New framework synchronizes Miocene ocean temperature records

Researchers have developed a consistent chronological framework for Miocene ocean temperature records, addressing a fundamental challenge in paleoclimate science: determining exactly when past climate changes occurred. The study, titled “The MioOcean Age Framework: Age Model Database and Chronoinformatics Approach for synchronised Miocene Ocean Temperature, Climate and Proxy Records,” was authored by Anna Joy Drury, Deborah N. Tangunan, and a large international team including Diederik Liebrand, Gerald Auer, and Ann Holbourn. The work is currently under review for the journal Earth System Science Data and represents a critical step toward harmonizing the age information underlying global Miocene ocean temperature syntheses. By creating a consistent age framework, an open and updateable database, and a new approach for assessing chronological reliability, the team aims to provide a reproducible foundation for future climate assessments.

The Miocene Ocean Temperature Synthesis, known as MioOcean, serves as the primary test case for this new framework. It compiles upper ocean and bottom water temperature records spanning from 23.04 to 5.333 million years ago. Understanding climate evolution depends fundamentally on time, specifically when changes occurred, how rapidly they happened, and whether changes recorded at geographically disparate locations were synchronous. Paleoclimate syntheses provide important evidence for broader climate assessments, such as the Intergovernmental Panel on Climate Change Assessment Reports, but these require chronological frameworks that are sufficiently accurate and comparable between records across both Milankovitch and longer geological timescales. The MioOcean Age Model Group, or MioAGE, evaluates and harmonizes the depth and age models underlying these temperature records to develop a consistent chronological framework for reconstructing and interpreting the evolution of Miocene ocean temperatures across space and time.

The study applies a new approach called Chronoinformatics to 69 sites, from which 38 key sites were synchronised into the MioOcean Age Framework. This synchronisation involved detailed chronological evaluation and harmonisation of the age models using biostratigraphy, magnetostratigraphy, and/or astrochronology. The team critically assessed published depth and age models, then verified, standardised, and, where needed, revised the chronologies within a consistent framework anchored to the Geologic Time Scale 2012. These 38 sites comprise 53 individual age models, all of which required verification and standardisation. Notably, 33 of these models additionally required revision to ensure they met the standards of the new framework.

The resulting chronologies are integrated into the open, machine-readable, and updateable MioOcean Age Model Database. This database preserves depth and age models, chronological tie points, metadata, and provenance, ensuring that the underlying sample, depth, and chronological information required to reproduce and update paleoclimate records is preserved. The MioOcean age compilation is hosted on Zenodo, making it accessible to the global scientific community.

Across 10,560 Miocene temperature data points, the synchronisation process resulted in a mean age change of 28 thousand years. The largest offsets reached several million years, with the maximum offset being 7.121 million years. Such large discrepancies can alter the geological interval to which individual proxy observations are assigned, potentially changing the interpretation of past climate events.

The team also presents the MioAGE Reliability Grid, which evaluates differences in Age Model Quality and Reporting Quality among the major chronological approaches across all key sites. These evaluations are integrated into site-level assessments, providing a comprehensive view of the reliability of the chronological data for each location. By systematically organising, interrogating, evaluating, preserving, and updating chronological information, the Chronoinformatics approach offers a transferable method for other geological intervals and proxy systems. This approach is now available for use in large-scale community syntheses, ultimately feeding into IPCC’s Assessment Reports.

The study underscores the utmost importance of preserving the underlying sample, depth, and chronological information required to reproduce and update paleoclimate records. The MioOcean Age Framework provides a consistent and reproducible chronological foundation, which is essential for reliable climate histories. By harmonizing the age information underlying global Miocene ocean temperature records, the team has created a tool that can be applied to other paleoclimate syntheses, improving the overall accuracy and comparability of climate data.

The implications of this work extend beyond the Miocene epoch.

Subject of Research: Development of a synchronized age framework and database for Miocene ocean temperature records

Article Title: The MioOcean Age Framework: Age Model Database and Chronoinformatics Approach for synchronised Miocene Ocean Temperature, Climate and Proxy Records

Article References: Drury, A. J., Tangunan, D. N., Liebrand, D., Auer, G., Kasbohm, J., King, D. J., Westerhold, T., Crocker, A. J., Kochhann, K. G. D., Kuhnt, W., Ochoa, D., van Peer, T. E., Krijgsman, W., Robinson, M. M., Shah, N. S., Sibert, E. C., Wade, B. S., Sosdian, S. M., Auderset, A., … Holbourn, A. (2026). The MioOcean Age Framework: Age Model Database and Chronoinformatics Approach for synchronised Miocene Ocean Temperature, Climate and Proxy Records. https://doi.org/10.5194/essd-2026-724

Image Credits: AI Generated

DOI: 10.5194/essd-2026-724

Keywords: Miocene climate, ocean temperature, paleoclimate chronology, age model harmonization, Chronoinformatics, MioOcean synthesis, biostratigraphy, magnetostratigraphy, astrochronology, Geologic Time Scale, Milankovitch cycles, climate syntheses, IPCC assessments, paleoceanography, data provenance, open science, Zenodo database, climate variability, geological timescales, proxy records