Revealing the Extent of Submarine Permafrost and Gas Hydrates in the Canadian Arctic Beaufort Sea Using Seismic Reflection Indicators

• Published in: Geochemistry, Geophysics, Geosystems
• Main Authors: Grob, Hendrik, Riedel, Michael, Duchesne, M. J., Krastel, Sebastian, Bustamante, J., Fabien‐Ouellet, G., Jin, Y. K., Hong, J. K.
• Format: Article in Journal/Newspaper
• Language: English
• Published: AGU (American Geophysical Union) 2023
• Subjects: Arctic; Beaufort Shelf; Beaufort Sea; Climate change; permafrost
• Online Access: https://oceanrep.geomar.de/id/eprint/58858/; https://oceanrep.geomar.de/id/eprint/58858/1/Geochem%20Geophys%20Geosyst%20-%202023%20-%20Grob%20-%20Revealing%20the%20Extent%20of%20Submarine%20Permafrost%20and%20Gas%20Hydrates%20in%20the%20Canadian.pdf; https://oceanrep.geomar.de/id/eprint/58858/2/2023gc010884-sup-0001-supporting%20information%20si-s01.docx; https://doi.org/10.1029/2023GC010884

The Canadian Arctic Southern Beaufort Sea is characterized by prominent relict submarine permafrost and gas hydrate occurrences formed by subaerial exposure during extensive glaciations in Pliocene and Pleistocene. Submarine permafrost is still responding to the thermal change as a consequence of the marine transgression that followed the last glaciation. Submarine permafrost is still underexplored and is currently the focus of several research projects as its degradation releases greenhouse gases that contribute to climate change. In this study, seismic reflection indicators are used to investigate the presence of submarine permafrost and gas hydrates on the outer continental shelf where the base of permafrost is expected to cross-cut geological layers. To address the challenges of marine seismic data collected in shallow water environments, we utilize a representative synthetic model to assess the data processing and the detection of submarine permafrost and gas hydrate by seismic data. The synthetic model allows us to minimize the misinterpretation of acquisition and processing artifacts. In the field data, we identify features along with characteristics arising from the top and base of submarine permafrost and the base of the gas hydrate stability zone. This work shows the distribution of the present submarine permafrost along the southern Canadian Beaufort Sea region and confirms its extension to the outer continental shelf. It supports the general shape suggested by previous works and previously published numerical models. Key Points Seismic reflection data reveal occurrences and extent of submarine permafrost and associated gas hydrates at the Canadian Beaufort Shelf Synthetic modeling of permafrost and gas hydrate is required to assess seismic processing minimizing the potential for misinterpretation Indicators of top and base of permafrost and the base of gas hydrate stability support previously published numerical models