Multiproxy Cretaceous-Paleogene boundary event stratigraphy: An Umbria-Marche basin-wide perspective

The complete and well-studied pelagic carbonate successions from the Umbria-Marche Basin (Italy) permit the study of the event-rich stratigraphical interval around the Cretaceous-Paleogene (K-Pg) boundary (e.g., Deccan volcanism, boundary impact, Paleocene recovery and climate). To test the robustness of various proxy records (bulk carbonate δ13C, δ18O, 87Sr/86Sr and Ca, Fe, Sr and Mn concentrations) inside the Umbria-Marche basin, several stratigraphically equivalent sections were investigated (Bottaccione Gorge, Contessa Highway, Fornaci East quarry, Frontale, Morello and Petriccio Core). Besides the classical Gubbio sections of Bottaccione and Contessa, the new Morello section is put forward as an alternative location for this stratigraphical interval as it is less altered by burial diagenesis. Elemental profiles (Ca, Fe, Sr, Mn) acquired by handheld X-Ray Fluorescence (pXRF) efficiently provide regional chemostratigraphical and paleoenvironmental information. The Deccan volcanism, the K-Pg boundary, the characteristic pattern of the Sr/Ca profile across the boundary driven by the extinction and recovery of coccolithophores, and the Dan-C2 hyperthermal event are examples of such recorded paleoenvironmental events. Moreover, cyclostratigraphic analyses of proxies of detrital input (magnetic susceptibility and Fe concentrations) show the imprint in the sedimentary record of a 2.4 Myr eccentricity minimum around 66.45-66.25 Ma and suggest that the occurrence of the Dan-C2 hyperthermal event was astronomically paced.