Sedimentology, petrography and geochemistry of the Kuruman Banded Iron Formation in the Prieska area, Northern Cape Province of South Africa

The sedimentary sequences hosted by the Griqualand West Basin within the Transvaal Supergroup, Northern Cape Province of South Africa, contain several iron and manganese ore deposits. Many studies have been conducted in the Griqualand West basin, particularly within the northern Ghaap plateau compartment where most iron and manganese mines are located, with less attention to the southern Prieska Compartment. Thus, the current study is targeted at the Kuruman Formation in the Prieska area to investigate the geological occurrence, including sedimentology, geochemistry, origin, and post-depositional alteration of the banded iron formation (BIF). Four stratigraphic sections were measured, and the fifth section was only mapped for lithology and sedimentary facies. These sections constitute portions of the stratigraphic sequence of the Transvaal Supergroup that occurs within the study area. The stratigraphic sequence of the area comprises nine successional cycles with five upward fining cycles and four upward-coarsening cycles. These cycles reflect fluctuation of the sea level and shallowing- and filling-up processes of the final basin. Four mineral paragenetic groups constituting primary minerals, diagenetic minerals, low-grade minerals, and weathering mineral assemblages were encountered in the area. The primary mineral assemblage includes magnetite, hematite, siderite, chert, quartz, and smectite. The diagenetic assemblage minerals in the area are martite, quartz (cement), illite, calcite, ankerite, and stilpnomelane. Low-grade assemblage minerals are riebeckite, crocidolite, and minnesotaite, whereas goethite, limonite, calcite (calcrete), quartz (silcrete), and clay minerals are the supergene (weathering) assemblage minerals. These mineral assemblages were confirmed by microscope petrography, XRD, SEM-EDX, and diagenesis studies. Eight sedimentary facies including Horizontal-laminated BIF facies (Hlb), Horizontal thin to medium bedded BIF facies (Hbb), Ripple laminated BIF facies (Rlb), Thin to medium bedded mudstone facies (Mbm), Medium to thick-bedded mudstone facies (Tbm), Medium to thick-bedded fine-sandstone facies (Mts), Laminated dolomite stromatolite facies (Ld), and Dome-shaped stromatolitic BIF facies (Dbif) were identified in the field. Five facies associations including Facies association 1 (Hlb + Hbb), Facies association 2 (Hlb + Hbb + Mbm + Tbm), Facies association 3 (Hlb + Hbb + Mbm + Tbm + Rlb), Facies association 4 (Mbm + Tbm + Mts), and Facies association 5 (Ld + Dbif + Mts) have been recognised. Mineralogy, petrography, and geochemical studies indicate that the studied samples have all been subjected to recent weathering that altered the primary mineralogy and the geochemical composition. Mineral assemblages of the Kuruman BIF within the Prieska area are dominated by quartz, which constitutes about 53 wt.percent, followed by the iron oxides averaging about 44 wt.percent. Other minerals such as carbonates and silicates are only occurring in concentrations of less than 3 wt. percent combined. The Prieska BIF is enriched in cobalt, tungsten, molybdenum, barium (Ba), and nickel compared to the BIF in the northern parts of the Griqualand West basin and other localities. Post-depositional mineral alteration studies show that most of the primary minerals had suffered various degrees of alteration. The bulk of quartz, silicate, and iron oxide minerals in the area have been recrystallized, partially replaced, dissolved, or leached out. Multiple formation processes were involved in the origin of the banded iron formation: (1). Deposition of iron-rich mud material in the deep ocean floor and formation of a mixture of iron-rich mud (felutite) on the seafloor; (2). Differentiation of felutite and formation of disseminated iron-oxide from mud; (3). Cohesion and diagenesis of disseminated iron-oxide and formation of iron-rich (magnetite/hematite) and silica-rich (chert/quartz) patches, lenses (pod), microbands, and laminations; (4). Consolidation and compaction, leading to the formation of the final banded iron formation (BIF).Thesis (MSc) -- Faculty of Science and Agriculture, 202

Sedimentology, petrography and geochemistry of the Kuruman Banded Iron Formation in the Prieska area, Northern Cape Province of South Africa

The sedimentary sequences hosted by the Griqualand West Basin within the Transvaal Supergroup, Northern Cape Province of South Africa, contain several iron and manganese ore deposits. Many studies have been conducted in the Griqualand West basin, particularly within the northern Ghaap plateau compartment where most iron and manganese mines are located, with less attention to the southern Prieska Compartment. Thus, the current study is targeted at the Kuruman Formation in the Prieska area to investigate the geological occurrence, including sedimentology, geochemistry, origin, and post-depositional alteration of the banded iron formation (BIF). Four stratigraphic sections were measured, and the fifth section was only mapped for lithology and sedimentary facies. These sections constitute portions of the stratigraphic sequence of the Transvaal Supergroup that occurs within the study area. The stratigraphic sequence of the area comprises nine successional cycles with five upward fining cycles and four upward-coarsening cycles. These cycles reflect fluctuation of the sea level and shallowing- and filling-up processes of the final basin. Four mineral paragenetic groups constituting primary minerals, diagenetic minerals, low-grade minerals, and weathering mineral assemblages were encountered in the area. The primary mineral assemblage includes magnetite, hematite, siderite, chert, quartz, and smectite. The diagenetic assemblage minerals in the area are martite, quartz (cement), illite, calcite, ankerite, and stilpnomelane. Low-grade assemblage minerals are riebeckite, crocidolite, and minnesotaite, whereas goethite, limonite, calcite (calcrete), quartz (silcrete), and clay minerals are the supergene (weathering) assemblage minerals. These mineral assemblages were confirmed by microscope petrography, XRD, SEM-EDX, and diagenesis studies. Eight sedimentary facies including Horizontal-laminated BIF facies (Hlb), Horizontal thin to medium bedded BIF facies (Hbb), Ripple laminated BIF facies (Rlb), Thin to medium bedded mudstone facies (Mbm), Medium to thick-bedded mudstone facies (Tbm), Medium to thick-bedded fine-sandstone facies (Mts), Laminated dolomite stromatolite facies (Ld), and Dome-shaped stromatolitic BIF facies (Dbif) were identified in the field. Five facies associations including Facies association 1 (Hlb + Hbb), Facies association 2 (Hlb + Hbb + Mbm + Tbm), Facies association 3 (Hlb + Hbb + Mbm + Tbm + Rlb), Facies association 4 (Mbm + Tbm + Mts), and Facies association 5 (Ld + Dbif + Mts) have been recognised. Mineralogy, petrography, and geochemical studies indicate that the studied samples have all been subjected to recent weathering that altered the primary mineralogy and the geochemical composition. Mineral assemblages of the Kuruman BIF within the Prieska area are dominated by quartz, which constitutes about 53 wt.percent, followed by the iron oxides averaging about 44 wt.percent. Other minerals such as carbonates and silicates are only occurring in concentrations of less than 3 wt. percent combined. The Prieska BIF is enriched in cobalt, tungsten, molybdenum, barium (Ba), and nickel compared to the BIF in the northern parts of the Griqualand West basin and other localities. Post-depositional mineral alteration studies show that most of the primary minerals had suffered various degrees of alteration. The bulk of quartz, silicate, and iron oxide minerals in the area have been recrystallized, partially replaced, dissolved, or leached out. Multiple formation processes were involved in the origin of the banded iron formation: (1). Deposition of iron-rich mud material in the deep ocean floor and formation of a mixture of iron-rich mud (felutite) on the seafloor; (2). Differentiation of felutite and formation of disseminated iron-oxide from mud; (3). Cohesion and diagenesis of disseminated iron-oxide and formation of iron-rich (magnetite/hematite) and silica-rich (chert/quartz) patches, lenses (pod), microbands, and laminations; (4). Consolidation and compaction, leading to the formation of the final banded iron formation (BIF).Thesis (MSc) -- Faculty of Science and Agriculture, 202

Teaching chunks of language: um trabalho com o seriado Gilmore Girls em aulas de inglês como língua estrangeira

Este trabalho tem como objetivo estudar o uso de seriados de televisão norte-americanos em aulas de inglês como língua estrangeira por meio do levantamento dos chunks da língua inglesa. Iniciamos, então, esta dissertação pela descrição da CLT e seus preceitos inovadores apresentando competência comunicativa e suas quatro subdivisões competência estratégica, gramatical, discursiva e sociolinguística com base nos estudos de pesquisadores como Hymes (1972), Brown (2000), Richards (2006), Richards e Roberts (1986), Savignon (1983; 1991). Além disso, em nossa pesquisa, descrevemos o uso de realia em sala de aula, e em nosso recorte optamos pelos seriados norte-americanos. Ainda falando sobre a CLT, discorremos acerca da aula comunicativa apresentando suas características, bem como discutimos as quarto habilidades linguísticas: a leitura (reading), a escrita (writing), a habilidade oral (speaking) e habilidade de ouvir (listening), tratamos, igualmente, do ensino de gramática (teaching grammar), de vocabulário (teaching vocabulary), e cultura acompanhadas de sugestões de atividades relacionadas ao uso de seriados. A justificativa da escolha de seriados norte-americanos deu-se por se tratar de uma rica fonte cultural e linguística e dos chunks da língua inglesa e suas subdivisões collocations, phrasal verbs e idioms está centrado na cultura americana. Em nossa análise, fizemos o levantamento das referências culturais e linguísticas de um episódio do seriado Gilmore Girls - Pilot (Episódio Piloto) - utilizando o programa de computador Unitex® que realiza uma varredura no texto e localiza os chunks of language no roteiro do episódio e, por fim apresentamos algumas atividades baseadas na análise feita.This paper aims to study the usage of American TV series in English as a foreign language classes through the gathering of chunks of language. Though we start this dissertation from the description of the communicative and its innovative principles by presenting the communicative competence and its four divisions strategic, grammatical, discursive and sociolinguistic based on researches like Hymes (1972), Brown (2000), Richards (2006), Richards e Roberts (1986) and Savignon (1983; 1991). Besides we describe the importance of the realia in a communicative class. As well as we discuss the lesson of the communicative approach and the four abilities reading, writing, speaking and listening. Still talking about the communicative lesson we discuss about teaching grammar, vocabulary and culture. The choice of using TV series is justified because they are a rich source both linguistic and cultural of the English language (North American) and we can find a plenty of examples chunks of language, collocations, phrasal verbs, and idioms. In our analysis we gathered not only the linguistics but also the cultural references of the first episode of Gilmore Girls by using software known as Unitex® that searches the chunks in the script selected and finally we propose some activities based on the analysis

Analytical quality in environmental studies: uncertainty evaluation of chemical concentrations determined by INAA

Instrumental neutron activation analysis (INAA) is a measurement technique of high metrological level for the determination of chemical elements. In the context of BIOTA/FAPESP Program, leaves of trees have been evaluated by INAA for biomonitoring purposes of the Atlantic Forest. To assure the comparability of results in environmental studies, a leaf sample of Marlierea tomentosa (Myrtaceae family) showing the lowest concentrations of chemical elements was selected for the evaluation of analytical quality of the determination under unfavorable conditions. Nevertheless, the homogeneity of chemical concentrations of sample at the 95% of confidence level has been achieved and INAA has presented repeatability of 2% for the determination of Br, Co, Cs, Fe, K, Na, Rb and Sr, the uncertainty could have been overestimated. For the evaluation of uncertainty due to the variability of chemical concentrations in the sample, Jackknife and Bootstrap methods were used to estimate the maximum expected percent standard deviation. The uncertainty budget was considered adequate for the reporting chemical concentrations of environmental samples determined by INAA.<br>A análise por ativação neutrônica instrumental (INAA) é uma técnica analítica de alto nível metrológico para a determinação de elementos químicos. No contexto do programa BIOTA/FAPESP, folhas de árvores vêm sendo avaliadas empregando-se INAA para a biomonitoração da Mata Atlântica. Para garantir a comparabilidade dos resultados em estudos ambientais, amostra de folhas de Marlierea tomentosa, cujas concentrações de elementos químicos obtidas foram as menores, foi selecionada para a avaliação da qualidade analítica na mais desfavorável situação. Esta avaliação levou em consideração a homogeneidade das concentrações de elementos e a estimativa da repetitividade analítica. Embora a homogeneidade das concentrações tenha sido detectada em nível de 95% de confiança e a INAA tenha apresentado repetitividade estimada em 2% para Br, Co, Cs, Fe, K, Na, Rb e Sr, a incerteza pode ter sido superestimada. Para a avaliação da incerteza devido à variabilidade das concentrações químicas na amostra, os métodos Jackknife e Bootstrap foram empregados para estimar o desvio padrão máximo esperado. A estimativa de incerteza foi considerada adequada para a geração de resultados de concentrações químicas em estudos ambientais