Cyclochronology of the Early Eocene carbon isotope record from a composite Contessa Road-Bottaccione section (Gubbio, central Italy)

High-resolution geochemical time series from the composite Contessa Road-Bottaccione (CR-BTT) section (central Italy) allows testing the global significance of Early Eocene short- and long-term carbon isotope trends by comparison with available records from oceanic successions. Spectral analysis reveals Milankovitch frequency band fluctuations in the concentration of CaCO3. Extraction of the short- and long-eccentricity orbital periodicities from the wt.% CaCO3 record provides a relative cyclochronology for the interval spanning similar to 49.5 Ma to similar to 52.5 Ma corresponding to magnetochron C22r to the top of C24n thus extending the cyclochronology already available from the same section in the interval between similar to 52.0 to similar to 56 Ma, spanning the lower C24r to upper C23r. Recognition of orbitally forced sedimentary cycles, corresponding to the long (405 kyr) and short (100 kyr) eccentricity, allows to test the chemostratigraphic alignment with ODP Site 1258 and ODP Site 1263 records and to obtain a correlation of hyperthermal events to an unambiguous magnetostratigraphic record across the interval corresponding to the Early Eocene Climatic Optimum and to refine the astrochronological interpretation of the Ypresian Stage.