New XRF data for the upper Maastrichtian in Gubbio, Bottaccionne section, central Italy.

The Gubbio sections from the Umbria-Marche basin in central Italy form the basis of numerous stratigraphic studies spanning the Jurrasic to the Miocene. The Bottaccione gorge is renowned for its pioneer work on the Cretaceous-Paleogene boundary. A multiproxy (δ18O, δ13C, MS, CaCO3) study at high-resolution (5 cm) sampled the uppermost 7.2 m from the Maastrichtian Bottaccionne Gorge is now completed with new XRF data. These were carried out both with the new portable and micro X-Ray Fluorescence scanners at the AMGC department of the VUB.
A close covariation between the δ18O and Sr concentration is observed. The largest shift in these covariant proxies coincides with a change in characteristics of the variation of other elements (e.g. Ti). Interestingly the stratigraphical interval of this transition corresponds with a drop in Os-isotope values, which is classically explained as caused by the Deccan volcanism. Surface XRF mapping reveals heterogeneities in the sampled material as concentrated areas show elevated concentrations of elements (e.g. K) related to the presence of clays. Furthermore, periodic relative variations in elemental concentrations allow an evaluation of the existing cyclostratigraphic framework and accompanying palaeoclimatological interpretations.