Husson, Dorothée; Galbrun, Bruno; Gardin, Silvia; Thibault, Nicolas (2014): Susceptibility measurements at Gubbio sections [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.829778,

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Supplement to: Husson, D et al. (2014): Tempo and duration of short-term environmental perturbations across the Cretaceous-Paleogene boundary. Stratigraphy, 11(2), 159-171, https://inria.hal.science/ISTEP/hal-01092775v1

The complex interplay between extraterrestrial events and earth-bound processes that triggered one of the greatest biological crises of the Phanerozoic requires a high resolution timescale. Detailed magnetic susceptibility measurements at the Contessa Highway and Bottaccione sections (Italy) span the Cretaceous-Paleogene boundary and reveal clear orbital signatures in the sedimentary record. Identification of precession and 405 kyr eccentricity cycles allows an estimate of 324+/-40 kyr for the duration of the Maastrichtian part of Chron C29r. We present in the same high resolution time frame sites in Spain and the North and South Atlantic and bio-horizons, biotic changes, stable isotopic excursions and the decrease in Osmium isotopes recorded in these sections. The onset of 187 Os/ 188 Os decrease coincides with the d13 C negative excursion K-PgE1, thus suggesting a first pulse in Deccan volcanism at 66.64 Ma. The K-PgE3 d13 C negative excursion is possibly the expression of a second pulse at 66.26 Ma. Late Maastrichtian d13 C negative excursions are of low intensity and span durations of one to two eccentricity cycles, whereas early Danian excursions are brief (about 30 kyr) and acute. In Biotic response to late Maastrichtian perturbations occurred with a delay of ca. 200 kyr after the beginning of K-PgE1 shortly before K-PgE3. The biotic perturbation could be thus either a delayed response to K-PgE1, or a direct response to K-PgE3, and possibly, a threshold response to the stepwise buildup of CO2 atmospheric injections. No delay is evident in response to early Danian hyperthermal events. These differences suggest that short-lived, volcanically-derived environmental perturbations were buffered within the stable late Maastrichtian oceanic realm whereas they were amplified by the more sensitive and highly disturbed early Danian oceanic ecosystem.

Magnetic susceptibility measured on samples from the Contessa (43° 22' 45'' N 13° 33' 42'' E) and Bottaccione (43° 21' 57'' N 12° 34' 57'' E) sections (Gubbio, Italy). The signal corresponds to the magnetochron C29r, extending on both sides of the K-Pg boundary. The Contessa section covers C29r Paleogene part, the Bottaccione section covers C29r Maastrichtian part.

Depth [m] means the stratigraphical position of the sample in the composite section (m).