New geochronological, geochemical and carbon isotope data from the Igarka Uplift constrain the age and reveal geodynamic evolution of the northwestern Siberian Platform in the latest Mesoproterozoic and Neoproterozoic. Dolostones of the Medvezhy Formation, the oldest part of the sedimentary succession, correspond to the latest Mesoproterozoic (∼1000 Ma) according to stable isotopic composition. Overlaying volcano-sedimentary Ludy, Gubinskaya and Igarka formations are no older than 715 Ma according to detrital zircon ages and carbon isotope data. Chemical composition of the Igarka Formation and synchronous mafic intrusions of the Gubinskaya Formation suggest a single magma source developed in an intraplate rifting environment. The Ediacaran Chernaya Rechka and Izluchina formations unconformably cover both meso- and mid-Neoproterozoic sequences. The age of the Ediacaran units are confirmed by the Pb-Pb isochron age of 610 ± 50 Ma and large positive C-isotope anomaly in the Chernaya Rechka limestones. Abundant Neoproterozoic (950–800 Ma) detrital zircons in the studied Neoproterozoic sedimentary rock units points to the existence of a hypothetic large Neoproterozoic orogenic belt on the northeastern periphery of the Siberian Platform unexposed nowadays. The pre-Ediacaran rift trough of the Igarka Uplift and other similar structures, mark extensional environments along the present western margin of the Siberian platform in the mid-Neoproterozoic. These structures are coeval to a large igneous province (ca. 720 Ma) at the northern Laurentia associated with the Rodinia breakup.
|Publication status||Published - Nov 2022|
- Carbon isotopes chemostratigraphy
- Mafic rock geochemistry
- Pb-Pb carbonate age
- Siberian Platform
- U-Pb detrital zircon
- 1.05 EARTH AND RELATED ENVIRONMENTAL SCIENCES