Geophysical characterization of the red lake peatland complex, Northern Minnesota

The Red Lake Peatland Complex in Northern Minnesota is one of the largest and most studied peatlands in North America (140 km2), but the logistical impediments of working in such large remote wetlands limit direct subsurface data collection to a few widely spaced samples. This mid-continent forested bog complex is comprised of three major peat landforms, each of which was surveyed using ground penetrating radar (GPR), electrical resistivity, and induced polarization (IP): (1) a raised, ombrotrophic, wooded crest; (2) a sphagnum lawn down slope of the bog crest; (3) a spring fen water track where water flows across the peat surface around ovoid wooded islands. GPR was used to obtain peat thickness and to distinguish the peat stratigraphy as a function of variable water content between organic soil horizons. Resistivity data was collected to characterize the peat thickness and structure and to image the hydrogeologic framework beneath the organic soil. The results form a novel data set of a well studied bog complex, offering new insights into the peat structure and hydrogeologic framework. These observations have implications for general models of peatland development and carbon cycling.