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TitleGas hydrate contribution to late Permian global warming
AuthorMajorowicz, J; Grasby, S E; Safanda, J; Beauchamp, B
SourceEarth and Planetary Science Letters vol. 393, 2014 p. 243-253,
Alt SeriesEarth Sciences Sector, Contribution Series 20140324
PublisherElsevier BV
Mediapaper; on-line; digital
File formatpdf
Subjectsenvironmental geology; fossil fuels; gas; hydrate; hydrocarbons; hydrocarbon gases; carbon isotopes; extinctions, biotic; climatic fluctuations; climatology; global warming; Paleozoic; Permian
Illustrationsplots; cross-sections
ProgramGEM2: Geo-mapping for Energy and Minerals, Mackenzie Corridor Project Management
AbstractRapid gas hydrate release (the "clathrate gun" hypothesis) has been invoked as a cause for the rapid global warming and associated negative carbon isotope excursion observed during the Latest Permian Extinction (LPE). We modeled the stability of gas hydrates through a warming Middle to Late Permian world, considering three settings for methane reservoirs: 1) terrestrial hydrates, 2) hydrates on exposed continental shelves during glacial sea level drop, and 3) hydrates in deep marine settings. Model results show that terrestrial hydrates would rapidly destabilize over ~400 ky after deglaciation for moderate heatflow (40 mW/m2), and more rapidly for higher heat flow values. Exposed continental shelves would lose hydrates even more rapidly, after being flooded due to loss of ice storage on land. These two major hydrate reservoirs would thus have destabilized during the Middle to Late Permian climate warming, well prior to the LPE event. However, they may have contributed to the >2 perthousand negative C-isotopic shift during the late Middle Permian. Deep marine hydrates would have remained stable until LPE time. Rapid warming of deep marine waters during this time could have triggered destabilization of this reservoir, however given the configuration of one super continent, Pangea, hydrate bearing continental slopes would have been less extensive than modern day. This suggests that any potential gas hydrate release would have had only a minor contributing impact to the runaway greenhouse during the Latest Permian extinction.
Summary(Plain Language Summary, not published)
As part of GEM related research on permafrost stability in the Beaufort-Mackenzie region, new methods where developed to model permafrost decay and associated release of gas hydrates under a warming climate. These methods were adapted to test previous predictions that massive release of methane occurred through permafrost melt during the Permian extinction 252 million years ago. Results show that most gas hydrates would have been lost millions of years prior to the extinction, and thus hydrate release cannot have been a main extinction driver as previously speculated.