DINOSTRAT: towards accurate and complete regional calibration of the stratigraphic ranges of all organic-walled dinoflagellate cysts

For the construction of age models of sedimentary sections, biostratigraphy remains a crucial tool. The emergence of astrochronology, and the ever-growing need for higher-resolution reconstructions of paleoclimate and paleoceanography now stimulates the biostratigraphic community to tie biostratigraphic zonations to astrochronological cycles (10⁴–10⁵ years). This foremost requires that the biostratigraphic community assesses the accuracy of the ages of microfossil ranges to that kind of temporal scale, and to what extent these are synchronous at such short timescales. This implies a review and revisit of previously published microfossils records, and perhaps the generation of new records. Over the past five years, I have been working towards a complete, open-access, FAIR, and iteratively updateable stratigraphic database for dinoflagellate cysts. Knowing that stratigraphic ranges of dinoflagellate cysts show considerable diachroneity (which creates uncertainty but also may represent a paleoceanographic signal) and that many taxa are provincial, the need arose for the development of regional calibrated dinoflagellate cyst stratigraphies. In other words: DINOSTRAT shows the stratigraphic range of taxa is per region. The continuously evolving stratigraphic framework over the past decades necessitated going back to original sources to avoid inherited errors, apply synonymy and recalibrate sequences to state-of-the-art time scales. Data entry in DINOSTRAT is in two ways. Sites from which stratigraphic ranges of dinocysts were published were added, with their modern geographic coordinates, age span and through that, their paleolatitudinal pathway. A qualification of the dinocyst-independent age control was added (other biostratigraphy, magnetostratigraphy, astrochronology). Then, for each site, the stratigraphic positions of first and last occurrences of dinocyst taxa relative to the independent age control were added. A lookup-file then calculates from that stratigraphic position the age, which enables future updating of the data. The paleolatitude of that age at that site is interpolated, creating regional context for that stratigraphic range. The database has multiple entries per taxa, creating a way of evaluating its regional synchroneity. DINOSTRAT now has at least best-guess ranges of all dinocyst taxa (over 18000 entries for ~6000 taxa), as well as regional calibrations of the mostly used stratigraphic taxa. Range charts can be plotted for all sites that were entered, as well as range charts per species, genus and on suprageneric level. The result is a holistic and still-augmented image of regional calibration of dinoflagellate cyst ranges, towards full application for the next-generation Geologic Time Scale. It shows which taxa are particularly synchronous and useful as biostratigrapic tool, and where. Output from DINOSTRAT is interactively coupled to the open taxonomic database palsys.org, that contains the species descriptions and images of dinoflagellate cysts. I will present the database structure and opportunities it creates, providing quality control of dinocyst biostratigraphic data.