Garnet of eclogite (formerly termed garnet clinopyroxenite) hosted in lenses of orogenic garnet peridotite from the Granulitgebirge, NW Bohemian Massif, contains unique inclusions of granitic melt, now either glassy or crystallized. Analysed glasses and re‐homogenized inclusions are hydrous, peraluminous, and enriched in highly incompatible elements characteristic of the continental crust such as Cs, Li, B, Pb, Rb, Th, and U. The original melt thus represents a pristine, chemically evolved metasomatic agent, which infiltrated the mantle via deep continental subduction during the Variscan orogeny. The bulk chemical composition of the studied eclogites is similar to that of Fe‐rich basalt and the enrichment in LILE and U suggest a subduction‐related component. All these geochemical features confirm metasomatism. In comparison with many other garnet+clinopyroxene‐bearing lenses in peridotites of the Bohemian Massif, the studied samples from Rubinberg and Klatschmühle are more akin to eclogite than pyroxenites, as reflected in high jadeite content in clinopyroxene, relatively low Mg, Cr, and Ni but relatively high Ti. However, trace elements of both bulk rock and individual mineral phases show also important differences making these samples rather unique. Metasomatism involving a melt requiring a trace element pattern very similar to the composition reported here has been suggested for the source region of rocks of the so‐called durbachite suite, that is, ultrapotassic melanosyenites, which are found throughout the high‐grade Variscan basement. Moreover, the Th, U, Pb, Nb, Ta, and Ti patterns of these newly studied melt inclusions (MI) strongly resemble those observed for peridotite and its enclosed pyroxenite from the T‐7 borehole (Staré, České Středhoři Mountains) in N Bohemia. This suggests that a similar kind of crustal‐derived melt also occurred here. This study of granitic MI in eclogites from peridotites has provided the first direct characterization of a preserved metasomatic melt, possibly responsible for the metasomatism of several parts of the mantle in the Variscides.

中文翻译：

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在Variscan地幔岩石中现场测量的隐密交代剂：榴辉石石榴石中的熔融包裹体，德国格拉纳吉博格

榴辉岩的石榴石（以前称为石榴石斜辉石）装在来自西北波西米亚山地Granulitgebirge的造山石榴石橄榄石的晶状体中，含有独特的花岗岩熔体包裹体，无论是玻璃状还是结晶状。经过分析的玻璃和重新均质的夹杂物是含水的，高铝质的，并富含大陆壳特有的高度不相容元素，例如Cs，Li，B，Pb，Rb，Th和U。变质作用剂，在瓦里斯卡造山运动中通过深陆俯冲作用渗透到地幔中。研究的榴辉岩的大体化学组成与富铁玄武岩的化学组成相似，而LILE和U的富集则暗示了与俯冲有关的成分。所有这些地球化学特征证实了交代作用。与波西米亚山体橄榄岩中许多其他带有石榴石和斜晶石的晶状体相比，Rubinberg和Klatschmühle的研究样品比辉石晶石更类似于榴辉岩，这体现在斜晶石中翡翠含量高，Mg，Cr和Ni含量相对较低。但钛含量较高。但是，大块岩石和单个矿物相的痕量元素也显示出重要的差异，使得这些样品相当独特。对于所谓的Durbachite套件的岩石的源区，即超钾质的黑褐藻岩，在整个高级Variscan地下室中都发现了涉及熔体的交代作用，该熔体需要与此处报道的成分非常相似的微量元素。而且，Th，U，Pb，Nb，Ta，这些新近研究的熔体夹杂物（MI）的Ti模式和Ti模式与N波西米亚T-7钻孔（Staré，ČeskéStředhoři山）中的橄榄岩及其封闭的辉石体观察到的模式相似。这表明在这里也发生了类似的地壳衍生熔体。橄榄岩中榴辉岩中花岗岩MI的这项研究提供了保存的交代熔体的第一个直接特征，可能是Variscides中地幔几个部分的交代作用。