Causes and Characteristics of Electrical Resistivity Variability in Shallow (<4 m) Soils in Taylor Valley, East Antarctica

Airborne electromagnetic surveys collected in December 2011 and November 2018 and three soil sampling transects were used to analyze the spatial heterogeneity of shallow (<4 m) soil properties in lower Taylor Valley (TV), East Antarctica. Soil resistivities from 2011 to 2018 ranged from ∼33 Ωm to...

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Bibliographic Details
Published in:Journal of Geophysical Research: Earth Surface
Main Authors: Gutterman, W. S., Doran, P. T., Virginia, R. A., Barrett, J. E., Myers, K. F., Tulaczyk, S. M., Foley, N. T., Mikucki, J. A., Dugan, H. A., Grombacher, D. J., Bording, T. S., Auken, E.
Format: Article in Journal/Newspaper
Language:English
Published: 2023
Subjects:
active layer
airborne electromagnetic surveys
McMurdo dry valleys
permafrost dynamics
Antarc*
Antarctica
Antarctica Journal
East Antarctica
McMurdo Dry Valleys
permafrost
Online Access:https://pure.au.dk/portal/en/publications/7ad41af1-83bf-49bd-bf65-58067996b659
https://doi.org/10.1029/2022JF006696
http://www.scopus.com/inward/record.url?scp=85148716616&partnerID=8YFLogxK
Description
Summary:Airborne electromagnetic surveys collected in December 2011 and November 2018 and three soil sampling transects were used to analyze the spatial heterogeneity of shallow (<4 m) soil properties in lower Taylor Valley (TV), East Antarctica. Soil resistivities from 2011 to 2018 ranged from ∼33 Ωm to ∼3,500 Ωm with 200 Ωm assigned as an upper boundary for brine-saturated sediments. Elevations below ∼50 m above sea level (masl) typically exhibit the lowest resistivities with resistivity increasing at high elevations on steeper slopes. Soil water content was empirically estimated from electrical resistivities using Archie's Law and range from ∼<1% to ∼68% by volume. An increase in silt- and clay-sized particles at low elevations increases soil porosity but decreases hydraulic conductivity, promoting greater residence times of soil water at low elevations near Lake Fryxell. Soil resistivity variability between 2011 and 2018 shows soils at different stages of soil freeze-thaw cycles, which are caused predominantly by solar warming of soils as opposed to air temperature. This study furthers the understanding of the hydrogeologic structure of the shallow subsurface in TV and identifies locations of soils that are potentially prone to greater rates of thaw and resulting ecosystem homogenization of soil properties from projected increases in hydrological connectivity across the region over the coming decades.

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