M.Sc. / The Lower Devonian Bokkeveld Group is the Middle unit of the tripartite Cape Supergroup, which outcrops along the western, southern and eastern coastline of South Africa. A well-established sedimentary and stratigraphic understanding of the Bokkeveld Group allowed for geochemical and geochronological investigation in order to gain insight into the provenance characteristics, as well as the paleotectonic environment of the provenance areas. In order to observe any changes within the Bokkeveld Basin, complete profiles for geochemical investigation were sampled in the western, southern and eastern parts of the basin, and compared. Major and trace element patterns suggest that the western part of the basin received detrital input from felsic, magmatically evolved, and possibly alkaline sources, and that the sediment was highly recycled before deposition. Furthermore, the geochemistry suggests that the western part of the basin experienced “passive margin” type sedimentation. The geochemistry of the southern basin, in contrast, suggests input from less evolved, non-alkaline sources, and predicts sedimentation under “active margin” conditions for the lower part of the group. The eastern basin is geochemically intermediate between the western and southern basins. Zircon populations for the three parts of the basin further suggest that sources of different ages fed the three parts of the basin. The zircon population of the western basin suggests that the Namaqua Natal Belt (Mesoproterozoic) and Neoproterozoic cover successions were the major source of detritus, with only minor input from Paleozoic sources. The eastern basin also appears to have sourced mainly Namaquan aged material as well as Neoproterozoic material, with no Paleozoic input. The southern basin has a remarkably different zircon population, with the majority of grains being Paleozoic in age, and only a few Neoproterozoic and Mesoproterozoic grains. Furthermore, many of the grains are younger than any known source-rocks on the Kalahari Craton, and thus allude to input from an extra-Kalahari source into the southern part of the basin. The youngest grain from the southern basin overlaps with the established depositional age of the Bokkeveld Group, suggesting some syn-depositional or briefly pre-depositional magmatic activity in the source area(s) of the southern basin, as predicted by the geochemistry. The complete lack of zircon ages older than the Namaqua Natal Belt (Mesoproterozoic), would suggest that the Archean to Paleoproterozoic inner part of the Kalahari Craton, the Kaapvaal Craton, was not sourced by the Bokkeveld Group. This is most likely due to the Namaqua Natal Belt having served as a large east-west trending morphological divide during Bokkeveld deposition, preventing transport of detritus from the craton interior. Remarkably, this would suggest that the Namaqua Natal Mountain Range must have survived erosion and persisted as a morphological boundary for ca. 600 Ma to serve as the major source of detritus for the Bokkeveld Group. Even an extensive, craton-fringing sedimentary cover-succession such as the Bokkeveld Group, may thus not provide a “detrital fingerprint” of the craton interior, and paleogeographical implications must be taken into consideration during provenance studies. Paleocurrent directions for the Bokkeveld Group indicate a west to east transport direction in the southern part of the basin, and as such, a western, extra-Kalahari source, most likely the Rio de La Plata Craton and surrounds, is expected to have been the source of both the young Paleozoic zircons, as well as undifferentiated material as revealed in the geochemistry.

M.Sc. (Geology) / The purpose of this study was to assess the MLA’s ability to characterise (e.g. modal mineralogy, elemental assay, particle size distribution, particle density distribution and mineral associations) a coal product from New Vaal Colliery, with the aim to determine any liberation and beneficiation characteristics. In general the MLA assessment on coal is comparatively new and novel, especially at Spectrum (University of Johannesburg), hence research in this regard is required. For the first time New Vaal coal product was characterised with the MLA 600 FEG SEM. The coal product supplied to Lethabo Power Station for the study’s samples, consisted of Top Seam and Middle Seam coal from New Vaal Colliery which is located in the Cornelia subbasin of the Vereeniging-Sasolburg coalfield, South Africa. The proximate analysis characterised the coal as a high-ash (42.25% air-dried) and low calorific value (13.92 MJ/kg air-dried) product. Chemically SiO2 was the most abundant oxide followed by Al2O3 for the XRF analysis, which was mostly derived from the abundant kaolinite clay mineral (determined by petrography, XRD and MLA analysis). Mineralogically inertinite was the most abundant coal maceral encountered during the petrographic analysis. With geochemical characterisation, chalcophile, siderophile, lithophile and radioactive trace elements were found to be mostly comparable to the global average.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND LINDGREN / Bibliography: leaves 209-226. / by Harlan Wheelock Stockman. / Ph.D.

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, in fulfilment of the requirements for the degree of Doctor of Philosophy, Johannesburg 2014 / Namibia is renowned for its abundant mineral resources, a large proportion of which are hosted in the metasedimentary lithologies of the Damara Belt, the northeast-trending inland branch of the Neoproterozoic Pan-African Damara Orogen. Deposit types include late- to post-tectonic (~ 523 – 506 Ma) LCT (Li-Be, Sn-, and miarolitic gem-tourmalinebearing) pegmatites, and uraniferous pegmatitic sheeted leucogranites (SLGs), which have an NYF affinity. Fluid inclusion studies reveal that although mineralization differs between the different types of pegmatites located at different geographic locations, and by extension, different stratigraphic levels, the fluid inclusion assemblages present in these pegmatites are similar; thus different types of pegmatites are indistinguishable from each other based on their fluid inclusion assemblages. Thorough fluid inclusion petrography indicated that although fluid inclusions are abundant in the pegmatites, no primary fluid inclusions could be identified, and rather those studied are pseudosecondary and secondary. Fluid inclusions are aqueo-carbonic (± NaCl), carbonic, and aqueous. It is proposed that all of the pegmatites studied share a similar late-stage evolution, with fluids becoming less carbonic and less saline with the progression of crystallisation. Oxygen isotope ratios allow the discrimination of different pegmatites into two groups, Group A (Sn-, Li-Sn-, and gem-tourmaline-bearing LCT pegmatites), and Group B (Li-Bebearing LCT, and U-bearing NYF pegmatites). Group A pegmatites have O-isotope ratios ranging from 11 to 13 ‰ suggesting that they have an I-type affinity. These values are, however, elevated above those of typical I-type granites (7 - 9 ‰), indicating either a postemplacement low-temperature exchange with meteoric fluid, high-temperature hydrothermal exchange with δ18O country rocks during emplacement, or the derivation of these pegmatites from a non-pelitic/S-type metaigneous source. Group B pegmatites have higher δ18O ratios (δ18O = 15 - 16 ‰), indicative of their S-type affinity, and their derivation from metapelitic source rocks. δD values of all the pegmatites range from -40 ‰ to -90 ‰ indicating that the pegmatitic fluids are primary magmatic with a metamorphic fluid component. Trends in the trace element concentrations of both Group A and Group B pegmatites are very similar to each other, making the two groups indistinguishable from each other on this basis. The Damaran pegmatites also share similar geochemical trends with their country rocks. There is, however, no direct field evidence to suggest that the pegmatites were derived from the in situ anatexis of the country rocks. It is more likely that anatexis occurred some distance away from where the pegmatites were ultimately emplaced, and that the melts migrated and were finally emplaced in pre-existing structures, possibly formed during Damaran deformation. O-isotope and Ti-in-quartz geothermometry indicate that Damaran pegmatites can be subdivided into two groups based on their crystallisation temperatures. LCT pegmatites crystallised at temperatures ranging from ~ 450 - 550 ºC, while the NYF pegmatites crystallised at higher temperatures, ranging from 630 - 670 ºC. It is important to note that the subdivision of pegmatites in Groups A and B based on their O-isotope systematics does not correspond with their subdivision into the LCT and NYF pegmatite families according to their crystallisation temperatures. In addition to clarifying aspects of the emplacement and evolution of the Damaran pegmatites, this study points out that there are several discrepancies in the current classification schemes of pegmatites. It shows that in addition to the problems encountered when trying to distinguish between LCT and NYF pegmatites based on their mineralogy, they also cannot truly be distinguished from each other using their geochemical and isotopic characteristics, or their tectonic settings. It is tentatively proposed that crystallisation temperature be considered as an alternative or additional characteristic in the classification of pegmatites, and that it be considered on a regional scale rather than only in the evaluation of the highly evolved end-members of a pegmatite swarm.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2001. / Bibliography: leaves 109-115. Also available online.

Thesis (Ph.D.) -- University of Western Sydney, Nepean, 1998. / CD-ROM (appendix) contains complete lists of the species distribution for each water sample; the constant correction spreadsheet; and, the possible stability constants for aqueous ionic species as well as the data ranges for both the Girilambone study and the North Mungana study. A thesis presented in accordance with the regulations governing the award of the degree of Doctor of Philosophy in the University of Western Sydney, Nepean, School of Science. Includes bibliographical references at end of each chapter.

The origin of the earliest solids in the solar system, preserved for 4.56 Ga in primitive chondritic meteorites, is poorly understood, in particular because of the lack of detailed chemical data on individual phases within these solids. Because chondrite constituents record the environmental conditions and local chemistry of the protoplanetary disk in which they were formed, examining their chemical composition across chondrite groups enhances our understanding of and provides quantitative constraints on the origin of the earliest solar system bodies, the precursors to our planets. This dissertation examines chondritic meteorites using (1) geochemical analysis of the major and trace element distributions within and among carbonaceous chondrite constituents to address chemical source reservoirs and formation mechanisms, and (2) visible near-infrared (VNIR) spectroscopy of ordinary chondrites under a variety of conditions to improve compositional interpretations of remotely sensed asteroids. Chapter 1 presents a brief introduction to the field of meteoritics via an overview of meteorite types and the various contexts they preserve. Primitive chondritic meteorites and their components fossilize the chemical and physical conditions that existed at the time of their formation in the early solar system, whereas achondritic meteorites provide insight into the structure of planetary interiors. This chapter also reviews fundamentals of mineral condensation in the early solar system environment, and the implications of the presence (or lack) of these minerals in the components that comprise chondrites. In Chapter 2 of this dissertation, I investigate the distribution of trace elements in the components of the carbonaceous Vigarano-type (CV) chondrite group to better reveal the solar system processes that led to the fundamental cosmochemical mechanisms of chondrule formation and chondrite accretion. While the major element and bulk chemical compositions of chondritic meteorites are well established, the distribution of trace elements amongst chondrite components and in the individual minerals within them is not well constrained. The geochemical behavior of trace elements enables them to reveal precursor characteristics, formation conditions, and processing histories of chondrite constituents. In determining the large-scale distribution of trace elements, in particular the rare earth elements (REE), across multiple meteorites in the CV chondrite group, I produced a statistically significant trace element dataset that complements existing major element and isotopic datasets. I observe variable REE patterns in individual mineral phases in chondrite components which combine to produce overall flat bulk REE patterns for each meteorite. This chemical evidence, which is necessary to constrain dynamical accretion mechanisms in astrophysical models of the early solar system, supports the idea of a single reservoir origin for these chondrites, and suggests that some chondrules are in chemical disequilibrium and have inherited CAI-like precursor material. In Chapter 3, I evaluate common standardization techniques used for analysis of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) data and assess the implications for high-precision elemental analyses. LA-ICP-MS has become popular in part due to its ability to measure low trace element abundances in small sample volumes while preserving petrographic context. The capacity for in-situ mineral-scale and sub-mineral scale analyses is particularly useful for diffusion studies or for assessing element partitioning between co-existing solids. Standardization techniques have been developed in order to obtain high-precision concentration data from LA-ICP-MS analyses. Common practice dictates the use of reference material spot sizes similar or equal to the chosen spot sizes of the unknown samples under investigation. However, the effects of using reference material spot sizes for calibration that differ from sample spot sizes are not quantitatively constrained. In this chapter I evaluate the coupled effects of differences in ablation yield and of matching compositions between samples and reference materials (matrix matching), as well as the differences in calculated element abundance resulting from internal standard element choice. I show that element abundances derived from LA-ICP-MS analyses are heavily dependent on the chosen combination of measured element, internal standard element, unknown spot size, and reference spot size. Even varying just one of these parameters does not necessarily yield predictable effects on resulting data. In Chapter 4, I explore the effects of both chemical and physical variables on laboratory infrared spectral analysis of well-characterized meteorite samples with the goal of better quantitatively analyzing asteroid remote sensing data in conjunction with returned extraterrestrial samples. Temperature and grain size are known to each have individual effects on the VNIR spectra of silicate and meteorite powders. Here, I examine the combined effects of physical variables (temperature, particle size) and chemical variables (petrologic type, metal fraction) on VNIR spectra of ordinary chondrite meteorite powders. I prepared six equilibrated (petrologic types 4-6) ordinary chondrite meteorite falls, spanning groups H, L, and LL, at a variety of particle sizes to capture the spectral diversity associated with asteroid regoliths dominated by various grain sizes. VNIR spectra of the ordinary chondrite materials were measured under simulated asteroid surface conditions (~10-6 millibar, -100°C chamber temperature, and low intensity illumination) at a series of temperatures chosen to mimic near-Earth asteroid surfaces. Iused X-ray element maps of meteorite thick sections to calculate the exact mineral abundances for each meteorite, in order to characterize changes in spectral features due to variations in mineralogy. The VNIR spectra show minimal variation in both major orthosilicate absorption bands across the simulated near-Earth asteroid temperature regime. Spectral changes due to particle size are consistent across samples, with the smallest and largest grain sizes having the highest reflectance. Unlike previous spectral investigations of ordinary chondrites, I retained the metal fraction in the meteorite powders instead of analyzing the silicate fraction only. In the measurements, I observe distinct offsets in spectral features when compared to analyses of purely silicate fractions. XRD analysis shows that the largest size fraction of nearly every sample contains relatively more metal, likely due to the retention of metal nuggets in the largest size fraction during sieving. The more petrologically pristine samples (e.g., LL4) from each ordinary chondrite group display relatively shallower band depths than their more petrologically altered counterparts (e.g., LL6). The band depths shift to higher wavelengths as temperature, grain size, and petrologic type increase. Spectral studies of meteorites combined with detailed petrologic analysis of the samples should greatly enhance interpretation of current and future planetary remote sensing data sets. Importantly, understanding the spectral contribution of the metal fraction will aid in upcoming investigations of metal-rich mission targets such as asteroid 16 Psyche.

Different aspects of natural organic matter composition and cycling have been studied using solid-state 13C and 31P Nuclear Magnetic Resonance (NMR) spectroscopy. Depending on the specific study, complementary analytical techniques such as elemental, isotopic and molecular analyses have also been applied. Samples from a variety of environments were examined including ocean waters, marine sediments and atmospheric aerosols. Studies from all these environments illustrate differences in natural organic matter composition resulting from various factors such as sources, cycling mechanisms and redox conditions. In the marine water column, organic matter of two different size fractions (dissolved and particulate) is found to have distinctly different bulk chemical and isotopic compositions. Overall, this indicates that particulate organic matter does not form from the simple physical aggregation of dissolved organic matter, and dissolved organic matter is not the primary source for particulate organic matter. Comparison of carbon and phosphorus compositional changes with depth in the ocean within the dissolved and particulate fractions reveals differences in cycling mechanisms. In the marine water column, selective mineralization of specific carbon compounds such as carbohydrates and amino acids occurs relative other species such as lipids. Whereas for phosphorus, the relative proportion of the different functional groups are unvarying with depth. In marine sediments, NMR spectroscopy reveals P cycling for specific phases such as polyphosphates is a function of sediment redox conditions. In atmospheric aerosols 13C NMR spectroscopy shows differences in water-soluble organic carbon composition from urban versus biomass burning sources. Urban aerosols have higher aliphatic and lower aromatic compound contents relative to samples derived from biomass burning. The results of these studies provide new insights into carbon and phosphorus cycling in the environment and demonstrate the capabilities of solid-state NMR as a tool for investigating natural organic matter composition.

Indiana University-Purdue University Indianapolis (IUPUI) / The shale and mudstone directly superjacent to Desmoinesian coal seams of southern Indiana (Springfield, Houchin Creek, Survant, and Seelyville coals) were initially deposited under marine waters and are shown to exhibit high concentrations of organic carbon, sulfur and redox-sensitive metals (Mo, V, Ni, Fe, and U) that were sequestered during times of benthic anoxia and intermittent to sustained euxinia (anoxic and sulfidic). Strata upsection display geochemical signatures that indicate increasingly oxic and nearshore sedimentation that mirrors cyclothemic sequence stratigraphic trends Carbon source, nearshore and offshore proximity, freshwater and marine influence, and redox conditions of the epeiric sea overlying southern Indiana during the Late Middle Pennsylvanian were identified and tracked throughout the deposition of four drill cores of the Petersburg, Linton and Staunton Formations. Carbon, nitrogen, and sulfur data (total organic carbon [TOC], total nitrogen [TN], and total sulfur [TS]); paleoredox proxies ([Mo/Al], [V/Al], [Th/U], [Fetot/Al]); organic carbon isotopes (δ13Corg); and detrital influx concentrations (Zr) were all used in conjunction with lithological and paleontological interpretations to better understand the mode of deposition in this unique midcontinent ancient epeiric sea. Geochemical results when combined with lithologic and paleontologic interpretations reveal a dynamic environmental system where water column geochemistry varies with the influence of variable magnitudes of epeiric seawater flooding on the extensive peatlands of equatorial Late Middle Pennsylvanian southern Indiana.

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. Johannesburg, 2016. / In current Middle Stone Age research there is interest in understanding whether climatic and environmental factors played a role in behaviours related to subsistence, mobility patterns and material culture production. From a palaeoenvironmental perspective, the southern Cape is recognized as an important study region for exploring the link, if any, between past environmental conditions and key MSA occurrences. The research presented in this thesis aimed to contribute to the existing database of past environments in the southern Cape through the geochemical analysis of speleothems from a previously uninvestigated locality in the De Hoop Nature Reserve. Together, the De Hoop speleothems provide a discontinuous record of environmental change from marine oxygen isotope stage MIS 5a to MIS 3 (and the Holocene). Results from the De Hoop records indicate warm summer rain and C4 vegetation in early MIS 5a (c. 85 ka to 80 ka) but more variability by late MIS 5a (c. 79 ka to 74 ka). At Klasies River main site, also on the southern Cape coast, the upper MSA II is associated with the warm early MIS 5a conditions. At Blombos Cave, another important coastal MSA site, the Still Bay occurring within terminal MIS 5a was linked to warm but more variable late MIS 5a conditions. While early MIS 4 (c. 73 ka to 68 ka) was comparatively cooler, conditions were similar to those in early MIS 5a. From this research, the earlier phase of the Howiesons Poort at Klasies River main site and the Howiesons Poort at Klipdrift Shelter were correlated with the early MIS 4 conditions in De Hoop. By late MIS 4 (c. 67 ka to 60 ka), conditions remained cool, but were seemingly more variable than during the earlier part of this iii stage / GR2016