TY - JOUR

T1 - Lower Maastrichtian cyclostratigraphy of the Bidart section (Basque Country, SW France)

T2 - A remarkable record of precessional forcing

AU - Husson, Dorothée

AU - Thibault, Nicolas Rudolph

AU - Galbrun, Bruno

AU - Gardin, Silvia

AU - Minoletti, Fabrice

AU - Sageman, Bradley

AU - Huret , Emilia

PY - 2014

Y1 - 2014

N2 - 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 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 δ13C record to the astronomically calibrated δ13C signal of ODP hole 762C shows that the studied section extends from 71.65 to 70.22 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 replaced 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.

AB - 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 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 δ13C record to the astronomically calibrated δ13C signal of ODP hole 762C shows that the studied section extends from 71.65 to 70.22 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 replaced 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.

U2 - 10.1016/j.palaeo.2013.12.008

DO - 10.1016/j.palaeo.2013.12.008

M3 - Journal article

VL - 395

SP - 176

EP - 197

JO - Palaeogeography, Palaeoclimatology, Palaeoecology - An International Journal for the Geo-Sciences

JF - Palaeogeography, Palaeoclimatology, Palaeoecology - An International Journal for the Geo-Sciences

SN - 0031-0182

ER -