Mongolian micro‐continental blocks in Columbia/Nuna: Zircon U–Pb–Hf isotopic evidence for long‐lasting Mongolia–Western Siberia connection

Abstract

The Mongolian micro‐continental fragments play an important geodynamic role in the Palaeozoic evolution of the Central Asian Orogenic Belt. However, the original provenance of individual blocks within the Nuna/Columbia and Rodinia supercontinents is not well constrained. In this work, we present zircon U–Pb and Lu–Hf isotopic data from the Mesoproterozoic to Neoproterozoic metamorphosed cover of the Baidrag Block in central Mongolia. These data reveal important maxima in the Neoarchean, Palaeoproterozoic and locally Neoproterozoic. Although the majority of the new data can be attributed to local sources within the basement of the Mongolian micro‐continental fragments, an important contribution of juvenile 2.0 Ga zircons is linked to the western margin of the Siberian Craton, and 1.5 Ga zircons are either directly derived from North Australia or indirectly recycled from sediments in NW Laurentia.