EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

A record of seafloor methane seepage across the last 150 million years

Davide Oppo1, Luca De Siena2, and David Kemp3
Davide Oppo et al.
  • 1University of Louisiana at Lafayette, School of Geosciences, Lafayette, United States of America (
  • 2Johannes Gutenberg University Mainz, Institute of Geosciences, D-55128 Mainz, Germany (
  • 3China University of Geosciences, School of Earth Sciences and State Key Laboratory of Biogeology and Environmental Geology, Wuhan 430074, China (

Methane seepage at the seafloor is a source of carbon in the marine environment and has long been recognized as an important window into the deep geo-, hydro-, and bio-spheres. However, the processes and temporal patterns of natural methane emission over multi-million-year time scales are still poorly understood. The microbially-mediated methane oxidation leads to the precipitation of authigenic carbonate minerals within subseafloor sediments, thus providing a potentially extensive record of past methane emission. In this study, we used data on methane-derived authigenic carbonates to build a proxy time series of seafloor methane emission over the last 150 My. We quantitatively demonstrate that variations in sea level and organic carbon burial are the dominant controls on methane leakage since the Early Cretaceous. Sea level controls variations of methane seepage by imposing smooth trends with cyclicities in the order of tens of My. Organic carbon burial shows the same cyclicities and instantaneously controls the volumes of methane released thanks to the rapid generation of biogenic methane. The identified fundamental (26-27 My) cyclicity matches those observed in the carbon cycle associated with plate tectonic processes, the atmospheric CO2, the oceanic anoxic events, and mass extinction events. A higher (12 My) cyclicity relates to modulations of Milankovitch eccentricity cycles and to variations in global tectonics. These analogies demonstrate that the seafloor methane seepage across the last 150 My relates to a large spectrum of global phenomena and thus has key implications for a better understanding of methane cycling at the present day. Temporal correlation analysis supports the evidence that the modern expansion of hypoxic areas and its effect on organic carbon burial may lead to higher seawater methane concentrations over the coming centuries.

How to cite: Oppo, D., De Siena, L., and Kemp, D.: A record of seafloor methane seepage across the last 150 million years, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8396,, 2020


Display file

Comments on the display

AC: Author Comment | CC: Community Comment | Report abuse

displays version 1 – uploaded on 24 Apr 2020, no comments