Major- and trace-elements in cratonic mantle eclogites and pyroxenites reveal heterogeneous sources and metamorphic processing of low-pressure protoliths
Major- and trace-elements in cratonic mantle eclogites and pyroxenites reveal heterogeneous sources and metamorphic processing of low-pressure protoliths
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DOI：
10.1016/j.lithos.2016.07.026
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发表时间：
2016-10-01
期刊：
影响因子：
3.5
通讯作者：
Jacob, Dorrit E.
中科院分区：
文献类型：
--
作者：
Aulbach, Sonja;Jacob, Dorrit E.
有越来越多的证据表明，在现今再生的洋底中，白垩纪地幔蛇绿岩捕虏体是由低压形成的。因为他们的原岩最终来自对流地幔，他们的研究可能会产生前所未有的见解，但鲜为人知的古地球动力学制度，一旦初级（部分结晶，积累，混合）和次级过程（金伯利岩渗透，交代作用）影响他们的组成被理解。这是通过使用分析和地质学上最强大的元素（主要和次要元素，过渡金属，稀土元素）的诊断浓度或比率，并通过与天然和模拟类似物的比较来实现的。在这里，从文献中提取的矿物成分被用来重建大块岩石，并将样品分配给榴辉岩（进一步分为高Mg，低Mg和高Ca类型），辉石岩及其辉长岩（Eu* >1.05）对应物。
There is a growing body of evidence for the origin of cratonic mantle edogite xenoliths by low-pressure formation in now-recycled ocean floors. Because they have protoliths ultimately derived from the convecting mantle, their study can potentially yield unprecedented insights into as yet little-understood palaeo-geodynamic regimes, once primary (fractional crystallisation, accumulation, mixing) and secondary processes (kimberlite infiltration, metasomatism) affecting their compositions are understood. This is achieved using diagnostic concentrations or ratios of the analytically and geologically most robust elements (major and minor elements, transition metals, REE), and aided by comparison to natural and modelled analogues. Here, mineral compositions taken from the literature were used to reconstruct bulk rocks and assign the samples to eclogites (further divided into high-Mg, low-Mg and high-Ca types), pyroxenites and their gabbroic (Eu* >1.05) counterparts.Various protolith types formed predominantly by