Decoding Devonian Dynamics: Ancient Carbon Isotopes as Windows into Paleo-Carbon Cycles and Environmental Shifts (2025)

The Devonian Period was an interval in Earth’s history marked by significant changes in the biosphere and a shift to icehouse conditions. Using stable carbon isotopes that document perturbations to the global carbon cycle during this time can help us to understand the connection between the biosphere and climate. For the Late Devonian of Montana, that record is preserved in the Jefferson Formation. However, the extensive dolomitization of the Jefferson Formation has led some to argue that the geochemistry of these rocks has been altered and cannot provide an accurate depiction of the ancient carbon cycle. To better understand this record of the Jefferson Formation this study focused on the Baker Mountain section on the eastern flanks of the Beartooth Mountains in south central Montana. We measured and described 84.5 meters of strata and formed our data set. Using our dataset, we explore the relationship between environment, carbon, and sea.