Anchoring the Late Devonian mass extinction in absolute time by integrating climatic controls and radio-isotopic dating

Da Silva, Anne-Christine; Sinnesael, Matthias; Claeys, Philippe; Davies, Joshua H.F.L.; de Winter, Niels J.; Percival, L.M.E.; Schaltegger, Urs; De Vleeschouwer, David

Abstract

The Devonian Frasnian–Famennian (F–F) boundary marks one of the five main extinction intervals of the Phanerozoic Aeon. This time was characterized by two pulses of oceanic anoxia, named the Lower and Upper Kellwasser events, during which massive marine biodiversity losses occurred. This paper presents high-resolution magnetic susceptibility, X-ray fluorescence elemental geochemistry and carbon isotope datasets obtained from the Steinbruch Schmidt F–F boundary section (Germany). These records lead to an astronomical time calibration of the environmental changes associated with the two ocean anoxia pulses. Cyclostratigraphic interpretation indicates deposition of the black argillaceous Lower and Upper Kellwasser horizons over ~ 90 and ~ 110 kyr, respectively; approximately equivalent to the duration of one short eccentricity cycle. This study confirms that the succession of events within the Upper Kellwasser event is paced by obliquity, under a low-eccentricity orbit. Hence, astronomical insolation forcing likely contributed to the expansion of ocean anoxia and other environmental perturbations associated with these two crises. The new floating chronology established for the Steinbruch Schmidt section is anchored in numerical time by means of a radio-isotopic date, obtained from a bentonite layer interbedded between the two Kellwasser horizons. After anchoring, this time scale gives a high-precision age of 371.870 ± 0.108 Ma for the F–F boundary.

Citation

Da Silva, A.-C., Sinnesael, M., Claeys, P., Davies, J. H., de Winter, N. J., Percival, L., Schaltegger, U., & De Vleeschouwer, D. (2020). Anchoring the Late Devonian mass extinction in absolute time by integrating climatic controls and radio-isotopic dating. Scientific Reports, 10(1), Article 12940. https://doi.org/10.1038/s41598-020-69097-6

• Journal Article Type: Article
• Acceptance Date: Jun 11, 2020
• Online Publication Date: Jul 31, 2020
• Publication Date: 2020
• Deposit Date: Aug 3, 2020
• Publicly Available Date: Aug 4, 2020
• Journal: Scientific Reports
• Publisher: Nature Research
• Peer Reviewed: Peer Reviewed
• Volume: 10
• Issue: 1
• Article Number: 12940
• DOI: https://doi.org/10.1038/s41598-020-69097-6
• Public URL: https://durham-repository.worktribe.com/output/1265029