Thesis (MSc)--University of Stellenbosch, 2006. / Bibliography. Also available via the Internet.

The As- and Mo- bearing secondary mineral phases formed during the neutralization of uranium mill wastes were studied for a variety of ore blends including current and future ore sources at the Key Lake milling operation, northern Saskatchewan, Canada. A lab-scale plant model was employed to characterize secondary precipitates obtained during the mill waste neutralization process. Three scenarios of ore blends were processed through the lab-scale plant to produce mill waste solutions for neutralization before combination into final tailings. Slurry samples (n = 12) were collected from the secondary precipitates formed during the neutralization of mill wastes (raffinate) by precipitation with Ca(OH)2 (slaked lime) from pH 1.5 to 10.5. Synchrotron based X-ray absorption spectroscopy of mill and lab-scale plant precipitates showed arsenate adsorbed to ferrihydrite was the dominant As mineral phase regardless of pH or sample blend (53-77%), with fractional contributions from ferric arsenates, and adsorption to aluminum phases (AlOHSO4, As(OH)3 and hydrotalcite). Molybdate adsorbed to ferrihydrite was the dominant Mo mineral phase, regardless of pH or sample blend, with fractional contribution decreasing with increasing pH, and minor contributions from calcium molybdate, ferric molybdate and nickel molybdate. These results were used in geochemical modelling to predict the source terms for these mineral phases in tailings facilities. Sequestration of As and Mo in the model showed solubility was controlled by adsorption to both Fe and Al oxide surfaces as well as by direct precipitation with other dissolved constituents (Ni, Ca and SO4).The models developed pH profiles of mineral phase precipitation to explain the solubility of As, Mo, Fe, Al, Mg and Ni during sequestration from pH 1.5 to 10.5 that were consistent regardless of ore blend used in simulations. Since adsorption of anions to the surface of ferrihydrite has been shown to slow conversion to crystalline forms of Fe oxides (goethite and hematite) and sequestration of arsenate effectively controls As solubility at high pH (pH >10), As-bearing mineral phases are expected to be stable for thousands of years. With adsorption as well as direct precipitation considered, Mo phases though effectively sequestering below pH 8, became unstable and released Mo back into the tailings porewater (pH >10), as predicted by the thermodynamic model. Historical data obtained from as-discharged tailings as well as previously published U mill tailings studies agree with these findings.

Background Empirical research on how and why nutritional supplements (including vitamin/mineral supplements and herbal supplements) are being taken by middle-income populations in South Africa is lacking. This study quantifies the types of nutritional supplements being taken. It unpacks beliefs regarding benefits and risks. This information is useful for healthcare practitioners in similar settings as it could affect their practice of history taking and alert practitioners to the need to know more about nutritional supplement benefits and risks. The information could be used to influence policy regarding advertising and labelling of nutritional supplements. Method The study was a cross-sectional survey. An anonymous self-completed structured questionnaire was completed by 123 participants attending a medical centre during the data collection period. Face-to-face semi-structured interviews were conducted on 16 participants to gather qualitative information. Results Nutritional supplements were widely taken in this questionnaire sample (59%). Consumption was not related to age, language, ethnic group, education and smoking, but nutritional supplements were more commonly used by women and higher income groups. Women who felt they had fair/poor health, women with chronic medical conditions, especially those with depression or women on chronic prescription medication were more likely to take nutritional supplements than those without these characteristics. Wellness, treating tiredness and short-term disease prevention were the most common reasons for taking the supplements, although research proving these benefits is lacking. Chronic disease prevention was an uncommon reason for consumption. Participants were mostly unaware of possible drug interactions and side-effects and therefore felt it unnecessary to inform their practitioner of consumption habits. Conclusion Healthcare professionals should include a nutritional supplement question in their routine history taking, especially when prescribing chronic medication and in the presence of chronic conditions. They should be knowledgeable regarding efficacy, safety, possible side-effects and drug interactions of commonly consumed nutritional supplements in order to advise patients appropriately. Further empirical research is needed into proven benefits of nutritional supplements.

Thesis (MscAgric (Horticulture))--University of Stellenbosch, 2006. / Protea, Leucadendron and Leucospermum belong to the Proteaceae family. These three genera form an important part of the floriculture industry in South Africa and are commonly used as fresh cut flowers or dried flowers for both the local and international market. The distribution of macro and micro - nutrients was investigated in Protea ‘Cardinal’ using rooted cuttings grown from October 2001 to March 2002. The plants were divided into 1st flush leaf and stem, 2nd flush leaf and stem, basal leaf and basal stem, roots and the flower bud. These tissues were analysed to determine N, P, K, Ca, Mg, Fe, S, Na, B and Mn concentration. Results indicated that N decreased over time in all tissues and accumulated more in leaves than in stems. P in leaves and stems increased with time, while K increased in leaf tissues and remained stable in stem tissue. Ca did not change in young leaves but was high in old leaves. Mg in leaves increased but in basal stem, 1st flush stem and roots Mg decreased over time. Fe in leaves and roots increased with time and not a less significant change occurred in stems. In most tissues, B and Na decreased with time. S increased in leaves and decreased in stems with time. Mn was relatively stable in most tissues except in basal leaves where it increased. Nutrient concentration in tissues, especially in leaves, showed no distinct pattern in the distribution of nutrients. Eleven cultivars from the three genera, namely Protea, Leucadendron and Leucospermum, were used to develop deficiency symptoms of macro - nutrients by using different nutrient compositions. The plants were grown in 20cm pots from December 2002 to September 2003. The eleven cultivars were chosen because of their high market value. Visual symptoms were recorded in two stages with a five - month interval for each stage. The first stage was recorded from December 2002 to April 2003 and the second stage was recorded from May 2003 to September 2003. Observed symptoms indicated significant differences between the control and treatments in which specific nutrients were withheld. Some cultivars exhibited some symptoms that are commonly noticed under field conditions, e.g. in the N deficiency treatment the upper leaves of Protea ‘Sylvia’ were reddish and the lower leaves were chlorotic especially at the later stage. Protea ‘Red Rex’ in the P deficiency treatment had random red tints around the leaf including the petiole, these symptoms are also commonly noticed in Protea ‘Red ‘Rex’ in field conditions. Leucadendron ‘Rosette’ also showed some uncommon symptoms of accumulating “sugar” on leaf tips in Ca deficiency treatment that was not observed in any other cultivar. In some cultivars the symptoms were systematic e.g. Leucadendron ‘Chameleon’ while in other cultivars the deficiency affected a certain leaf age e.g. Leucospermum ‘High Gold’ in the Ca deficiency treatment. The buds in 'High Gold' died prematurely in the Ca deficiency treatment. Protea ‘Cardinal’ was used to determine the optimal N and P source and concentrations for optimal growth. Protea ‘Cardinal’ was grown in a temperaturecontrolled glasshouse for seven months using silica sand as growth medium. Different levels and sources of N and P were applied. The N was applied in a complete nutrient solution as NH4 +, NO3 -, NH4 +: NO3 - (1: 1, 1: 4 and 4: 1 ratios) and Urea, at different concentration levels: 5 mM, 1 mM and 0.1 mM. P was applied at 1 mM, 0.1 mM and 0.01 mM. The plants were fertigated manually with 1L nutrient solution on every second day of the week. P at 0.01 mM and 0.1 mM resulted in optimal plant growth. The 1 mM P resulted in marginal leaf scorching or dryness. When N was applied at 5 mM plant growth was more optimal than when N was applied at 1 mM and 0.1 mM. More dry weight was accumulated at 5 mM than at 1 mM or 0.1 mM N. The dry weight of leaves, stem and roots tissues at 5 mM were higher in the NO3 - treatment.

Made available in DSpace on 2015-04-17T14:49:39Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 940588 bytes, checksum: 5120d3efc15e1e3d58af5bf40a2d3b75 (MD5) Previous issue date: 2013-05-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The Brazil wastes annually 26.3 million tons of food waste generated for banana 30% is composed of the shell, the industrialization these are usually discarded serving only as animal feed. However, if properly handled, can be used as a raw material for producing new products. The banana peel flour has nutritional elements relevant, especially with regard to the minerals, and thus has the potential to be applied to value-added products. This study aimed to develop flour biscuit base of banana (Musa sapientium), the variety Pacovan, rich in potassium, calcium and magnesium. The flour was obtained by convective drying under the conditions of a temperature of 60 ° C, 60 minutes and air velocity of 1 m / s, then was held grinding operation. Analyses were performed using physicochemical, for the raw material fresh, flour and biscuits. Five formulations were defined for the cookies: control, 25%, 50%, 75% and 100% flour banana peel. In the sensory analysis, we used a panel of 57 tasters were asked to evaluate these, in general, the acceptability of each sample using a nine point hedonic scale. The analysis of the data, with the exception of the sensory analysis was performed by analysis of variance. To the flour was found moisture values (7.83 %) and ash (7.56 %) in accordance with current legislation, and excellent levels of minerals potassium (3.670 mg/100 g), calcium (610 mg/100g) and magnesium (290 mg/100g). The biscuits also showed moisture and water activity within the standards and values of ash high, as expected. With respect to sensory analysis, the control formulations, 25 and 50% achieved the best scores with respect to all attributes and overall acceptability. Thus, it can be stated that the flour banana peel is considered a good choice of raw material for the production of biscuits and bakery products. / O Brasil desperdiça, anualmente 26,3 milhões de toneladas de alimentos, dos resíduos gerados para banana 30% são compostos da casca, na industrialização estas são geralmente descartadas servindo apenas como ração para animais. Contudo, se devidamente tratadas, podem ser utilizadas como matéria-prima para a produção de novos produtos. A farinha da casca da banana possui elementos nutricionais relevantes, principalmente no que diz respeito aos minerais , e desta forma possui potencial para ser aplicada a produtos com valor agregado. Objetiva-se com este trabalho desenvolver biscoitos a base de farinha de casca de banana (Musa sapientium), da variedade Pacovan, ricos em potássio, cálcio e magnésio. A farinha foi obtida através de secagem convectiva da casca da banana, nas condições de temperatura de 60 ºC, tempo de 60 minutos e velocidade do ar de 1 m/s, em seguida foi realizada a operação de moagem. Foram realizadas as análises físico-químicas, para a matéria-prima in natura, farinha e os biscoitos. Cinco formulações foram definidas para os biscoitos: controle, 25, 50, 75 e 100 % de farinha de casca de banana. Na análise sensorial, foi utilizado um painel de 57 provadores, estes foram instruídos para avaliar, em geral, a aceitabilidade de cada amostra utilizando escala hedônica de nove pontos. A análise dos dados, com exceção os da análise sensorial, foi realizada mediante análise de variância . Para a farinha foi foram encontrados valores de umidade (7,83 %) e cinzas (7,56 %) de acordo com a legislação vigente, e excelentes teores dos minerais potássio (3.670 mg/100g), cálcio (610 mg/100g) e magnésio (290 mg/100g). Os biscoitos também apresentaram umidade e atividade de água dentro dos padrões, e valores de cinzas elevados, como esperado. Com relação à análise sensorial, as formulações controle, 25 e 50 % obtiveram os melhores escores com relação a todos os atributos analisados e a aceitação global. Desta forma, pode-se afirmar que a farinha da casca de banana é considerada uma boa opção de matéria-prima para produção de biscoitos e produtos de panificação.

Esta dissertação trata do estudo da assembléia de minerais pesados para a determinação da proveniência dos depósitos de areia inconsolidados do Rio Jacuí e seus principais afluentes, congregando principalmente as bacias hidrográficas do Baixo Jacuí e do Vacacaí-Vacacaí Mirim. O Rio Jacuí é o maior rio do estado do Rio Grande do Sul e, apesar da sua importância para o mercado de mineração de areia, pouco se sabe a respeito das áreas-fonte que contribuem para estes depósitos e das principais rotas de distribuição das mesmas. A análise de minerais pesados é uma importante ferramenta utilizada na investigação de sedimentos, pois a diversidade e ocorrência de paragêneses diagnósticas de rochas-fonte particulares tornam esta técnica a mais sensível e precisa, aplicada aos estudos de proveniência sedimentar. A amostragem de sedimentos ativos foi realizada em 19 pontos da bacia de drenagem. Separou-se a fração de areia fina e muito fina para a obtenção dos concentrados de minerais pesados. Os principais minerais pesados translúcidos identificados são: granada, turmalina, hornblenda, zircão, apatita, epidoto e estaurolita, e minoritariamente rutilo, piroxênio, cianita, silimanita, andaluzita, titanita, actinolita e tremolita. O principal piroxênio identificado foi o hiperstênio. Os minerais opacos principais identificados foram: magnetita, ilmenita, hematita e, ocasionalmente pirita. Os resultados demonstram que as principais áreas-fonte que contribuem na composição dos sedimentos do Rio Jacuí são o Escudo Sul- Riograndense, cujos sedimentos são trazidos através de afluentes, localizados a sul, e as rochas sedimentares da Bacia do Paraná. As rochas das formações Serra Geral e Tupanciretã contribuem minoritariamente como fonte de sedimentos arenosos nos pontos estudados. A redução pequena, mas consistente do índice ATi, nas amostras coletadas no Rio Jacuí, em direção à jusante do rio, indica a atuação do intemperismo ácido sobre os grãos de apatita. Um padrão semelhante é identificado no índice GZi indicando dissolução parcial da granada devido ao intemperismo. O índice ZTR baixo (< 12) mantém-se praticamente inalterado ao longo do curso principal do Jacuí, demonstrando uma forte contribuição de sedimentos trazidos pelos afluentes do rio. O índice de arredondamento da apatita, consistentemente baixo, também não possui grandes variações (6 – 12, exceto em uma amostra), corroborando esta hipótese. Desta forma, estes índices representam a assinatura de minerais pesados do Rio Jacui e podem ser utilizados para avaliar a contribuição dos sedimentos do rio no preenchimento da porção mais jovem da bacia de Pelotas. / This monography focus on heavy mineral analysis apply to provenance studies of unconsolidated sand deposits of Jacui River and his main afluents, evolving the hydrographic basins of Baixo Jacui and Vacacai-Vacacai Mirim. The Jacui River is the major river of Rio Grande do Sul state and despite his importance for the aggregate mineral industry, very low attention has been concentrated in knowledge of source-areas and the main routes of sand distribution. The heavy mineral analysis is an important tool used in sedimentologic investigations, because the diversity and diagnostic paragenesis found in specific source rocks make the analysis of heavy minerals the most sensitive and robust technique for provenance studies. Sampling of load sediments was done in 19 spots along the drainage basin. Fine to very fine sand fraction was split-out in order to obtain the heavy mineral portion. The main heavy mineral assemblage identified are: garnet, tourmaline, hornblende, zircon, apatite, staurolite, and minor rutile, pyroxene, kyanite, sillimanite, andaluzite, titanite, actinolite and tremolite. The principal pyroxene is hypersthene. The identified opaque minerals are magnetite, ilmenite, hematite and pyrite. Results indicate that the main source-area for unconsolidated sands of Jacui River is the Rio Grande do Sul Shield through his afluents coming from south Jacui river margin. Sedimentary rocks from Parana basin formations are also important source-area for unconsolidated river sands. Volcanic rocks from Serra Geral and sedimentary fluvial rocks from Tupanciretã formations source-areas show minor contribution. The low but consistent decreasing of ATi index, in samples from main course Jacui River, going to jusante direction, indicates acid weathering on apatite grains. Similar pattern is observed in the GZi index which indicates partial dissolution of garnet due to weathering action. The low ZTR index (< 12) is virtually conserved along the main course of Jacui River showing a strong contribution of sediments coming from the river afluents. The rounded apatite index, consistently low, also is almost constant (Ari = 6-12, except one sample) and agrees with that idea. Further, the heavy minerals signature of Jacui River would help to better understand the provenance and filling of young section of Pelotas marginal basin.

Made available in DSpace on 2016-08-15T20:31:25Z (GMT). No. of bitstreams: 1 JoseneyML_DISSERT.pdf: 1758755 bytes, checksum: 5bb7c7ade5b2c9067221295b0d20cfdb (MD5) Previous issue date: 2015-02-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Aiming to evaluate the effect of season on the mineral profile of goats, fifty males were divided into two groups, one group had mineral supplementation in their diet and the other was the control group, they were kept in native caatinga pastures in the semiarid region. The seasonal evaluation took place during four periods: end of drought season, middle of rainy season, beginning of the drought season, middle of the drought season. To analyze the accumulation of minerals, biopsies of ribs and liver were performed and blood was sampled in each period. The concentration of calcium (Ca), phosphorus (P), copper (Cu), iron (Fe), molybdenum (Mo), zinc (Zn) and cobalt (Co) was measured through Inductively Coupled Plasma Optical Emission Spectrometry after nitric/perchloric digestion. Levels of calcium and phosphorus in the serum and in the bones were within normality in both groups at all periods, as well as levels of molybdenum in the serum and in the liver. High levels of iron in the serum and in the liver were observed during all periods. On the other hand, serum concentrations of copper in the control group, at the end of drought season were inside the levels considered critical for deficiency and hepatic levels were deficient throughout all season periods. A hepatic deficiency of zinc was observed at the beginning and in the middle of drought season and serum deficiency of cobalt in the control group at the end of drought season and in the middle of rainy season. It is suggested that a diet with specific mineral supplements, formulated for animals bred in the semiarid region, be supplied to them, allowing cost reduction / Objetivando avaliar os efeitos da sazonalidade sobre o perfil mineral de caprinos, cinquenta machos foram divididos em dois grupos, um grupo com suplementação mineral e outro controle, e mantidos em pastagem de caatinga nativa em propriedade na região semiárida. A avaliação sazonal foi realizada em quatro períodos: fim do período seco, meio do chuvoso, início do período seco e meio do período seco. Para avaliação do acúmulo mineral, foram realizadas biopsias de costela e fígado e coleta de sangue a cada período. As concentrações de cálcio (Ca), fósforo (P), cobre (Cu), ferro (Fe), molibdênio (Mo), zinco (Zn) e cobalto (Co), foram determinados através de Espectrometria de emissão óptica por plasma acoplado indutivamente, após digestão nítrico-perclórica. Foram constatados valores séricos e ósseos normais de cálcio e fósforo em ambos os grupos e períodos, assim como os níveis séricos e hepáticos de molibdênio. Observou-se valores séricos e hepáticos elevados de ferro em todos períodos. Por outro lado, as concentrações séricas de cobre do grupo controle no final do período seco se mostrou dentro da faixa considerada crítica para deficiência e níveis hepático deficiente em todos os períodos sazonais. Foi observado deficiência hepática de zinco no início e meio do período seco e deficiência sérica de cobalto no grupo controle no final do período seco e meio do período chuvoso. Sugere-se o fornecimento de suplemento mineral específico, formulado para animais criados no semiárido, permitindo redução de custos

This study was conducted in the old arable land located in Lushington communal area in the Eastern Cape province of South Africa. The objectives of the study were to assess the effect of legume introduction on biomass yield, forage and soil mineral levels of the arable lands planted to four leguminous pastures in four seasons. Planting was done in March and October 2008 in Lushington. All legumes were subjected to grow under rain fed conditions. Trifolium vesiculosum (arrowleaf clover), Lespedeza cuneata (sericea lespedeza), Trifolium repens (white clover) and Lotus corniculatus (birdsfoot trefoil) are the four forage legume species that were sampled for the purposes of this study. The four legume species persisted out of the fourteen species that were initially tested for adaptability and persistence in the environmental conditions of Lushington communal area. The legumes, grasses and soils from these legume plots were sampled to determine the effect of legume introduction on the forage yield, mineral contents of the companion grasses and soils over four seasons. Plant and soil samples were collected once in spring (November) 2013, summer (February), autumn (March) and winter (May) 2014 for biomass production, macro and micronutrients determination. Results indicated that legume inclusion and season affected (P < 0.05) the total dry matter (TDM) yield production. Plots with Lespedeza cuneata had the highest TDM (1843 kg/ha) and control plots had the least dry matter production (1091 kg/ha). Summer season provided the highest (P < 0.05) TDM compared to the other seasons. Both legume and grass quality was also affected (P < 0.05) by legume inclusion in different seasons. Accordingly, grasses harvested from Trifolium repens plot showed higher CP level (10.90 percent) than those harvested from other plots whereas the lowest grass CP content (6.90 percent) was measured in the control treatment. L. cuneate had the highest (P < 0.05) CP level (11.00 percent) and T. repens had the least CP (6.63 percent) level. Grasses harvested in autumn had the highest (P < 0.05) CP level (12.50 percent) and those harvested in winter had the least CP level (4.60 percent). Similarly, all legume pastures harvested in spring had superior (P < 0.05) CP (10.80 percent) levels and those harvested in winter had the least CP (3.50 percent) level. Legume inclusion had an effect (P < 0.05) on both grass and legume macro nutrient contents. Trifolium repens plot had the highest grass K (1.07 percent), Ca (1.50 percent) and Mg (1.83 percent), whereas there were lower K (0.12 percent), Ca (1.25 percent) and Mg (1.08 percent) contents in grasses harvested from the control and T. vesiculosum plots, respectively. In legumes, macro nutrient concentrations: K (0.68 percent), Ca (1.75 percent) were superior in the T. vesiculosum plot in comparison to other plots. Season also affected (P < 0.05) both grass and legume macro nutrient content. There was higher K (0.90 percent), Ca (1.30 percent) and Mg (0.94 percent) content in grasses harvested in autumn whereas there were lower levels in winter harvests. In legumes, superior K (0.74 percent) and Mg (1.87 percent) content were attained during spring while the least were measured in winter (0.07 percent) and autumn (0.75 percent), respectively. Likewise, both legume inclusion and season had an significant effect (P < 0.05) on the forages micronutrient levels. During spring, there was superior soil P content (36.28 mg/kg) while during autumn; there was less P (22.58 mg/kg) content. The highest SOC level (1.49 percent) was measured in the T. repens plot whereas the lowest SOC (1.15 percent) was attained in the control plot. The results of this study showed that grass legume mixtures produced forages with high nutrient content and herbage yield. Legume planting in the old arable lands has a potential to improve soil quality parameters such as soil P and SOC content.

Esta dissertação trata do estudo da assembléia de minerais pesados para a determinação da proveniência dos depósitos de areia inconsolidados do Rio Jacuí e seus principais afluentes, congregando principalmente as bacias hidrográficas do Baixo Jacuí e do Vacacaí-Vacacaí Mirim. O Rio Jacuí é o maior rio do estado do Rio Grande do Sul e, apesar da sua importância para o mercado de mineração de areia, pouco se sabe a respeito das áreas-fonte que contribuem para estes depósitos e das principais rotas de distribuição das mesmas. A análise de minerais pesados é uma importante ferramenta utilizada na investigação de sedimentos, pois a diversidade e ocorrência de paragêneses diagnósticas de rochas-fonte particulares tornam esta técnica a mais sensível e precisa, aplicada aos estudos de proveniência sedimentar. A amostragem de sedimentos ativos foi realizada em 19 pontos da bacia de drenagem. Separou-se a fração de areia fina e muito fina para a obtenção dos concentrados de minerais pesados. Os principais minerais pesados translúcidos identificados são: granada, turmalina, hornblenda, zircão, apatita, epidoto e estaurolita, e minoritariamente rutilo, piroxênio, cianita, silimanita, andaluzita, titanita, actinolita e tremolita. O principal piroxênio identificado foi o hiperstênio. Os minerais opacos principais identificados foram: magnetita, ilmenita, hematita e, ocasionalmente pirita. Os resultados demonstram que as principais áreas-fonte que contribuem na composição dos sedimentos do Rio Jacuí são o Escudo Sul- Riograndense, cujos sedimentos são trazidos através de afluentes, localizados a sul, e as rochas sedimentares da Bacia do Paraná. As rochas das formações Serra Geral e Tupanciretã contribuem minoritariamente como fonte de sedimentos arenosos nos pontos estudados. A redução pequena, mas consistente do índice ATi, nas amostras coletadas no Rio Jacuí, em direção à jusante do rio, indica a atuação do intemperismo ácido sobre os grãos de apatita. Um padrão semelhante é identificado no índice GZi indicando dissolução parcial da granada devido ao intemperismo. O índice ZTR baixo (< 12) mantém-se praticamente inalterado ao longo do curso principal do Jacuí, demonstrando uma forte contribuição de sedimentos trazidos pelos afluentes do rio. O índice de arredondamento da apatita, consistentemente baixo, também não possui grandes variações (6 – 12, exceto em uma amostra), corroborando esta hipótese. Desta forma, estes índices representam a assinatura de minerais pesados do Rio Jacui e podem ser utilizados para avaliar a contribuição dos sedimentos do rio no preenchimento da porção mais jovem da bacia de Pelotas. / This monography focus on heavy mineral analysis apply to provenance studies of unconsolidated sand deposits of Jacui River and his main afluents, evolving the hydrographic basins of Baixo Jacui and Vacacai-Vacacai Mirim. The Jacui River is the major river of Rio Grande do Sul state and despite his importance for the aggregate mineral industry, very low attention has been concentrated in knowledge of source-areas and the main routes of sand distribution. The heavy mineral analysis is an important tool used in sedimentologic investigations, because the diversity and diagnostic paragenesis found in specific source rocks make the analysis of heavy minerals the most sensitive and robust technique for provenance studies. Sampling of load sediments was done in 19 spots along the drainage basin. Fine to very fine sand fraction was split-out in order to obtain the heavy mineral portion. The main heavy mineral assemblage identified are: garnet, tourmaline, hornblende, zircon, apatite, staurolite, and minor rutile, pyroxene, kyanite, sillimanite, andaluzite, titanite, actinolite and tremolite. The principal pyroxene is hypersthene. The identified opaque minerals are magnetite, ilmenite, hematite and pyrite. Results indicate that the main source-area for unconsolidated sands of Jacui River is the Rio Grande do Sul Shield through his afluents coming from south Jacui river margin. Sedimentary rocks from Parana basin formations are also important source-area for unconsolidated river sands. Volcanic rocks from Serra Geral and sedimentary fluvial rocks from Tupanciretã formations source-areas show minor contribution. The low but consistent decreasing of ATi index, in samples from main course Jacui River, going to jusante direction, indicates acid weathering on apatite grains. Similar pattern is observed in the GZi index which indicates partial dissolution of garnet due to weathering action. The low ZTR index (< 12) is virtually conserved along the main course of Jacui River showing a strong contribution of sediments coming from the river afluents. The rounded apatite index, consistently low, also is almost constant (Ari = 6-12, except one sample) and agrees with that idea. Further, the heavy minerals signature of Jacui River would help to better understand the provenance and filling of young section of Pelotas marginal basin.

As características vulcanológicas e geoquímicas das rochas vulcânicas da Formação Serra Geral (Eo-Cretáceo da Bacia do Paraná, América do Sul) foram integradas para avaliar os aspectos genéticos e a distribuição dos minerais secundários que são encontrados nas cavidades (vesículas, etc) dessas rochas. Mais de 70 afloramentos e pedreiras em uma área de 65.000 km2 no NE do estado do Rio Grande do Sul (Brasil) permitiram o reconhecimento dos padrões locais e regionais de distribuição dos minerais secundários. Sua distribuição em três pedreiras é apresentada em detalhes, evidenciando alterações quantitativas e qualitativas da mineralogia secundária a distâncias que podem ser inferiores a dez metros. Sete fatores principais definem os minerais que se formam nas cavidades. A composição do derrame de lava hospedeiro e as porosidades primárias e secundárias dos derrames de lava individuais e da seqüência vulcânica são muito importantes. Voláteis vulcânicos do próprio derrame de lava que abriga as cavidades foram responsáveis pela cristalização de minerais secundários nessas cavidades provavelmente apenas em circunstâncias muito específicas. O baixo gradiente geotérmico e a ausência de outras fontes de calor na bacia intracratônia do Paraná restringem o metamorfismo de soterramento como agente formador de minerais secundários provavelmente apenas a grandes profundidades. Metamorfismo de contato, representado pelo impacto de calor e de voláteis vulcânicos dos derrames de lava sobre derrames pré-existentes, é o principal processo de formação de minerais secundários de temperaturas mais altas (T>100ºC). Fenômenos meteorológicos (tempestades de poeira e chuva) durante o extravasamento dos derrames de lava e a interação dos derrames com águas superficiais criaram condições específicas e muito localizadas de formação de minerais secundários. Fluidos ascendentes do aqüífero Botucatu-Pirambóia sotoposto e fluidos descendentes do aqüífero contido no edifício vulcânico são os principais responsáveis pela formação de minerais de baixas temperaturas (T<100ºC). Essa interação de vários fatores e processos genéticos de intensidades variáveis foi responsável pela distribuição dos minerais secundários por "domínios". Domínios são definidos como volumes muito variáveis de rocha, de um ou mais derrames de lava, cujas cavidades abrigam as mesmas espécies minerais secundários com as mesmas morfologias e propriedades físicas (cor). Domínios normalmente são formados por rochas de derrames com as mesmas características vulcanológicas e da mesma composição química, apresentando tamanhos decamétricos a quilométricos. Os minerais cristalizam em todos os tipos de cavidades das rochas vulcânicas, mudam com o tipo e o tamanho das cavidades e se distribuem aleatoriamente nas paredes das cavidades. Muito freqüentes são pseudomorfoses, perimorfoses e minerais com feições de dissolução, demonstrando que os minerais secundários são os produtos de várias fases de cristalização e de dissolução que se sucederam nas cavidades. As temperaturas elevadas (T>100ºC) necessárias para a cristalização de apofilita, laumontita, escolecita, heulandita, estilbitaestellerita e mordenita restringem a formação desses minerais à duração do evento vulcânico Serra Geral. Minerais de temperaturas mais baixas (T<100ºC) e ampla distribuição são chabasita, calcita e minerais do Grupo da Sílica (calcedônia, ágata e quartzo macrocristalino), cada qual com condicionantes genéticos específicos. / The volcanological and geochemical characteristics of the volcanic rocks of the Serra Geral Formation (Eo-Cretaceous of the Paraná Basin, South America) were integrated to evaluate the genetic aspects and the distribution of the secondary minerals found in the cavities (vesicles, etc.) of these rocks. More than 70 outcrops and quarries in an area of 65.000 km2 in the NE of the state of Rio Grande do Sul (Brazil) made it possible to recognize local and regional distribution patterns of the secondary minerals. Their distribution in three quarries is presented in detail, showing quantitative and qualitative changes, sometimes at distances of less than ten meters. Seven main factors define the kind of secondary minerals in the cavities. The composition of the host lava flow and the primary and secondary porosities of the individual lava flows and of the volcanic succession are very important. Volcanic volatiles of the cavity-hosting lava flow itself very rarely allowed the crystallization of secondary minerals in its cavities, probably only in very specific settings. The low geothermal gradient and the absence of other heat sources in the intracratonic Paraná Basin limit burial metamorphism as a secondary mineral forming agent probably only to great depths. Contact metamorphism, represented by the impact of heat and volcanic volatiles of lava flows over earlier flows, is considered the main process for the generation of secondary minerals of higher temperatures (T>100oC). Meteorological phenomena (dust storms and rain) during the emplacement of the lava flows and the interaction of the flows with superficial waters created very specific and localized mineral-forming conditions. Ascending fluids from the underlying Botucatu-Pirambóia aquifer and descending fluids of the aquifer hosted in the volcanic edifice were responsible for low-temperature (T<100oC) minerals. This interaction of different genetic factors and processes of variable intensities generated a distribution of secondary minerals in "domains". Domains are very variable volumes of rocks, belonging to one or several lava flows, whose cavities host the same species of secondary minerals, with the same morphologies and physical properties (colors). Domains are usually formed by rocks from flows with the same volcanological characteristics and the same chemical composition, with sizes ranging from decametric to quilometric. The secondary minerals crystallize in all types of cavities of the volcanic rocks. They change according to the kind and the size of the cavities and occur randomly distributed on the walls of the cavities. Very frequent are pseudomorphosis, perimorphosis and minerals with dissolution features, proving that the secondary minerals are the product of several phases of crystallization and dissolution which happened in the cavities. The higher temperatures (T>100oC) necessary to crystallize apophyllite, laumontite, scolecite, heulandite, stilbite-stellerite and mordenite limit the formation of these minerals to the time of the volcanic Serra Geral event. Very frequent minerals of lower temperatures (T<100oC) are chabazite, calcite and minerals of the silica group (chalcedony, agate and macrocrystalline quartz), each one with specific genetic conditions.