Tempo and duration of short-term environmental perturbations across the Cretaceous-Paleogene boundary

TY - JOUR

T1 - Tempo and duration of short-term environmental perturbations across the Cretaceous-Paleogene boundary

AU - Husson, Dorothée

AU - Galbrun, Bruno

AU - Gardin, Silvia

AU - Thibault, Nicolas

PY - 2014

Y1 - 2014

N2 - 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 187Os/188Os decrease coincides with the δ13C negative excursion K-PgE1, thus suggesting a first pulse in Deccan volcanism at 66.64 Ma. The K-PgE3 δ13C negative excursion is possibly the expression of a second pulse at 66.26 Ma. Late Maastrichtian δ13C 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. 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.

AB - 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 187Os/188Os decrease coincides with the δ13C negative excursion K-PgE1, thus suggesting a first pulse in Deccan volcanism at 66.64 Ma. The K-PgE3 δ13C negative excursion is possibly the expression of a second pulse at 66.26 Ma. Late Maastrichtian δ13C 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. 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.

M3 - Journal article

AN - SCOPUS:84907992175

SN - 1547-139X

VL - 11

SP - 159

EP - 171

JO - Stratigraphy

JF - Stratigraphy

IS - 2

ER -