Thesis (Ph. D.)--University of Wisconsin--Madison, 1960. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis--University of Missouri, School of Mines and Metallurgy, 1907. / The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed December 5, 2008)

Thesis (Ph. D.)--University of Michigan, 1934. / Bibliography: p. 19.

Thesis (Ph. D.)--University of Chicago, 1929. / Lithoprinted. "Private edition, distributed by the University of Chicago libraries, Chicago, Illinois."

Thesis (doctoral)--Universität Leipzig, 1907. / Vita. Includes bibliographical references.

Base-metal late Hercynian vein and stratabound-type deposits occur in the Linares-La Carolina mining district (Sierra Morena, Spain). No other ore deposits than iron beds and a supergene iron-manganese karst-related deposit were found in the studied area. However, Upper Ordovician-Lower Silurian rocks show Ni, Zn, Pb content above the average values of sandstones. Upper Ordovician-Lower Silurian country rocks are grouped into two stratigraphical sequences that reflect sea-level rise-fall cycles in a basin developed in a passive margin. The duration of these cycles indicates that they were caused by a combination of eustatic processes and intraplate extensional tectonics. The Late Hercynian hydrothermal deposits hosted by metasediments and granitoids, comprise (Ba)-(Pb-Zn-Cu- [Ag]) vein and stratabound type deposits that were emplaced before the Ladinian, during an extensional stage starting in the Upper Permian. Three stages of ore deposition have been recognised, the first stage is characterised by the formation of pyrrhotite, arsenopyrite, Ag sulphosalts and minor arsenopyrite and Bi sulphides. In the second stage, pyrite, Cu sulphides, barite and Ni-Co mineral s precipitated. Main deposition of galena and sphalerite took place at the end of the first stage and the beginning of the second stage. There is no evidence of selective Ag enrichment. Hydrothermal alteration of granitic host rocks is characterised by argillic-phyllic, argillic-propylitic assemblages overprinted by a late alkai metasomatism. There is a strong relation between composition of secondary minerals, mineralogy of the alteration zone and whole-rock composition. Mass transfers of alumina appear to be important. There is a significant introduction of Si, AI, K, Na, Rb and Pb, together with a depletion in Ca and Sr. Chlorite and illite geothermometers indicate temperatures of 276.7-321.5 ·C. Three events of fluid entrapment at hydrostatic pressures have been recognised, with fluids evolved from low to moderate, locally carbonaceous hot fluids to highmoderately polysaline cooler fluids. Ore-lead was derived from Palaeozoic U-'enriched' country rocks, although some participation from the Hercynian granitoids can not be ruled out. The distribution of sulphur isotopes is not homogeneous in the scale of the district. Differences exist between those deposits at the El Centenillo-Santa Elena sector (where the dominant process was the mixing of 'magmatic'-derived sulphur and sulphur derived from the metasediments) and those occurrences at the Linares-La Carolina sector (where the dominant sulphur was 'magmatic'-derived).

The purpose of this thesis is to investigate the isotopic composition of primary leads. The leads analysed were selected by R. L. Stanton in accordance with his geologic description for conformable deposits. It was anticipated that, of all available terrestrial leads, these were the least likely to have been modified isotopically by crustal processes. Detailed analyses and interpretations for fifty-six samples from nine different districts in Eastern Australia, Tasmania, Canada and New Zealand are presented. A precision of better than ±.05 per cent in the measurement of the Pb²⁰⁶/Pb²⁰⁴, Pb²⁰⁷/Pb²⁰⁴ and Pb²⁰⁸/Pb²⁰⁴ ratios was achieved for all samples by means of an intercomparison technique derived from that used by P. Kollar and R. D. Russell, and improved methods for reducing the data. As expected, the geologic criteria used by Stanton to identify conformable deposits have been found to be sufficient to identify deposits which are very uniform in isotopic composition. The findings of this research indicate that the criteria, although remarkably good, are not completely adequate for identifying primary leads. In particular, leads from two conformable deposits (Manitouwadge and Rosebery) were found to be anomalous, and those from two other deposits (Hall's Peak and Bathurst) may be anomalous. The single-stage lead model was found to be a very good approximation for isotopic development of the leads from the remainder of the conformable deposits studied by the writer, as well as for leads analysed by other workers at the University of British Columbia and assumed to be primary. These results suggest that primary leads have formed in a region for which there are very narrow limits of ±.6% and ± .8% to the variations in U²³⁸/Pb²⁰⁴ and Th/U ratios. They substantiate the hypotheses of Russell and Stanton that: (1) primary leads lie very closely to a unique single-stage growth curve in a plot of the ratios Pb²⁰⁷/Pb²⁰⁴ against Pb²⁰⁶/Pb²⁰⁴, and in a plot of Pb²⁰⁸/Pb²⁰⁴ against Pb²⁰⁶/Pb²⁰⁴; (2) leads away from this growth curve are anomalous. From the fit of the conformable leads to a single-stage growth curve, values of 4.52 ± .03 Gyr. and 4.54 ± .02 Gyr. have been calculated for the age of the earth. With the identification of a unique growth curve for primary leads, severe restrictions are placed on anomalous lead interpretations. These are illustrated in the interpretations of anomalous leads studied by the writer. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

A new method has been proposed for determining the age of lead sulfide mineralization from anomalous lead Isotope abundances. The anomalous leads are most readily recognized by the linear relationship of the isotope ratios on any compositional diagram. The method assumes that the initial stage of lead isotope development occurred in a system having a uniform distribution of uranium, thorium and lead. This accords with experimental results obtained by the writer and other research workers at the University of British Columbia that single-stage isochrons as proposed by Houtermans are either very short or do not exist. Consider t₁ to be a time of tectonic activity during which ordinary leads were differentiated from a deep source and either concentrated to form a lead deposit at this time or disseminated throughout the upper crust. Contemporaneously uranium and thorium bearing solutions were incorporated into the same environment. At time t₂ tectonic activity recurred in the area. Some of the ordinary leads were remobilized and became contaminated with radiogenic lead to form anomalous lead deposits. Existing lead isotope analyses yield the following results. At Broken Hill, Australia, t₁ is 1600 million years, while t₂ is 510 ± 80 m.y. For Goldfields, Saskatchewan, t₁, is 2015 m.y. while t₂ is 560 ± 250 m.y. At Sudbury, Ontario, t₁ is 1730 m.y. and t₂ is 870 ± 280 m.y. For lead deposits around the Ozark Dome area, including Joplin and Bonne Terre, Missouri, t₁ is 1350 m.y. and t₂ is about 115 m.y. For leads in west-central New Mexico, t₁ is 1490 m.y. and t₂ is about 69 m.y. The errors in the estimates are generally quite large but the values quoted are consistent with available geological and chronological data. The simplest type of anomalous leads which can occur is a mixture of two ordinary leads. This has only been found to occur on the boundary between two geological provinces. Examples of this type have been identified in the Cobalt area, Ontario and in the Baltic Shield along the border between the Fenno-Karelides and Svecofennides. A large proportion of anomalous lead Isotope measurements may be interpreted on the basis of the two-stage models outlined above. Extension of this model to an n-stage system is considered. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The atomic and ionic spectra of lead have been photographed in the region between 350 A and 7680 A, using a three meter normal incidence vacuum grating spectrograph, and a Hilger large quartz-glass prism spectrograph. Spectroscopic sources used throughout this region were the electrodeless discharge, and the condensed spark in helium. Approximately 4075 lead lines were measured, and of these, 1006 have been classified in the spectra of Pb I, Pb II, Pb III, and Pb IV. The Pb IV analysis has been extended: relative energies have been assigned to eight even and two odd levels arising from the 5d¹ºns, np, nd and ng configurations, and tentative values given to several levels from the 6s7s and 6s6d configurations of the 5d⁹ core. The core-polarization theory has been applied to the observed 5g - nh transitions of Pb IV, giving a value for the ionization potential of 341438 cm⁻¹. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The kinetics and mechanism of the "roast-reaction" of lead sulfide have been examined. The investigation, partitioned by the nature of the problem, included a study of (a) the "roast" which is the several reactions between galena (lead sulfide) and oxygen (or air) yielding oxides, sulfates and basic sulfates of lead, and (b) the reduction "reaction", between lead sulfide and the oxidation products of the roast leading to the production of lead metal. The mechanism of the roasting of lead sulfide does not lead to the formation of distinct PbO and PbSO₄ phases. The products appear to be a mixture of basic sulfates throughout. The rate of the reaction between PbS and PbO or PbSO₄ has been shown to be controlled by the transport of SO₂ from the reacting surface with gas velocities up to 5 cm./min. Under conditions of reduced pressure (<5mm. of Hg) the reduction reactions are shown to be heterogeneous and probably proceed by the adsorption of PbS vapor on the oxidized surface to form a (PbS.xPbO)‡ basic sulfate type activated complex which subsequently decomposes to lead metal. The stoichiometry of this heterogeneous reaction has been checked for the PbS-PbO case with the use of a Pb²¹² tracer. The average value was measured to be 1PbS + 3.4 PbO →4.4Pb + - - - . / Applied Science, Faculty of / Mining Engineering, Keevil Institute of / Graduate