Hydrogeochemical and stream sediment detailed geochemical survey for Lakeview, Oregon

Field and laboratory data are reported for 231 groundwater, 881 stream sediment, and 303 stream water samples. Statistical and areal distributions of uranium and possible uranium-related variables are displayed. A generalized geologic map of the area is provided and pertinent geologic factors which may be of significance in evaluating the potential for uranium mineralization are discussed. Uranium concentrations in groundwater average 0.82 ppB. High uranium concentrations are generally associated with high concentrations of dissolved solids. Scattered areas displaying anomalous uranium (greater than or equal to 1.00 ppB), low dissolved solid content, high uranium/boron and uranium/specific conductance values, and significant arsenic and molybdenum concentrations occur in waters derived from volcanic rocks and are considered more favorable indications of uranium mineralization. Stream sediment data reveal that above background values of soluble uranium are commonly associated with Pliocene rhyolitic intrusive plugs. Anomalous uranium is also found in tuffaceous and basaltic units of the Upper Cedarville Formation, which have been intruded by the rhyolite plugs and influenced by hydrothermal fluid activity presumably accompanying plug emplacement. High mercury and arsenic concentrations are commonly associated with significant uranium concentrations. Low uranium concentrations are generally observed in stream waters. Samples where relatively high uranium concentrations are present generally contain significant concentrations of dissolved solids which are probably derived from volcanic source rocks. Scattered samples which are anomalous with respect to uranium (greater than or equal to 0.80 ppB) and display low to moderate dissolved solids content, high uranium/boron and uranium/specific conductance values, and high arsenic values may define potentially favorable areas for uranium mineralization