Informatics Publishing Limited

Young-Gyun Kim ¹, Young Keun Jin ², Sookwan Kim ², Seung-Goo Kang ², Jong Kuk Hong ²

Affiliations
1 Research Institute for Earth Resources, Kangwon National University, KP
2 Korea Polar Research Institute, KIOST, KP

Abstract

The Arctic continental shelves experienced subsea permafrost degradation because of the long-term warming and sea level rise since the Last Glacial Maximum (LGM), when the sea level was ~100 m lower than its present level. However, the current status of the subsea permafrost limit is not yet clearly defined due to a lack of evidence. New subbottom profiling and subsurface temperatures were acquired to examine the subsea permafrost limit on the eastern slope of the Mackenzie Trough during Korean Icebreaker R/V Araon expeditions in the summer of 2013 and 2014. We found anomalous subbottom acoustic features indicating ice-bonded sediments where cold bottom water and a subsurface with subzero temperature exists. The cold bottom water belongs to the Arctic halocline. We conclude that with help from cold Arctic halocline, ice-bonded sediments can exist at shallow water depths of <100 m. We argue that they are relict subsea permafrost from the LGM, but further investigation is required to clarify their origin. Our conclusion implies that ice-bonded sediments can occur at shallow water depths over the Arctic continental shelves and that their fate depends on the temperature change in seawater.

Keywords

Beaufort Sea, IBRV Araon, Mackenzie Trough, Subsea Permafrost Limit, Subbottom Profile, Subsurface Temperature.

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