Marine heat flow measurements on subsea permafrost degradation area of the eastern Mackenzie Trough, Canadian Beaufort.

Kim, Y. G., Hong, J. K., Jin, Y. K., Riedel, Michael , Melling, H., Kang, S. G. and Dallimore, S. (2015) Marine heat flow measurements on subsea permafrost degradation area of the eastern Mackenzie Trough, Canadian Beaufort. [Poster] In: AGU Fall Meeting 2015. , 14.-18.12.2015, San Francisco, USA .

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Abstract

Marine heat flow measurements using a 5 m-long Ewing-type heat probe were made during Korean icebreaker R/V Araon's Arctic expeditions (ARA04C in 2013 and ARA05B in 2014) to better know the shallow subsurface thermal structure in the eastern slope of Mackenzie Trough, the Canadian Beaufort Sea, in which associative geological processes of permafrost degradation and gas hydrate dissociation occur because of long-term warming since the Last Glacial Maximum. Heat flow in the continental slope was collected for the first time and is rather higher than those from deep boreholes (up to a few km below the seafloor) in the continental shelf. However, the smaller geothermal gradient and thermal conductivity were observed from sites along a transect line across permafrost limit on the eastern slope of the trough. It is noted that geothermal gradients are relatively constant in the vicinity of permafrost limit but are much smaller (even minus) only at deeper depths with positive bottom water temperature. Reason for such distribution is unclear yet. Based on observed geothermal gradient and bottom water temperature, permafrost table shown in subbottom profile seems to be controlled not by temperature. On the other hand, our finding of permafrost evidence on the other subbottom profile located landward may support that permafrost limit in the trough is along with ~100 m isobath.

Document Type: Conference or Workshop Item (Poster)
Research affiliation: OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-GDY Marine Geodynamics
Date Deposited: 14 Dec 2016 09:04
Last Modified: 14 Dec 2016 09:04
URI: http://oceanrep.geomar.de/id/eprint/35226

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