Thesis (M.S.)--University of Delaware, 2005. / Principal faculty advisor: Ronald E. Martin, Dept. of Geology. Includes bibliographical references.

Thesis (M.S.)--University of Tennessee, Knoxville, 2009. / Title from title page screen (viewed on Nov. 5, 2009). Thesis advisor: Carol Harden. Vita. Includes bibliographical references.

The sedimentary rocks of the Karoo Supergroup in the Tuli Basin (South Africa) consist of various terrigenous clastic and chemical deposits (parabreccias, conglo-breccias, conglomerates, sandstones, fine-grained sediments, calcretes and silc~etes). Four stratigraphic units were identified: the Basal, Middle and· Upper Units, and the CI~rens Formation. The palaeo-environmental reconstructions of the four stratigraphic units are based on evidence provided by primary sedimentary structures, palaeo-flow measurements, clast size/shape analysis, petrographic studies, palaeontological findings, borehole data and stratigraphic relations. The facies associations of the Basal Unit are interpreted as colluvial fan and low sinuosity, braid~d river channel with coal-bearing overbank and thaw-lake deposits. The interpreted depositional environment implies a cold climate, non-glacial subarctic fluvio-Iacustrine system. The current indicators of the palaeo-river system suggest flow direction from ENE to WSW. The lithologies of the Basal Unit are very similar to the deposits of the fluvial interval in the Vryheid Formation (Ecca Group) of the main Karoo Basin. There is no indubitable evidence for glacial activity (e.g. striated pavements or clasts, varvites, etc.), therefore the presence of unequivocal Dwyka Group correlatives in the Tuli Basin remains uncertain. The sedimentary structures and palaeo-current analysis indicate that the beds of the Middle Unit were deposited by an ancient river system flowing in a north-northwesterly direction. A lack of good quality exposures did not allow the reconstruction of the fluvial style, but the available data indicate a high-energy, perhaps braided fluvial system. The lack of bio- and chronostr~~igraphic control hampers precise correlation and enables only the lithocorrelation of the Middle Unit with other braided river systems either in the Beaufort Group or in the Molteno Formation of the main Karoo Basin. The depositional environment of the Upper Unit is interpreted as a low-sinuosity, ephemeral stream system with calcretes and silcretes in the dinosaur-inhabited overbank area. During the deposition of the unit, the climate was semi-arid with sparse precipitation resulting -iFlhighmagnitude, low-frequency devastating flash floods. The sediments were built out from a distant northwesterly source to the southeast. The unambiguous correspondence between the Upper Unit and the Elliot Formation (main Karoo Basin) is provided by lithological similarities and prosauropod dinosaurs remains. The palaeo-geographic picture of the Clarens Fonnation indicates a westerly windsdominated erg environment with migrating transverse dune types. The ephemeral stream deposits, fossil wood and trace fossils are only present in the lower part of the Formation, indicating that the wet-desert conditions were progressively replaced by dry-desert conditions. Based on lithological and palaeontological evidence, the Formation correlates with the Clarens Formation in the main Karoo Basin. At this stage, it remains difficult to establish the exact cause of the regional palaeo-slope changes during the deposition of the Karoo Supergroup in the Tuli Basin. It is probable that foreland system tectonics, which affected the lower part of the Supergroup (Basal Unit and Middle Unit?), were replaced by incipient continental extension and rift related tectonic movements in the Middle and Upper Units, and Clarens Formation.

COSTA, Kassius Vinissius de Morais. Parâmetros hidrossedimentológicos da bacia hidrográfica do São José, no Cariri cearense. 2013. 103 f. Dissertação (Mestrado em engenharia agrícola)- Universidade Federal do Ceará, Fortaleza-CE, 2013. / Submitted by Elineudson Ribeiro (elineudsonr@gmail.com) on 2016-06-24T17:22:39Z No. of bitstreams: 1 2013_dis_kvmcosta.pdf: 4699170 bytes, checksum: b38622d32b7063f4ee60f9622a7b3d7e (MD5) / Approved for entry into archive by José Jairo Viana de Sousa (jairo@ufc.br) on 2016-07-21T20:17:34Z (GMT) No. of bitstreams: 1 2013_dis_kvmcosta.pdf: 4699170 bytes, checksum: b38622d32b7063f4ee60f9622a7b3d7e (MD5) / Made available in DSpace on 2016-07-21T20:17:34Z (GMT). No. of bitstreams: 1 2013_dis_kvmcosta.pdf: 4699170 bytes, checksum: b38622d32b7063f4ee60f9622a7b3d7e (MD5) Previous issue date: 2013 / This study aimed to analyse the São José river catchment (BHSJ) hydrosedimentological parameters, evaluate the sediment yield and define the susceptibility of soils to erosion based on the Equation Universal Soil Loss (USLE). Therefore, it was determined: (i) the rainfall erosivity (R - factor) at catchment, based on the formulations proposed by Wischmeier and Smith (1958) and Fournier (1960), (ii) the soil erodibility (K – factor) at catchment, it was calculated using the nomograph developed by Wischmeier et al. (1971), (iii) the topographic factor (LS – factor) was obtained through the method of Bertoni and Lombardi Neto (1990), using the Digital Elevation Model (DEM) generated by the Shuttle Radar Topography Mission (SRTM), (iv) identification, delineation and description of the land cover (C – factor), using GIS, through by the classification techniques of multitemporal satellite images. The sediment delivery ratio (SDR) of the catchment was estimated based in equations proposed by Maner (1958), Roehl (1962), Vanoni (1975), Renfro (1975) and Williams and Brendt (1972). The equation that presented the best fit was selected, comparing modelled and measured data at the catchment outlet, for hydrological year monitored since September 2011 to September 2012. The results show the following: (i) the rainfall erosivity, determined by the equation developed in this study and validated with Nash and Sutcliffe coefficient of 0.81; presented satisfactory results in the adjustment of the USLE equation for BHSJ, with best adjustments among the compared methods, that presented percentage errors of at least 50%; (ii) the soil erodibility determined was spatialized in the catchment by Kriging, using the method of interpolation Gaussian model tested and validated; (iii) the topographic factor was determined and spatialized in the catchment, considering average values for six distinct classes of slopes; (iv) the use types and occupation of the basin were divided into agriculture, caatinga, cerrado, tropical rainforest, bare soil, urban and undergrowth. In the catchment, the rate of erosion was estimated at 364 t ha-1.year-1 from the USLE, corresponding to a sediment yield of 1.48 x 106 t in the hydrological year. The map of erosion susceptibility showed that the degree of erosion basin presented: low, medium, high and very high, respectively, 26.39, 34.34, 30.37 and 8.90% of the area. SDR determined by the equations proposed by Maner (1958) and Vanoni (1975) presented values near suspended sediment discharge measured at the catchment outlet during the monitored events, with percentage errors of -12.4 and -2.6%, respectively. / Este trabalho teve como objetivo principal analisar os parâmetros hidrossedimentológicos da bacia hidrográfica do São José (BHSJ), avaliar a produção de sedimentos e definir o mapa de susceptibilidade dos solos à erosão, a partir da Equação Universal de Perdas do Solo (USLE). Para isso determinou-se: (i) a erosividade da chuva na bacia, a partir de formulações desenvolvidas com base em Wischmeier e Smith (1958) e Fournier (1960); (ii) a erodibilidade do solo na bacia, desenvolvida a partir do nomograma de Wischmeier et al. (1971); (iii) o fator topográfico da bacia, através do método de Bertoni e Lombardi Neto (1990), utilizando o Modelo Numérico do Terreno (MNT) gerado através de dados do Shuttle Radar Topography Mission (SRTM); (iv) a identificação, delimitação e descrição dos tipos de uso e ocupação dos solos na bacia, através de SIGs, utilizando a classificação de imagens de satélite multitemporais pré-processadas. A razão de aporte de sedimentos (RAS) da bacia foi estimada a partir de equações propostas por Maner (1958), Roehl (1962), Vanoni (1975), Renfro (1975) e Williams e Brendt (1972), a partir das quais escolheu-se a que apresentou resultado mais próximo do valor de descarga sólida em suspensão medido no exutório para o ano hidrológico monitorado de Setembro de 2011 a Setembro de 2012. Os resultados mostraram que: (i) a erosividade, determinada a partir da equação desenvolvida nesse trabalho e validada com coeficiente de Nash e Sutcliffe de 0,81; apresentou resultados satisfatórios no ajuste da equação da USLE para a BHSJ, com melhor ajuste dentre as metodologias comparadas, que apresentaram erros percentuais de pelo menos 50%. (ii) a erodibilidade determinada foi espacializada na bacia por Krigagem, utilizando modelo Gaussiano testado e validado; (iii) o fator topográfico foi determinado e espacializado na bacia, considerando-se valores médios para seis classes distintas de declividades; (iv) os tipos de uso e ocupação dos solos na bacia foram divididos em agricultura, caatinga, cerrado, floresta úmida, solo exposto, área urbana e vegetação rasteira. A partir da USLE estimou-se uma taxa de erosão na bacia de 364 t.ha-1.ano-1, correspondendo a uma produção de 1,48 x 106 t de sedimentos no ano hidrológico. O mapa de susceptibilidade à erosão mostrou que a bacia apresentou grau de erosão: baixo, médio, alto e muito alto, respectivamente, em 26,39, 34,34, 30,37 e 8,90% da área. A SDR determinada pelas equações propostas por Maner (1958) e Vanoni (1975) apresentaram valores bem próximos da descarga sólida em suspensão medida no exutório durante os eventos monitorados, com erros percentuais de –12,4 e – 2,6%, respectivamente.

The study investigates the nature and extent of erosion and deposition in the Maqalika catchment, Maseru. Components of the study include (i) the re-construction of erosion and land use history in the catchment from 1961 to 1985, (li) determination of dominant factors or combinations of factors responsible for the observed erosion distribution at each date, (iii) the identification and evaluation of erosion and deposition features, and their spatial and temporal variations, and (iv) identification of socia-economic problems associated with observed erosion and deposition. Methods employed for the re-construction of erosion and land use history include the use of sequential aerial photography of 1961, 1979 and 1985, orthophoto maps and review of literature from past studies. It has been possible to map erosion and land use for the three time periods pinpointing areas of major change. Results are presented in map form showing the spatial distribution of each erosion class and each land use category. It was however not possible to derive any meaningful relationship between erosion distribution and land use, on the aforementioned maps. The only observation made from the comparison of the maps is that erosion degree and distribution sometimes changes with land use, while land use sometimes changes in response to erosion. Major land use changes are the conversion of agricultural land to urban land use, and grazing land. Due to the mnlti-dimensional nature of soil erosion, hand 'actor analysis was employed to determine which factors or combinations of factors were dominant at each date. Despite the extensive research on the various factors affecting erosion such as those used for the USLE and SLEMSA there is a growing uncertainty as to which factors are more important to erosion. Soil erodibility has been found to be a component of the major controlling factor combinations in all three periods under study. At each date erodibility combined with a number of other factors determined the observed erosion distribution. As suggested by Mosley (1980), Cambell (1985) and Coleman and Scatena (1986) sediment from a catchment is derived principally from spatially limited portions of the catchment. Likewise eroded sediment becomes deposited in spatially limited areas with special characteristics which encourage deposition. Aerial photographic survey aided by ground survey and oblique photographs were employed to identify sediment sources and sinks within the catchment. Some sediment sources are fIxed such as gully floors and sides, while some change location from time to time such as construction sites. An evaluation of portions of the catchment for their ability to supply and deliver sediment has shown that the most eroded areas are not the most active sediment sources. Sediment yield is limited by either supply or transport. Sediment yield was estimated using reservoir survey data which indicate that there is a high rate of soil loss from the catchment. One flaw of this method as a measure of soil loss is that it treats the measured sediment yield as if it were contributed uniformly from the basin. This method however affords the researcher to estimate minimum erosion rates, taking into account that large amounts of sediment are stored at various places within the catchment. The possible socio-economic consequences of erosion and deposition have been identified. These include loss of cropland, destruction of roads and building sites which require methods of reclamation, sedimentation of small reservoirs and ponds, and the formation of gully bottom fills which are potential sediment sources. Conservation measures presently applied in the catchment are assessed and found to be irrelavant to the present erosion problem. Data from the reservoir survey revealed that the estimated rate of soil loss is more important to on-site erosion damage than to off-site damage in the form of the sedimentation of Maqalika reservoir. Appropriate conservation measures such as those suggested by Amimoto (1981) would be relevant to the study area, however the main constraint in their implementation would be lack of legislation and the absence of a sound land use policy. It is therefore concluded that the present land use situation which does not take into consideration the physical constraints of the catchment is partly responsible for accelarated erosion in the catchment.

Thesis (M.Sc. (Zoology)) -- University of Limpopo, 2019 / Freshwater ecosystems in South Africa are losing their quality and quantity over time due to pollution mainly from mining, agriculture, industries, deforestation, sewage systems, construction of dams, channel modification and over extraction of water. The Dwars River, a tributary of the Olifants River, is of no exception, as recent studies indicated an increase in nutrient input possibly from agriculture. The Dwars River is an important source of water for nearby communities (Ga-Mampuru). The aim of the study was to assess water and sediment quality of the Dwars River using macroinvertebrates as bioindicators of pollution. Water and macroinvertebrates sampling were done seasonally from July 2017 to May 2018. The water quality results indicated that non-toxic constituents such as salinity and EC (Electrical Conductivity) were above permissible limits stipulated by the DWAF (1996) guidelines. More sensitive taxa were found upstream, despite high concentrations of some nutrients and metals in the water column. The high abundance and distribution of macroinvertebrates observed upstream was confirmed by the Canonical Correspondence Analysis (CCA), South African Scoring System (SASS5) and Average Score Per Taxon (ASPT) results during the study. Site 1 was dominated by the most sensitive taxa and this could be due to high dissolved oxygen content and increased heterogeneity of the area. Site 4 was dominated by the most tolerant taxa, according to the CCA, SASS score and ASPT results. This could possibly be due to the nutrients and heavy metals washed from upstream, which get adsorbed by the sediment. The results for species abundance, diversity and richness indicated that Ephemeroptera was the most abundant, while Diptera was the most diverse. Ephemeropterans are known to be indicators of good water quality. Site 1 had the highest number of families and orders while site 4 had the least families and orders. Ephemeroptera, Plecoptera and Tricoptera (EPT) taxa richness and Shannon diversity (H’) index values are high upstream and decrease downstream. Overall, the SASS5 indices, CCA and physicochemical results indicated that the water quality in the Dwars River is deteriorating in most impacted sites / National Research Foundation (NRF) and VLIR

Thesis (M.Sc.(Chemistry)) -- University of Limpopo, 2019 / Rivers provide the main water sources for domestic, industrial, and irrigational purposes; however, they could be polluted by receiving wastes from municipal and industrial sources as well as runoff from agricultural land. This could leave rivers contaminated with chromium (Cr) and other potentially toxic elements. Chromium can be either essential or carcinogenic depending on the chemical form. The aim of this study was to assess and quantify trivalent Cr [Cr(III)] and hexavalent Cr [Cr(VI)] in water and sediment samples, collected from Mokolo and Blood Rivers in the Limpopo province. Water and sediment samples were collected from ten sampling sites from each river. Microwave assisted acid digestion and microwave assisted extraction methods were used to obtain a simple, rapid and safe method for the determination of total Cr and Cr(VI) in sediments. Water samples were acidified with ultra-pure HNO3 and analysed directly to quantify total Cr. The accuracy of the method was evaluated by employing a sediment standard reference material (SRM 8704) and trace elements in water reference material (SRM 1643f). Total Cr and Cr(VI) in water and sediment samples were quantified using flame atomic absorption spectrometry (FAAS) and graphite furnace-atomic absorption spectrometry (GF-AAS). The Cr concentrations in water and sediment samples collected from Blood River were found in the range 1.56 to 6.11 μg/L and 129.2 to 252.9 μg/g, respectively. The concentrations of Cr in water and sediment samples obtained from Mokolo River ranged from 1.34 to 3.53 µg/L and 25.7 to 156.4 μg/g, respectively. A new solid phase extraction method was developed using chromabond-NH2 column to determine Cr(VI) in water. In order to achieve separation of Cr(VI), the sample was pre-concentrated and passed through a conditioned chromabond-NH2 column at a flow rate of 3 mL/min. Hexavalent Cr was selectively adsorbed onto the column and the contents were dried under vacuum. The retained Cr(VI) was subsequently eluted with two column volumes of 2 M HNO3 and diluted to a final volume of 10.0 mL. The limit of detection was 0.105 µg/L and the relative standard deviations were less than 2%. The validation of the procedure was performed by spiking standard solutions containing Cr(III) and Cr(VI) and the percentage recoveries were higher than 88%. The concentrations of Cr(VI) in BloHexavalent Cr in sediment samples was determined by employing leaching reagents of 0.1 M Na2CO3 and 0.01 M Na3PO4. Determination of Cr(VI) by using 0.1 M Na2CO3 as leaching reagent followed by atomic spectrometric measurements provided satisfactory results with percentage recoveries of 94.9 to 105%. This was achieved by extracting the sediment–reagent solution mixture for a period of 15 min at maximum pressure and temperature of 700 psi and 120 ºC, respectively. The leached Cr(VI) was then quantified by GF-AAS after filtration of the sample solutions through a hydrophilic Millipore PVDF 0.45 µm filter. The quantified levels of Cr(VI) leached by 0.1 M Na2CO3 in sediment samples of Blood and Mokolo Rivers were in the range 0.41 to 1.32 μg/g and 0.17 to 0.82 μg/g, respectively. The concentrations of Cr(VI) obtained employing the leaching reagent of 0.01 M Na3PO4 were found to be below LOD value of 0.06 µg/g in Mokolo River in all the sites and were in the range of 0.07 to 0.09 µg/g in Blood River. The low values of Cr(VI) in water and sediments show that Cr(III) did not oxidise to Cr(VI) during sample preparation. In Blood and Mokolo Rivers, although the concentrations of Cr(VI) are low, their values suggest a link with the industrial and agricultural activities in the area. od and Mokolo Rivers ranged from 0.13 to 1.99 µg/L and 0.13 to 0.55 µg/L, respectively / National Research Foundation (NRF) and , the Sasol Inzalo Foundation

A method with the potential for comprehensive microplastic monitoring in river sediments is presented in this study. We introduce a novel combination of electrostatic separation, density separation, and differential scanning calorimetry (DSC). Currently, microplastic analysis in sediments is limited in terms of sample masses, processing time, and analytical robustness. This work evaluated a method to process large sample masses efficiently and still obtain robust results. Four particulate matrices, including commercial sands and river sediments, were spiked with PCL, LD-PE, and PET microplastic particles (63–200 µm). Samples with a mass of 100 g and 1,000 g (sand only) contained 75 mg of each microplastic. After electrostatic separation, the mass of sand samples was reduced by 98%. Sediment samples showed a mass reduction of 70–78%. After density separation, the total mass reduction of sediment samples was above 99%. The increased concentration of total organic carbon seems to have the highest impact on mass reduction by electrostatic separation. Nevertheless, the recovery of microplastic was independent of the particulate matrix and was polymer-specific. In 100 g samples, the average recovery rates for PCL, LD-PE, and PET were 74 ± 9%, 93 ± 9%, and 120 ± 18%, respectively. The recoveries of microplastic from 1,000 g samples were 50 ± 8%, 114 ± 9%, and 82 ± 11%, respectively. In scale up experiments, high recoveries of all microplastics were observed with a decrease in standard deviation. Moreover, the biodegradable polymer PCL could be used as an internal standard to provide quality assurance of the process. This method can overcome the current limitations of routine microplastic analysis in particulate matrices. We conclude that this method can be applied for comprehensive microplastic monitoring in highly polluted sediments. More studies on electrostatic separation and polymer-specific recovery rates in complex matrices are proposed.

Graduation date: 1995

Cette thèse a les objectifs suivants :1. Mieux comprendre comment les isotope du bore dans les sédiments fluviaux modernes enregistrent le régime d’altération à l'échelle du bassin versant. 2. Mieux comprendre comment le « signal » d’altération porté par les sédiments fluviaux est transféré des zones sources vers l’environnement de dépôt. 3. Déterminer si les isotopes du B dans les dépôts sédimentaires (paléo-canaux) peuvent être utilisés pour reconstituer les conditions paléo-climatiques et paléo-environnementales et ainsi révéler comment l’altération continentale au sens large (production et transport de sédiments) a réagi à la variabilité climatique au cours du dernier cycle glaciaire-interglaciaire (derniers 100 ka). Ces objectifs ont été examinés en étudiant les matériaux fluviaux des fleuves Gandak (Himalaya) et Murrumbidgee (NSW, Australie) et des dépôts de sédiments fluviaux de la Riverine Plain (basin versant de Murrumbidgee). La connaissance des paramètres qui contrôlent le fractionnement isotopique du bore des sédiments fluviaux au cours de la formation et du transport a d'abord été acquise dans les systèmes modernes, puis appliquée à d'anciens dépôts de paléochenaux. / This thesis has the following objectives: 1) To better understand how boron isotopes in modern fluvial sediments record the weathering regime at the catchment scale. 2) To better understand how the weathering “signal” carried by river sediments is transferred from source areas to the depositional environment. 3) To determine if boron isotopes in sediment deposits (paleochannels) can be used to reconstruct paleo-weathering and paleo-environmental conditions and reveal how continental weathering at large (production and sediment transport) responds to climatic variability over the last glacial-interglacial cycle (last 100 ka). These objectives were addressed by studying fluvial material from the Gandak (Himalayas) and Murrumbidgee (NSW, Australia) Rivers and fluvial sediment deposits from the Riverine Plain (Murrumbidgee catchment, Australia). Knowledge of the parameters that control boron isotope fractionation of river sediment during formation and transport was first gained in the modern systems and then applied to ancient paleochannel deposits.