Vanadium in peridotites, mantle redox and tectonic environments: Archean to present
Vanadium in peridotites, mantle redox and tectonic environments: Archean to present
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DOI：
10.1016/s0012-821x(01)00582-9
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发表时间：
2002-01-30
影响因子：
5.3
通讯作者：
Canil, D
中科院分区：
文献类型：
--
作者：
Canil, D
钒（V）在尖晶石之间分配的新测量。本文给出了地幔固相线上的石榴石和似鸽子岩的高压（P）辉石和镁液体与氧逸度（fO（2））的关系。尖晶石-液体实验表明，尖晶石中Cr/Al对分配有影响，并进一步表明，在fO（2）的熔体中，V以V3+、V4+和V5-的形式存在。钒是温和的不兼容的'鸽子'辉石和石榴石之间的4.5和6.5 GPa的地幔固相线。结合橄榄岩熔融实验的成分数据，分析了地幔矿物和熔体之间对钒的fO（2）敏感的分配，模拟了在1.0 ~ 7.0GPa的不同fO（2）条件下，橄榄岩残留物中钒和At的协变。在1.0 ~ 3.0GPa的部分熔融模型中，深海橄榄岩中V和At在fO（2）s时的协变与大洋中脊玄武岩中V和At在fO（2）s时的协变非常相似。在一系列构造环境中，许多造山带地幔岩和尖晶石二辉橄榄岩捕虏体代表形成于fO（2）高于洋中脊的地幔。大部分尖晶石相太古代地幔岩石圈形成于fO（2）s，明显高于深海橄榄岩，可能与会聚边缘（弧）构造环境有关。它可能是在高得多的压力下形成的（7.0 GPa），或在尖晶石相在较低的压力，但在显着较高的fO（2）比深海橄榄岩观察。大洋石榴子石相地幔与尖晶石相弧幔的叠瓦作用可以解释某些太古代地幔的数据。总的来说，太古代地幔熔融和残留物的数据清楚地表明，模型不能指望减少。含有氢和一氧化碳的幔源火山气体，以产生早期生命合成，或促进氢逃逸和太古代地球系统的逐渐氧化。(C)2002 Elsevier Science B. V.保留所有权利。
New measurements of partition of vanadium (V) between spinel. garnet and a pigeonite-like high pressure (P) pyroxene and magnesian liquids on the mantle solidus as a function of oxygen fugacity (fO(2)) are presented. The spinel-liquid experiments show an effect of Cr/Al in spinel on partitioning, and further suggest that V exists as V3+, V4+ and V5- in melts at terrestrial fO(2). Vanadium is mildly incompatible in both 'pigeonitic' pyroxene and garnet between 4.5 and 6.5 GPa on the mantle solidus. Analysis of the fO(2)-sensitive partitioning for V between mantle minerals and melts are combined with compositional data from peridotite melting experiments to model the covariation of V and At in peridotite residues produced by non-modal, fractional melting under different fO(2) from 1.0 to 7.0 GPa. The partial melting models at 1.0 to 3.0 GPa tit the covariation of V and At in abyssal peridotites quite well at fO(2)s similar to those of mid-ocean ridge basalt. Many orogenic massifs and spinel lherzolite xenoliths represent mantle that formed at fO(2) higher than that produced at mid-ocean ridges in a range of tectonic environments. A large proportion of spinel-facies Archean cratonic lithosphere formed at fO(2)s significantly higher than those of abyssal peridotites possibly linking its formation to a convergent margin (arc) tectonic setting, The case for garnet-facies cratonic mantle is equivocal; it may have formed at significantly higher pressures (7.0 GPa), or within the spinel-facies at lower pressures but at significantly higher fO(2) than is observed for abyssal peridotites. The imbrication of both oceanic garnet-facies mantle with spinel-facies arc mantle may explain the datasets for some Archean cratons. Overall, the data for Archean mantle melts and residues make clear that models cannot look to reduced. mantle-derived volcanic gases containing H, and CO to engender early life synthesis, or to promote hydrogen escape and gradual oxygenation of the Archean earth system. (C) 2002 Elsevier Science B.V. All rights reserved.