The distribution of trace elements in bedrock, soils and plants, was studied in twelve areas of British Columbia where mineralization was known to occur below different kinds and depths of overburden. Samples were taken from two soil profiles and the bedrock at each location, and second and third year twigs of the principal vegetation found within a radius of fifty feet of each profile were also collected. The bedrock, soil and plant samples were analysed. The soil samples were used for the determination of pH, organic matter content, percentage of material <80 mesh, cation exchange capacity, exchangeable heavy metals, and content of Cu, Mo, Zn, Pb, As, Co, Ni, Fe and Hg. The same elements were determined in the bedrock and vegetation samples. The results were examined graphically for relationships between elemental contents of the bedrock, soil horizons and vegetation. The data were then statistically analysed.(a) soil horizons and plant relationship with bedrock. (b) inter-elemental relationship of individual horizons of soils and of plants, as well as all horizon relationships. (c) multiple correlation study of cation exchange capacity, percentage of organic material and -80 mesh of element content of individual and all soil horizons. These studies showed that, although most of the soil horizons were developed from transported materials, (glacial, alluvial, etc.), there was a highly significant correlation with B and C horizons and bedrock that confirmed the value of soil sampling in prospecting, since horizon development includes the upwards migration of the elements from bedrock. The secondary dispersion of the halo elements (Mo, Zn, Pb, As, Co, Ni, Hg) proved useful as pathfinders where major economic elements may have been masked during the upward migration process. Secondary dispersion may also be in some degree, helpful in identifying the origin of soils and plants. A great divergence in the affinity of various plants for different elements, and of the same species at different locations, was noted. It was also observed that plants have a closer relationship to the soils than to the bedrock itself, but even so, indicate mineralization. The important relationships between elemental distributions in soil horizons and in plants with bedrock, indicated a logarithmic relationship. The multiple correlation study indicated that some of the major factors of influencing the level of element content in soils developed on transported material-covered areas, are the size of the soil particles and frequently the pH of the soil. In general, the study indicated that the distribution of trace elements is highly complex and that bedrock, soils, and plants, should all be combined into one study; since the study of one of these alone would be incomplete without the others. / Land and Food Systems, Faculty of / Graduate

Orientador: Elson Paiva de Oliveira / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-18T13:34:45Z (GMT). No. of bitstreams: 1 Piaia_Patricia_M.pdf: 22497674 bytes, checksum: ca688c1a7bfc4bf7fbbbc2fe2a92815e (MD5) Previous issue date: 2011 / Resumo: Complexos máfico-ultramáficos são comuns em faixas orogênicas e podem representar diferentes ambientes tectônicos, tais como raízes de arco, restos obductados de ofiolitos, platôs oceânicos, lascas do manto litosférico ou ainda ramos abortados de riftes. Características de campo, petrográficas, de química mineral e litogeoquímicas são importantes no intuito de diferenciar o ambiente de formação desses corpos. O orógeno Itabuna-Salvador-Curaçá corresponde a uma das faixas precambrianas do Brasil consolidada durante o Paleoproterozóico. Ele hospeda diversos complexos máficos-ultramáficos cuja compreensão petrogenética é dificultada por suas rochas muitas vezes se encontrarem metamorfisadas em fácies granulito. Um desses complexos é a Suíte metamórfica gabro-anortosítica São José do Jacuípe que compreende um conjunto de rochas cumuláticas estratificadas, formado por metaanortositos, meta-leucogabros, meta-leuconoritos, meta-gabros e meta-gabronoritos, com meta-piroxenitos subordinados. As rochas da suíte possuem características litogeoquímicas e de química mineral semelhantes ao magmatismo máfico de arco e foram interpretadas como pertencentes a um remanescente de arco, podendo representar um fragmento da raiz máfica de arco magmático que, no caso do cinturão Salvador-Curaçá, seria o Complexo Caraíba. Outros complexos máfico-ultramáficos que se destacam na região são os enxames de diques máficos que ocorrem em abundância na porção norte do Orógeno Itabuna-Salvador-Curaçá. Um deles é o enxame de diques máficos Aroeira, que ocorre na porção central e mais deformada do orógeno, cujas rochas de composição gabronorítica muitas vezes são confundidas com as rochas pertencentes à Suíte São José do Jacuípe. O enxame intrudiu a crosta continental, possui caráter tholeiítico e subalcalino, sendo que suas rochas possuem afinidade com magmas basálticos. Modelagem geoquímica indica que o derrame se formou provavelmente a partir de baixas taxas de fusão de uma fonte mantélica pobre em granada e, a partir de então, evoluiu por processos de cristalização fracionada - cujos principais minerais a cristalizarem foram plagioclásio, olivina e piroxênio - seguida de contaminação crustal. No que se refere aos aspectos petrográficos e litogeoquímicos, as rochas da Suíte São José do Jacuípe e do enxame de diques máficos Aroeira são muito semelhantes e de difícil diferenciação. No entanto aspectos macroscópicos das rochas pertencentes aos diques como presença de fenocristais, falta de outros litotipos associados, diferenças de granulação e no grau metamórfico entre diques, além das próprias relações de contato com as encaixantes, permitem separá-los dos meta-gabronoritos pertencentes à Suíte São José do Jacuípe / Abstract: Mafic and ultramafic complex are commons in orogenics belts and can represent differents tectonics environments like arcs roots, obducted parts of ophiolites, oceanic plateaus, litospheric mantle wedge or an aborted rift. Field, petrographic, mineral chemistry and litogeochemistry characteristics are important to characterize the formation environment. The Itabuna-Salvador-Curaçá belt is one of the Precambrian belts consolidated during the Paleoproterozoic. This belt hosts a lot of mafic and ultramafic bodies and the petrogenesis understanding of these bodies is difficult because they are often metamorphosed in granulite facies. The São José do Jacuípe metamorphic gabbro-anorthositic suit is one of these bodies. It's a conjunct of stratified cumulatic rocks constituted by metaanorthosites, meta-leucogabbros, meta-leuconorites, meta-gabbros and meta-gabbronorites with associated metapyroxenite. These rocks have lithogeochemistry and mineral chemistry characteristics similar to arc mafic magmatism. They are being interpreted as a remaining of a mafic root of a magmatic arc and, in case of Itabuna- Salvador Curaçá belt, this arc probably is represented by the Caraíba Complex. Others complex that stand out in this region are the mafic dykes swarms. They are abundant in the north part of the Itabuna-Salvador-Curaçá belt. One of them is Aroeira swarm that occurs in the central and more deformed part of the belt. Their rocks have a gabbronoritic composition and sometimes are confounded with São José do Jacuípe's rocks. The swarm intruded a continental crust, has a tholeitic and sub-alcaline character and affinity with basaltics magmas. Geochemistry modeling shows this magma was formed from low rates of melt of a mantle font poor in garnet and then, evolved by fractional crystallization and crustal contamination. The main minerals that crystallize were plagioclase, olivine and pyroxene. São José do Jacuípe and Aroeira's rock are petrographically and lithgeochemically similar and difficult to differentiate. However, characteristics of dyke's rocks like presence of phenocrysts, absence of any other litho type associated, differences of granulation and of the metamorphic degree between dykes and the relations of contact with the other rocks allow differentiate them of the meta-gabbonorites of São José do Jacuípe suite / Mestrado / Geologia e Recursos Naturais / Mestre em Geociências

The effectiveness of catechol, an aromatic vic-diol, in dissolving silicate minerals was studied. A synthetic amorphous magnesium trisilicate, Mg₂Si₃O₈∙5H₂O, as well as the minerals olivine, sepiolite, diopside, augite, and enstatite were used to react with catechol in slightly acidic, basic, and neutral solutions. It was found, depending on the solvent used, that 33-52, 8-17, 14-30, 5-11, 3-6, and 0.5-1 % of the minerals dissolved, respectively. The reaction with Mg₂Si₃0₈·5H₂0 resulted in the formation of crystals of magnesium tris (catecholato) siliconate nonahydrate Mg[Si(Cat)₃]∙9H₂0. Dehydration of the crystals at room temperature resulted in the loss of 6 moles of water to form a trihydrated complex, Mg[Si(Cat)₃]·3H₂0; further dehydration at 100°C gave an anhydrous complex, Mg[Si(Cat)₃]. By adding guanidine hydrochloride, CN₃H₆Cl, to the reaction mixture after filtering, crystals of guanidinium tris (catecholato) siliconate monohydrate, (CN₃H₆)₂[Si(Cat)₃]∙H₂0, were obtained. Infrared and nmr spectra, and analytical and x-ray powder diffraction data are presented. The possible structures of the magnesium salts of tris (catecholato) siliconate are also discussed. The reaction of catechol with the minerals listed above gave a water soluble silicon-catechol complex, Si (Cat)₃⁼, which was isolated as (CN₃H₆)₂[Si(Cat)₃]·H₂0 by adding guanidine hydrochloride to the reaction mixture after filtering. The dissolution of these minerals by catechol to form Si(Cat)₃⁼ leads to the conclusion that aromatic vic-diols in nature may play a role in chemical weathering, in transport of silicon into rivers or seas, in soil development, in interconversion of minerals, and in accumulation of silica in plants.

A Dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfillment of the requirement for the degree of Master of Science. 2016. / An important feature of the Merensky Cyclic Unit in the Bushveld Complex is the association of platinum group metals with narrow chromitite layers. The appearance and removal of chromitite layers in this unit has been used to define facies types. This study explores the hypothesis that individual chromitite layers within the Merensky Cyclic Unit at Marikana have distinguishing major element concentrations or ratios which could assist in tracing the continuity of the chromitite layers between facies types which is characterized by single or multiple layers. The examination of field relationships of the chromitite layers at the transition between facies types will be useful to improve understanding of lithological continuity. This study has two approaches; the first being the examination of underground exposures and petrographic analysis, and secondly by chemical analysis of chromite grains within the chromitite layers. No chromite mineral compositional trends or similarities were observed for grains in chromitite layers hosted by the same silicate mineral. The mineral chemistry evidence suggests that post cumulus processes are considered to have changed the primary chromite compositions and that reequilibration has occurred due to reaction with trapped intercumulus liquid. Little to no reaction with the host silicates of plagioclase and pyroxene is envisaged. The slow cooling of the Bushveld Complex has allowed intercumulus liquid a greater opportunity to equilibrate with the early minerals, destroying the early magmatic history by reaction and recrystallization. The cumulate deposition model envisaged to have formed the Merensky Cyclic unit at Marikana is by the emplacement of several pulses of superheated magma, supported by the occurrence of several chromitite layers within the sequence. / LG2017

No description available.

Several deposits in the Mt Isa - Cloncurry region have been studied, including those held by Australian Resources near Selwyn (Plume, Slate Ridge, Mobs Lease and Straight Eight),in particular, with respect to cobalt and gold mineralisation. Cobalt is associated with pyrite, pyrrhotite and arsenic sulfosalts. Other cobalt deposits in the Eastern Fold Belt of the Mt Isa Block were studied; these include the Queen Sally, Lorena and the Great Australia mine. Varying styles of Co-bearing mineralisation were encountered. In the Queen Sally mine a curious vanadium - substituted heterogenite has been found. This is only the world's second reported occurrence of this mineral of the halotrichite group. At the Great Australia, primary Co mineralisation has been shown to be confined to one generation of cobaltian pyrite. Several generations of pyrite are noted for this and other deposits. / Master of Science (Hons)

Mineralization has the potential to capture CO₂. In nature, mineralization is the chemical weathering of alkaline-earth minerals in which stable carbonate minerals are formed, which leads to the removal of CO₂ from the atmosphere. The adsorptive carbonation reaction of olivine ((Mg,Fe)₂SiO₄)), consisting mainly of pure magnesium silicate (Mg₂SiO₄), a main constituent of the Earth’s crust, was carried out to estimate its potential application to the separation of CO₂ in the presence of water vapor in combustion plumes. Based on the thermodynamics for a basis of the reaction mechanism, the olivine carbonation reaction is thermodynamically favorable. Water vapor was found to play an important role in improving the carbonation rate, and experimental results revealed that carbon dioxide carbon dioxide can bind into olivine minerals to form highly stable surface carbonates. The reaction activity of olivine and pure Mg₂SiO₄ in the presence/absence of water vapor was carried out by varying the temperature, reactant concentrations, and space time. Based on changes in CO₂ concentration with time, the reaction kinetic model of pure Mg₂SiO₄carbonation was developed. The reaction order was found to be approximately 1 for CO₂. The activation energy derived for the Arrhenius equation of Mg₂SiO₄-based carbonation is 76.2 ± 4.8 kJ/mol based on the changes in the reaction rates with temperature in the range of 150-200°C. To investigate the molecular reaction mechanism of CO₂ adsorption on the metal oxide surface, forming carbonates, we performed the quantum mechanical calculation of CO₂ adsorption on a CaO (100) surface. It shows that CO₂ molecules strongly react with the CaO surface due to its high reactivity and high basicity. Consequently, this study will basically lay the groundwork for the chemical mechanism of mineral carbonation of olivine with carbon dioxide in the presence of water vapor and as provide relevant information for the practical application of CO₂ sequestration by stable adsorption on mineral silicates.

M. Tech. Metallurgical Engineering. / Investigate the dissolution behaviour of sphalerite minerals in sulphuric acid using ferric ions as oxidants. The specific objectives are to study the following: 1. the mineralogical characteristics of sphalerite ores ; 2. mineralogical effects on dissolution kinetics in sulphuric acid and 3. Effect of ferric ion concentration on the dissolution kinetics of sphalerite ores in sulphuric acid. Mineralogy is a critical area in mineral processing and has to be considered during process design stage, and during each processing stage. The type and concentration of oxidizing agent depend on the mineralogical composition of the ore. Many researchers investigations and test-works have been reported on leaching of sphalerite using both ferric sulphate and ferric chloride (Al-Harahsheh and Kingman, 2007; Rath et al., 1981). However, little or no studies have been reported on the combined oxidants.

Thesis (M.Sc (Hons.))-- University of Western Sydney, Nepean, 1998. / Bibliography : leaves 105-106.

Thesis (M. Sc.) (Hons.) -- University of Western Sydney, Nepean, 1998. / Thesis submitted for the degree of Master of Science (Honours) in the University of Western Sydney. Bibliography : p. 100-105.