Lower Maastrichtian cyclostratigraphy of the Bidart section (Basque Country, SW France): A remarkable record of precessional forcing

Abstract

Cyclostratigraphic analysis of the Maastrichtian limestone-marl alternations of Bidart (SW France) allows the hypothesis of orbital control on lithological cycles to be evaluated. Magnetic Susceptibility (MS), oxygen and carbon isotope measurements, sampled at a high resolution, are analyzed using various cyclostratigraphic tools. A statistically significant orbital signal is detected, with a remarkable record of the precession corresponding to the limestone-marl couplets. This well expressed orbital forcing allows the building of a relative cyclostratigraphic time scale for the MS and !13C records based on the 100 kyr eccentricity cycle. The total duration of the section is estimated at 1.44 ± 0.22 Myr. Correlation based on calcareous nannofossil biostratigraphy and comparison of the scaled Bidart !13C record to the astronomically calibrated !13C signal of ODP hole 762C shows that the studied section extends from-71.5 to-70 Ma, covering the upper part of Chron C32n.1n and 2/3 of Chron C31r. Oxygen isotope data suggest a 2°C cooling of sea-surface temperatures during the studied interval. When placed on the long-term !18O trend of the Bidart section, this interval is here recognized as the onset of the early Maastrichtian cooling event. With its excellent record of the precessional forcing, the Bidart section, along with other sections of the Basque country, is a useful tool for the refinement of the Maastrichtian timescale.

The end-Cretaceous in the southwestern Tethys (Elles, Tunisia): orbital calibration of paleoenvironmental events before the mass extinction

“…3c). These observations reflect amplitude modulations in this frequency band which is generally characteristic of eccentricitymodulated precession forcing affecting p1 and p2 (Hinnov 2000;Husson et al 2014b).…”

“…3,4). Spectral analyses were performed using the multitaper method (MTM, Thomson 1982) with a red noise simulation from Schulz and Mudelsee (2002) developed for Matlab™ by Husson et al (2014b). The red noise simulation allows the estimation of confidence levels based on a Chi-square statistical test performed on the theoretical spectrum of the red noise.…”

Planktonic foraminiferal biostratigraphy and quantitative analysis during the Campanian-Maastrichtian transition at the Oued Necham section (Kalâat Senan, central Tunisia)

“…Considering the newly defined C/M boundary age of -72, 15 ± 0.5 Ma (after Husson et al, 2011;Gardin et al, 2012;Thibault et al, 2012;Cohen et al, 2013;Batenburg et al, 2014;Husson et al, 2014;Thibault et al, 2015), the boundary seems to be located within the "Cam9" sequence, corresponding to a regressive cycle, bounded by a major (-73.14 Ma) and a minor (-70.78 Ma) relative sea level change (Snedden and Chengjie, 2010). This could probably be related to poleward development of ice caps during the late Cretaceous cooling event, especially through the early Maastrichtian (Barrera, 1994;Keller, 1998a, 1998b).…”

Astronomical calibration and global correlation of the Santonian (Cretaceous) based on the marine carbon isotope record

“…Spectral analyses were performed using the Multi‐Taper Method (MTM) with a red noise simulation from Schulz and Mudelsee [] developed for Matlab TM by Husson et al . []. The red noise simulation allows the estimation of confidence levels based on a chi‐square statistical test performed on the theoretical spectrum of the red noise.…”