Timing and pacing of the Late Devonian mass extinction event regulated by eccentricity and obliquity

• Published in: Nature communications Vol. 8; no. 1; p. 2268
• Main Authors: De Vleeschouwer, David, Da Silva, Anne-Christine, Sinnesael, Matthias, Chen, Daizhao, Day, James E., Whalen, Michael T., Guo, Zenghui, Claeys, Philippe
• Format: Journal Article Web Resource
• Language: English
• Published: London Nature Publishing Group UK 22-12-2017; Nature Publishing Group; Nature Pub.lishing Group; Nature Portfolio
• Subjects: 140/58; 704/106/413; 704/106/47/4113; 704/445/209; Chronology; Climate change; Cretaceous; Devonian; Earth sciences & physical geography; Eccentricity; Environmental changes; Extinction; Fossils; Humanities and Social Sciences; Intervals; Mass extinctions; Mesozoic; multidisciplinary; Physical, chemical, mathematical & earth Sciences; Physique, chimie, mathématiques & sciences de la terre; Science; Science (multidisciplinary); Sciences de la terre & géographie physique; Stratigraphy
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-017-02407-1

The Late Devonian envelops one of Earth’s big five mass extinction events at the Frasnian–Famennian boundary (374 Ma). Environmental change across the extinction severely affected Devonian reef-builders, besides many other forms of marine life. Yet, cause-and-effect chains leading to the extinction remain poorly constrained as Late Devonian stratigraphy is poorly resolved, compared to younger cataclysmic intervals. In this study we present a global orbitally calibrated chronology across this momentous interval, applying cyclostratigraphic techniques. Our timescale stipulates that 600 kyr separate the lower and upper Kellwasser positive δ
13
C excursions. The latter excursion is paced by obliquity and is therein similar to Mesozoic intervals of environmental upheaval, like the Cretaceous Ocean-Anoxic-Event-2 (OAE-2). This obliquity signature implies coincidence with a minimum of the 2.4 Myr eccentricity cycle, during which obliquity prevails over precession, and highlights the decisive role of astronomically forced “Milankovitch” climate change in timing and pacing the Late Devonian mass extinction.
Understanding of Late Devonian mass extinction mechanisms is poor due to imprecise stratigraphies. Here, using cyclostratigraphic techniques, the authors present a global orbitally-calibrated chronology and reveal the key role of astronomically-forced Milankovitch climate change.