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J. Karen Felmlee

Publications and source records attributed to J. Karen Felmlee.

8 recordsLinked to original sources
USGS1979

Radioactive springs geochemical data related to uranium exploration: basic data and use of multivariate factor scores

Radioactive springs and wells at 33 localities in the States of Colorado, Utah, Arizona, and New Mexico have been studied and sampled to obtain geochemical data to determine whether such data are useful in a uranium exploration program. Most samples were collected from mineral-rich springs probably related to hydrothermal systems of various ages. Two sets of data were obtained, the first based on the chemical composition and physical and chemical properties of spring and ground water, and the second based on the chemical composition of mineral precipitates deposited by radioactive springs. Multivariate statistical analysis of the water data suggests four major geochemical factors affecting the 23 parameters measured. These factors were labeled as total dissolved solids, alkalinity, temperature, and Fe-U concentration. Multivariate statistical analysis of the precipitate data suggests five factors affecting the 32 element values measured. These factors were labeled as mineral contamination, Mn precipitation, Fe-As-Be precipitation, heavy metals precipitation, and Ba-Ra precipitation. Relative intensities of the geochemical processes represented by the factors were computed using factor scores. Sample localities were ranked on the basis of relative intensities, and the five localities with the highest intensities were selected as being the most favorable for more intensive exploration for uranium. Immediate use of such selection would be experimental because of the lack of industry experience at this time in the exploration of active hydrothermal systems for uranium.

Open-File Report↗
USGS1979

Radium and uranium concentrations and associated hydrogeochemistry in ground water in southwestern Pueblo County, Colorado

Radium and uranium concentrations in water from 37 wells tapping the aquifer system of the Dakota Sandstone and Purgatoire Formation in southwestern Pueblo County, Colorado, have a wide range of values and define several areas of high radioactivity in the ground water. Radium ranges from 0.3 to 420 picocuries per liter and has a median value of 8.8, and uranium ranges from 0.02 to 180 micrograms per liter and has a median value of 2.4. Radon concentrations, measured in 32 of the 37 wells, range from less than 100 picocuries per liter to as much as 27,000 and have a median value of 580. Relationships among the radioactive elements and 28 other geochemical parameters were studied by using correlation coefficients and R-mode factor analysis. Five factor groups were determined to represent major influences on water chemistry: (1) short-term solution reactions, (2) oxidation reactions, (3) hydrolysis reactions, (4) uranium distribution, and (5) long-term solution reactions. Uranium concentrations are most strongly influenced by oxidation reactions but also are affected by solution reactions and distribution of uranium in the rocks of the aquifer system. Radon and radium concentrations are mostly controlled by uranium distribution; radium also shows a moderate negative relationship with oxidation. To explain the statistical and spatial relationships among the parameters, a model was developed involving the selective leaching of uranium-bearing phases and metal sulfides which occur in discontinuous zones in sandstone and shale. When reducing conditions prevail, uranium is immobile, but radium can be taken into solution. When faults and associated fractured rocks allow oxidizing conditions to dominate, uranium can be taken into solution; radium can also be taken into solution, or it may become immobilized by coprecipitation with iron and manganese oxides or with barite. Several areas within the study area are discussed in terms of the model.

Open-File Report↗
USGS1978

Uranium values from ion-filter water sampling compared with values from bulk-water sampling

Analytical values of uranium from well water sampled by means of ion-filters were compared with analytical values of the same water sampled by the standard bulk (1-liter) water-sampling technique (Brown, Skougstad and Fishman, 1970). A fluorometric extraction method of analysis was used on both sets of samples. Duplicate samples from pumped wells in Pueblo County, Colorado were used. Regression and correlation statistical analysis indicated that while analytical results of the two sets of samples had a highly significant correlation (r = 0.98), the ion-filter samples yielded only 20 percent as much uranium as the 1-liter water samples. It is possible to predict U values from the ion-filter analysis results that would be comparable with the values for the 1-liter samples, using the linear regression formula. The predicted values, however, compared with the 1-liter values, using a chi-square test, were found to be significantly different at the 5-percent level. Major deviations were found in two pairs, 10 percent of the samples, suggesting that the predicted values might be used if one were willing to accept the fact that an average of 10 percent of the samples would yield erroneous results. Sources of the absolute deviations between the two sets of samples may lie in chemical characteristics of the filters, or waters, or extraction method of the analytical technique or some combination of these. The results of the chi-square test also indicate that uranium values from at least 10 percent of the ion-filter samples that we obtained, deviate significantly from those obtained from the 1-liter samples. Sources of the deviations may lie in chemical characteristics of the filters, or waters, or extraction technique, part of the analytical technique or some combination of these.

Open-File Report↗
USGS1978

Radium and uranium data for mineral springs in eight Western States

Data for 116 mineral springs in eight Western States show a wide range of values. Specific conductance, temperature, and pH were measured at the sites between 1975 and 1977, and samples for radium and uranium analysis were collected. Correlation and regression analyses among the five measured parameters indicate that a positive correlation exists between radium and specific conductance and that negative correlations exist between radium and pH, specific conductance and pH, and uranium and temperature.

Open-File Report↗
USGS1976

Radioactive mineral springs in Delta County, Colorado

The system of springs in Delta County, Colo., contains geochemical clues to the nature and location of buried uranium-mineralized rock. The springs, which occur along the Gunnison River and a principal tributary between Delta and Paonia, are regarded as evidence of a still-functioning hydrothermal system. Associated with the springs are hydrogen sulfide and sulfur dioxide gas seeps, carbon dioxide gas-powered geysers, thick travertine deposits including radioactive travertine, and a flowing warm-water (41?C) radioactive well. Geochemical study of the springs is based on surface observations, on-site water-property measurements, and sampling of water, travertine, soft precipitates, and mud. The spring deposits are mostly carbonates, sulfates, sulfides, and chlorides that locally contain notable amounts of some elements, such as arsenic, barium, lithium, and radium. Samples from five localities have somewhat different trace element assemblages even though they are related to the same hydrothermal system. All the spring waters but one are dominated by sodium chloride or sodium bicarbonate. The exception is an acid sulfate water with a pH of 2.9, which contains high concentrations of aluminum and iron. Most of the detectable radioactivity is due to the presence of radium-226, a uranium daughter product, but at least one spring precipitate contains abundant radium-228, a thorium daughter product. The 5:1 ratio of radium-228 to radium-226 suggests the proximity of a vein-type deposit as a source for the radium. The proposed locus of a thorium-uranium mineral deposit is believed to lie in the vicinity of Paonia, Colo. Exact direction and depth are not determinable from data now available.

Open-File Report↗