Application of a towed time-domain electromagnetic (tTEM) imaging system in Jamestown, North Dakota

Time-Domain Electromagnetic (EM) methods have been used for decades in support of groundwater investigations. A new towed Time-Domain EM system called “tTEM”, designed by Aarhus University, is being tested and evaluated under a collaborative research agreement with the U.S. Geological Survey (USGS). The tTEM system is rapid and efficient, providing high-resolution, nearly continuous profiles of subsurface resistivity useful for hydrostratigraphic mapping and assessment of aquifer materials. Here we provide an example of a tTEM survey conducted in Jamestown, North Dakota (ND). The purpose of the ND investigation was to assess tTEM the ability of the system to map coarse-grained materials within the Spiritwood Aquifer. The tTEM survey results compare favorably with the results of an airborne EM (AEM) survey previously conducted in the area and to lithologic logs from nearby boreholes.