Chitinozoan biostratigraphy of a new Upper Ordovician stratigraphic framework for Anticosti Island, Canada

A new Upper Ordovician stratigraphic framework for Anticosti Island, Canada, reveals significant east-west correlations between the Ellis Bay and Vauréal formations, resolving long-standing discrepancies. Chitinozoan biostratigraphy demonstrates that most strata of the Ellis Bay Formation at the eastern end correlate with the mid-upper Vauréal Formation in the west, while the Schmitt Creek and Mill Bay members of the Vauréal are older than the uppermost Vauréal eponym members. The study also identifies a Hirnantian age for the gamachiana Zone and provides insights into the timing and magnitude of the Hirnantian Isotopic Carbon Excursion (HICE), aligning with global stratigraphic data from China and Scotland. This research integrates chitinozoan, geochemical, sedimentological, and sequence stratigraphic data to refine understanding of Upper Ordovician stratigraphy.

Achab, A., Asselin, E., Desrochers, A., Riva, J. F., & Farley, C. (2010). Chitinozoan biostratigraphy of a new Upper Ordovician stratigraphic framework for Anticosti Island, Canada. Geological Society of America Bulletin, 123(1-2), 186–205. https://doi.org/10.1130/b30131.1