Late Paleocene to Early Eocene Magneto-Biostratigraphy of the Cicogna section (Belluno Basin, NE Italy)

During the Late Paleocene-Early Eocene (~60 Ma to 50 Ma), Earth's climate experienced a warming trend that culminated at the Early Eocene Climatic Optimum (EECO). The EECO was characterized by warm conditions at even extreme high latitudes, subdued latitudinal temperature gradients, and virtually nonexistent polar ice sheets. A persistent cooling trend occurred during the Middle and Late Eocene and eventually drove the Earth climate into the current glacial mode. The early Paleogene long-term climate was punctuated by several short-lived hyperthermal events, the most prominent of which is the Paleocene Eocene Thermal Maximum (PETM). Here we present paleomagnetic and calcareous nannofossil data from the Tethyan marine Cicogna section (Belluno Basin, NE Italy). The paleomagnetic results, integrated with calcareous nannofossil biostratigraphy, indicate that the Cicogna section extends from Chron C25r to Chron C23r spanning the NP7/NP8-NP12 nannofossil Zones with a relatively constant sediment accumulation rate of ~18 m/My. To extend the magnetic property characterization of the Belluno Basin sediments in the Early and Middle Eocene, we integrated the Cicogna magnetic analysis results with data from the neighboring Possagno section. Rock-magnetic data show a gradual relative increase in pigmentary (fine-grained) hematite within the sediments that peaked at ~49-50 Ma. This datum is interpreted as related to enhanced continental weathering processes under EECO warm climate conditions. The Middle-Late Eocene cooling trend following the EECO was than characterized by a gradual relative decrease of the fine-grained hematite content of the sediments toward pre-warming values. Our findings contribute to the understanding of the coupling between long-term Earth's climate and silicate weathering processes during the Eocene.