The measurement of lead isotope abundances with a gas source mass spectrometer has been limited to lead ores and minerals. This thesis describes a technique by means of which the sample size necessary for a precise gas source analysis has been decreased by more than two orders of magnitude. In this way, the range of minerals which may be studied by means of a gas source mass spectrometer has been greatly extended. No particular effort has been made to analyze very small samples. The technique which has been developed begins with the evaporation of lead from a mineral to form a mirror. The synthesis of tetramethyllead is completed by the reaction of free methyl radicals with the lead mirror followed by gas chromatographic purification. The free radical method has been applied to the study of lead isotope abundance variations in the mining district of Sudbury, Ontario. A satisfactory chronological history for this region has not been obtained from the many conventional age determinations that exist. The analysis of lead from various sulphides has yielded lead isotope ratios which are linearly related on a plot of Pb²⁰⁷/Pb²⁰⁴ vs. Pb²⁰⁶/Pb²⁰⁴ with a slope of 0.131 ± 0.003. The standard deviation of points from their best straight line is 0.37% of the average Pb²⁰⁷/Pb²⁰⁴ value. From these results it is concluded that the linear relationship is the result of just two geological events, which fact simplifies the possible interpretations. The maximum ages for these two events are 2150 ± 50 million years and 1280 ± 50 million years. Two interpretations of the results are suggested. The first gives ages of 1950 million years and 350 million years for the primary and secondary events. The two events in the second interpretation are considered to have occurred 1600 million years and 950 million years ago. The second interpretation is more easily defended on geological grounds. The simple relationship of lead isotope ratios which has been observed in the Sudbury district is particularly significant in view of the geological complexity of this region. Thus the technique developed may be expected to have wide application. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Bean plants were grown in a phosphate-free nutrient solution to the early trifoliate stage. At this time, they were transferred to a minus phosphate nutrient solution containing 100 p.p.m. 3-amino-1,2,4-triazole for 48 hours, and then placed into a labelled phosphate nutrient solution for another hour. The plants were then returned to a phosphate-free nutrient solution and harvested one, 24, 48, and 96 hours after the period of initial phosphate uptake. AT-treatment did not affect uptake of P³² but did decrease loss of P³² to the phosphate-free nutrient solutions after it had been absorbed by the plants. The proportion of absorbed phosphate found in the stems and leaves of AT-treated plants was higher than in these organs in the control plants. This phosphate represented an increase in both acid-soluble activity and acid-insoluble activity. The accumulation of acid-soluble activity in the shoots of AT-treated plants was an accumulation of inorganic phosphates, sugar phosphates, and nucleotides. AT appeared to inhibit downward translocation of acid-soluble and acid-insoluble activity. The incorporation of P³² into esterified compounds (i.e., nucleotides and sugar phosphates) was unaffected by AT indicating that AT does not interfere with oxidative phosphorylation nor with glycolysis. However, AT did inhibit transfer of P³² from the acid-soluble fraction to the acid-insoluble fraction. Therefore, the principal effect of AT is to inhibit the incorporation of phosphate into one or more of the nucleic acid, phospholipid, or phosphoprotein fractions. / Science, Faculty of / Botany, Department of / Graduate

Most of the remaining oil reserves are stored in carbonate reservoirs. Improving recovery from these reserves is paramount to uninterrupted energy supply and any future energy transition, should it happen. One of the aspects of recovery improvement is crude oil-brine-carbonate rock interface chemistry. The study of these interactions must be supported by: 1) a correct reactive transport model that describes the advective-dispersive forces in porous media; and 2) convincing experimental evidence consonant with the reactive transport model. As a part of such a larger study, this work addresses some modeling and experimental aspects of dispersive tracer transport through porous media. At both field and laboratory scales, tracer data allows estimation of brine-accessible pore volume and hydrodynamic dispersion. In addition to tracer transport during laboratory-scale coreflood experiments, one typically observes adsorption, dissolution/precipitation, ion-exchange, or all. Without proper tracer data interpretation, these phenomena cannot be distinguished. Therefore, tracer experiments are vital for a meaningful interpretation of any coreflood experiment. The modeling part of the work first discusses choice of boundary conditions that capture the peculiarities of laboratory-scale experiments. We find that Robin or third-kind boundary condition in both inlet and outlet is appropriate for description of the experimental results. Next, the modeling part presents a validated numerical approach to simulate dispersive tracer transport through the experimental system with high hydrodynamic dispersion. Tracer coreflood experiments are performed on $1.5''$ by $3''$ Indiana limestone core plugs with high hydrodynamic dispersion due to extreme rock heterogeneity. Chloride ion is used as the tracer in these experiments. Effluent from the cores is collected each 0.1 pore volume, and the concentration history data are recorded for at least 3 pore volumes. Finally, in the last part of this work, we present how the recorded concentration history data were scaled to the dimensionless model output and assess fit quality. The scaling parameters yield porosity and Péclet number that allow estimation of fluid accessible pore volume and hydrodynamic dispersion. The porosity of the core samples estimated from tracer data is close to those measured using helium pycnometer and/or brine imbibition. Very high hydrodynamic dispersion coefficients obtained from the tracer points correlate well with the scarcely published data on Indiana limestone.

No description available.

No description available.

Thesis (M.S. - Hydrology and Water Resources)--University of Arizona, 1986. / Includes bibliographical references (leaves 136-139).

Call number: LD2668 .T4 1966 M678 / Master of Science

Iodine, a minor constituent in ground water, is valuable as an indicator of subsurface sources of salinity. A review of iodine geochemistry reveals that exceptions to conservative behavior include sorption onto iron and aluminum oxides and incorporation into marine organic matter with additional enrichment due to sorption. Data from the Milk River aquifer in Alberta, Canada indicate that iodide in the ground water is derived from residual waters in the fine grained, marine sediments within the sandstone formation. This localized enrichment of iodide is superimposed on a more general enrichment of halides downgradient from the recharge area, probably due to ion filtration.

No description available.

The use of trichlorofluoromethane (C1₃CF) as a refrigerant, aerosol-can propellant, and foam-blowing agent leads to the subsequent release of C1₃CF into the atmosphere. During the mid-1970's, the build-up of C1₃CF in the stratosphere resulted in much atmospheric research investigating the destruction of the earth's ozone layer by C1₃CF. C1₃CF enters the hydrologic cycle during precipitation. Hydrologic investigations led to the detection of C1₃CF in ground water and postulation of C1₃CF as a tracer and age dating technique. The Edwards Aquifer in the vicinity of San Antonio, Texas, was chosen as a test case for demonstration of C1₃CF as an environmental tracer. The aquifer has been modeled for mass transport using extensive tritium measurements to calibrate and verify a discrete-state model (DSM). The DSM was the first successful attempt at modeling both flow and mass transport in that aquifer. Without changing the calibration, the DSM was used to model the input-output and predict the concentration of C1₃CF in the aquifer. Field sampling of surface water, well discharge, springs, and the atmosphere was done in 1977 in order to compare actual with predicted results. C1₃CF was measured using a custom field operable gas chromatograph (FOGC). The FOGC has a solute-stripping bottle, a backflushing column, a pulsed electron capture detector, and an automatic peak-window integrator. The theoretical detection limit is 10⁻⁴ grams per second. The FOGC was calibrated for a dynamic range of 0.25 to 300 picograms, using a permeation tube and dynamic gas sampler. The FOGC can measure C1₃CF in ground waterat concentrations of 0.01 picograms per milliliter (pg/ml) within 2 percent. Analysis and interpretation of the ground-water data indicated two distinct associations -- regional data points and plume data points. The regional data points fell into two separate groups, those above and those below the lower calibration limit. The data points were high in the recharge areas, intermediate in the center of the aquifer, lower at the discharge points (springs), and below the calibration limit in areas of low circulation in the aquifer. Comparison of the regional data with other investigations indicates that the C1₃CF technique works. The data points in the plume area indicate artificial introduction of C1₃CF into the aquifer near San Antonio. The distribution of the concentrations follows the flow paths toward the springs and confirms the movement of ground water as determined from previous investigations utilizing other techniques. The artificial introduction of C1₃CF may have been accidental or intentional. It appears that about 15 liters C1₃CF would be required to produce the concentrations detected. Air sample concentrations of C1₃CF (0.42 pg/ml) were about half those reported for recent global measurements. Surface water concentrations of C1₃CF (0.12 pg/ml) were very close to recent global measurements (0.13 pg/ml), but below the input to the model (0.34 pg/ml). The data indicate that the C1₃CF technique is workable in the Edwards Aquifer and should be in other systems containing water recharged during the last 30 years. The consistency of the data indicates that the technique probably is more usable than tritium because of the much simpler input function. The FOGC is appealing because of its portability, low cost, and ease of operation.