No direct contribution of recycled crust in Icelandic basalts
No direct contribution of recycled crust in Icelandic basalts
复制标题
DOI：
10.7185/geochemlet.1728
复制
发表时间：
2017-07
期刊：
影响因子：
--
通讯作者：
S. Lambart
中科院分区：
文献类型：
--
作者：
S. Lambart
使用Melt-PX模拟非均质地幔的减压熔融，研究了源区岩性的主要元素组成对岩浆生产力的作用，以及与主体地幔组成无关的微量元素和同位素熔体组成。我的计算表明，岩浆产生的体积不受岩性非均质性的显著影响，而取决于主体地幔的组成。然而，等化学块状地幔可以产生不同的微量元素和同位素熔体成分，这取决于源区存在的岩性的主要元素组成。结果表明，冰岛裂谷带的地壳厚度与源区约10%的再生地壳厚度一致，但也表明不需要涉及来自再生玄武岩成分的熔体的贡献来解释裂谷带冰岛玄武岩的成分变化，而是促进再生地壳与橄榄岩之间的固相反应形成的含橄榄石混合岩的贡献。
Using Melt-PX to model the decompression melting of a heterogeneous mantle, I investigated the role of major-element composition of the lithologies present in the source on magmatic productivity, and trace element and isotopic melt compositions, independently of the bulk mantle composition. My calculations demonstrate that the volume of magma produced is not significantly affected by the nature of the lithological heterogeneity, but depends on the bulk mantle composition. However, an isochemical bulk mantle can produce contrasting trace element and isotopic melt compositions depending on the major-element compositions of the lithologies present in the source. Results show that the observed crust thickness of the Icelandic rift zones is consistent with about 10 % of recycled crust in the source, but also demonstrate there is no need to involve the contribution of melts derived from a recycled basalt component to explain the compositional variability of the Icelandic basalts in rift zones, and rather advance the contribution of olivine-bearing hybrid lithologies formed by solid-state reactions between the recycled crust and the peridotite.