Upper-mantle amphiboles: a review
Upper-mantle amphiboles: a review
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上地幔角闪石：综述
作者：
J. Dawson;J. Smith
摘要 回顾了铬-透辉石系和铝辉石系捕虏体中出现的角闪石的结构和化学数据；作为各种火成岩环境中的巨型晶体；也作为上地幔橄榄岩构造切片中的次要阶段。给出了来自坦桑尼亚的二辉橄榄岩中的斜长辉石和伴生相以及南非金伯利岩捕虏体中取代石榴石的钾长辉石的新数据。结论是，只有Cr-透辉石系块体中的闪长岩和含钛闪长岩是在上地幔条件下形成的。尽管正如 Oxburgh (1964) 所指出的那样，角闪石存在于上地幔中，但其相对较少表明它不是主要的碱和水储存场所；金云母是更有可能的候选者，特别是在上地幔的较深处。
Abstract Textural and chemical data are reviewed for amphiboles occurring in Cr-diopside series and Al-augite series xenoliths; as megacrysts in a variety of igneous environments; and also as minor phases in tectonic slices of upper-mantle peridotite. New data are given for pargasite and associated phases in a lherzolite from Tanzania and in kelyphite replacing garnet in a S. African kimberlite xenolith. It is concluded that only pargasites and titaniferous pargasites occurring in Cr-diopside series blocks have formed under upper-mantle conditions. Although amphibole is present in the upper mantle, as suggested by Oxburgh (1964), its relative paucity suggests it is not a major alkali and water storage site; phlogopite is a more likely candidate, particularly in the deeper parts of the upper mantle.