Abstract

Based on new geological, structural, mineralogical, geochemical, and isotope (Sm–Nd, Rb–Sr, and U–Th–Pb) data for igneous intrusions and metamorphic rocks of the Zimoveinyi massif, an adakite-gabbroid association was identified for the first time in the Yenisei Ridge (southwestern framing of the Siberian craton). This study demonstrates that the adakites (quartz diorites, tonalites, and plagiogranites) and associating gabbro-anorthosites of this massif formed in the interval 576–546 Ma (U–Th–Pb zircon SHRIMP-II analysis) at the final Neoproterozoic evolution stage of the active continental margin of the Siberian craton. Our results point to a genetic relationship between the adakites and the host Nb-enriched metabasites of the Zimoveinyi massif. The studied late Neoproterozoic adakites might have formed in the setting of transform strike-slip of lithospheric plates during a halt in subduction from both crustal and mantle-crustal source, similarly to Cenozoic igneous complexes of the transform margin in the eastern framing of Eurasia.

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