Iron oxides as a cause of GPR reflections

R.L. van Dam, W. Schlager, M. Dekkers, J.A. Huisman

    Research output: Contribution to JournalArticleAcademicpeer-review

    Abstract

    Iron oxides frequently occur as secondary precipitates in both modern and ancient sediments and may form bands or irregular patterns. We show from time-domain reflectometry (TDR) field studies that goethite iron-oxide precipitates significantly lower the electromagnetic wave velocity of sediments. Measured variations in magnetic permeability do not explain this decrease. The TDR measurements and a dielectric mixing model also show that neither electrical conductivity nor relative permittivity of the solid material are altered significantly by the iron-oxide material. From drying during all of the measurements, the amount of iron oxides appears to correlate with the volumetric water content, which is the result of differences in water retention capacity between goethite and quartz. These variations in water content control relative permittivity and explain the observed variation in electromagnetic wave velocity. Using 2-D synthetic radar sections, we show that the pattern of iron-oxide precipitation may have a profound influence on the GPR reflection configuration and can cause major difficulties in interpretation.
    Original languageEnglish
    Pages (from-to)536-545
    JournalGeophysics
    Volume67
    Issue number2
    DOIs
    Publication statusPublished - 2002

    Fingerprint Dive into the research topics of 'Iron oxides as a cause of GPR reflections'. Together they form a unique fingerprint.

  • Cite this

    van Dam, R. L., Schlager, W., Dekkers, M., & Huisman, J. A. (2002). Iron oxides as a cause of GPR reflections. Geophysics, 67(2), 536-545. https://doi.org/10.1190/1.1468614