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Prospecting frost‐wedge pseudomorphs and their polygonal network using the electromagnetic induction sensor EM38DD
Author(s) -
Cockx Liesbet,
Ghysels Gunther,
Van Meirvenne Marc,
Heyse Irénée
Publication year - 2006
Publication title -
permafrost and periglacial processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.867
H-Index - 76
eISSN - 1099-1530
pISSN - 1045-6740
DOI - 10.1002/ppp.546
Subject(s) - pseudomorph , geology , wedge (geometry) , prospecting , mineralogy , mining engineering , geometry , paleontology , quartz , mathematics
Electromagnetic induction was used to locate near‐surface Pleistocene frost‐wedge pseudomorphs at a test site where a polygonal network was exposed. The soil apparent electrical conductivity (EC a ) was measured simultaneously with the EM38DD in the vertical and horizontal orientation, allowing the profile ratio (PR) to be calculated. Based on a fuzzy k ‐means classification the PR map was classified into two zones with a mean PR difference of 10%. A detailed drawing of the polygonal network served as a validation. A cross‐tabulation yielded an overall accuracy of 81% when only wedges wider than 0.25 m wide were considered. The overall accuracy increased to 83% by introducing an uncertainty zone. Due to differences in composition between the wedge fillings and the host material, the PR was found to be a useful indicator of these phenomena. Copyright © 2006 John Wiley & Sons, Ltd.