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| Titel |
Record of methane emissions from the Arctic during the last Deglaciation |
| VerfasserIn |
Giuliana Panieri, Chiara Consolaro, Rachael James, Graham Westbrook, Tine Rasmussen, Jürgen Mienert |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250096485
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| Publikation (Nr.) |
 EGU/EGU2014-11992.pdf |
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| Zusammenfassung |
| The methane hydrates of the Arctic represent potentially significant carbon resources
that are sensitive to climate change. Methane hydrate provinces are widespread
in the Arctic, but their stability and longevity through time, and the significance
of their contribution to the global carbon budget, is still poorly understood. It is,
therefore, critical to resolve the frequency of methane (CH4) seafloor emissions through
time, in relation to past climate change with a special focus on periods of climate
warming.
The values of δ13C in benthic foraminifera have been measured in two cores, one
collected from an area of active methane venting and one from an inactive area on the
Vestnesa Ridge (NW Svalbard continental margin), in order to reconstruct the local
history of methane emissions over the past 16,000 years BP. The chronostratigraphic
framework of the cores has been derived from biostratigraphic analysis and AMS
14C dates. While foraminifera from some intervals have δ13C within the normal
marine range (0 to -1), several intervals are characterized by much lower δ13C,
as low as -17.4oin the active core and as low as -4.37oin the inactive core.
These intervals are interpreted to record the incorporation of 13C-depleted carbon in
the presence of methane emissions at the seafloor during biomineralization of the
carbonate foraminiferal tests and subsequent secondary mineralization. The longest
of these ‘methane emission events’ (MEE) coincides with the start of the warm
Bølling-Allerød Interstadial (GI-1 in the Greenland ice core record). The lack of
correlation between the values of δ13C and δ18O, however, appears to preclude
warming of bottom waters as the principal control on methane release. Rather, it seems
likely that methane release is related to changes in gas migration pathways, or other
geological processes still under debate. Details on the CAGE research plan and
organization can be found on www.cage.uit.no to foster opportunities for cross-disciplinary
collaboration. Based in Tromsø, at the world’s northernmost University, CAGE establishes
the intellectual and infrastructure resources for studying the amount of methane
hydrate and magnitude of methane release in Arctic Ocean environments on time
scales from the Neogene to the present. The Centre of Excellence is funded by
the Norwegian Research Council (grant No. 223259) over a period of ten years. |
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