MioOcean: database compilation and temperature proxy systematics in the Miocene oceans

Abstract. The Miocene epoch has been highlighted as containing reference intervalsfor near future warmer climates; however, to realize the full potential of this analogue, discrepancies must be addressed, including those between model predictions and proxy data for ocean temperatures. Over recent years, new insights into ocean temperature proxy systematics have come to light, thus providing robust Miocene ocean temperature estimates requires re-evaluation of available data. In tandem, collaboration between stratigraphers and geochemists emphasises the importance of refining and synchronising age models to ensure robust comparisons of temperature patterns across space and time. Here, we compiled published Miocene temperature proxy records from 101 publications and 94 sites into the new MioOcean database, recalculated temperatures using state of the art proxy constraints, and revised and/or verified age models for 38 key sites. The MioOcean database includes upper and bottom ocean temperature records from organic (U^K’₃₇ and TEX₈₆) and inorganic (Mg/Ca, δ¹⁸O, and Δ₄₇) marine geochemical proxies. To improve confidence in, and comparability between, datasets, we convert proxies into temperature in an internally consistent manner, including updating all associated input variables. To aid usability, the database provides propagated numerical uncertainty estimates encompassing as many sources of error as possible. The MioOcean database improves accessibility of proxy-based Miocene ocean temperature reconstructions to non-specialists, simplifies model-data comparison and validation, and provides the necessary groundwork for in-depth inter-proxy comparison studies. The data compilation (https://doi.org/10.5281/zenodo.22258386, Sosdian et al., 2026) is also hosted on www.mioocean.com, including interactive data visualization, enabling interrogation and comparison of re-evaluated MioOcean records.