A high-resolution sequence stratigraphic framework for the eastern Ellis Bay Formation, Canada: A record of Hirnantian sea-level change

A high-resolution sequence stratigraphic framework for the eastern Ellis Bay Formation on Anticosti Island, Canada, reveals six fourth-order depositional sequences bounded by subtle, regionally traceable unconformities. These sequences, marked by quartz pebble lags and depleted carbon isotopic values, provide a detailed record of Hirnantian sea-level changes during the Late Ordovician mass extinction. The framework enables the integration of paleobiological, stratigraphic, and geochemical data into a basin-wide perspective, suggesting that other coeval sections may be incomplete at the level of these fourth-order cycles.

Zimmt, J. B., Holland, S. M., Desrochers, A., Jones, D. S., & Finnegan, S. (2024). A high-resolution sequence stratigraphic framework for the eastern Ellis Bay Formation, Canada: A record of Hirnantian sea-level change. Geological Society of America Bulletin, 136(9-10), 3825–3849. https://doi.org/10.1130/b37190.1