The Middle (?) to Late Paleozoic ophiolite association of West Chukotka comprises the large Aluchin, Atamanov, and Gromadnen–Vurguveem mafic–ultramafic massifs, which are spatially associated with Late Paleozoic volcanic rocks of the Yarakvaam terrane. This paper is devoted to the dikes of the Gromadnen–Vurguveem massif, which form two spatially isolated complexes: “dikes 1” and “dikes 2.” Both complexes intrude the plutonic gabbroids of the massif. The “dikes 1” complex forms a dike body nappe structurally linked with Paleozoic island-arc volcanics. The rocks of the complex are differentiated from basalts to dacites and chemically correspond to island-arc tholeiites. The “dikes 2” complex consists of separate basaltic dikes, some of which are similar to the “dike 1” rocks. The Ar/Ar dating of these samples gave 264–266 Ma. The other part of the rocks of this complex shows mixed signatures of island-arc tholeiites and N-MORB. It was concluded that the studied dike complexes, together with the earlier studied dikes of the Aluchin massif, marks the early (Late Permian) stage of the back-arc basin evolution. The Late Triassic dikes of the Atamanov massif reflect a more mature stage in the evolution of this basin.

中文翻译：

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西楚科奇的Gromadnen–Vurguveem Ophiolite地块的Dike复合体：组成和地球动力学背景

西楚科奇的中（晚期）到晚古生代蛇绿岩组合包括大的Aluchin，Atamanov和Gromadnen-Vurguveem镁铁质-超镁铁质断层，它们在空间上与Yarakvaam地层的晚古生代火山岩有关。本文专门针对Gromadnen-Vurguveem地块的堤防，该堤防形成两个空间隔离的复合体：“堤防1”和“堤防2”。两种复合物都侵入了地块的古生物。“堤坝1”复合体形成堤坝体，其结构与古生代岛弧火山有关。该复合物的岩石从玄武岩到辉石都不同，并且在化学上对应于岛弧型菱镁矿。“堤防2”群由分开的玄武岩堤构成，其中一些类似于“堤1”岩体。这些样品的Ar / Ar测年得到264-266 Ma。该复合体的另一部分岩石显示出岛弧型冲孔岩和N-MORB的混合特征。得出的结论是，所研究的堤防复合体以及对Aluchin地块的较早研究的堤防，标志着后弧盆地演化的早期（晚二叠纪）阶段。阿塔玛诺夫地块的三叠纪晚期堤防反映了该盆地演化的更成熟阶段。