High-resolution carbon isotope record from Svalbard reveals elevated atmospheric CO2 during the Middle Devonian Taghanic crisis

The Devonian was a time of climatic upheaval, with many biotic crises, anoxic events and dramatic climatic changes. It is yet unclear what the controls and triggers were for most of these crises, and our understanding is hampered by poorly constrained paleogeographic reconstructions and the limited number and low-resolution of atmospheric CO 2 records. To improve our understanding of paleogeography, atmospheric CO 2 and climate in the Middle Devonian, we obtained paleomagnetic data and a high-resolution carbon isotope record of Givetian (389–383 Ma) organic-rich terrestrial rocks in Svalbard. The section consists of three intervals, with the top of the section in a ~ 100 m interval that likely covers the Taghanic Crisis. While our paleomagnetic data are unsuccessful, our carbon isotope record reveals a baseline value of −25.9 ± 0.8‰, with several smaller excursions and one larger negative excursion of magnitude ~4.0‰. We correlate this excursion to the Taghanic Crisis based on the available biostratigraphy. We use these data to produce a high-resolution atmospheric CO 2 record based on changes in the δ 13 C value of terrestrial organic matter. We find that atmospheric CO 2 varied significantly on short (