Beaufort offshore permafrost and gas hydrates – Climate change impact on Arctic transgressed continental shelves

• Applicants: Professor Dr. Sebastian Krastel; Dr. Michael Riedel
• Subject Area: Geophysics
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 425875279

Arctic continental shelf regions with water depths of less than 100 m comprise ~30% of the total area of the Arctic Ocean. Throughout the Quaternary, the Arctic shelf experienced a varied climatic and dynamic geologic history. During periods of low sea level many of these marine shelf areas were not covered with water but were exposed to mean annual air temperatures of -20ºC or less. These cold temperatures caused the formation of significant permafrost and also established favorable pressure and temperature conditions for gas hydrates. In contrast, sea level rise during interglacial periods resulted in marine transgression, yielding degradation of offshore permafrost and associated gas hydrates. The repeated changes between permafrost/hydrate formation and degradation have had substantial impacts on the geology of Arctic shelves and slope regions in form of fast-changing styles of sedimentation pattern and sediment types, erosion and re-deposition, mass-transport deposits, changes to fluid-flow patterns, and changes in sediment compaction. These geologic processes result in the occurrence of significant and still poorly understood geohazards such as land-slides, over-pressure and gas-release. The overarching objective of the proposal is to investigate permafrost degradation, gas hydrate dissociation, and gas migration from transgression and anthropogenic climate change along the southern Beaufort Sea (Canada). We have been invited to participate in the upcoming ARAON expedition in 2019 and propose to acquire new seismic data to advance our understanding of Arctic gas hydrate and offshore permafrost that are otherwise impossible to obtain. Participation in the 2019 expedition has been granted by the Korea Polar Research Institute (KOPRI) and Geological Survey of Canada (GSC). This unique opportunity allows us to answer three critical questions about offshore permafrost and Arctic gas hydrates: (1) What is the lateral and vertical extent and concentration of offshore permafrost, especially towards the shelf edge? (2) What is the extent and concentration of gas hydrates for the offshore Beaufort region in both, deep-water, and permafrost associated settings? (3) How large are gas flow rates in the shelf and shelf-break setting and can methane emitted at the seafloor reach the atmosphere? The proposal is highly leveraged through collaboration with international partners and allows participation at comparably low costs at an international icebreaker expedition to the Canadian Beaufort Sea. We intend using ocean bottom seismometers (OBS) instrumentation provided by GEOMAR to obtain high quality seismic refraction data as well as using the onboard provided multi-channel seismic equipment to acquire seismic reflection data across the region. This will be complemented by acquiring sub bottom profiler data as well as acoustic water column data, and a suite of other on board measurements (e.g. ocean water properties, atmospheric gas composition, etc.).

• DFG Programme: Research Grants