The 40Ar–39Ar Age of Folding in the Sedimentary Complexes of Chukotka and Wrangel Island (Northeastern Russia)

A groundbreaking study reveals that the sedimentary complexes of Chukotka and Wrangel Island, including UNESCO World Heritage Site components, experienced significant folding during the Tithonian period (150 million years ago). Using 40Ar–39Ar isotope dating on newly formed micas and chlorites from thrust zones, researchers identified two distinct deformation stages: one in the Late Permian (257 million years ago) affecting Silurian rocks on Wrangel Island's Dream-Head Mountains, and another involving Devonian to Triassic sedimentary rocks. The study also found that thrust formation was accompanied by substantial heating of sedimentary sequences to temperatures between 250–380°C, with minimal temperature variation within the thrust zone itself. This research provides critical insights into the tectonic history of this remote Arctic region.

Tuchkova, M. I., Sokolov, S. D., Moiseev, A. V., & Vatrushkina, E. V. (2024). The 40Ar–39Ar Age of Folding in the Sedimentary Complexes of Chukotka and Wrangel Island (Northeastern Russia). Doklady Earth Sciences, 514(2), 255–263. https://doi.org/10.1134/s1028334x2360295x