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Eduardo Luís Carneiro De ,oliveira - One of the best experts on this subject based on the ideXlab platform.
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Caracterização de minerais pesados usados como indicadores de depósitos minerais na bacia hidrográfica do Ribeirão Maynart, Sul do Quadrilátero Ferrífero, MG.
2016Co-Authors: Eduardo Luís Carneiro De ,oliveiraAbstract:Programa de Pós-Graduação em Evolução Crustal e Recursos Naturais. Departamento de Geologia. Escola de Minas, Universidade Federal de Ouro Preto.O estudo de minerais indicadores é uma das mais antigas técnicas de exploração mineral usadas no mundo. Os minerais indicadores são espécimes minerais encontrados em grãos que são transportados em sedimentos clásticos e indicam a presença de afloramentos, à montante do ponto de coleta da amostra, que contém esses minerais e são associados à alguma mineralização, alteração hidrotermal ou litologia. Os minerais indicadores tem como característica propriedades físicas e químicas, como alta densidade, facilidade de preservação em ambientes de intemperismo químico e físico acentuados e fácil identificação visual, de modo que permite sua correlação com um grande número de depósitos minerais, tais como: ouro, diamante, Ni-Cu, EGP, depósitos de cobre pórfiro, sulfetos maciços e tungstênio. Na porção sul do Quadrilátero Ferrífero, dentre os depósitos minerais conhecidos de ferro, manganês, ouro, Cu-Au-Sb, Hg-Sb e minerais raros como topázio e euclásio, existe uma ocorrência mineral de diamante reportada desde o período colonial na bacia hidrográfica do ribeirão Maynart que é objeto de curiosidade científica. Uma vez que a região da bacia hidrográfica do ribeirão Maynart encontra-se em um contexto geotectônico favorável à ocorrência de fontes primárias diamantíferas, e em função do estudo de minerais indicadores ser amplamente usado na pesquisa de fontes primárias diamantíferas, esse trabalho dedicou-se ao emprego das técnicas exploratórias de identificação e caracterização de minerais pesados usados como indicadores de depósitos minerais com ênfase nos minerais associados à fontes primárias diamantíferas. Porém, também foram analisados minerais indicadores de depósitos de sulfetos maciços e/ou de alteração hidrotermal. Dentre os principais resultados foram identificados 34 espécimes minerais das quais 03 foram analisadas do ponto de vista químico para determinar o ambiente de cristalização e sua possível correlação com depósitos minerais conhecidos. Como mineral indicador de fonte primária diamantífera reconhecido na bacia hidrográfica do ribeirão Maynart destaca-se o diopsídio, que foi classificado como diopsídio sub-cálcico, derivado de um manto eclogítico e/ou peridotítico, encontrado como xenocristais em lamproíto. O diopsídio é um mineral que se altera muito facilmente em ambientes de intemperismo químico acentuado, portanto sua recuperação em amostras de concentrados de bateia indica que esse mineral encontra-se muito próximo à fonte. Além do diopsídio, também foram estudados gahnita e oxicalcioroméita. A gahnita é um espinélio zincífero que ocorre como mineral acessório em granitos e pegmatitos, em rochas metamórficas de médio para alto grau, em depósitos de sulfetos maciços metamorfizados e em placers como minerais pesados. A composição química dos cristais de gahnita encontradas nas amostras de minerais pesados coletados na bacia hidrográfica do ribeirão Maynart sugere que elas estejam associadas a depósitos metamorfizados de sulfetos maciços de zinco ou a rochas metassedimentares ricas em Fe-Al. A oxicalcioroméita é um titano-antimoniato extremamente raro, porém com uma relativa abundância na região de Ouro Preto, especialmente no córrego Tripuí aonde a oxicalcioroméita correlaciona-se a um depósito de cinábrio. Uma hipótese para a formação da oxicalcioromeíta encontrada na bacia hidrográfica do ribeirão Maynart é a associação com o depósito de Au-Cu-Sb de Bico de Pedra. Outro ponto que merece ser destacado é que a relação Sb-Hg, como é encontrado no córrego Tripuí, pode ser verificada em depósitos vulcanogênicos de sulfetos maciços (VMS) de zinco. Portanto a ocorrência de oxicalcioroméita associada à gahnita na bacia hidrográfica do ribeirão Maynart pode estar relacionado à um depósito de sulfeto maciço de zinco.The study of indicator minerals is one of the oldest technique used for mineral exploration in the world. Indicator minerals are mineral specimens found in grains that are transported in clastic sediments and indicate the presence of outcrops, which contains these minerals and are associated with mineralization, hydrothermal alteration and lithology. The indicator minerals has physical and chemical properties, such as high density, preservation in chemical and physical weathering environments and easy visual identification which allows their correlation with a large number of mineral deposits, such as gold, diamond, Ni -Cu, PGE, porphyry copper deposits, massive sulphide and tungsten. In the southern portion of the Iron Quadrangle several minerals deposits are known, like iron, manganese, gold, Cu- Au- Sb, Hg - Sb and gemstones. However, there is a diamond occurrence reported since the colonial period in the basin of Maynart creek that is scientific curiosity object. Once the Maynart creek region is located in a favourable tectonic setting to the occurrence of diamondiferous primary sources, and due to the indicator mineral study is widely used in research of diamond primary sources, this work focused in the characterization of indicator mineral with emphasis on diamond indicator minerals. However, it was also analyzed indicator minerals of massive sulphide deposits and/or hydrothermal alteration. In total were identified 34 mineral specimens, that's 03 were analyzed from a chemical point of view to determine the crystallization environment and its possible correlation with known mineral deposits. As diamondiferous indicator mineral highlights the diopside which was classified as sub-calc diopside, derived from a eclogitic and/or peridotitic mantle found in xenocrysts of lamproite. Once the diopside is a mineral that is changed very easily in severe chemical weathering environments, their recovery in concentrated samples of panning, indicates that the mineral phase is very close to the source. Besides the diopside were also studied Gahnite and oxicalcioromeite . The Gahnite is a zinciferous spinel occurs as accessory mineral in granites and pegmatites, in medium to high grade metamorphic rocks and metamorphosed massive sulphide deposits and placers as heavy minerals. The chemical composition of Gahnite found in the Maynart Creek suggests that they are associated with metamorphosed massive zinc sulfides deposits or rich Fe-Al metasedimentary rocks.The study of indicator minerals is one of the oldest technique used for mineral exploration in the world. Indicator minerals are mineral specimens found in grains that are transported in clastic sediments and indicate the presence of outcrops, which contains these minerals and are associated with mineralization, hydrothermal alteration and lithology. The indicator minerals has physical and chemical properties, such as high density, preservation in chemical and physical weathering environments and easy visual identification which allows their correlation with a large number of mineral deposits, such as gold, diamond, Ni -Cu, PGE, porphyry copper deposits, massive sulphide and tungsten. In the southern portion of the Iron Quadrangle several minerals deposits are known, like iron, manganese, gold, Cu- Au- Sb, Hg - Sb and gemstones. However, there is a diamond occurrence reported since the colonial period in the basin of Maynart creek that is scientific curiosity object. Once the Maynart creek region is located in a favourable tectonic setting to the occurrence of diamondiferous primary sources, and due to the indicator mineral study is widely used in research of diamond primary sources, this work focused in the characterization of indicator mineral with emphasis on diamond indicator minerals. However, it was also analyzed indicator minerals of massive sulphide deposits and/or hydrothermal alteration. In total were identified 34 mineral specimens, that's 03 were analyzed from a chemical point of view to determine the crystallization environment and its possible correlation with known mineral deposits. As diamondiferous indicator mineral highlights the diopside which was classified as sub-calc diopside, derived from a eclogitic and/or peridotitic mantle found in xenocrysts of lamproite. Once the diopside is a mineral that is changed very easily in severe chemical weathering environments, their recovery in concentrated samples of panning, indicates that the mineral phase is very close to the source. Besides the diopside were also studied Gahnite and oxicalcioromeite . The Gahnite is a zinciferous spinel occurs as accessory mineral in granites and pegmatites, in medium to high grade metamorphic rocks and metamorphosed massive sulphide deposits and placers as heavy minerals. The chemical composition of Gahnite found in the Maynart Creek suggests that they are associated with metamorphosed massive zinc sulfides deposits or rich Fe-Al metasedimentary rocks. The oxicalcioromeite is an extremely rare titano-antimoniate, but has a relative abundance in Ouro Preto, like the Tripuí creek that oxicalcioromeite is associated with a deposit of cinnabar. One hypothesis for the formation of oxicalcioromeite found in the Maynart creek is the association with the Au-Cu-Sb "Bico de Pedra" Deposit. Another point that deserves to be highlighted is that the Sb-Hg relationship, as found in Tripuí creek, can be seen in zinc VMS deposits. Therefore the occurrence of oxicalcioromeite associated with Gahnite in the samples of heavy minerals from Maynart creek may be related to a massive zinc sulfide deposit
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Caracterização de minerais pesados usados como indicadores de depósitos minerais na bacia hidrográfica do Ribeirão Maynart, Sul do Quadrilátero Ferrífero, MG.
2016Co-Authors: Eduardo Luís Carneiro De ,oliveiraAbstract:Programa de Pós-Graduação em Evolução Crustal e Recursos Naturais. Departamento de Geologia. Escola de Minas, Universidade Federal de Ouro Preto.Submitted by giuliana silveira (giulianagphoto@gmail.com) on 2016-09-21T18:05:09Z No. of bitstreams: 1 DISSERTAÇÃO_CaracterizaçãoMineraisPesados.pdf: 6085191 bytes, checksum: 6b97c0f6db9bfb19717d922288889b86 (MD5)Approved for entry into archive by Gracilene Carvalho (gracilene@sisbin.ufop.br) on 2016-09-26T17:47:08Z (GMT) No. of bitstreams: 1 DISSERTAÇÃO_CaracterizaçãoMineraisPesados.pdf: 6085191 bytes, checksum: 6b97c0f6db9bfb19717d922288889b86 (MD5)Made available in DSpace on 2016-09-26T17:47:41Z (GMT). No. of bitstreams: 1 DISSERTAÇÃO_CaracterizaçãoMineraisPesados.pdf: 6085191 bytes, checksum: 6b97c0f6db9bfb19717d922288889b86 (MD5) Previous issue date: 2016O estudo de minerais indicadores é uma das mais antigas técnicas de exploração mineral usadas no mundo. Os minerais indicadores são espécimes minerais encontrados em grãos que são transportados em sedimentos clásticos e indicam a presença de afloramentos, à montante do ponto de coleta da amostra, que contém esses minerais e são associados à alguma mineralização, alteração hidrotermal ou litologia. Os minerais indicadores tem como característica propriedades físicas e químicas, como alta densidade, facilidade de preservação em ambientes de intemperismo químico e físico acentuados e fácil identificação visual, de modo que permite sua correlação com um grande número de depósitos minerais, tais como: ouro, diamante, Ni-Cu, EGP, depósitos de cobre pórfiro, sulfetos maciços e tungstênio. Na porção sul do Quadrilátero Ferrífero, dentre os depósitos minerais conhecidos de ferro, manganês, ouro, Cu-Au-Sb, Hg-Sb e minerais raros como topázio e euclásio, existe uma ocorrência mineral de diamante reportada desde o período colonial na bacia hidrográfica do ribeirão Maynart que é objeto de curiosidade científica. Uma vez que a região da bacia hidrográfica do ribeirão Maynart encontra-se em um contexto geotectônico favorável à ocorrência de fontes primárias diamantíferas, e em função do estudo de minerais indicadores ser amplamente usado na pesquisa de fontes primárias diamantíferas, esse trabalho dedicou-se ao emprego das técnicas exploratórias de identificação e caracterização de minerais pesados usados como indicadores de depósitos minerais com ênfase nos minerais associados à fontes primárias diamantíferas. Porém, também foram analisados minerais indicadores de depósitos de sulfetos maciços e/ou de alteração hidrotermal. Dentre os principais resultados foram identificados 34 espécimes minerais das quais 03 foram analisadas do ponto de vista químico para determinar o ambiente de cristalização e sua possível correlação com depósitos minerais conhecidos. Como mineral indicador de fonte primária diamantífera reconhecido na bacia hidrográfica do ribeirão Maynart destaca-se o diopsídio, que foi classificado como diopsídio sub-cálcico, derivado de um manto eclogítico e/ou peridotítico, encontrado como xenocristais em lamproíto. O diopsídio é um mineral que se altera muito facilmente em ambientes de intemperismo químico acentuado, portanto sua recuperação em amostras de concentrados de bateia indica que esse mineral encontra-se muito próximo à fonte. Além do diopsídio, também foram estudados gahnita e oxicalcioroméita. A gahnita é um espinélio zincífero que ocorre como mineral acessório em granitos e pegmatitos, em rochas metamórficas de médio para alto grau, em depósitos de sulfetos maciços metamorfizados e em placers como minerais pesados. A composição química dos cristais de gahnita encontradas nas amostras de minerais pesados coletados na bacia hidrográfica do ribeirão Maynart sugere que elas estejam associadas a depósitos metamorfizados de sulfetos maciços de zinco ou a rochas metassedimentares ricas em Fe-Al. A oxicalcioroméita é um titano-antimoniato extremamente raro, porém com uma relativa abundância na região de Ouro Preto, especialmente no córrego Tripuí aonde a oxicalcioroméita correlaciona-se a um depósito de cinábrio. Uma hipótese para a formação da oxicalcioromeíta encontrada na bacia hidrográfica do ribeirão Maynart é a associação com o depósito de Au-Cu-Sb de Bico de Pedra. Outro ponto que merece ser destacado é que a relação Sb-Hg, como é encontrado no córrego Tripuí, pode ser verificada em depósitos vulcanogênicos de sulfetos maciços (VMS) de zinco. Portanto a ocorrência de oxicalcioroméita associada à gahnita na bacia hidrográfica do ribeirão Maynart pode estar relacionado à um depósito de sulfeto maciço de zinco.The study of indicator minerals is one of the oldest technique used for mineral exploration in the world. Indicator minerals are mineral specimens found in grains that are transported in clastic sediments and indicate the presence of outcrops, which contains these minerals and are associated with mineralization, hydrothermal alteration and lithology. The indicator minerals has physical and chemical properties, such as high density, preservation in chemical and physical weathering environments and easy visual identification which allows their correlation with a large number of mineral deposits, such as gold, diamond, Ni -Cu, PGE, porphyry copper deposits, massive sulphide and tungsten. In the southern portion of the Iron Quadrangle several minerals deposits are known, like iron, manganese, gold, Cu- Au- Sb, Hg - Sb and gemstones. However, there is a diamond occurrence reported since the colonial period in the basin of Maynart creek that is scientific curiosity object. Once the Maynart creek region is located in a favourable tectonic setting to the occurrence of diamondiferous primary sources, and due to the indicator mineral study is widely used in research of diamond primary sources, this work focused in the characterization of indicator mineral with emphasis on diamond indicator minerals. However, it was also analyzed indicator minerals of massive sulphide deposits and/or hydrothermal alteration. In total were identified 34 mineral specimens, that's 03 were analyzed from a chemical point of view to determine the crystallization environment and its possible correlation with known mineral deposits. As diamondiferous indicator mineral highlights the diopside which was classified as sub-calc diopside, derived from a eclogitic and/or peridotitic mantle found in xenocrysts of lamproite. Once the diopside is a mineral that is changed very easily in severe chemical weathering environments, their recovery in concentrated samples of panning, indicates that the mineral phase is very close to the source. Besides the diopside were also studied Gahnite and oxicalcioromeite . The Gahnite is a zinciferous spinel occurs as accessory mineral in granites and pegmatites, in medium to high grade metamorphic rocks and metamorphosed massive sulphide deposits and placers as heavy minerals. The chemical composition of Gahnite found in the Maynart Creek suggests that they are associated with metamorphosed massive zinc sulfides deposits or rich Fe-Al metasedimentary rocks.The study of indicator minerals is one of the oldest technique used for mineral exploration in the world. Indicator minerals are mineral specimens found in grains that are transported in clastic sediments and indicate the presence of outcrops, which contains these minerals and are associated with mineralization, hydrothermal alteration and lithology. The indicator minerals has physical and chemical properties, such as high density, preservation in chemical and physical weathering environments and easy visual identification which allows their correlation with a large number of mineral deposits, such as gold, diamond, Ni -Cu, PGE, porphyry copper deposits, massive sulphide and tungsten. In the southern portion of the Iron Quadrangle several minerals deposits are known, like iron, manganese, gold, Cu- Au- Sb, Hg - Sb and gemstones. However, there is a diamond occurrence reported since the colonial period in the basin of Maynart creek that is scientific curiosity object. Once the Maynart creek region is located in a favourable tectonic setting to the occurrence of diamondiferous primary sources, and due to the indicator mineral study is widely used in research of diamond primary sources, this work focused in the characterization of indicator mineral with emphasis on diamond indicator minerals. However, it was also analyzed indicator minerals of massive sulphide deposits and/or hydrothermal alteration. In total were identified 34 mineral specimens, that's 03 were analyzed from a chemical point of view to determine the crystallization environment and its possible correlation with known mineral deposits. As diamondiferous indicator mineral highlights the diopside which was classified as sub-calc diopside, derived from a eclogitic and/or peridotitic mantle found in xenocrysts of lamproite. Once the diopside is a mineral that is changed very easily in severe chemical weathering environments, their recovery in concentrated samples of panning, indicates that the mineral phase is very close to the source. Besides the diopside were also studied Gahnite and oxicalcioromeite . The Gahnite is a zinciferous spinel occurs as accessory mineral in granites and pegmatites, in medium to high grade metamorphic rocks and metamorphosed massive sulphide deposits and placers as heavy minerals. The chemical composition of Gahnite found in the Maynart Creek suggests that they are associated with metamorphosed massive zinc sulfides deposits or rich Fe-Al metasedimentary rocks. The oxicalcioromeite is an extremely rare titano-antimoniate, but has a relative abundance in Ouro Preto, like the Tripuí creek that oxicalcioromeite is associated with a deposit of cinnabar. One hypothesis for the formation of oxicalcioromeite found in the Maynart creek is the association with the Au-Cu-Sb "Bico de Pedra" Deposit. Another point that deserves to be highlighted is that the Sb-Hg relationship, as found in Tripuí creek, can be seen in zinc VMS deposits. Therefore the occurrence of oxicalcioromeite associated with Gahnite in the samples of heavy minerals from Maynart creek may be related to a massive zinc sulfide deposit
Hala Zreiqat - One of the best experts on this subject based on the ideXlab platform.
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silk coating on a bioactive ceramic scaffold for bone regeneration effective enhancement of mechanical and in vitro osteogenic properties towards load bearing applications
Journal of Tissue Engineering and Regenerative Medicine, 2017Co-Authors: Jiao Jiao Li, Seyediman Roohaniesfahani, David L Kaplan, Hala ZreiqatAbstract:Bioactive ceramic scaffolds represent competitive choices for clinical bone reconstruction, but their widespread use is restricted by inherent brittleness and weak mechanical performance under load. This study reports the development of strong and tough bioactive scaffolds suitable for use in load-bearing bone reconstruction. A strong and bioactive ceramic scaffold (strontium-hardystonite-Gahnite) is combined with single and multiple coating layers of silk fibroin to enhance its toughness, producing composite scaffolds which match the mechanical properties of cancellous bone and show enhanced capacity to promote in vitro osteogenesis. Also reported for the first time is a comparison of the coating effects obtained when a polymeric material is coated on ceramic scaffolds with differing microstructures, namely the strontium-hardystonite-Gahnite scaffold with high-density struts as opposed to a conventional ceramic scaffold, such as biphasic calcium phosphate, with low-density struts. The results show that silk coating on a unique ceramic scaffold can lead to simple and effective enhancement of its mechanical and biological properties to suit a wider range of applications in clinical bone reconstruction, and also establish the influence of ceramic microstructure on the effectiveness of silk coating as a method of reinforcement when applied to different types of ceramic bone graft substitutes. Copyright © 2015 John Wiley & Sons, Ltd.
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Fracture behaviors of ceramic tissue scaffolds for load bearing applications.
Scientific Reports, 2016Co-Authors: Ali Entezari, Hala Zreiqat, Seyed-iman Roohani-esfahani, Zhongpu Zhang, Colin R. Dunstan, Qing LiAbstract:Healing large bone defects, especially in weight-bearing locations, remains a challenge using available synthetic ceramic scaffolds. Manufactured as a scaffold using 3D printing technology, Sr-HT-Gahnite at high porosity (66%) had demonstrated significantly improved compressive strength (53 ± 9 MPa) and toughness. Nevertheless, the main concern of ceramic scaffolds in general remains to be their inherent brittleness and low fracture strength in load bearing applications. Therefore, it is crucial to establish a robust numerical framework for predicting fracture strengths of such scaffolds. Since crack initiation and propagation plays a critical role on the fracture strength of ceramic structures, we employed extended finite element method (XFEM) to predict fracture behaviors of Sr-HT-Gahnite scaffolds. The correlation between experimental and numerical results proved the superiority of XFEM for quantifying fracture strength of scaffolds over conventional FEM. In addition to computer aided design (CAD) based modeling analyses, XFEM was conducted on micro-computed tomography (μCT) based models for fabricated scaffolds, which took into account the geometric variations induced by the fabrication process. Fracture strengths and crack paths predicted by the μCT-based XFEM analyses correlated well with relevant experimental results. The study provided an effective means for the prediction of fracture strength of porous ceramic structures, thereby facilitating design optimization of scaffolds.
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fabrication and characterization of a new strong and bioactive ceramic scaffold for bone regeneration
Materials Letters, 2013Co-Authors: Seyediman Roohaniesfahani, Yongjuan Chen, Jeffrey Shi, Hala ZreiqatAbstract:Abstract In this study we developed new ceramic compositions with competent mechanical properties at highly porous state. Strontium(Sr) doped hardystonite(Ca 2 ZnSi 2 O 7 ) powder was mixed with aluminium oxide(Al 2 O 3 ) powder of different weight fractions(0, 5, 10, 15 and 30 wt%) and the resultant ceramic labelled as SH, SH5, SH10, SH15 and SH30, respectively. Polymer sponge method was used to prepare the different ceramic scaffolds. Developed ceramics showed a unique microstructure consisted of three phases of (1) Sr doped Ca 2 ZnSi 2 O 7 grains, (2) a wetting glass phase at the grain boundaries and (3) submicron crystals of ZnAl 2 O 4 (Gahnite) embedded in the glass phase. The scaffolds at 85% porosity, average pore size of 400 µm and ∼100% interconnectivity between the pores, achieved a compressive strength range of 0.8–4.1 MPa, modulus range of 48–173 MPa and failure strain range of 0.4–3.1%. In-vitro cytotoxicity results not only indicated the biocompatibility of these scaffolds, but also their positive effects on inducing the proliferation of primary human osteoblasts (HOBs).
Sheida Makvandi - One of the best experts on this subject based on the ideXlab platform.
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PCA of Fe-oxides MLA data as an advanced tool in provenance discrimination and indicator mineral exploration : case study from bedrock and till from the Kiggavik U deposits area (Nunavut, Canada)
Journal of Geochemical Exploration, 2019Co-Authors: Sheida Makvandi, Georges Beaudoin, M. Beth Mcclenaghan, David Quirt, Patrick LedruAbstract:Abstract Magnetite and hematite grains from the 0.25–0.5 mm and 0.5–2.0 mm ferromagnetic fractions of ten till samples collected up-ice, overlying and down-ice of the Kiggavik U deposits (Nunavut, Canada), as well as eight bedrock samples from Kiggavik igneous and metasedimentary basement and overlying sedimentary rocks were characterized for their grain size and mineral association using optical microscopy, scanning electron microscopy (SEM) and mineral liberation analysis (MLA). Principal component analysis (PCA) was used to evaluate the MLA data for Fe-oxide mineral association and grain size distribution. PCA shows that mineralogical and granulometric differences in Fe-oxides from Kiggavik igneous rocks distinguish them from that of Kiggavik metasedimentary and sedimentary rocks. In addition, The PCA results indicate that the composition and abundance of minerals associated/intergrown with Fe-oxides are not only different in various till samples, but also in different size fractions of the same sample. Higher proportions of hornblende, quartz, Gahnite, grunerite, apatite, chromite and sulfides are intergrown with Fe-oxides in the 0.5–2.0 mm till fraction, as compared to the 0.25–0.5 mm fraction in which Fe-oxides are mostly associated with pyroxene, titanite, rutile, feldspars, calcite and zircon. The mineral associations and grain sizes of proximal bedrocks are reflected in smaller size fractions of Kiggavik till, whereas detrital grains in the 0.5–2.0 mm fraction of Kiggavik till may have originated from distal sources. PCA also shows that Fe-oxides from the Kiggavik bedrock and till can be discriminated from those of volcanogenic massive sulfide (VMS) deposits because of smaller grain sizes and higher abundances of sulfides, Gahnite, axinite, corundum, hypersthene and pyroxene intergrown with VMS Fe-oxides. This study emphasizes the importance of selecting suitable representative grain size fractions of till, or other sediments, when using indicator minerals for exploration. The results of PCA of Fe-oxides MLA data are consistent with the results of using Fe-oxides geochemical data in provenance discrimination of Kiggavik till.
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principal component analysis of magnetite composition from volcanogenic massive sulfide deposits case studies from the izok lake nunavut canada and halfmile lake new brunswick canada deposits
Ore Geology Reviews, 2016Co-Authors: Sheida Makvandi, Massoud Ghasemzadehbarvarz, Eric C Grunsky, Beth M Mcclenaghan, Georges Beaudoin, Carl DuchesneAbstract:Abstract Magnetite grains from the Izok Lake (Nunavut, Canada) and the Halfmile Lake (New Brunswick, Canada) volcanogenic massive sulfide deposits, and from till covering the nearby areas were investigated using the scanning electron microscopy (SEM), electron probe micro-analyzer (EPMA), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), and optical microscopy. The method of robust estimation for compositional data (rob-composition) was applied to censored geochemical data, and the results were analyzed by principal component analysis (PCA). Textural relationships and mineral association of magnetite reveal the history of formation, and contribute to the explanation of characteristic compositional differences of magnetite from different geological settings. The integration of petrography and mineral chemistry allows discriminating magmatic, metamorphic and hydrothermal magnetite grains in the VMS deposits bedrock samples. Magmatic magnetite is found in Izok Lake gabbro, and Halfmile Lake syenite, felsic ash tuff and gossan samples, whereas magnetite in Izok Lake massive sulfides, Gahnite-rich dacite and iron formations formed during the amphibolite facies metamorphism. In Halfmile Lake andesite, magnetite recrystallized during greenschist facies metamorphism. In the magnetite alteration zone associated to the Halfmile Lake deposit, hydrothermal magnetite has been overprinted by metamorphic magnetite. Halfmile Lake massive sulfides in chloritic argillite contain hydrothermal magnetite. PCA identifies discriminator elements and their contributions to magnetite composition from different Izok Lake Lake and Halfmile Lake bedrock samples. The results suggest that Si, Ca, Zr, Al, Ga, Mn, Mg, Ti, Zn, Co, Ni and Cr are discriminator elements for VMS deposits and their host bedrocks. The distinct chemical signatures for magnetite from various bedrock lithologies demonstrate that magnetite grains of the same origin share more similarities in chemistry, as high Ti indicates magmatic sources for magnetite, whereas high Si, Ca and Mg are indicative of hydrothermal settings. Variable compositions of metamorphic magnetite suggest that the chemistry of this type of magnetite is controlled by the composition of host rocks, the grade of metamorphism and oxygen fugacity. PCA of EPMA and LA-ICP-MS data of magnetite from the Izok Lake and Halfmile Lake bedrock samples yield discrimination models for classification of magnetite grains from till. Decreases in the proportion of magnetite grains with the chemical signature of the Izok Lake massive sulfides and Gahnite-rich dacite down-ice from the Izok Lake deposit show the use of magnetite chemistry in geochemical exploration. In the Halfmile Lake area, till magnetite grains with the signature of VMS mineralization make a glacial dispersal train more than 2 km down-ice from the deposit.
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the surface texture and morphology of magnetite from the izok lake volcanogenic massive sulfide deposit and local glacial sediments nunavut canada application to mineral exploration
Journal of Geochemical Exploration, 2015Co-Authors: Sheida Makvandi, Beth M Mcclenaghan, Georges Beaudoin, Daniel LaytonmatthewsAbstract:Abstract Magnetite is a common mineral found in a wide range of mineral deposits and in different geological environments. The study of surface textures and morphology of magnetite can provide information that is useful to 1) discriminate different types of magnetite such as that attributed to magmatic, metamorphic and supergene environments, 2) identify host bedrocks, 3) sediment provenance, and 4) recognize chemical and mechanical processes affecting grains during erosion, transport, and after deposition in sedimentary environments. In this study, magnetite grains from the Izok Lake volcanogenic massive sulfide deposit (Nunavut, Canada) and from till covering the area have been investigated using scanning electron microscopy, mineral liberation analysis, and optical microscopy to document their mineral associations, surface textures, grain shape and size distribution. Evidences such as 1) contact relations between magnetite and sphalerite, 2) sphalerite and chalcopyrite inclusions in magnetite, and 3) intergrowths of magnetite with actinolite and Gahnite suggest that in Izok Lake deposit and related Gahnite-rich stringer zone, magnetite formed by replacement of sulfide minerals during regional, upper greenschist to amphibolite facies metamorphism. Magnetite from iron formation also formed as a result of oxidation–dissolution of almandine, or breakdown of Fe-bearing minerals during metamorphism. Euhedral, fine-grained magmatic magnetite in association with ilmenite, plagioclase and hornblende was identified in bedrock gabbro. Magnetite overgrowths on the surface of existing magnetite and other metamorphic minerals fingerprinted the supergene processes affecting bedrocks and sediments after metamorphism. Magnetite in till around the Izok Lake deposit is mostly imprinted by mechanical microtextures such as crescentic gouges, deep grooves, arc-shaped steps, and troughs that are diagnostic of transportation by thick continental ice sheets. A small proportion of magnetite grains characterized by V-shaped percussion cracks also indicate transportation by fluvial and/or glaciofluvial environments. Shape, grain-size distribution, and mineral association of magnetite in till suggest that in vicinity of the Izok Lake deposit, till has mainly been fed by the deposit and related alteration zones, though, a high proportion of grains have been derived from iron formations, bedrock gabbro, and Mackenzie dikes.
Georges Beaudoin - One of the best experts on this subject based on the ideXlab platform.
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PCA of Fe-oxides MLA data as an advanced tool in provenance discrimination and indicator mineral exploration : case study from bedrock and till from the Kiggavik U deposits area (Nunavut, Canada)
Journal of Geochemical Exploration, 2019Co-Authors: Sheida Makvandi, Georges Beaudoin, M. Beth Mcclenaghan, David Quirt, Patrick LedruAbstract:Abstract Magnetite and hematite grains from the 0.25–0.5 mm and 0.5–2.0 mm ferromagnetic fractions of ten till samples collected up-ice, overlying and down-ice of the Kiggavik U deposits (Nunavut, Canada), as well as eight bedrock samples from Kiggavik igneous and metasedimentary basement and overlying sedimentary rocks were characterized for their grain size and mineral association using optical microscopy, scanning electron microscopy (SEM) and mineral liberation analysis (MLA). Principal component analysis (PCA) was used to evaluate the MLA data for Fe-oxide mineral association and grain size distribution. PCA shows that mineralogical and granulometric differences in Fe-oxides from Kiggavik igneous rocks distinguish them from that of Kiggavik metasedimentary and sedimentary rocks. In addition, The PCA results indicate that the composition and abundance of minerals associated/intergrown with Fe-oxides are not only different in various till samples, but also in different size fractions of the same sample. Higher proportions of hornblende, quartz, Gahnite, grunerite, apatite, chromite and sulfides are intergrown with Fe-oxides in the 0.5–2.0 mm till fraction, as compared to the 0.25–0.5 mm fraction in which Fe-oxides are mostly associated with pyroxene, titanite, rutile, feldspars, calcite and zircon. The mineral associations and grain sizes of proximal bedrocks are reflected in smaller size fractions of Kiggavik till, whereas detrital grains in the 0.5–2.0 mm fraction of Kiggavik till may have originated from distal sources. PCA also shows that Fe-oxides from the Kiggavik bedrock and till can be discriminated from those of volcanogenic massive sulfide (VMS) deposits because of smaller grain sizes and higher abundances of sulfides, Gahnite, axinite, corundum, hypersthene and pyroxene intergrown with VMS Fe-oxides. This study emphasizes the importance of selecting suitable representative grain size fractions of till, or other sediments, when using indicator minerals for exploration. The results of PCA of Fe-oxides MLA data are consistent with the results of using Fe-oxides geochemical data in provenance discrimination of Kiggavik till.
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principal component analysis of magnetite composition from volcanogenic massive sulfide deposits case studies from the izok lake nunavut canada and halfmile lake new brunswick canada deposits
Ore Geology Reviews, 2016Co-Authors: Sheida Makvandi, Massoud Ghasemzadehbarvarz, Eric C Grunsky, Beth M Mcclenaghan, Georges Beaudoin, Carl DuchesneAbstract:Abstract Magnetite grains from the Izok Lake (Nunavut, Canada) and the Halfmile Lake (New Brunswick, Canada) volcanogenic massive sulfide deposits, and from till covering the nearby areas were investigated using the scanning electron microscopy (SEM), electron probe micro-analyzer (EPMA), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), and optical microscopy. The method of robust estimation for compositional data (rob-composition) was applied to censored geochemical data, and the results were analyzed by principal component analysis (PCA). Textural relationships and mineral association of magnetite reveal the history of formation, and contribute to the explanation of characteristic compositional differences of magnetite from different geological settings. The integration of petrography and mineral chemistry allows discriminating magmatic, metamorphic and hydrothermal magnetite grains in the VMS deposits bedrock samples. Magmatic magnetite is found in Izok Lake gabbro, and Halfmile Lake syenite, felsic ash tuff and gossan samples, whereas magnetite in Izok Lake massive sulfides, Gahnite-rich dacite and iron formations formed during the amphibolite facies metamorphism. In Halfmile Lake andesite, magnetite recrystallized during greenschist facies metamorphism. In the magnetite alteration zone associated to the Halfmile Lake deposit, hydrothermal magnetite has been overprinted by metamorphic magnetite. Halfmile Lake massive sulfides in chloritic argillite contain hydrothermal magnetite. PCA identifies discriminator elements and their contributions to magnetite composition from different Izok Lake Lake and Halfmile Lake bedrock samples. The results suggest that Si, Ca, Zr, Al, Ga, Mn, Mg, Ti, Zn, Co, Ni and Cr are discriminator elements for VMS deposits and their host bedrocks. The distinct chemical signatures for magnetite from various bedrock lithologies demonstrate that magnetite grains of the same origin share more similarities in chemistry, as high Ti indicates magmatic sources for magnetite, whereas high Si, Ca and Mg are indicative of hydrothermal settings. Variable compositions of metamorphic magnetite suggest that the chemistry of this type of magnetite is controlled by the composition of host rocks, the grade of metamorphism and oxygen fugacity. PCA of EPMA and LA-ICP-MS data of magnetite from the Izok Lake and Halfmile Lake bedrock samples yield discrimination models for classification of magnetite grains from till. Decreases in the proportion of magnetite grains with the chemical signature of the Izok Lake massive sulfides and Gahnite-rich dacite down-ice from the Izok Lake deposit show the use of magnetite chemistry in geochemical exploration. In the Halfmile Lake area, till magnetite grains with the signature of VMS mineralization make a glacial dispersal train more than 2 km down-ice from the deposit.
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the surface texture and morphology of magnetite from the izok lake volcanogenic massive sulfide deposit and local glacial sediments nunavut canada application to mineral exploration
Journal of Geochemical Exploration, 2015Co-Authors: Sheida Makvandi, Beth M Mcclenaghan, Georges Beaudoin, Daniel LaytonmatthewsAbstract:Abstract Magnetite is a common mineral found in a wide range of mineral deposits and in different geological environments. The study of surface textures and morphology of magnetite can provide information that is useful to 1) discriminate different types of magnetite such as that attributed to magmatic, metamorphic and supergene environments, 2) identify host bedrocks, 3) sediment provenance, and 4) recognize chemical and mechanical processes affecting grains during erosion, transport, and after deposition in sedimentary environments. In this study, magnetite grains from the Izok Lake volcanogenic massive sulfide deposit (Nunavut, Canada) and from till covering the area have been investigated using scanning electron microscopy, mineral liberation analysis, and optical microscopy to document their mineral associations, surface textures, grain shape and size distribution. Evidences such as 1) contact relations between magnetite and sphalerite, 2) sphalerite and chalcopyrite inclusions in magnetite, and 3) intergrowths of magnetite with actinolite and Gahnite suggest that in Izok Lake deposit and related Gahnite-rich stringer zone, magnetite formed by replacement of sulfide minerals during regional, upper greenschist to amphibolite facies metamorphism. Magnetite from iron formation also formed as a result of oxidation–dissolution of almandine, or breakdown of Fe-bearing minerals during metamorphism. Euhedral, fine-grained magmatic magnetite in association with ilmenite, plagioclase and hornblende was identified in bedrock gabbro. Magnetite overgrowths on the surface of existing magnetite and other metamorphic minerals fingerprinted the supergene processes affecting bedrocks and sediments after metamorphism. Magnetite in till around the Izok Lake deposit is mostly imprinted by mechanical microtextures such as crescentic gouges, deep grooves, arc-shaped steps, and troughs that are diagnostic of transportation by thick continental ice sheets. A small proportion of magnetite grains characterized by V-shaped percussion cracks also indicate transportation by fluvial and/or glaciofluvial environments. Shape, grain-size distribution, and mineral association of magnetite in till suggest that in vicinity of the Izok Lake deposit, till has mainly been fed by the deposit and related alteration zones, though, a high proportion of grains have been derived from iron formations, bedrock gabbro, and Mackenzie dikes.
Seyediman Roohaniesfahani - One of the best experts on this subject based on the ideXlab platform.
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silk coating on a bioactive ceramic scaffold for bone regeneration effective enhancement of mechanical and in vitro osteogenic properties towards load bearing applications
Journal of Tissue Engineering and Regenerative Medicine, 2017Co-Authors: Jiao Jiao Li, Seyediman Roohaniesfahani, David L Kaplan, Hala ZreiqatAbstract:Bioactive ceramic scaffolds represent competitive choices for clinical bone reconstruction, but their widespread use is restricted by inherent brittleness and weak mechanical performance under load. This study reports the development of strong and tough bioactive scaffolds suitable for use in load-bearing bone reconstruction. A strong and bioactive ceramic scaffold (strontium-hardystonite-Gahnite) is combined with single and multiple coating layers of silk fibroin to enhance its toughness, producing composite scaffolds which match the mechanical properties of cancellous bone and show enhanced capacity to promote in vitro osteogenesis. Also reported for the first time is a comparison of the coating effects obtained when a polymeric material is coated on ceramic scaffolds with differing microstructures, namely the strontium-hardystonite-Gahnite scaffold with high-density struts as opposed to a conventional ceramic scaffold, such as biphasic calcium phosphate, with low-density struts. The results show that silk coating on a unique ceramic scaffold can lead to simple and effective enhancement of its mechanical and biological properties to suit a wider range of applications in clinical bone reconstruction, and also establish the influence of ceramic microstructure on the effectiveness of silk coating as a method of reinforcement when applied to different types of ceramic bone graft substitutes. Copyright © 2015 John Wiley & Sons, Ltd.
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fabrication and characterization of a new strong and bioactive ceramic scaffold for bone regeneration
Materials Letters, 2013Co-Authors: Seyediman Roohaniesfahani, Yongjuan Chen, Jeffrey Shi, Hala ZreiqatAbstract:Abstract In this study we developed new ceramic compositions with competent mechanical properties at highly porous state. Strontium(Sr) doped hardystonite(Ca 2 ZnSi 2 O 7 ) powder was mixed with aluminium oxide(Al 2 O 3 ) powder of different weight fractions(0, 5, 10, 15 and 30 wt%) and the resultant ceramic labelled as SH, SH5, SH10, SH15 and SH30, respectively. Polymer sponge method was used to prepare the different ceramic scaffolds. Developed ceramics showed a unique microstructure consisted of three phases of (1) Sr doped Ca 2 ZnSi 2 O 7 grains, (2) a wetting glass phase at the grain boundaries and (3) submicron crystals of ZnAl 2 O 4 (Gahnite) embedded in the glass phase. The scaffolds at 85% porosity, average pore size of 400 µm and ∼100% interconnectivity between the pores, achieved a compressive strength range of 0.8–4.1 MPa, modulus range of 48–173 MPa and failure strain range of 0.4–3.1%. In-vitro cytotoxicity results not only indicated the biocompatibility of these scaffolds, but also their positive effects on inducing the proliferation of primary human osteoblasts (HOBs).
