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Abstract Lakes and drained lake basins (DLBs) together cover up to ∼80% of the western Arctic Coastal Plain of Alaska. The formation and drainage of lakes in this continuous permafrost region drive spatial and temporal landscape dynamics. Postdrainage processes including vegetation succession and permafrost aggradation have implications for hydrology, carbon cycling, and landscape evolution. Here, we used surface nuclear magnetic resonance (NMR) and transient electromagnetic (TEM) measurements in conjunction with thermal modeling to investigate permafrost aggradation beneath eight DLBs on the western Arctic Coastal Plain of Alaska. We also surveyed two primary surface sites that served as nonlake affected control sites. Approximate timing of lake drainage was estimated based on historical aerial imagery. We interpreted the presence of taliks based on either unfrozen water estimated with surface NMR and/or TEM resistivities in DLBs compared to measurements on primary surface sites and borehole resistivity logs. Our results show evidence of taliks below several DLBs that drained before and after 1949 (oldest imagery). We observed depths to the top of taliks between 9 and 45 m. Thermal modeling and geophysical observations agree about the presence and extent of taliks at sites that drained after 1949. Lake drainage events will likely become more frequent in the future due to climate change and our modeling results suggest that warmer and wetter conditions will limit permafrost aggradation in DLBs. Our observations provide useful information to predict future evolution of permafrost in DLBs and its implications for the water and carbon cycles in the Arctic.
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Surface Nuclear Magnetic Resonance (NMR) Soundings on Drained Lake Basins, North Slope, Alaska, 2015-2016
This dataset contains surface nuclear magnetic resonance (NMR) geophysical soundings acquired on five drained lake basins and two control sites on terrestrial upland permafrost (primary surface sites) during spring fieldwork 2015 - 2016. Measurements were made using a Vista Clara GMR (Mukilteo, Washington, Unites States of America) with a circle coincident transmitter/receiver loop either 75 meters (m) or 90 m diameter. Raw data for nine soundings are provided in the proprietary format created by the instrument, and results after processing and inversion with the GMR software (Mukilteo, Washington, Unites States of America; Walsh, 2008) are included as tabular values. The purpose of this research is to identify unfrozen bodies or taliks below drained lake basins to better understand the process of permafrost aggradation after lake drainage. Surface NMR is the only non-invasive geophysical method that is able to directly detect unfrozen water as it measures the response of hydrogen protons on liquid water (Walsh, 2008). Walsh, D. O. (2008). Multi-channel surface NMR instrumentation and software for 1D/2D groundwater investigations. Journal of Applied Geophysics, 66(3–4), 140–150. https://doi.org/10.1016/j.jappgeo.2008.03.006
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- Award ID(s):
- 1806213
- PAR ID:
- 10303021
- Publisher / Repository:
- NSF Arctic Data Center
- Date Published:
- Subject(s) / Keyword(s):
- Geophysics Permafrost Surface Nuclear Magnetic Resonance Drained Lake Basin
- Format(s):
- Medium: X Other: text/xml
- Sponsoring Org:
- National Science Foundation
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