Tracking the ETM3, ETM2, and PETM hyperthermal events: New Age Model and Magnetostratigraphic Study

This work studies focuses on periods of dramatic temperature changes during the early Eocene hyperthermal events ETM3 (~52.8 Ma), ETM2 (~54 Ma), and the PETM (~56 Ma). We aim at developing a refined age model for IODP Site U1514 (Mentelle Basin) and carry out a suite of rock magnetic measurements as proxies for paleoclimatic changes. On 234 sediment samples from 248.2 to 324.68 m CSF-A we performed new magnetic measurements including AF demagnetization, AMS (Anisotropy of Magnetic Susceptiblity), bulk susceptibility, IRM (Isothermal Remanent Magnetization) acquisition and demagnetization, and ARM (Anysteretic Remanent Magnetization) acquisition and demagnetization. The integration of these new data with the previously available shipboard datasets allows us to characterise magnetic mineral assemblages, remanence carriers, and sedimentary processes at a resolution not previously available for this site. The new high-resolution paleomagnetic (Inclination only) data allow a clearer identification of polarity boundaries and reduce uncertainties in the placement of chron transitions. This improved temporal control enables a more precise determination of the depths and thicknesses of ETM3, ETM2, and the PETM. Variations in ARM/k ratios, IRM acquisition curves, and susceptibility reveal changes in magnetic grain size and concentration that align with intervals of elevated temperature. Applying Fourier transforms to continuous magnetic property curves, constructed from magnetic parameters, allowed us to detect statistically significant cyclicity consistent with short and long eccentricity. These Milankovic oscillations provide independent constraints on sedimentation rates and help refine accumulation histories surrounding the hyperthermal intervals. The orbital pacing observed in the background sedimentation also strengthens the reliability of the new age model. By combining the refined magnetostratigraphy, magnetic property analyses, and orbital cyclicity, we produce a high-quality framework to identify and correlate ETM3, ETM2, and the PETM. This improved temporal and stratigraphic resolution clarifies the relative timing between warming, environmental shifts, and changes in sediment properties.