NEW EVIDENCE FOR GRENVILLE AND VALHALLA TECTONIC EVENTS AT THE WESTERN MARGIN OF SIBERIAN CRATON: THE EXAMPLE OF THE GAREVKA METACOMPLEX, YENISEY RIDGE

Abstract

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. Zircon SHRIMP U–Pb analyses coupled with 40 Ar- 39 Ar dating constrain the timing of two new pulses of Neoproterozoic endogenous activity at the western margin of the Siberian Craton, associated with Grenville (930–900 Ma) and (880–845 Ma) post-Grenville Valhalla (880–845 Ma) accretion-and-collision processes.