Hammock, C. P., Kulessa, B., Hiemstra, J. F., Hodson, A. J., & Hubbard, A. (2021). Seismic and electrical geophysical characterization of an incipient coastal open-system pingo: Lagoon Pingo, Svalbard. Earth and Space Science, 9, e2021EA002093. https://doi.org/10.1029/2021EA002093
Seismic and electrical geophysical characterization of an incipient coastal open-system pingo : Lagoon Pingo, Svalbard
|Author:||Hammock, Craig P.1,2,3; Kulessa, Bernd1,4; Hiemstra, John F.1;|
1Department of Geography, College of Science, Swansea University, Swansea, UK
2Department of Geosciences, Centre for Arctic Gas Hydrate, Environment and Climate, UiT–The Arctic University of Norway, Tromsø, Norway
3Department of Arctic Geology, University Centre in Svalbard (UNIS), Longyearbyen, Norway
4School of Technology, Environments and Design, University of Tasmania, Hobart, TAS, Australia
5Department of Environmental Science, Western Norway University of Applied Sciences, Sogndal, Norway
6Department of Geography, University of Oulu, Oulu, Finland
|Online Access:||PDF Full Text (PDF, 2.7 MB)|
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe2022092760263
American Geophysical Union,
|Publish Date:|| 2022-09-27
Whilst there has been a recent appreciation for the role of open-system pingos in providing a fluid-flow conduit through continuous permafrost that enables methane release, the formation and internal structure of these ubiquitous permafrost-diagnostic landforms remains unclear. Here, we combine active-source seismic measurements with electrical resistivity tomography to investigate the structural and subsurface characteristics of an incipient open-system pingo actively emitting methane within the glacio-isostatically uplifting fjord valley of Adventdalen, Svalbard. Wavefront inversion of seismic refractions delineate a spatially heterogeneous active layer, whilst deeper reflections identify the lithological boundaries between marine sediments and underlying shales at ∼68 m depth (p-wave velocity of ∼1,790 ms−1). Low geometric mean inverted resistivities of 40–150 Ωm highlight the dominance of saline permafrost, whilst elevated resistivities (∼2 kΩm) occur close to the groundwater spring and in heaved areas around the pingo. Based on our results, we speculate that segregation ice dominates the pingo structure, given the absence of a notable resistivity contrast characteristic of injection ice that is typically expected within early open-system pingo formation, and provides the most plausible geomorphic agent within the local fine-grained sedimentology. Our results thereby indicate that sediment grain size and moisture availability can provide important controls on pingo formation. This study shows that open-system pingos in coastal, saline permafrost environments may form differently, with implications for localized permafrost structure, its permeability to underlying gas reservoirs and consequent methane release.
Earth and space science
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
519 Social and economic geography
Fieldwork was financially supported by the Swansea University College of Science Research Fund 2018/19, the Near Surface Geophysics Group of the Geological Society of London's Postgraduate Fieldwork Fund, and by the Research Council of Norway through its Centre of Excellence funding scheme (Grant No. 223259). Fieldwork was conducted within the CLIMAGAS project, funded by the Research Council of Norway (project no: 294764). Sara Mollie Cohen and UNIS logistics are thanked for the loan of ERT instruments, and for fieldwork logistical support. Richard Hann and Armin Dachauer are thanked for providing the Structure-from-Motion DEM (Hann & Dachauer, 2020). Emma Ciric, James Davidson, Veerle van Winden, Viktor Kröger, Will Hartz, Mikkel Toft Hornum, and Naomi Ochwat are thanked for fieldwork assistance. CPH is funded by a postgraduate scholarship awarded by the College of Science, Swansea University and by the Research Council of Norway through its Centre of Excellence funding scheme (Grant No. 223259).
© 2021. The Authors. Earth and Space Science published by Wiley Periodicals LLC on behalf of American Geophysical Union. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.