HR: 0800h
AN: PP11A-0230    [Abstracts]
TI: Triggering the Paleocene/Eocene Thermal Maximum: the Kilda Capacitor Hypothesis
AU: * Eagles, G
EM: g.eagles@gl.rhul.ac.uk
AF: Department of Geology, Royal Holloway University of London, Egham Hill, Egham, TW20 0EX, United Kingdom
AU: Nisbet, E
EM: e.nisbet@gl.rhul.ac.uk
AF: Department of Geology, Royal Holloway University of London, Egham Hill, Egham, TW20 0EX, United Kingdom
AU: Jones, S
EM: stephen.jones@tcd.ie
AF: Department of Geology, Trinity College, Dublin, Dublin, 2, Ireland
AU: Maclennan, J
EM: jmac05@esc.cam.ac.uk
AF: Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, United Kingdom
AB: The Paleocene/Eocene Thermal Maximum (PETM) may have been triggered by catastrophic expulsion of gas from an anoxic rift-basin great lake or silled ocean basin between Norway and Greenland (Lake Kilda), which formed when kilometre-scale uplift accompanying emplacement of the North Atlantic Igneous Province severed connection with the global ocean. Modern analogues to such basins are meromictic and hence can act as capacitors for methane and carbon dioxide. By analogy with modern African Lake Kivu, carbon dioxide and methane of both organic and hydrothermal origin would have accumulated in the stratified Lake Kilda capacitor until the gas saturation level rose to within a few hundred metres of the lake surface. Lake water overturn may have caused a catastrophic expulsion of up to 100 Gt of gas, in an event analogous to the African Lake Nyos emission. This pulse could have been large enough both to create an initial sharp warming phase by which the atmospheric residence time of methane was extended, allowing the initiation of positive feedback from other slower greenhouse gas release mechanisms, that in turn maintained global warming throughout the PETM.
DE: 4901 Abrupt/rapid climate change (1605)
DE: 4930 Greenhouse gases
DE: 4942 Limnology (0458, 1845, 4239)
DE: 4948 Paleocene/Eocene thermal maximum
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting