Synthetic model testing and distributed acquisition dc resistivity results over an unconformity uranium target from the Athabasca Basin, northern Saskatchewan

The dc resistivity method has become a preferred reconnaissance mapping tool for uranium exploration targets in the Athabasca Basin, in northern Saskatchewan, Canada. Regionally, uranium deposits can occur beneath 1 km thick sandstone cover rocks, are commonly associated with deeper basement graphitic metasedimentary units and are also often accompanied by clay-alteration zones in the sandstones. As a result, deep-penetrating electromagnetic and electrical geophysical techniques are ideally suited for indirect exploration of these types of deposits. A variety of electrode configurations are being used, however the pole-pole array is currently favoured in the Athabasca Basin due to its high signal levels, its deep penetration and its anomaly resolution. More recently, however, other technologies such as audio-magnetotellurics (AMT/MT) and 24-bit A/D distributed acquisition systems (DAS) have been introduced to extend the depth of exploration below 1 km. In the example presented here, a DAS acquisition system was used to acquire dc resistivity data, using a variety of electrode arrays, to examine the response parameters from the different configurations along a single line located along a known conductive trend at the M-Zone on the Wheeler River property.