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Astronomical pacing of methane release in the Early Jurassic period

Kemp, David B.; Coe, Angela; Cohen, Anthony S. and Schwark, Lorenz (2005). Astronomical pacing of methane release in the Early Jurassic period. Nature, 437(7057) pp. 396–399.

URL: http://www.nature.com/nature/journal/v437/n7057/fu...
DOI (Digital Object Identifier) Link: https://doi.org/10.1038/nature04037
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Abstract

A pronounced negative carbon-isotope (δ13C) excursion of ~5–7‰ 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‰. 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
Copyright Holders: 2005 Nature Publishing Group
ISSN: 1476-4687
Academic Unit/School: Faculty of Science, Technology, Engineering and Mathematics (STEM) > Environment, Earth and Ecosystem Sciences
Faculty of Science, Technology, Engineering and Mathematics (STEM)
Interdisciplinary Research Centre: Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)
Item ID: 34859
Depositing User: David Kemp
Date Deposited: 12 Mar 2013 10:56
Last Modified: 04 Oct 2016 11:21
URI: http://oro.open.ac.uk/id/eprint/34859
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