The intermontane Mackenzie Basin is located within the central South Island of New Zealand. The glacial basin contains three glacial lakes which are used for hydroelectric power generation via a canal system that links the lakes. The basin is an area of climate extremes, low rainfall, high summer temperatures, and snowy winters. The area is predominantly used for pastoral farming, however farming practices are changing and, combined with an increasing population, there is a need to define the groundwater resources to enable sustainable resource management. Little is currently known about the hydrogeological system within the Mackenzie Basin, and what is known is from investigations carried out during the construction of the canal system from 1935 to 1985. There are four glacial formations that overlie Tertiary sequences and Torlesse bedrock. However, due to the glacial processes that have been ongoing over at least the last 300 ka, determining the occurrence and extent of groundwater within the outwash gravels is difficult. It is suggested that the permeability of the formations decreases with depth, therefore horizontal and vertical hydraulic conductivity decrease with depth. A shallow groundwater table is present within the Post Glacial Alluvial Gravels which is recharged directly from fast flowing streams and rivers as well as rainfall. It appears that this shallow system moves rapidly through the system and it is unlikely that the water infiltrates downwards to recharge the deeper groundwater system. It is thought that a deep groundwater system flows preferentially through the Mt John Outwash Gravels, being the second youngest glacial formation. Water chemistry and age dating tracer analysis indicate that the deeper groundwater is over 80 years old and that the groundwater system is recharging slowly. The shallow groundwater in the Post Glacial Alluvial Gravels and within the major fans to the east of the basin is 10 to 20 years in age. Baseline data such as water chemistry, groundwater levels, and surface water gaugings have been collected which can be used for future investigations. More data needs to be collected to create a long term record to further define the hydrogeological system and to determine the best way to manage the resource for long term sustainable use in the future.

A chemical-isotopic equilibrium model was developed for adjustment of radiocarbon ages of groundwater from the arid Tucson basin for dilution of the initial groundwater C-14 activity by the solution of soil calcite having a C-14 of 25 ± 19% modern. Input to the model consisted of the laboratory chemical analyses for Ca⁺⁺, Mg⁺⁺, Na⁺, H₄SiO₄, SO₄⁼, HCO₃⁻, CO₃⁼, NO₃⁻, and pH, and δ C-13 for the total dissolved carbon in the groundwater. Output consisted of the equilibrium chemical composition of the groundwater, the ratio of soil CO₂ derived to total dissolved carbon, Q, and δ C-13 of total dissolved carbon, H₂CO₃, HCO₃⁻, and CO₃⁼, and δ C-13 for the soil CO₂ and calcite that initially dissolved in the surface water as it equilibrated with soil minerals. Radiocarbon age of the groundwater is computed from the equation T = 8270 ln [(Q + (1-Q) A(CaCO₃)/Am] where T is the age in years before A.D. 1950, A(CaCO₃) is the soil calcite activity and Am is the measured activity for the dissolved carbonate in the groundwater, both with respect to modern wood. The validity of the model was tested by comparing the predicted values for δ C-13 (CO₂), δ C-13 (CaCO₃) with measured values for samples from the Tucson basin. δ C-13 (CO 2) calculated = (-12.9 ± 1.9) per mil PDB. δ C-13 (CO2) measured = (-15.1 ± 2.8) per mil PDB. δ C-13 (CaCO3) calculated = (-3.9 ± 1.7) per nil PDB. δ C-13 (CaCO3) measured = (-3.6 ± 1.7) per mil PDB. On the basis of these results, the model adequately describes the natural system and may prove useful in future radiocarbon dating work in desert regions.

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This study contributes a procedure, based on data analysis and geostatistical methods, to evaluate the distribution of chemical ratios and differentiate natural and anthropogenic contaminant sources of groundwater quality in the East Texas Basin. Four aquifers were studied, Sparta, Queen City, Carrizo and Wilcox. In this study, Carrizo- Wilcox is considered as one aquifer, and Sparta-Queen City as another. These aquifers were divided into depth categories, 0-150 feet for Sparta-Queen City and 300-600 feet and 600-900 feet for Carrizo-Wilcox in order to identify individual sources of contamination. Natural sources include aquifer mineral make up, salt domes and lignite beds. Major anthropogenic sources include lignite and salt dome mining and oil-gas production. Chemical ratios selected were Na/Cl, Ca/Cl, Mg/Cl, SO4/Cl, (Na+Cl)/TDS, SO4/Ca and (Ca+Mg)/(Na+K). Ratio distributions and their relationships were examined to evaluate physical-chemical processes occurring in the study area. Potential contaminant sources were used to divide the Basin into three areas: Area 1 to the east, Area 2 in the west and Area 3 in the center. Bivariate analysis was used to uncover differences between the areas. The waters in Area 1 are potentially impacted primarily from oil field waters. Sources present in Area 2 include lignite beds and oil field operations. Area 3 is the cap rock of salt domes that can contain gypsum and anhydrite. Based on the exploratory data analysis (Na+Cl)/TDS, (Ca+Mg)/(Na+K), and SO4/Ca ratios were chosen for geostatistical analysis. Chemical ratios that provided indications of cation exchange, salt domes and oil fields were (Na+Cl)/TDS, (Ca+Mg)/(Na+K) and SO4/Ca. In the Sparta-Queen City 150 zone the procedure did not provide a good method for differentiating between contaminant sources. However, the procedure was effective to indicate impacted ground water in the Carrizo-Wilcox 600 and 900 foot zones.

This thesis uses the paleoceancirculation proxy ²³¹Pa/²³⁰Th, coupled with water mass tracers δ¹³C and εNd, to reconstruct circulation histories for southern source waters masses in the South Atlantic, in addition to North Atlantic Deep Water (NADW) far from its source, for the last ~25 kyrs. Downcore ²³¹Pa/²³⁰Th records from a suite of cores along a depth transect in the Argentine Basin show distinct differences with depth, suggesting that ²³¹Pa/²³⁰Th ratios in sediments are reflective of conditions in only the bottom most waters. This indicates the importance of consideration of changes in water mass distribution when interpreting ²³¹Pa/²³⁰Th records. Opal and particle flux data from these cores show little correlation with ²³¹Pa/²³⁰Th values meaning that changes in ²³¹Pa/²³⁰Th cannot be explained by a local composition or particle flux effect and are instead likely to be reflecting changes in circulation. A core bathed by Antarctic Intermediate Water (AAIW) throughout the last 25 kyrs (GeoB 2107, 1045 m), has relatively high ²³¹Pa/²³⁰Th values (0.075) during the Holocene and distincly lower values (0.055) at the LGM suggesting faster AAIW transport during the last glacial. At greater depths, ²³¹Pa/²³⁰Th, δ¹³C and εNd data in core GeoB 2109 (2504 m) indicate a change in both circulation and water mass distribution on glacial-interglacial timescales, with moderate flow of Antarctic Bottom Water (AABW) at the LGM being replaced by more vigorous flow of NADW during the Holocene. On millenial timescales, ²³¹Pa/²³⁰Th values in deep cores GeoB 2109 and GeoB 2112 (4010 m) indicate enhanced production of AABW during northern hemisphere stadials, when variations in ²³¹Pa/²³⁰Th records are of opposite sign between hemispheres, supporting a possible bipolar seesaw relationship in deep water formation between hemispheres. These data indicate that the ²³¹Pa/²³⁰Th proxy can be used to reconstruct past flow rates of multiple water masses in the Argentine Basin and provide evidence that southern source water masses play a dynamic counterpart to NADW formation on abrupt as well as glacial-interglacial timescales.

We use cosmogenic 10Be analysis of fluvial sediments and bedrock to estimate erosion rates (103 – 106 year timescale) and to infer the distribution of post-orogenic geomorphic processes in the Blue Ridge Province in and around Shenandoah National Park, VA. Our sampling plan was designed to investigate relationships between erosion rate, lithology, slope, and basin area. Fifty-nine samples were collected from a variety of basin sizes (<1 – 3351 km2) and average basin slopes (7 - 26°) in each of four different lithologies that crop out in the Park: granite, metabasalt, quartzite, and siliciclastic rocks. The samples include bedrock (n = 5), fluvial sediment from single-lithology basins (n = 43), and fluvial sediment from multilithology basins (n = 11): two of these samples are from rivers draining streams exiting the eastern and western slopes of the Park (Rappahannock and Shenandoah Rivers). Inferred erosion rates for all lithologies for fluvial samples range from 3.8 to 24 m/My. The mean erosion rate for single-lithology basins in the Park is 11.6 ± 4.8 m/My. Singlelithology erosion rates ranges for fluvial samples are: granite (basin size = ~0.4-40 km2 and slope = 11-23°), 7.9–22 m/My; metabasalt (basin size = ~1-25 km2 and slope = 11-19°), 4.8–24 m/My; quartzite (basin size = ~0.1-9 km2 and slope = 12-23°), 4.7–17 m/My; and siliciclastic rocks (basin size = ~0.3-13 km2 and slope = 18-26°), 6.2–17 m/My. The mean erosion rate for multilithology basins (basin size = ~1-3351 km2 and slope = 7-22°) is 10.2 m/My, and individually for the Shenandoah River 7.3 m/My and the Rappahannock River 13.8 m/My. Bedrock erosion rates range from 2.4-13 m/My across all lithologies, with a mean erosion rate of 7.9 ± 5.0 m/My. Grain-size specific 10Be analysis of four samples showed no consistent trend of concentration with grain size. These data support Hack’s dynamic equilibrium model. Slope and erosion rate are not well correlated, and mean erosion rates are similar for different lithologies. Cosmogenicallydetermined erosion rates in Shenandoah Park are similar to or lower than those reported elsewhere in the Appalachians including those of Matmon and others (2003), 25 to 30 m/My for metaclastic rocks in the steep Great Smoky Mountains, Reuter and others (2004), 4 – 54 m/My in Susquehanna River basin for shale, sandstone, and schist, and Sullivan and others (2006), 6-38 m/My in the micaceous schist and gneiss of the Blue Ridge Escarpment. Cosmogenic erosion rates (integration over 104 yrs) in the Blue Ridge province of Shenandoah National Park are consistent with long-term unroofing rates (integration over 107 yrs) estimated from U-Th/He measurements (11-18 m/My) in samples collected near the Blue Ridge Escarpment by Spotila and others (2004), and fission tracks (20 m/My) in the Appalachians by Naeser and others (2005). The consistency of denudation rates integrated over very different periods of time suggests steady erosion most likely in balance with, and driving isostatic uplift of rock.

Ph.D. - Geology / Geophysical, borehole and mapped data from the Kalahari Basin were used to create maps of the sub-Kalahari geology, isopachs of the Kalahari Group and basal gravels and a sub-Kalahari topographical surface. These are the first basin-wide maps of this type to be produced. These new data were interpreted with the aid of an extensive literature review as well as data gathered at three localities in the southern part of the Kalahari Basin and enabled several conclusions to be made regarding the tectonic evolution of the area. The sub-Kalahari Geological Map shows that rocks dating from the Archaean to present are exposed on the edges of the basin as well as covered by the Kalahari Group sedimentary rocks. Many of the rocks shown on the sub-Kalahari geological map record a history of rifting and subsequent collision, with the NE and SW trending structures appearing to have been reactivated at various times in the geological past. The extent of Karoo Supergroup rocks is greater than previously thought and Karoo sedimentary and volcanic rocks cover a large percentage of the sub-Kalahari surface. The Karoo Supergroup lithologies have been intruded by dolerite dykes and sills and the massive Botswana Dyke Swarm is shown on the sub-Kalahari map extending in a northwest direction across Botswana. The subtraction of the thicknesses of Kalahari Group sediments from the current topographical digital elevation model (DEM) of Africa in order to prepare a DEM of the sub-Kalahari topographical surface and the preparation of an isopach map of the basal gravels gives some indication of the courses followed by Mid-Cretaceous rivers. Topographic profiles along the proposed courses of these rivers show that the floor of the Kalahari Basin has a particularly low elevation in certain areas suggesting that downwarp of the interior of the basin rather than adjacent uplift was the driving force behind Kalahari Group sedimentation. When down-warp of the Kalahari Basin began in the Late Cretaceous these rivers were back-tilted into the newly formed basin and deposition of the Kalahari Group sediments began. The basal unit of the Kalahari Group consists of gravels deposited by the Cretaceous rivers as well as on scree slopes. As down-warp of the basin continued, so more gravels were deposited as well as the sand and -iifiner sediment carried by the rivers. Thick clay beds accumulated in the lakes that formed by the back-tilted rivers, with sandstone being deposited in braided streams interfingering with the clays and covering them in some areas as the shallow lakes filled up with sediment. During the Mid-Miocene there was a period of tectonic stability that saw the silcretisation and calcretisation of older Kalahari Group lithologies. At the end of the Miocene there was some uplift along the eastern side of southern Africa as well as along certain epeirogenic axes in the interior. In general this uplift was fairly gentle. Later more significant uplift in the Pliocene possibly elevated Kalahari Group and Karoo Supergroup sedimentary rocks above the basin floor and exposed many of them to erosion. The eroded sand was washed into the basin and reworked into dunes during drier periods. This uplift occurred along epeirogenic axes and was greater than the Miocene uplift. The development of the East African Rift System (EARS) in the Late Eocene or Oligocene has had a significant influence on the Kalahari Basin. Reactivation of older NE-SW trends by SWpropagating rifts extending from the main EARS is evident by recent movement along faults along the Damara Belt and those that were associated with Karoo sedimentation and post-Karoo graben formation. The propagating rifts have resulted in uplifting, faulting and in some cases, graben formation. In some cases lakes have formed in the grabens or half-grabens themselves and in other cases they have been formed between the uplifted arches related to parallel rifts. The propagating rifts have had a strong influence on the drainage patterns and shape of the Kalahari Basin, in particular in the middle parts of the basin where they have controlled the formation of the Okavango Delta and the Makgadikgadi pans

Resumo: A bacia hidrográfica do rio Caeté está inserida no nordeste do Pará e possui 2.195 km2 e extensão do rio principal de 149 km. O intuito principal foi o de elaborar um estudo da paisagem da bacia do Caeté e avaliar o nível de degradação ambiental. Os procedimentos foram divididos em quatro etapas: 1) levantamento bibliográfico e cartográfico, 2) trabalhos de campo, 3) análises laboratoriais da água superficial e subterrânea e 4) trabalhos de gabinete. Realizou-se: i) levantamento socioeconômico; ii) caracterização das unidades geoambientais; iii) elaboração do diagnóstico da qualidade da água; iv) avaliação das condições do lixão e v) identificação dos fatores de degradação. Foram identificadas quatro unidades: Planalto Costeiro, Planície Costeira, Planície Fluvial e Planície Estuarina. O saneamento básico é inexistente e as principais atividades estão relacionadas com a agropecuária, extrativismo vegetal e pesca artesanal e semi-industrial. Como principais problemas foram identificados o desmatamento, a prática da mineração, a potencial poluição hídrica no rio e seus afluentes e a forte tendência à contaminação pela disposição incorreta dos resíduos sólidos. Além de causar problemas ao meio, esses fatores também acarretam prejuízos diretos para as comunidades, haja vista o consumo de água de baixa qualidade e a disseminação de doenças. / Abstract: The Caeté river hydrographic basin is located in the northeastern of Pará and has 2.195 km2 and extent of the main river of 149 km. The main goal of this research was preparing an integrated study of the environment context of Caeté's river and to assess the level of environmental degradation. The analysis was based on landscape study and the procedures were divided into four stages: 1) analyses bibliographic and mapping, 2) work of field, 3) analysis of water quality and 4) work office. There were analyses related to the definition and characterization of the environmental units, socioeconomic survey, diagnosis of water quality, environmental assessment of the public dumps and identification of the factors of environmental degradation. The survey found that the environmental units inserted in the basin are the Coastal Plateau and Coastal Plain. The main economic activities are related to agriculture and extraction of plant and fishing. As main environmental problems had been identified the deforestation, the practice of mining, the potential water pollution and the strong trend to water contamination by the incorrect disposal of solid waste. / Orientador: Magda Adelaide Lombardo / Coorientador: Luci Cajueiro Carneiro Pereira / Banca: Marcello Martinelli / Banca: Valdir Schalch / Banca: Antônio Carlos Tavares / Banca: Sérgio dos Anjos Ferreira Pinto / Doutor