The paper presents the results of geochemical and Sm–Nd isotope study of the metavolcanic rocks of the western part of the Tukuringra Terrane, one of the largest terranes of the Mongol–Okhotsk fold belt. It is shown that among the metavolcanics of the Teplokluchevskaya, Garmakan, and Algaja formations there are varieties similar to OIB and N-MORB, yet no rocks revealing features characteristic of the subduction origin are found. Being of Early Mesozoic age, the studied metabasalts are the youngest rocks within the Mongol–Okhotsk belt. The Lower Mesozoic deposits of the western part of the Tukuringra Terrane, including the volcanics of the OIB and N-MORB types, may have been relics of the residual ocean basin. The data obtained reflect the absence of subduction processes in the Late Triassic–Middle Jurassic at the final stages of the formation of the Mongol–Okhotsk fold belt. The closure of the Early Mesozoic basin was probably due to large-scale shear displacements.

中文翻译：

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蒙古–鄂霍次克褶皱带Tukuringra地带西部早期中生代玄武岩的地球化学特征

本文介绍了Tukuringra地带西部的超火山岩的地球化学和Sm-Nd同位素研究结果，该地区是蒙古-鄂霍次克褶皱带最大的地层之一。结果表明，在Teplokluchevskaya，Garmakan和Algaja地层的超火山岩中，存在与OIB和N-MORB相似的变种，但没有发现具有俯冲成因特征的岩石。作为中生代早期，研究的玄武岩是蒙古-鄂霍次克带内最年轻的岩石。Tukuringra Terrane西部的下部中生代沉积物，包括OIB和N-MORB类型的火山，可能是残留海盆的遗迹。所获得的数据反映了在蒙古-鄂霍次克褶皱带形成的最后阶段，晚三叠世-中侏罗世没有俯冲过程。早中生代盆地的关闭可能是由于大规模的剪切位移造成的。