Orbital calibration of the Early Kimmeridgian (southeastern France): implications for geochronology and sequence stratigraphy |
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| Authors: | S Boulila B Galbrun L A Hinnov P‐Y Collin |
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| Institution: | 1. CNRS – UMR 7072 Tectonique – Evolution et Modélisation des Bassins Sédimentaires, Université Paris VI, Case 117, 4 Place Jussieu, 75252 Paris Cedex 5, France;2. Morton K. Blaustein Department of Earth and Planetary Sciences, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA |
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| Abstract: | Classic stratigraphic methods rarely provide high‐resolution correlations between intrabasinal sedimentary sequences, which are important to understand the origin of sedimentation process and its environmental change. In this study, we investigate high‐resolution cyclostratigraphic correlation from magnetic susceptibility in two Early Kimmeridgian pelagic marl‐limestone successions, at La Méouge and Châteauneuf‐d'Oze, southeastern France. Spectral analysis reveals the complete suite of orbital frequencies (precession, obliquity, and eccentricity) with the marl‐limestone couplets being primarily precession‐driven. Frequencies detected by the spectral analysis are similar between the sections, but their relative amplitudes are somewhat different, linked to the palaeoenvironmental position and the completeness of the sections. High‐resolution correlation reveals two significant hiatuses at Châteauneuf‐d’Oze. Early Kimmeridgian Platynota, Hypselocyclum, and Divisum ammonite zones were orbitally calibrated for an ultra‐high resolution assessment of geological time. Finally, strong 405‐kyr eccentricity cycles are recorded as third‐order depositional sequences. |
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