The uncertainty associated with stratigraphic correlations and numerical ages of sedimentary successions increases with time, hampering our understanding of forcing factors of past climate changes and their consequences for paleoecosystems. Stratigraphic correlations and time scale refinement beyond 100 Ma face unique challenges, including increasing uncertainties on radiometric ages, a lack of astronomical solutions, and the potential for non-actualistic processes. These issues are further exacerbated in terrestrial and coastal strata, complicating the construction of terrestrial-to-marine correlation schemes. Apparent disagreement may exist between inferred ages, durations and correlations, depending on the region and the methodology. The ‘pre-100 Ma’ world remains beyond the ambitious time scale refinement effort of the TIMES (“Time Integrated Matrix for Earth Sciences”) initiative for now.
At the same time, the past decade has seen rapid improvements in the pre-100 Ma geologic time scale, as well as our understanding of global events anchored to it. Especially for these older strata, a fully integrated stratigraphic approach, aiming at more robust correlations across geologic settings, is crucial.
Here, we propose a session to gather the efforts to advance the dating of sedimentary series older than 100 Ma using different approaches, including geochronology, astrochronology, chemostratigraphy, biostratigraphy, magnetostratigraphy, event stratigraphy, and numerical modelling; as well as methods to improve correlations at global scales at an increasingly higher time resolution and between marine and terrestrial records. This session aims to foster constructive discussion on how we can progress as a deep-time stratigraphic community, and we welcome researchers from all career stages. Studies working on an integrated approach and aiming at constructing a converging time scale for different geological periods beyond 100 Ma are particularly encouraged.