A study of the geoelectrical properties of peatlands and their influence on ground-penetrating radar surveying

A variety of geophysical methods have been used on peatlands, including ground penetrating radar (GPR), resistivity, and electromagnetic induction (EM) surveying. The full potential of these techniques remains largely unexplored, mainly because the understanding of the physical factors that control the instrument response in peatlands is incomplete. The water table is normally at, or slightly below, the ground surface; the peat thickness can range from 40 cm to 10 m. In bulk, peat is mostly water, with a supporting matrix made of purely organic materials. The organic materials are the partially decomposed remains of plants, which can take millennia to accumulate in the form of peat. Internal stratigraphic features and thicknesses of peatlands can vary dramatically with little predictability on the basis of surface vegetation. The authors discuss the use of geophysics, alone and as a supplement to conventional coring programs. They have investigated three peatland sites, and have carried out comparisons of the electrical property variations and of the heat physical properties that may be detected by geophysical methods, from site to site and within individual peatlands. They also suggest a systematic protocol for the geophysical investigation of peatlands, specifically, and for GPR surveys generally.