Master of Science / Department of Geology / Sambhudas Chaudhuri / Rare earth element (REE) concentrations were measured in a source (reference) clay Ca-smectite standard and in the roots, stems, and leaves of a species of poplar plant (Populus eugenei). The poplar plant was grown in the clay standard under controlled laboratory conditions during a period of about three months. REEs were shown to fractionate in the clay mineral and plant materials with greater fractionation observed in plant materials. The REE data provide insight into the process of weathering of clay minerals such as a Ca-bearing smectite and provide insight into the degradation of and the composition of clay minerals in the plant environment. The degradation process is not followed by significant interlayer ion exchange effect on remaining clay minerals in the root environment. REEs were found to be transported into complex forms, potentially as REE-carboxylic anion pair complexes. The plant materials in this study were in general heavy REE (HREE) enriched relative to the source clay minerals due to the complexation effect. The REE anomalies observed in this study, in addition to the Ce and Eu anomalies, may be explained by the selective uptake by the plant by an enzyme effect rather than due to the influence of oxidation-reduction. The enzyme influence was more evident in the REE distribution when compared among the plant organs. These REE characteristics described for the plants may eventually be incorporated with data from numerous other studies and also used as a guide in the assessment of the contribution of plant materials to dissolved REE content in surface water and groundwater.

Master of Science / Department of Geology / Kirsten Nicolaysen / The Kerguelen Archipelago and the submarine Northern Kerguelen Plateau consist primarily of basalt erupted by the intraplate Kerguelen hotspot. The exposed volcanic rocks are tholeiitic basalts (29 Ma) followed by lesser alkalic basalts, highly alkaline phonolites, and syenites (24 Ma). This study presents the mineralogy, isotopic and geochemical compositions of lavas (n=59) from a 650 m section exposed in the wall of a glacial valley at Trois Menestrels in the Kerguelen Archipelago. This basalt section, exposed south of the Cook Ice Cap and closest to the Raillier du Baty alkalic plutonic complex, is further south and west of previously studied basalts exposed on the Plateau Central. Results of 40Ar/39Ar dating show the Trois Menestrels lavas erupted approximately 25 Ma, approximately contemporaneously with other Plateau Central lavas and thus provide an opportunity to examine spatial compositional variations within the Kerguelen hotspot. Though the Trois Menestrels lavas are tholeiitic, The samples plot on the tholeiitic field at the stratigraphic section of Trois Menestrels, 80% of lavas from Mt. Tourmente are transitional to alkalic in the younger rocks (25.6 Ma). This sequence of tholeiitic to transitional to alkalic compositions is mirrored at Mt. Capitole and Mt. Marion Dufresne. Sr, Ba, Pb, Nb, Zr versus Nb plots show similar patterns across the Plateau Central and abundances overlap within error. Variations in isotopic composition reveal that Trois Menestrels is rather homogeneous compared to the other sections. A fundamental issue that derives from these results is the close relationship between these different rocks of the various region of the Plateau Central.

This thesis addresses various issues in U-Pb zircon geochronology, proposing new experimental protocols in conventional chemical abrasion-isotope dilution thermal ionization mass spectrometry or CA-(ID)-TIMS and developing a new method for Pb evaporation-condensation from zircon that allows high precision Pb-Pb age determination on Precambrian samples. Various experiments are also done on zircon to extract U-Pb information by in situ flux aided fusion methods and to optimize a better silica gel Pb-ionization activator. Radiation damage caused by U decay in zircon disrupts its ‘closed system’ behavior leading to the loss of daughter radiogenic Pb and resulting in inaccurate ages. A high temperature thermal annealing procedure has been proposed to prevent such Pb loss. Studies presented here have been carried out using Laser Raman Spectroscopy and Scanning Electron Microscopy to characterize radiation damage and effects of laboratory induced thermal annealing on such damage. Backscattered electron images reveal a variety of textures for ZrO2 overgrowths on zircon annealed at 1450oC. Highly damaged zircon produces finer polycrystalline aggregates (<5µm) than zircon with less damage. Raman spectroscopy indicates that crystals with different levels of radiation damage are only partially restored by annealing at 1000oC for 2–3 or 20 days. Annealing at 1450oC for 1 h results in partial breakdown of zircon but restores Raman peak widths and wave numbers. Raman spectra are much less sensitive to polarization angle for annealed highly damaged grains than for weakly damaged zircon showing that when highly damaged zircon is recrystallized, it becomes a polycrystalline aggregate that pseudomorphs the original single crystal. The whole grain Pb evaporation-condensation method is based on 206Pb-207Pb age analyses where zircon grains are pre-treated at 1450oC to drive out all disturbed Pb and then they are kept at 1600oC for an hour or two during which Pb atoms are evaporated out of the grain and deposited directly into a clean Savillex teflon vial or a wide Re filament. This technique allows the use of a 202Pb-205Pb double spike for precise isotopic fractionation correction. Examples are shown in which application of this technique to zircon from Precambrian samples has successfully yielded sub-million year age precisions.

Master of Science / Department of Geology / Matthew E. Brueseke / Previous studies of the northern Great Basin have indicated that mid-Miocene epithermal gold and silver ore deposits distributed regionally are temporally related to the magmatic activity associated with the onset of widespread extension and the Yellowstone hotspot (Saunders and Crowe, 1996; Kamenov et al., 2007). This study is focused on the volcanic rocks and ore deposits from the Silver City district (SCD), ID to address the petrogenesis and magmatic evolution that was influential in forming local precious metal deposits. The goal is to understand the tectonomagmatic conditions that contributed to the petrogenesis of the volcanic suite in the Silver City district, which can be used to provide details on the relationship between coeval mid- Miocene magmatism and mineralization across the northern Great Basin and Oregon Plateau. In order to better constrain the magmatic evolution of the SCD and potential sources of the precious metals, we have undertaken detailed sampling of local crust and mid-Miocene volcanic units to constrain their physical, geochemical, isotopic, and geochronological characteristics, as well as provide constraints on the petrogenesis of the mid-Miocene volcanic package. Prior studies of the local volcanism have yielded K-Ar and [superscript]40Ar/[superscript]39Ar ages of ~16.6 to 14 Ma (Bonnichsen, 1983), while others have dated adularia from one SCD mineral vein and obtained [superscript]40Ar/[superscript]39Ar ages of between 15.6 and 16.3 Ma (Hames et al., 2009; and Aseto et al., 2011). Field observations are consistent with earlier work (Lindgren, 1900; Asher, 1968; Pansze, 1975; Halsor et al., 1988; Bonnichsen and Godchaux, 2006; Camp and Ross, 2009) and reveal a sequence of basalt consisting of regionally prevalent Steens Basalt that pre-dated precious metal mineralization. Some of the basalt appears to have been erupted locally, based on the presence of mafic dikes and thick pyroclastic deposits similar to other regional mid-Miocene magmatic systems. Stratigraphically overlying this lower basalt suite is a complex package of rhyolite flows and domes, thin silicic pyroclastic units, additional basaltic lava flows, intermediate lava flows, and mafic/silicic shallow intrusives. Geochemical analysis indicates that the basaltic and basaltic andesite lava flows are locally erupted flows of Steens Basalt while the intermediate and silicic volcanism in SCD can be classified into nine distinct units including two andesites, one dacite, four rhyolites and two rhyolite tuffaceous units. Geochemical modeling suggest that the intermediate and silicic magmas were formed by a combination of open system processes, including low pressure partial melting and assimilation of mid to upper crustal granitoid basement rock, and magma mixing between silicic and basaltic endmembers. The formation of silicic volcanism in the SCD is similar to other regional mid-Miocene silicic volcanic systems (e.g. Santa Rosa-Calico volcanic field and Jarbidge Rhyolite). Based on new [superscript]40Ar/[superscript]39Ar geochronology of both volcanic units and epithermally emplaced mineralization, SCD volcanism appears to have erupted over a relatively short amount of time that overlaps with local epithermal Au-Ag mineralization.

Master of Science / Department of Geology / Saugata Datta / In response to increasing concerns over release of anthropogenic greenhouse gases the Arbuckle saline aquifer in south-central Kansas has been proposed as a potential site for geologic storage for CO2. Two wells (KGS 1-32 and 1-28) have been drilled to provide data for site specific determination of the storage potential of the Arbuckle. Cores from specific depths within Arbuckle (4164`-5130`) were utilized for study and flow-through experiments. Examination of formation rocks by thin section studies, SEM, XRD and CT scans was carried out to characterize the mineralogy of the core. Dominant mineralogy throughout the formation is dolomite with large chert nodules and occasional zones with pyrite and argillaceous minerals. Carbonate-silica contacts contain extensive heterogeneity with sulfide minerals and argillaceous material in between. Extensive vugs and microfractures are common. This study focuses on three zones of interest: the Mississippian pay zone (3670`-3700`), a potential baffle in Arbuckle (4400`-4550`) and the proposed CO2 injection zone (4900`-5050`). Drill stem tests and swabbed brine samples collected from 13 depths throughout the aquifer reveal a saline brine (~50,000-190,000 TDS) dominated by Na+, Ca2+ and Cl-. Elemental ratios of major cations with Cl- demonstrate a typical saline aquifer system. Cl/Br ratios reveal mixing between primary and secondary brines within the aquifer. Ca/Cl and Mg/Cl ratios suggest effect of dolomitization within the brines. δ18O and δ2H isotopes and Li/Cl ratios in the brine suggest the separation of upper and lower Arbuckle by a baffle zone. Swabbed waters provide Fe speciation data and reveal the importance of it in the system. Laboratory experiments carried out at 40°C and 2100 psi using formation core plug and collected brine identify reaction pathways to be anticipated when supercritical CO2 is injected. Results showed fluctuating chemistries of elements with Ca2+, Mg2+, Na+ and Cl- increasing during the first 15 hours, while Fe, S, and SO42- decrease. For the next 15 hours a reverse trend of the same elements were observed. Alkalinity and pH show inverse relationship throughout the experiment. We conclude that dominant reactions will occur between brine, CO2 and dolomite, calcite, chert, pyrite and argillaceous minerals. There is no perceived threat to freshwater resources in Kansas due to CO2 injection.

Master of Science / Department of Geology / Matthew Totten / The REE distribution patterns and total concentrations of the organic matter of the Woodford shale reveal a potential avenue to investigate hydrocarbon maturation processes in a source rock. Ten samples of the organic matter fraction and 10 samples of the silicate-carbonate fraction of the Woodford shale from north central Oklahoma were analyzed by methods developed at KSU. Thirteen oil samples from Woodford Devonian oil and Mississippian oil samples were analyzed for REE also. REE concentration levels in an average shale range from 170 ppm to 185 ppm, and concentration levels in modern day plants occur in the ppb levels. The REE concentrations in the organic matter of the Woodford Shale samples analyzed ranged from 300 to 800 ppm. The high concentrations of the REEs in the Woodford Shale, as compared to the modern-day plants, are reflections of the transformations of buried Woodford Shale organic materials in post-depositional environmental conditions with potential contributions of exchanges of REE coming from associated sediments. The distribution patterns of REEs in the organic materials normalized to PAAS (post-Archean Australian Shale) had the following significant features: (1) all but two out of the ten samples had a La-Lu trend with HREE enrichment in general, (2) all but two samples showed Ho and Tm positive enrichments, (3) only one sample had positive Eu anomalies, (4) three samples had Ce negative anomalies, although one was with a positive Ce anomaly, (5) all but three out of ten had MREE enrichment by varied degrees. It is hypothesized that Ho and Tm positive anomalies in the organic materials of the Woodford Shale are reflections of enzymic influence related to the plant physiology. Similar arguments may be made for the Eu and the Ce anomalies in the Woodford Shale organic materials. The varied MREE enrichments are likely to have been related to some phosphate mineralization events, as the Woodford Shale is well known for having abundant presence of phosphate nodules. The trend of HREE enrichment in general for the Woodford Shale organic materials can be related to inheritance from sources with REE-complexes stabilized by interaction between the metals and carbonate ligands or carboxylate ligands or both. Therefore, a reasonable suggestion about the history of the REEs in the organic materials would be that both source and burial transformation effects of the deposited organic materials in association with the inorganic constituents had an influence on the general trend and the specific trends in the distribution patterns of the REEs. This study provides a valuable insight into the understandings of the REE landscapes in the organic fraction of the Woodford Shale in northern Oklahoma, linking these understandings to the REE analysis of an oil generated from the same source bed and comparing it to oil produced from younger Mississippian oil. The information gathered from this study may ultimately prove useful to trace the chemical history of oils generated from the Woodford Shale source beds.

In this dissertation, I discuss the role of organic residue analysis in identifying economic activities and subsistence practices associated with the first uses of pottery in the Middle East, and present the results of my analyses of 280 potsherds recovered from 22 Neolithic and early Chalcolithic settlements dating between 7300 and 4300 cal BC. The adoption of pottery vessels in the early agricultural villages and pastoral encampments of the Middle East was not a uniform phenomenon, with this new technology not immediately of benefit, apparently, to all human groups. Results of my analyses have demonstrated that ‘conventional’ solvent extraction and alkaline hydrolysis techniques have limited utility in the recovery of diagnostic organic compounds from pottery from early ceramic horizons in the Middle East (Gregg et al. 2007), and that increased yields can be achieved through the use of a microwave-assisted liquid chromatography protocol (Gregg et al. 2009; Gregg and Slater in press). My research has established that there is greater diversity in the fractionation of stable carbon isotopes associated with the synthesis of fatty acids in domesticated animals than has previously been reported. In many instances, the ranges of modern isotopic values that have been used to categorize animal fats in archaeological potsherds in northern Europe cannot distinguish between the ∂13C ratios of ancient dairy residues and carcass fats of ruminant and non-ruminant species in central Europe or the Middle East (Gregg et al. 2009; Gregg and Slater in press). In light of these results, I evaluate the diagnostic potential and limitations of different methodological approaches in the recovery and characterization of organic residues, and propose a series of measures that will allow more confident categorization of the substances in early pottery vessels from the Middle East. I also make a number of recommendations for archaeologists considering the use of organic residue analysis, and suggest some practical ideas on how to develop the degree of confidence necessary to assess the methods used in acquisition of molecular and isotopic data, and ultimately, to evaluate the adequacy of the analytical criteria used to address specific archaeological research questions.

The 87Rb-86Sr system is a widely used long-lived isotope geochronometer. 87Rb, the naturally occurring radioactive isotope of Rb, undergoes beta-decay to stable 87Sr with a half-life of approximately 50 Ga. Decay of 87Rb to 87Sr results in variable 87Sr/86Sr in minerals with different Rb/Sr, and measurement of 87Rb/86Sr and 87Sr/86Sr allows for the determination of the age of the rock. Accurate ages depend both on the quality of the isotopic analysis and on the accuracy of the 87Rb decay constant, lambda87. Although the currently accepted value for lambda87 of 1.42 × 10-11a-1 has been in use for over 30 years, there is growing evidence that it is not accurate. Recent attempts to refine lambda87 and its precision have not reached a consensus. This thesis describes a new experiment to measure lambda87 by 87Sr accumulation over a period of about 30 years, and the preparation of a 84-86Sr double-spike in conjunction with that experiment. Radiogenic 87Sr produced in aliquots of a RbClO4 salt was measured by isotope dilution thermal ionization mass spectrometry. An average of 31 measurements yields a value of 1.398 ± 0.003 × 10-11a-1 . This requires a substantial revision from the previously accepted decay constant and makes Rb-Sr ages calculated with it 1.5% older. A Rb-Sr and U-Pb isotopic chronometry study was carried out on thirteen ordinary chondrites – the most common type of meteorite, the origin and history of which are still unclear. Some meteorites appear disturbed, possibly by recent shock during breakup of the parent body, whereas others yielded accurate and precise U-Pb and Pb-Pb ages. For example, L5 Elenovka yielded distinct ages for silicates (4555 Ma) and phosphates (4535 Ma), allowing the cooling rate of this meteorite from approximately 1055 K to 759 K to be constrained to 15 ± 3 K/Ma. Rb-Sr yielded less precise ages than U-Pb, but using the new decay constant allows accurate comparison between the two methods. This study creates a firm foundation for future studies in thermal history of chondrites and terrestrial metamorphic complexes using Rb-Sr together with other isotopic chronometers.

Viruses are ubiquitous biological entities whose importance and role in aquatic habits is beginning to take form. However, several habitats have undergone limited to no examination with viral-geochemical parameters minimally examined and viral-mineral relationships in the natural environment and the role of mineralization on viral-host dynamic completely lacking. To further develop knowledge on the presence and abundances of viruses, how viruses impact aquatic systems, and how viral-host interactions can be impacted under mineralizing conditions, viruses were examined under a variety of habitats and experimental conditions. Water samples were collected from the deep subsurface (up to 450 m underground) and acid mine drainage (AMD) systems in order to determine the presence, abundance, and viral-geochemical relationships within the systems. Samples were also collected from a variety of freshwater habitats, which have undergone limited examination, to determine viral-geochemical and viral-mineral relationships. Lastly, bacteriophage-host dynamics were examined under authigenic mineral precipitation to determine how mineralization impacts this relationship. Results reveal that not only are viruses present in the deep subsurface and AMD systems, but they are abundant (up to 107 virus-like particles/mL) and morphogically diverse. Viruses are also the strongest predictor of prokaryotic abundance in southern Ontario freshwater systems where potential nutrients are rich. Geochemical variables, such as pH and Eh, were shown to have negative impacts of viral abundance indicting that AMD environments are detrimental for free viruses (i.e. not particle associated). Direct evidence of viral-mineral interactions was found using transmission electron microscopy as viral particles were shown attached to iron-bearing mineral phases (determined through elemental analysis). In addition, evidence of viral participation in mineralization events was found in both AMD and freshwater environments where inverse correlations were noted between viral abundance and jarosite saturation indices (r = -0.71 and r = -0.33, respectively), and goethite saturation indices were also noted to be the strongest predictor of VLP abundance in freshwater habitats explaining 78% of the variability in the data. Lastly, iron precipitation and/or metal ion binding to bacterial surfaces greatly reduced phage replication (~98%) revealing bacterial mineralization has a protective benefit strongly hindering viral replication.

The 87Rb-86Sr system is a widely used long-lived isotope geochronometer. 87Rb, the naturally occurring radioactive isotope of Rb, undergoes beta-decay to stable 87Sr with a half-life of approximately 50 Ga. Decay of 87Rb to 87Sr results in variable 87Sr/86Sr in minerals with different Rb/Sr, and measurement of 87Rb/86Sr and 87Sr/86Sr allows for the determination of the age of the rock. Accurate ages depend both on the quality of the isotopic analysis and on the accuracy of the 87Rb decay constant, lambda87. Although the currently accepted value for lambda87 of 1.42 × 10-11a-1 has been in use for over 30 years, there is growing evidence that it is not accurate. Recent attempts to refine lambda87 and its precision have not reached a consensus. This thesis describes a new experiment to measure lambda87 by 87Sr accumulation over a period of about 30 years, and the preparation of a 84-86Sr double-spike in conjunction with that experiment. Radiogenic 87Sr produced in aliquots of a RbClO4 salt was measured by isotope dilution thermal ionization mass spectrometry. An average of 31 measurements yields a value of 1.398 ± 0.003 × 10-11a-1 . This requires a substantial revision from the previously accepted decay constant and makes Rb-Sr ages calculated with it 1.5% older. A Rb-Sr and U-Pb isotopic chronometry study was carried out on thirteen ordinary chondrites – the most common type of meteorite, the origin and history of which are still unclear. Some meteorites appear disturbed, possibly by recent shock during breakup of the parent body, whereas others yielded accurate and precise U-Pb and Pb-Pb ages. For example, L5 Elenovka yielded distinct ages for silicates (4555 Ma) and phosphates (4535 Ma), allowing the cooling rate of this meteorite from approximately 1055 K to 759 K to be constrained to 15 ± 3 K/Ma. Rb-Sr yielded less precise ages than U-Pb, but using the new decay constant allows accurate comparison between the two methods. This study creates a firm foundation for future studies in thermal history of chondrites and terrestrial metamorphic complexes using Rb-Sr together with other isotopic chronometers.