National uranium resource evaluation, Dickinson quadrangle, North Dakota

The Dickinson Quadrangle, North Dakota, was evaluated to a depth of 1500 m to identify environments and delineate areas favorable for uranium deposits. Criteria used in the evaluation were developed for the National Uranium Resource Evaluation program. The evaluation primarily consisted of a surface study, subsurface investigation, and an in-house ground-water geochemical study. These studies were augumented by aerial radiometric and hydrogeochemical and stream-sediment studies. The evaluation results indicate that the Sentinel Butte and Tongue River Members of the Fort Union Formation have environments favorable for uraniferous lignite deposits. The Sentinel Butte, Tongue River, and Ludlow Members of the Fort Union Formation are favorable for sandstone uranium deposits. Environments unfavorable for uranium deposits are the remaining Cenozoic rocks and all the rocks of the Cretaceous.