Genesis of manganese ores and their position in sedimentary basins of the eastern segment of the Paleoasian Ocean: Sm-Nd isotopic and geochemical evidence

The first geochemical and Sm-Nd isotopic characteristics of Neoproterozoic-Cambrian manganese ores from the south folded framing of the Siberian Craton have been obtained. For manganese ores from the Podikat deposit, Tsagan-Zaba and, in part, for Slyudyanka ore manifestations, an explicit positive Eu anomaly and variable Ce behavior are typical no depending on degree of metamorphism. In the rocks of Itantsa ore manifestation and, in part, in those of Slyudyanka, REEs have distribution patterns similar to the normal sedimentary pattern and are characterized by a gentle slope with a negative Eu anomaly and by the absence of a Ce anomaly. With the geochemical peculiarities, including REE distribution in them, on aggregate, reconstruction of vast hydrothermal fields within the south framing of the Siberian Craton and spatial position of the studied manganese basins relative to the craton has become possible.