The Open UniversitySkip to content

Astronomical pacing of methane release in the Early Jurassic period

Kemp, David B.; Coe, Angela L.; Cohen, Anthony S. and Schwark, Lorenz (2005). Astronomical pacing of methane release in the Early Jurassic period. Nature, 437 pp. 396–399.

DOI (Digital Object Identifier) Link:
Google Scholar: Look up in Google Scholar


A pronounced negative carbon-isotope (delta-13C) excursion of 5–7 per mil indicates the occurrence of a significant perturbation to the global carbon cycle during the Early Jurassic period (early Toarcian age, 183 million years ago). The rapid release of 12C-enriched biogenic methane as a result of continental-shelf methane hydrate dissociation has been put forward as a possible explanation for this observation. Here we report high-resolution organic carbon-isotope data from well-preserved mudrocks in Yorkshire, UK, which demonstrate that the carbon-isotope excursion occurred in three abrupt stages, each showing a shift of -2 to -3 per mil. Spectral analysis of these carbon-isotope measurements and of high-resolution carbonate abundance data reveals a regular cyclicity. We interpret these results as providing strong evidence that methane release proceeded in three rapid pulses and that these pulses were controlled by astronomically forced changes in climate, superimposed upon longer-term global warming. We also find that the first two pulses of methane release each coincided with the extinction of a large proportion of marine species.

Item Type: Journal Item
ISSN: 1476-4687
Keywords: methane hydrate; precession; carbon-isotope; Toarcian; Jurassic; climate change; spectral analysis
Academic Unit/School: Faculty of Science, Technology, Engineering and Mathematics (STEM) > Environment, Earth and Ecosystem Sciences
Faculty of Science, Technology, Engineering and Mathematics (STEM)
Item ID: 5901
Depositing User: Angela Coe
Date Deposited: 16 Nov 2006
Last Modified: 08 Jan 2018 11:28
Share this page:


Actions (login may be required)

Policies | Disclaimer

© The Open University   contact the OU