化學上被歸類為總體鹼與二氧化矽（TAS）示意圖B區（玄武岩）中的岩石，它的CIPW標準中含有霞石。不含標準霞石的玄武岩特徵為亞鹼性玄武岩，包括拉斑玄武岩和鈣鹼性玄武岩^[6]。

岩相

鹼性玄武岩基質主要由橄欖石、富鈦輝石和斜長石長石組成，可能有鹼性長石或似長石間隙，但缺乏二氧化矽礦物，如紫蘇輝石和石英^[4]。

斑晶普遍存在於鹼性玄武岩中，與基質類似，通常由橄欖石和富鈦輝石組成，但也可能含有斜長石和出現率較低的氧化鐵^[3]^[4]。

地質背景

鹼性玄武岩可發現於與火山活動相關的地區，如海洋島嶼（夏威夷、馬德拉群島^[7]、聖赫倫那^[8]、阿森松島）等以及大陸裂谷和火山區^[3]。大陸鹼性玄武岩可在各大洲發現，突出的例子是美國格蘭德河裂谷（Rio Grande Rift）、東非裂谷和帕里埃克火山區^[9]。

前蘇聯金星8號上的伽馬射線光譜儀測量結果表明，它降落在了金星鹼性玄武岩上^[10]。

參考資料

^ 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 （英語）.
^ Basalt | Definition, Properties, & Facts. Encyclopedia Britannica. [2021-11-03]. （原始內容存檔於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. (編). 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 （英語）.
^ 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 （英語）.
^ Farmer, G.L. Rudnick, R.L. , 編. 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.

外部連結

Alkali basalt on Mindat.org （頁面存檔備份，存於網際網路檔案館）

[1] 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 （英語）.

[2] Basalt | Definition, Properties, & Facts. Encyclopedia Britannica. [2021-11-03]. （原始內容存檔於2021-12-02）.

[:2-3] 3.0 ^3.1 ^3.2 Haldar, S. K. Platinum-Nickel-Chromium Deposits. Elsevier. 2017: 45. ISBN 9780128020418.

[:0-4] 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.

[5] 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.

[:3-6] 6.0 ^6.1 Le Maitre, R. W.; Streckeisen, A.; Zanettin, B.; Le Bas, M. J.; Bonin, B.; Bateman, P. (編). Igneous Rocks: A Classification and Glossary of Terms . Cambridge University Press. 2002: 36–37. ISBN 9780521662154.

[7] 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 （英語）.

[8] 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 （英語）.

[9] Farmer, G.L. Rudnick, R.L. , 編. Treatise on Geochemistry: The crust. Gulf Professional Publishing. 2005: 97. ISBN 9780080448473.

[Ulivi159-10] Ulivi, Paolo; Harland, David M. Robotic Exploration of the Solar System Part I: The Golden Age 1957-1982. Springer. 2007: 159–160. ISBN 9780387493268.

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