Evidence of Greenville age events at the western margin of the Siberian Craton: the case of Ryazanovsky granitoid massif (Yenisei Range)

Studies of the geological history of the Yenisei Range, which is a collisional accretionary orogen in the western margin of the Siberian Craton, are crucial not only for understanding the tectonic evolution of mobile fold-and-thrust belts at the boundaries of ancient cratons, but also for solving the problem of the possible incorporation of the Siberian Craton into the Rodinia supercontinent, an issue that has been debated for more than 20 years. Based on the results of mineralogical-petrological, geochemical and isotope-geochronological studies, new data were obtained on the major- and trace-element composition, petrogenesis, zircon U-Pb age, Sr and 147Sm-143Nd isotopic parameters for rocks of the Ryazanovsky granitoid massif located near the Yenisei fault zone of the Yenisei Range. These rocks are represented by high-ferruginous peraluminous varieties and are comparable to A-granites or highly differentiated I-granites. Their composition evolves from normal to subalkaline granites and leucogranites, characterized by increased concentrations of highly charged and radioactive elements. Isotopic (Sr, Nd) characteristics of the rocks indicate generation from an ancient crustal substrate, the average age of which corresponds to the Paleoproterozoic. The formation of these granites at the Meso-Neoproterozoic boundary (1013 ± 9.9 Ma) corresponds to the early stage of the Grenville orogeny at the western margin of the Siberian Craton. This episode of regional crustal evolution is correlated with the synchronous successions and similar style of tectonothermal events along the Arctic margin of Rodinia and supports the spatial proximity of Siberia and North Atlantic cratons (Laurentia and Baltica), which is consistent with the proposed Neoproterozoic paleogeographic reconstructions of the Rodinia configuration. New evidence of Grenville-age collision events, combined with other age equivalents within the western margin of the Siberian Craton, helps resolve a number of controversies in the interpretation of key issues in the geology and tectonics of this region.