EAP - earth publications

PUBLISHED
SINCE 1952

Estonian Journal of Earth Sciences

ISSN 1736-7557 (Electronic)
ISSN 1736-4728 (Print)

Open Access Journal

CiteScore: 1.4

Impact Factor (2022): 1.1

Ground-penetrating radar study of the Rahivere peat bog, eastern Estonia; pp. 31–42

PDF | doi: 10.3176/earth.2011.1.03

Authors

Jüri Plado, Ivo Sibul, Mario Mustasaar, Argo Jõeleht

Abstract

The current case study presents results of the ground-penetrating radar (GPR) profiling at one of the Saadjärve drumlin field interstitial troughs, the Rahivere bog, eastern Estonia. The study was conducted in order to identify the bog morphology, and the thickness and geometry of the peat body. The method was also used to describe the applicability of GPR in the evaluation of the peat deposit reserve as the Rahivere bog belongs among the officially registered peat reserves. Fourteen GPR profiles, ~ 100 m apart and oriented perpendicular to the long axis of the depression, covering the bog and its surrounding areas, were acquired. In order to verify the radar image interpretation as well as to evaluate the velocity of electromagnetic waves in peat, a common source configuration was utilized and thirteen boreholes were drilled on the GPR profiles. A mean value of 0.036 m ns^–1 corresponding to relative dielectric permittivity of 69.7 was used for the time–depth conversion. Radar images reveal major reflection from the peat–soil interface up to a depth of about 4 m, whereas drillings showed a maximum thickness of 4.5 m of peat. Minor reflections appear from the upper peat and mineral soil. According to the borehole data, undecomposed peat is underlain by decomposed one, but identifying them by GPR is complicated. Mineral soil consists of glaciolimnic silty sand in the peripheral areas of the trough, overlain by limnic clay in the central part. The calculated peat volumes (1 200 000 m³) were found to exceed the earlier estimation (979 000 m³) that was based solely on drilling data. Ground-penetrating radar, as a method that allows mapping horizontal continuity of the sub-peat interface in a non-destructive way, was found to provide detailed information for evaluating peat depth and extent.

References

Allikvee, H. & Orru, M. 1979. Jõgeva rajooni turbamaardlate otsingulis-uuringuliste tööde aruanne [Report of the Search and Investigations at the Peat Deposits in the Jõgeva District]. Geoloogia Valitsus, Tallinn, 446 pp. (EGF 5182) [in Estonian].

Bjelm, L. 1980. Geological interpretation with subsurface interface radar in peat lands. In Proceedings of the 6th International Peat Congress, pp. 7–8. Duluth, Minnesota.

Boelter, D. H. 1968. Important physical properties of peat materials. In Proceedings of the 3rd International Peat Congress, pp. 150–154. Québec, Canada.

Boelter, D. H. 1969. Physical properties of peats as related to degree of decomposition. Soil Science Society of America Journal, 33, 606–609.
doi:10.2136/sssaj1969.03615995003300040033x

Comas, X., Slater, L. & Reeve, A. 2005. Stratigraphic controls on pool formation in a domed bog inferred from ground penetrating radar (GPR). Journal of Hydrology, 315, 40–51.
doi:10.1016/j.jhydrol.2005.04.020

Comas, X., Slater, L. & Reeve, A. 2008. Seasonal geophysical monitoring of biogenic gases in a northern peatland: implications for temporal and spatial variability in free phase gas production raters. Journal of Geophysical Research, 113, G01012.
doi:10.1029/2007JG000575

Daniels, D. J. 2004. Ground Penetrating Radar (2nd Edition). IEE Radar, Sonar and Navigation Series 15. The Institution of Electrical Engineers, London, 726 pp.

Davis, J. L. & Annan, A. P. 1989. Ground-penetrating radar for high-resolution mapping of soil and rock stratigraphy. Geophysical Prospecting, 37, 531–551.
doi:10.1111/j.1365-2478.1989.tb02221.x

Godio, A. 2009. Georadar measurements for the snow cover density. American Journal of Applied Sciences, 6, 414–423.
doi:10.3844/ajassp.2009.414.423

Kettridge, N., Comas, X., Baird, A., Slater, L., Strack, M., Thompson, D., Jol, H. & Binley, A. 2008. Ecohydrologically important subsurface structures in peatlands revealed by ground-penetrating radar and complex conductivity surveys. Journal of Geophysical Research, 113, G04030.
doi:10.1029/2008JG000787

Lowry, C. S., Fratta, D. & Anderson, M. P. 2009. Ground penetrating radar and spring formation in a groundwater dominated peat wetland. Journal of Hydrology, 373, 68–79.
doi:10.1016/j.jhydrol.2009.04.023

Mellet, J. S. 1995. Profiling of ponds and bogs using ground-penetrating radar. Journal of Paleolimnology, 14, 233–240.
doi:10.1007/BF00682425

Meyer, J. H. 1989. Investigation of Holocene organic sediments – a geophysical approach. International Peat Journal, 3, 45–57.

Päivänen, J. 1973. Hydraulic conductivity and water retention in peat soils. Acta Forestalia Fennica, 129, 1–70.

Pirrus, R. & Raukas, A. 1996. Late-Glacial stratigraphy in Estonia. Proceedings of the Estonian Academy of Sciences, Geology, 45, 34–45.

Pirrus, R., Rõuk, A.-M. & Liiva, A. 1987. Geology and stratigraphy of the reference site of Lake Raigastvere in Saadjärv drumlin field. In Palaeohydrology of the Temperate Zone II. Lakes (Raukas, A. & Saarse, L., eds), pp. 101–122. Valgus, Tallinn.

Radar Systems, Inc. 2005. Prism 2 Software Package. User’s Manual. Riga, 45 pp.

Rattas, M. & Kalm, V. 2001. Lithostratigraphy and distribution of tills in the Saadjärve drumlin field, East-Central Estonia. Proceedings of the Estonian Academy of Sciences, Geology, 50, 24–42.

Rattas, M. & Piotrowski, J. A. 2003. Influence of bedrock permeability and till grain size on the formation of the Saadjärve drumlin field, Estonia, under an east-Baltic Weichselian ice stream. Boreas, 32, 167–177.
doi:10.1080/03009480310001849

Rial, F. I., Pereira, M., Lorenzo, H., Arias, P. & Novo, A. 2008. Resolution of GPR bowtie antennas: an experimental approach. Journal of Applied Geophysics, 67, 367–373.
doi:10.1016/j.jappgeo.2008.05.003

Rosa, E., Larocque, M., Pellerin, S., Gagné, S. & Fournier, B. 2009. Determining the number of manual measurements required to improve peat thickness estimations by ground penetrating radar. Earth Surface Processes and Landforms, 34, 377–383.
doi:10.1002/esp.1741

Rosentau, A., Hang, T. & Kalm, V. 2007. Water-level changes and palaeogeography of proglacial lakes in eastern Estonia: synthesis of data from the Saadjärve Drumlin Field area. Estonian Journal of Earth Sciences, 56, 85–100.

Rõuk, A.-M. & Raukas, A. 1989. Drumlins of Estonia. Sedimentary Geology, 62, 371–384.
doi:10.1016/0037-0738(89)90126-7

Slater, L. D. & Reeve, A. 2002. Investigating peatland stratigraphy and hydrogeology using integrated electrical geophysics. Geophysics, 67, 365–378.
doi:10.1190/1.1468597

Stein, M. L. 1999. Interpolation of Spatial Data: Some Theory for Kriging. Springer Series in Statistics XVIII, Springer-Verlag, New York, 247 pp.

Warner, B. G., Nobes, D. C. & Theimer, B. D. 1990. An application of ground penetrating radar to peat stratigraphy of Ellice Swamp, southwestern Ontario. Canadian Journal of Earth Sciences, 27, 932–938.

Back to Issue