# A converging astronomical time scale for the Aptian Stage

Mathieu Martinez

► To cite this version:

Mathieu Martinez. A converging astronomical time scale for the Aptian Stage. 29 ème édition de la réunion des sciences de la Terre (RST 2025), Société Géologique de France (SGF), Oct 2025, Montpellier, France. pp.658460. insu-05376494

HAL Id: insu-05376494

https://insu.hal.science/insu-05376494v1

Submitted on 21 Nov 2025

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# A converging astronomical time scale for the Aptian Stage

Mathieu Martinez*¹

¹Géosciences Rennes, OSUR – Université de Rennes I, CNRS : UMR6118 Géosciences Rennes, Observatoire des Sciences de l'Univers de Rennes – France

## Résumé

In the last years, several astrochronological frameworks have been published on the Aptian Stage and yield scattered duration of this stage, ranging from 7.2 to 9.6 Ma (Leandro et al., 2022; Charbonnier et al., 2023). Here, I reassess the time scale of the Aptian by using several datasets published from Spain, France and Italy (Beil et al., 2020; Leandro et al., 2022; Charbonnier et al., 2023; Rodriguez-Martinez et al., 2024) to provide a consistent time scale between these basins. The 405-ka eccentricity is recorded and can be correlated thanks to biostratigraphy and chemostratigraphy between these basins. A provision duration of the Aptian Stage falls in between 8 and 9 Ma, with a preferred duration of 8.3 Ma, starting 121.15 Ma and ending 112.9 Ma. Importantly the duration of the OAE1a is assessed at 1.2 Ma. According to the timescale I propose here, the OAE1a started 119.9 Ma and ended 118.7 Ma, in a good agreement with recently published U-Pb from Japan (Li et al., 2024). Altogether, these data point toward a converging astrochronology for the Aptian Stage from multiple sites.

## References:

Beil, S., et al., 2020. Climate of the Past 16, 757-782. https://doi.org/10.5194/cp-16-757-2020.

Charbonnier, G., et al., 2023. Earth and Planetary Science Letters 610, 118104. https://doi.org/10.1016/j.epsl.2023.02.031.

Leandro, C.G., et al., 2022. Nature Communications 13, 2941. https://doi.org/10.1038/s41467-022-30075-3.

Li, Y., et al., 2024. Science Advances 10, eadn8365. https://doi.org/10.1126/sciadv.adn8365.

Martinez-Rodriguez, R., et al., 2024. Global and Planetary Change 233, 104361. https://doi.org/10.1016/j.gloplachg.2023.06.011.

**Mots-Clés:** Aptian, astrochronology, Milankovitch cycles, Geologic Time Scale

<footnote>*Intervenant</footnote>