Quantifying uncertainty in the structure and duration of silurian biogeochemical events

The rock record preserves the physical, chemical, and biological history of the Earth including dozens of biogeochemical events that fundamentally altered the Earth system. In order to evaluate the structure and duration of these events and accompanying Earth system changes, both rock sequences and numerical time must be integrated. Historically, these two exercises, chronostratigraphy for the rock record, and geochronology for the numerical record, have been decoupled due to uneven or sparse data developed in globally dispersed rock sequences via traditionally disparate disciplines (stratigraphy and radioisotope geochemistry). Here, we present an interdisciplinary study of the Silurian Altajme drill core (Gotland, Sweden) to illustrate how high-resolution carbon isotope stratigraphy conditioned by new high-precision CA-ID-TIMS U/Pb zircon bentonite dates within a Bayesian age-depth model dramatically changes perspectives on the rates of change and detailed substructure of two major Silurian positive carbon isotope excursions (Ireviken and Mulde) with implications for the potential drivers of these biogeochemical events.