橄长岩(英语:Troctolite) 是一种镁铁质侵入岩类型。 它主要由变量的橄榄石和钙质斜长石以及少量辉石组成。 它是富含橄榄石的斜长岩,或贫辉石的辉长岩。 然而,与辉长岩不同的是,当橄榄岩进行部分熔融时,其成分上和和橄长岩不同。 因此,橄长岩必然是从熔体中分离出来的火成堆积岩 [1]

橄长岩
火成岩
阿波罗 17 着陆点的橄长岩76535
成分
橄榄石, 钙质 斜长石, 及少量辉石

产状 编辑

橄长岩通常产于层状侵入岩中,例如西澳大利亚太古宙 Windimurra 侵入体、拉布拉多北部的 Voisey's Bay 镍-铜-钴岩浆硫化物矿床[2],蒙大拿州斯蒂尔沃特火成岩复合体、北美德卢斯复合体 Midcontinent Rift[3],和苏格兰 Rùm 岛的第三纪朗姆层状侵入岩 [4]。在南非 Bushveld 火成岩复合体的 Merensky 礁和康沃尔的Lizard复合体中也发现了橄长岩[5]

参考文献 编辑

  1. ^ Emeleus, C. H.; Troll, V. R. (2014-08-01). "The Rum Igneous Centre, Scotland". Mineralogical Magazine. 78 (4): 805–839. doi:10.1180/minmag.2014.078.4.04. ISSN 0026-461X.
  2. ^ Sulphide segregation in the Mushuau Intrusion of northern Labrador as recorded by nickel-in-olivine magmatic stratigraphy abstract, BRADLEY, L.A. and SYLVESTER, P.J., Department of Earth Sciences, Memorial University of Newfoundland, St. John's, NF, A1B 3X5
  3. ^ Paces, James B.; Miller, James D. (1993). "Precise U-Pb ages of Duluth Complex and related mafic intrusions, northeastern Minnesota: Geochronological insights to physical, petrogenetic, paleomagnetic, and tectonomagmatic processes associated with the 1.1 Ga Midcontinent Rift System". Journal of Geophysical Research: Solid Earth. 98 (B8): 13997–14013. doi:10.1029/93JB01159. ISSN 0148-0227.
  4. ^ http://www.turnstone.ca/rhumal.htm页面存档备份,存于互联网档案馆) Troctolite (allivalite): Isle of Rhum, northwestern Scotland
  5. ^ The Lizard