Abstract The Monte Cagnero sedimentary section, which crops out in the northeastern Apennines near Urbania in the Umbria–Marche Basin (Italy), contains well-exposed strata spanning the middle Eocene to lower Oligocene interval. We use an integrated magnetobiostratigraphic approach to generate a high-resolution age model for the Monte Cagnero section, with the goal of obtaining a reliable chronostratigraphic framework for studying Eocene–Oligocene palaeoceanographic changes during the switch from greenhouse to icehouse conditions. The studied sediments consist of alternating reddish and greenish limestones and marlstones. A new integrated age model for the section is based on high-resolution palaeomagnetic analyses, combined with detailed planktonic foraminiferal and calcareous nannofossil biostratigraphic results. Rock magnetic measurements show that the magnetic mineralogy is dominated by a mixture of high- and low-coercivity minerals, probably representing a combination of hematite and magnetite. A robust magnetostratigraphic signal, together with the identification of key planktonic foraminiferal and nannofossil biostratigraphic events, allows construction of a detailed age model for the section. Based on these results, we infer that the section spans a continuous interval (within magnetochron resolution) from the middle Eocene to lower Oligocene ( c . 41–27 Ma; Chrons C18r–C12r). The Monte Cagnero section, therefore, represents a sequence that is suitable for studying the impact of the Neo-Tethyan gateway closure on subtropical Eocene circulation and determining the nature and timing of palaeoceanographic changes in the Tethys through the late middle Eocene to early Oligocene interval.

Abstract Ocean Drilling Program (ODP) Site 711, located in the western equatorial Indian Ocean near the Seychelles Archipelago on Madingley Rise, is an important site for studying middle Eocene to early Oligocene climatic evolution. This site is ideal for studying the impact of Neo-Tethyan gateway closure on Indian Ocean currents and circulation to further understand global climate changes through the greenhouse to icehouse transition. Middle Eocene-to-lower Oligocene strata recovered within Hole 711A (Cores 711A-14X to 21X) primarily consist of clay-bearing nannofossil oozes/chalks, with layers rich in radiolarians. Here, we report a high-resolution magnetostratigraphic record and a new integrated age model for the middle Eocene-to-lower Oligocene section of Hole 711A. Correlation of the polarity pattern to the geomagnetic polarity timescale provides a record from Chron C19r (middle Eocene) to C12r (early Oligocene). Our results extend the existing polarity record down into the middle Eocene and confirm published results from the lower Oligocene section of the hole. Overall, these new results from Hole 711A have important implications for identifying and dating global climate change events, and for reconstructing calcite compensation depth history at this site. Supplementary material: Magnetostratigraphic data used for construction of age models for Hole 711A included in this study are available at: http://www.geolsoc.org.uk/SUP18595