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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
221

Mineralization and Alteration of the Late Triassic Glacier Creek Cu-Zn VMS Deposit, Palmer Project, Alexander Terrane, Southeast Alaska

Steeves, Nathan January 2013 (has links)
The Glacier Creek volcanogenic massive sulfide (VMS) deposit is hosted within Late Triassic, oceanic back-arc or intra-arc, rift-related, bimodal volcanic rocks (Hyd or Tats Group) of the allochthonous Alexander terrane known as the Alexander Triassic Metallogenic Belt (ATMB). The deposit presently consists of four tabular massive sulfide lenses with a resource of 4.75 Mt. at 1.84% Cu, 4.57% Zn, 0.15% Pb, 0.28 g/t Au and 29.07 g/t Ag. A deposit-scale thrust fault offsets stratigraphy along the axial surface of a deposit-scale anticline. The massive sulfide lenses are barite-rich and are divided into 6 main ore-types based on mineral assemblages. There is a large range of sphalerite compositions, with low-Fe sphalerite dominant throughout the lenses and high-Fe sphalerite at the top and bottom of the lenses in pyrrhotite-rich zones. Lenses contain anomalous Sb, Hg and Tl. Gangue minerals include barite, quartz, barian-muscovite, calcite, albite, highly subordinate chlorite and locally hyalophane and celsian. Overlying massive sulfide is a tuffaceous hydrothermal sediment with anomalous REE patterns and local hyalophane. The general footwall to all four lenses is a thick unit of coherent to volcaniclastic feldspar-phyric basalt containing extensive lateral alteration. Four alteration facies are recognized based on mineral assemblages. Mass balance calculations for the footwall indicate general gains of S, Fe, Si and K with coincident loss of Ca, Na and Mg, along with trace element gains of Tl, Sb, Hg, Ba, Zn, Cu, As and loss of Sr with increased alteration intensity. Short wavelength infrared (SWIR) spectroscopy shows a general decrease in Na, K and Al content of muscovite and increase of Fe+Mg and Ba content towards ore. Integrated petrographic, mineral, chemical and sulfur-isotope data suggest a transition during deposit formation, from high-temperature, acidic, reduced hydrothermal fluids mixing with oxidized, SO4-rich seawater, to later cooler, low fO2-fS2 conditions of formation and a lack of SO4 in seawater.
222

The Metalliferous Sediments of the Atlantis II Deep (Red Sea)

Laurila, Tea Elisa January 2015 (has links)
The Atlantis II Deep is a location of modern submarine hydrothermal activity along the slowly spreading Red Sea rift axis. Venting of high-temperature hydrothermal fluids, similar to those associated with black smokers, takes place in a brine pool and has led to the accumulation of 90 Mt (dry, salt free) of stratiform, metalliferous sediment. The conditions of mineralization are unique in the modern oceans, but have been widely suggested as a possible analog of some important ancient stratiform base metal ore deposits. This study shows that many of the proposed genetic models for these ancient deposits may be highly simplified and do not take into account rapid diagenetic transformations, widespread non-equilibrium processes, and many other aspects of metal deposition. Sediment cores of the Atlantis II muds were last studied more than 30 years ago. High-resolution sampling and careful re-examination of the mineralogy and geochemistry of the sediments, using modern analytical techniques has significantly improved the understanding of the different processes responsible for the formation of the finely layered metallifeous sediments. The geochemistry of the individual layers is controlled by highly variable detrital, hydrogenic and hydrothermal input. Primary depositional pathways from the brine pool are the main control on basin-wide metal distribution (e.g., increasing Cu/Zn away from the vents) including variable enrichment in trace metals via scavenging from the brine pool and from the enriched pore waters. Cu and Zn have been deposited not only as sulfides but also with poorly crystalline Si-Fe-(oxy)hydroxides. A significant proportion of the original non-sulfide Cu and Zn are diagenetically transformed into sulfides, but also carbonates and clays, in large part reflecting sulfide deficient pore waters. Negative δ34S values, previously unrecognized in the sulfide- and metal-rich units, indicate a source of bacteriogenic sulfide. Syn-diagenetic processes also appear to have been responsible for the sharp laminations in the sediments, as well as distinctive zoning of carbonate and clay minerals around the vent source. The early diagenetic transformations observed in the Atlantis II Deep may not be preserved in the ancient rock record but nevertheless have important implications for metal deposition in some of the world’s largest and richest base metal ore deposits.
223

Geology of the Kidd Creek Deep Orebodies - Mine D, Western Abitibi Subprovince, Canada

Gemmell, Thomas P. January 2013 (has links)
The giant Kidd Creek Mine is an Archean Cu-Zn-Ag deposit in the Abitibi Greenstone belt, located in the Superior Province of Canada and is one of the largest known base metal massive sulfide mines in the world with a tonnage of 170.7 Mt (Past production, Resource and Reserve). The massive sulfides in Mine D comprise a number of ore lenses that are interpreted to be the downplunge continuation of the Central orebody from the upper mine. These are referred to as the West, Main, and South lenses. The massive sulfides overlie a silicified rhyolitic unit at the top of a mixed assemblage of rhyolite flows, volcaniclastic sediments and ultramafic flows. The sheared nature of the fragmental units in the hanging wall of the deposit, at depth, illustrates the greater deformation that has occurred than in the upper mine. Metal zonation and the distribution of Cu stringer mineralization suggest that the West and Main lenses may be part of a single massive sulfide body (Main orebody) that has been structurally dismembered. The South Lens is a detached body, separated by late faults. The large Cu stringer zone beneath the West and Main lenses has a thickness of up to 150 metres, and is much broader and structurally remobilized in Mine D partially due to a newly identified series of vertically trending offset faults, that extends along the entire length of the massive sulfide bodies. A number of features of the North, Central and South orebodies in the upper part of the mine (e.g., Se-rich halo around Cu-rich zones) have been recognized in Mine D and provide an important framework for correlating the deep orebodies with the upper levels of the mine. Drilling below the current mine levels indicates that the massive sulfide and Cu stringer zones continue below 10,200 feet (3109 m) and highlight the remarkable continuity of the deposit downplunge with no end in sight. Two main ore suites have been recognized in the upper part of the mine and in Mine D: a low-temperature, polymetallic assemblage of Zn, Ag, Pb, Cd, Sn, Sb, As, Hg, ±Tl, ±W, and a higher-temperature suite of Cu, Co, As, Bi, Se, In, ±Ni. More than 25 different ore minerals and ore-related gangue minerals are present, including Co-As-sulfides, Cu-Sn-sulfides, Ag-minerals, and selenides. The massive ores consist mainly of pyrite, pyrrhotite, sphalerite, magnetite and chalcopyrite, together with minor galena, tetrahedrite, arsenopyrite, and native silver with a quartz and siderite gangue. Despite the high Ag content of the ores, the majority of the massive sulfides are remarkably Au poor except for a local gold zone that has been recognized in the deep mine in association with high-temperature mineralization. The trace elements in the ores exhibit strong zonation and diverse mineralogy. Spectacular albite porphyroblasts, up to 1 cm in size occur in the most Cu-rich ores of Mine D which are coincident with the peak of regional metamorphism and likely represent higher metamorphic or hydrothermal temperatures. Overall the orebodies have remained remarkably similar downplunge. However, unlike the upper part of the mine, pyrrhotite is dominantly hexagonal, only tetrahedrite was observed as the dominant sulfosalt, and magnetite occurs as both blebby porphyroblasts and as abundant intergrowths with sphalerite-chalcopyrite ores and siderite. These characteristics suggest that the deep mine has been subjected to higher metamorphic temperatures, possibly related to depth of burial, and that the original hydrothermal fluids may of had a lower H2S/CO2 and/or higher temperatures.
224

Nepeněžité vklady / Non-monetary deposits

Rodová, Michaela January 2011 (has links)
This Master's thesis analyses the equity of companies, especially the non-monetary deposits into equity. The goal of the thesis is to describe the equity from the terms of harmonization of European Union and from the terms of Czech legislation, i.e. Commercial Code, Accounting Act and the related regulations. Non-monetary deposits are described in more detail in the terms of Czech law.
225

Individualização de subfáceis e alterações deutéricas do albita granito rico em F no depósito de Sn-Nb-Ta-ETR Madeira (Mina Pitinga, Amazonas)

Rodrigues, Juliano Nunes January 2018 (has links)
O albita granito de Pitinga, em geral porfirítico e de composição modal monzogranítica a granodiorítica, possui uma complexa variação mineralógica e petrográfica, resultante tanto de processos da transição magmático-hidrotermal, como de alterações deutéricas. O mapeamento da frente de lavra norte no contato das subfácies de borda (AGB) e de núcleo (AGN), a petrografia e geoquímica de amostras representativas revelam duas paragêneses parcialmente superpostas de alteração no AGB, uma marrom avermelhada com restos de mica verde rica em ferro e outra vermelha onde a mica verde foi completamente substituída por clorita e fluorita e/ou argila amarela. Adicionalmente o AGN cinza porfirítico é transformado gradualmente em porfirítico branco (AGNb), mais rico em albita; amarelo, quando argilizado por ilita e caulinita; com manchas localizadas de óxidos de ferro vermelhas, silicificado e criolitizado. No quartzo tardio (silicificação), foram encontradas inclusões fluidas primárias e pseudo-secundárias até então não descritas em fenocristais de quartzo do albita-granito Madeira de Pitinga, AM. Estas são bifásicas aquosas, eventualmente associadas com inclusões escuras gasosas. Ambos os tipos de inclusões bifásicas possuem temperaturas de homogeneização similares entre si variando entre 100 e 250°C e dois grupos de diferentes salinidades, um com valores em torno de 5% peso eq. NaCl e outro entre 15 e 23% peso eq. NaCl Considera-se que estas inclusões são representativas do fluido hidrotermal exsolvido a partir do magma durante um processo de resfriamento e queda de pressão. Este fluido possui as mesmas características físico-químicas descritas para o fluido responsável pela alteração hidrotermal do albita granito. Ambas subfácies AGB e AGN são cortadas por corpos irregulares brancos afaníticos compostos essencialmente por quartzo e albita. O padrão de ETR dos corpos afaníticos brancos é similar ao padrão do AGB e AGN, porém com a soma total de ETR menor, sugerindo cogeneticidade. A subfácies AGB resulta do resfriamento concêntrico da câmara magmática inicial produzindo uma borda que sofre alteração autometassomatica por fluidos deutéricos, criando os óxidos de ferro que lhe conferem uma cor marrom avermelhada. Com a continuação do resfriamento do magma, cristaliza-se o AGN cinza. Paralelamente, com a criação de um crystal mush e, em um possível processo de filter pressing, novos fluidos hidrotermais são gradualmente expelidos, precipitando o quartzo tardio intersticial no AGB ou com aspecto de fenocristal no AGN, e forma concentrados no centro do corpo, produzindo lentes maciças de criolita, provocando a alteração deutérica do AGN e talvez a fase branca afanítica. / The Madeira albite granite, located in Amazon state, northern Brazil, compositionally varying from monzogranite to granodiorite, has a complex mineralogical and petrographic diversity due both to magmatic-hydrothermal transition and deuteric alteration processes. North mining front geological mapping of the border subfacies (BAG) and core subfacies (CAG) contact, petrographic description and geochemical analysis of representative samples showed two partially superposed BAG alteration paragenesis, first one red-brown characterized by traces of green Fe rich mica and another red paragenisis where this green Fe-rich mica was replaced either by fluorite and chlorite or yellow clay. The porphyritic gray CAG is gradually transformed to a white porphyritic rock richer in albite; a yellow argillized illite and kaolinite rock; locally with red iron oxide spots, silicification and criolitization. In the late quartz (silicification), primary and Pseudo-secondary fluid inclusions were found in the quartz phenocrystals from the Madeira albite-granite, Pitinga, Amazonas State, Brazil. Both inclusions types are aqueous two-phased, sometimes associates to black vapor inclusions. Their homogenization temperatures range from 100 to 250°C and there are two salinities groups, one around 5 wt. % NaCl eq. and the other ranging from 15 to 23 wt. % NaCl eq They are considered as samples of the hydrothermal fluid exsolved during a magma cooling and decompression process. This fluid show the same physic-chemical characteristics described for the fluid responsible of the albite granite hydrothermal alteration. Both BAG and CAG subfacies are cut by irregular aphanitic white rock bodies essentially composed by quartz and albite. The REE pattern of these white aphanitic rocks is similar to BAG and CAG REE signature, but with lower total contents, suggesting that they are coeval. The BAG subfacies was the first formed during a concentric magmatic chamber cooling process, fluid exsolution allowed the autometasomatic deuteric alteration creating the red-brown iron oxides. The continuos magma chamber cooling could have created the gray CAG and, parallel to a crystal mush and filter pressing process, could have exsolved new deuteric fluids responsible for the new red BAG alterations, the late quartz (silicification) and cryolite lens deposition, local CAG deuteric alteration and also the white aphanitic phase.
226

The role of the alternative pathway of the complement system in the development of dense deposit disease

Abeleda, Maria Asuncion Abrera 01 July 2010 (has links)
Dense Deposit Disease (DDD) causes chronic renal dysfunction which progresses to end-stage renal disease in about half of patients within 10 years of diagnosis. Deficiency of and mutations in complement Factor H (CFH) are associated with the development of DDD, suggesting that dysregulation of the alternative pathway (AP) of the complement cascade is important in disease pathophysiology. Patients with DDD are studied to determine whether specific allele variants of the genes of the alternative pathway of the complement system segregate preferentially with the DDD. We have screened coding and intronic regions of genes of the complement system in DDD cases and controls using PCR, restriction digest and bidirectional sequencing. We have been able to identify novel mutations, allele variants and haplotypes in several genes of the complement system which are associated with the DDD phenotype based on statistical analyses. Since we have identified several genes associated with DDD, we have determined possible gene-gene interactions using computational analyses. We have found a strong synergistic interaction between polymorphisms in CFH and C3. To ascertain if the associated allele variants had a functional impact in the complement activity of an individual, we have obtained blood samples from normal individuals and measured AP complement activity and genotyped CFH and C3 for these samples. Association between AP activity and genotypes is analyzed using statistical methods. Significant association of CFH and C3 variants with AP complement activity has been observed. We also have generated a mice deficient of CFH and Factor D (CFD). CFH deficient mice develop renal pathology similar to DDD in humans. Renal function and complement activity have been determined in the double knockout in comparison to CFH deficient and CFD deficient mice. Results have shown that absence of Factor D can inhibit complement activation in CFH mice. Our data imply that DDD is a complex genetic disease and that genes of the AP complement system contribute to level of complement activity and the pathogenesis of DDD. With this study, we hope to develop an effective diagnosis and treatment plan for DDD patients.
227

Zdanění poskytnutí vkladů do základního kapitálu a mimo základní kapitál a zdanění výběru těchto vkladů / Taxation of the provision of contributions to share capital and outside share capital and taxation of these deposits

Růžička, Josef January 2021 (has links)
Taxation of the provision of contributions to share capital and outside share capital and taxation of these deposits - Abstract This diploma thesis describes the basic tax context in the case of deposits in the company and withdrawals from the company always in connection with equity. The diploma thesis focuses on domestic legal entities. It does not describe the connection with deposits in foreign companies. The diploma thesis is based on the domestic tax system. This system includes the following resources. Domestic regulations (laws that are affected by the so-called transcription of EU directives), international contracts (contracts of prevention of double taxation), domestic case law, and legitimate expectations outside the aforementioned sources. Legitimate expectations consist mainly of conveys from General Financial Directorate and minutes from the Coordinating Committees. The result of the performed analysis of documents is a summary of the basic tax context. The tax context includes the registration obligation (especially Value-added tax on the plant deposit), the notification obligation for payments abroad and the settlement of withheld tax. The key tax for non-monetary deposits is Value added tax. Non-monetary deposits by type are considered to be a service or goods according to ZDPH. The key...
228

Mineralogical characterization of oresamples of different pH in the Björkdal golddeposit, northern Sweden – implications formineral processing

Ekholm, Niklas January 2021 (has links)
The Björkdal gold deposit is situated in the Skellefte mining district, northern Sweden. The ore is mined from a complex system of quartz veins ranging from a few cm to a meter in width. The mineral processing steps at Björkdal comprises a flotation circuit, which performance is dependent on the pH of the ore feed. A total of ten samples from five different ore zones from the underground development was investigated with the purpose of improving the understanding of factors that causes the pH value of rock samples to vary which is deleterious to the metal recovery. The samples were investigated with optical microscopy together with scanning electron microscopy (SEM) and automated mineralogy (QEMSCAN) to carry out the modal mineralogy. The analyses identified a total of 37 different minerals in the samples. Chlorite was identified with significantly higher values in parts of the investigated ore zones and especially in the sample with the highest pH value, suggesting chlorite-hosting shear zones that crosscut the sampled ore zones to be a contributing factor that could be affecting the elevated pH values, resulting in a decreased recovery of gold.
229

Structural controls and associated alterations in the West Maurliden volcanic-hosted massive sulfide deposit, Skellefte district, northern Sweden

Zhivkov, Nikolay January 2021 (has links)
Volcanic-hosted massive sulfide (VMS) deposits are one of the main sources for zinc, copper, lead, silver and gold in Sweden. The majority of VMS deposits in Sweden are located in the Bergslagen region and the Skellefte district (Fig. 1). The Skellefte district hosts approximately 80 VMS deposits whereas 21 deposits have been mined since 1924 and 6 mines are currently in operation. VMS deposits tend to form more often on the intersection of the normal/reverse and transfer faults since there is an increased conductivity for hydrothermal fluids and increased fluid flow, so a structural interpretation of regional and deposit scale is important for exploration. The alteration patterns and mapped structures observed in the West Maurliden coincide with major structures found in the Skellefte district. Using this data and data from previous authors a general structural evolution of the Maurliden deposit has been constructed which shows the presumed outcome from the early extensional and later compressional stages ongoing in the region. Study of the mineralization shows that there is also the possibility to find mineralized rock within possible low strain blocks which might contain preserved primary textures and structures. A schematic plan view of the structure assemblage in the Skellefte district was established which shows perspective areas for future exploration.
230

Vlastnosti a aplikace vybraných anti-depozitních a anti-graffiti polymerních povlaků / Properties and application of anti-deposite and anti-graffiti polymer coatings

Linhartová, Daniela January 2009 (has links)
Properties of selected types of anti-deposit and anti-graffiti polymer coatings on selected background materials are presented. It is focused on drying value, hardness and adherence of protective coatings, as well as resistance of background material, anti-deposit and anti-graffiti coatings against selected solvents. Removability of selected deposits and graffiti from anti-deposit and anti-graffiti coatings by force of solvents is also evaluated.

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