Imaging a polygonal network of ice-wedge casts with an electromagnetic induction sensor

Images of the morphology of a polygonal network of ice-wedge casts are a valuable aid to paleoclimatological reconstructions. Usually such images are obtained by aerial photography showing polygonal crop marks reflecting textural differences between wedge filling and host material. Our objective was...

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Bibliographic Details
Published in:Soil Science Society of America Journal
Main Authors: Meerschman, Eef, Van Meirvenne, Marc, De Smedt, Philippe, Saey, Timothy, Islam, Mohammad Monirul, Meeuws, Fun, Van De Vijver, Ellen, Ghysels, Gunther
Format: Article in Journal/Newspaper
Language:English
Published: 2011
Subjects:
Mathematics and Statistics
EM38DD
DUALEM-21S SENSORS
PSEUDOMORPHS
SENSITIVITY
FLANDERS
BELGIUM
CANADA
DEPTH
SOIL
USA
Canada
Ice
permafrost
wedge*
Online Access:https://biblio.ugent.be/publication/1959985
http://hdl.handle.net/1854/LU-1959985
https://doi.org/10.2136/sssaj2011.0063
https://biblio.ugent.be/publication/1959985/file/1959995
Description
Summary:Images of the morphology of a polygonal network of ice-wedge casts are a valuable aid to paleoclimatological reconstructions. Usually such images are obtained by aerial photography showing polygonal crop marks reflecting textural differences between wedge filling and host material. Our objective was to investigate an alternative method by measuring the soil apparent electrical conductivity (EC(a)) with an electromagnetic induction (EMI) sensor. Based on an aerial photograph showing polygonal crop marks in an agricultural field in Belgium, a test area of 0.63 ha was selected. A small part of the test area (6 by 6 m) was excavated revealing a clear pattern of ice-wedge casts. The wedges penetrated clay-rich Tertiary marine sediments, covered by a 0.6-m layer of eolian sandy sediments, and were associated with the permafrost during the last glacial period. We took 94 subsoil (0.6-0.8 m) samples distributed over the test area and analyzed their texture. The results showed a clear difference between the Eocene host material (on average 21% clay) and the Quaternary wedge filling (on average 6% clay). The test area was surveyed with an EMI sensor (we used an EM38DD) which resulted in an accurate image of the polygonal network. We concluded that an EMI survey is an appropriate technique to image the morphology of a polygonal network of subsoil ice-wedge casts. A final perspective comprises the strong heterogeneity of the subsoil, since nearly half of the subsoil consists of ice-wedge material. This might open perspectives for precision agriculture in such landscapes.

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