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

Dorothée Husson*, Nicolas Thibault, Bruno Galbrun, Silvia Gardin, Fabrice Minoletti, Brad Sageman, Emilia Huret

*Corresponding author for this work

Research output: Contribution to journalArticle

20 Scopus citations

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 δ13C records based on the 100kyr eccentricity cycle. The total duration of the section is estimated at 1.44±0.22Myr. Correlation based on calcareous nannofossil biostratigraphy and comparison of the scaled Bidart δ13C record to the astronomically calibrated δ13C signal of ODP Hole 762C shows that the studied section extends from -71.5 to -70Ma, 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 δ18O 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.

Original languageEnglish (US)
Pages (from-to)176-197
Number of pages22
JournalPalaeogeography, Palaeoclimatology, Palaeoecology
Volume395
DOIs
StatePublished - Feb 1 2014

Keywords

  • Carbon-isotope stratigraphy
  • Cyclostratigraphy
  • Maastrichtian
  • Magnetic susceptibility
  • Marl-limestone alternations
  • Precession

ASJC Scopus subject areas

  • Oceanography
  • Ecology, Evolution, Behavior and Systematics
  • Earth-Surface Processes
  • Palaeontology

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