Evidence of Grenville and Valhalla Tectonic Events at the Western Margin of the Siberian Craton from Rocks of the Garevka Complex (North Yenisei Ridge)

Abstract

The tectonic evolution of the Siberian cratonic margins offers important clues for global paleogeographic reconstructions, particularly with regard to the complex geological history of Central Asia. The Yenisey Ridge fold-and-thrust belt at the western margin of the Siberian Craton forms part of the Central Asian Orogenic Belt (CAOB) and is a key to understand the Precambrian tectonic evolution of the Siberian Craton and crustal growth in the CAOB. Understanding the tectonic evolution of the Yenisei Ridge is crucial for solving the debate related to the role of the Siberian Craton within the Rodinia supercontinent assemblies and breakup with the opening of the Paleoasian ocean. Here we report new data on the petrogenesis, tectonic settings, thermodynamic conditions, metamorphism and protolith ages for compositionally contrasting rocks of the Garevka metamorphic complex, obtained from the results of mineralogical-petrological, geochemical, and isotope-geochronological studies. Possible models and geodynamic settings for their formation are discussed. Based on the results of U-Pb dating of zircons, two new pulses of Neoproterozoic endogenous activity at the western margin of the Siberian craton were established, associated with Grenville (930–900 Ma) and (880–845 Ma) post-Grenville Valhalla (880–845 Ma) accretion-and-collision processes. These episodes of regional crustal evolution are correlated with the synchronous successions and similar style of rocks 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.