Integrated chemostratigraphy and detrital zircon geochronology of the Ediacaran–Cambrian transition in the Western Anabar Uplift: Implications for the Neoproterozoic evolution of the northern Siberian Platform

Abstract

The Terreneuvian strata of the Anabar Uplift (northern Siberian Platform) represent one of the reference sections for the periodization of the Early Cambrian geological record and global correlation. The age of the underlying Staraya Rechka Formation remains unclear due to a lack of biostratigraphic data, equivocal carbon isotope record and controversial geochronological age constraints. Herein we present the detailed chemostratigraphic (carbonate carbon isotope analysis) and geochronological (U-Pb analysis of detrital zircons) study of the Staraya Rechka Formation in the Western Anabar Uplift. Our data reveal that this evaporite-associated carbonate succession accumulated in the terminal Ediacaran within 550–540 Ma and is unconformably overlapped by the Nemakit-Daldyn Formation no older than 537 Ma. Hence, the carbonate isotope record of the Western Anabar Uplift lacks the BACE isotope excursion. At the beginning of the accumulation of the Staraya Rechka Formation, the clastic material in the paleobasin was derived from the Central Taymyr Fold Belt and crystalline basement of the Siberian Platform. In contrast, detrital zircons in the upper Staraya Rechka and basal Nemakit-Daldyn formations mostly originate from the rift magmatism that occurred in the northeastern Siberian Platform around the Ediacaran–Cambrian transition.