過鹼性岩石

過鹼性岩石（英語：Peralkaline rock）是指缺乏鋁的火成岩。它們的鈉和鉀的含量超過了形成長石所需的含量。通常岩石有霓石(aegerine)和铁钠闪石 (riebeckite)就代表過鹼性的地質環境。例如過鹼性流紋岩、钠闪碱流岩(comendite) 和碱流岩(pantellerite) ^[1]，其中 comendite 是含長石質更多（含二氧化矽多）的岩石^[2]。另一個例子是在北大西洋 Rockall 島的高鹼性花崗岩 ^[3]。

過鹼性岩石代表與大陸裂谷相關的火山活動（例如肯尼亞中部東非裂谷的過鹼性流紋岩）以及與大陸和海洋熱點的火山活動（例如澳大利亞東部玻璃屋山和加那利群島的過鹼性流紋岩）^[4] ^[5]^[6]。火山活動在俯衝帶亦有報導過鹼性岩石的實例（例如意大利的撒丁島）^[5]。

當分離結晶去除斜長石，比去除鎂鐵質礦物更多時，可能會形成過鹼性岩漿^[7]。

參考文獻

^ Philpotts, Anthony R.; Ague, Jay J. (2009). Principles of igneous and metamorphic petrology (2nd ed.). Cambridge, UK: Cambridge University Press. pp. 143–146. ISBN 9780521880060.
^ McBirney, Alexander R. (1984). Igneous petrology. San Francisco, Calif.: Freeman, Cooper. p. 502. ISBN 0198578105.
^ Sutherland, D. S. (editor) (1982). Igneous Rocks of the British Isles. Chichester: John Wiley and Sons. p. 413. ISBN 978-0-471-27810-8.
^ Scaillet, Bruno; Macdonald, Ray (2003). "Experimental Constraints on the Relationships between Peralkaline Rhyolites of the Kenya Rift Valley". Journal of Petrology. 44 (10): 1867–1894. Bibcode:2003JPet...44.1867S. doi:10.1093/petrology/egg062
^ ^5.0 ^5.1 Shao, Fengli; Niu, Yaoling; Regelous, Marcel; Zhu, Di-Cheng (2015). "Petrogenesis of peralkaline rhyolites in an intra-plate setting: Glass House Mountains, southeast Queensland, Australia". Lithos. Elsevier. 216: 196–210. Bibcode:2015Litho.216..196S. doi:10.1016/j.lithos.2014.12.015. ISSN 0024-4937.
^ Troll, Valentin R.; Schmincke, Hans-Ulrich (2002). "Magma Mixing and Crustal Recycling Recorded in Ternary Feldspar from Compositionally Zoned Peralkaline 'A', Gran Canaria, Canary Islands". Journal of Petrology. Oxford Academic Journals. 43 (2): 246. doi:10.1093/petrology/43.2.243. ISSN 0022-3530.
^ McBirney 1984, pp. 396–397.

[”1”-1] Philpotts, Anthony R.; Ague, Jay J. (2009). Principles of igneous and metamorphic petrology (2nd ed.). Cambridge, UK: Cambridge University Press. pp. 143–146. ISBN 9780521880060.

[”2”-2] McBirney, Alexander R. (1984). Igneous petrology. San Francisco, Calif.: Freeman, Cooper. p. 502. ISBN 0198578105.

[”3”-3] Sutherland, D. S. (editor) (1982). Igneous Rocks of the British Isles. Chichester: John Wiley and Sons. p. 413. ISBN 978-0-471-27810-8.

[”4”-4] Scaillet, Bruno; Macdonald, Ray (2003). "Experimental Constraints on the Relationships between Peralkaline Rhyolites of the Kenya Rift Valley". Journal of Petrology. 44 (10): 1867–1894. Bibcode:2003JPet...44.1867S. doi:10.1093/petrology/egg062

[”5”-5] 5.0 ^5.1 Shao, Fengli; Niu, Yaoling; Regelous, Marcel; Zhu, Di-Cheng (2015). "Petrogenesis of peralkaline rhyolites in an intra-plate setting: Glass House Mountains, southeast Queensland, Australia". Lithos. Elsevier. 216: 196–210. Bibcode:2015Litho.216..196S. doi:10.1016/j.lithos.2014.12.015. ISSN 0024-4937.

[”6”-6] Troll, Valentin R.; Schmincke, Hans-Ulrich (2002). "Magma Mixing and Crustal Recycling Recorded in Ternary Feldspar from Compositionally Zoned Peralkaline 'A', Gran Canaria, Canary Islands". Journal of Petrology. Oxford Academic Journals. 43 (2): 246. doi:10.1093/petrology/43.2.243. ISSN 0022-3530.

[”7”-7] McBirney 1984, pp. 396–397.

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