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The quartz dioritic Quottoon Igneous Complex (QIC) is a major Paleogene (65-56 Ma) magmatic body in NW British Columbia and SE Alaska that was emplaced along the Coast shear zone (CSZ). The QIC contains two different igneous suites that provide information about source regions, magmatic processes and evolving tectonic regimes that changed from a dominantly convergent to a dominantly strike-slip regime between 65 to 55 Ma. Heterogeneous suite I rocks (e. g. along Steamer Passage) have a pervasive solid-state fabric, abundant mafic enclaves and dikes, metasedimentary screens, and variable color indices (25-50). The homogeneous suite II rocks (e. g. along Quottoon Inlet) have a weak (to absent) fabric developed in the magmatic state (aligned feldspars, melt filled shears), and more uniform color indices (24-34) than in suite I. Suite I rocks have Sr concentrations <750 ppm, avg. LaN/YbN = 10.4, and initial 87Sr/86Sr ratios that range from 0.70513 to 0.70717. The suite II rocks have Sr concentrations >750 ppm, avg. LaN/YbN = 23.1, and initial 87Sr/86Sr ratios that range from 0.70617 to 0.70686. This study proposes that the parental QIC magma (initial 87Sr/86Sr = 0.706) can be derived bypartial melting of an amphibolitic source reservoir at lower crustal conditions. Geochemical data (Rb, Sr, Ba and LaN/YbN) and initial 87Sr/86Sr ratios preclude linkages between the two suites by fractional crystallization or assimilation and fractional crystallization (AFC) processes. The suite I rocks are interpreted to be the result of magma mixing between the QIC parental magma and a mantle derived magma. The samples do not lie along a single mixing line due to continued evolution through fractional crystallization/AFC processes subsequent to magma mixing. The suite II rocks may be generated by AFC. Initial 87Sr/86Sr ratio data suggests that similar processes to those that affected the QIC may also have operated during the generation of other portions of the Great Tonalite Sill of southeast Alaska. / Master of Science

No / Mineral waters in Britain show a wide range of 87Sr/86Sr isotope compositions ranging between 87Sr/86Sr = 0.7059 from Carboniferous volcanic rock sources in Dunbartonshire, Scotland to 87Sr/86Sr = 0.7207 in the Dalradian aquifer of Aberdeenshire, Scotland. The 87Sr/86Sr composition of the waters shows a general correlation with the aquifer rocks, resulting in the waters from older rocks having a more radiogenic signature than those from younger rocks. This wide range of values means that the Sr isotope composition of mineral water has applications in a number of types of studies. In the modern commercial context, it provides a way of fingerprinting the various mineral waters and hence provides a method for recognising and reducing fraud. From an environmental perspective, it provides the first spatial distribution of bio-available 87Sr/86Sr in Britain that can be used in modern, historical and archaeological studies

O Quadrilátero Ferrífero (MG) é uma importante unidade geotectônica do Cráton do São Francisco que alberga jazidas de ferro e ouro hospedadas na seqüência greenstone belt Rio das Velhas e cuja evolução geodinâmica esteve regida por vários eventos tectonometamórficos. Depósitos de ouro gerados por fluidos epitermais e remobilizações orogênicas proterozóicas se associam intimamente com camadas bandas de ferro e raramente disseminados em metapelitos no topo do greenstone. Nas mineralizações é comum uma paragênese que cristalizou mediante diversos processos e em distintos estágios com predomínio de sulfetos de ferro. Em geral os minérios possuem forte controle estrutural por dobras, falhas e cisalhamentos transcorrentes, desenvolvidos durante vários eventos deformacionais de diversa índole e estreita relação com processos de alteração hidrotermal como sericitização, carbonatação, cloritização, entre outros de menor incidência. O depósito de ouro Córrego do Sítio hospeda-se na seqüência silisiclástica de origem turbidítica metamorfisada em fácies xisto verde denominada Associação de Litofácies Ressedimentada que faz parte do Grupo Nova Lima, se apresenta disseminado em metapelitos e em veios de quartzo com carbonato. A mineralização que acompanha o ouro cristalizou em vários estágios principais nos que predominaram (i) pirita + pirrotita, (ii) arsenopirita + pirrotita + pirita com texturas finas e orientadas, (iii) arsenopirita com pirrotita e sulfosais em veios de quartzo, (iv) pirita grossa pervasiva em todas as rochas hospedeiras. O estudo da composição isotópica Pb, Sr e Nd, permitiu identificar que as fontes dos fluidos mineralizantes foram as rochas hospedeiras, que na evolução policíclica da mineralização participaram eventos metamórficos e hidrotermais a 2.2, 2.0 Ga. e sobreimpostos a ~600 Ma. os quais induziram os processos de circulação hidrotermal na área de estudo. Mediante comparativa com outros depósitos da região, sugere-se que os metais formadores do minério depositaram-se em Córrego do Sítio à idade de 2.2 Ga. originados a partir da BIF tipo São Bento e remobilizados por fluidos através de falhas inversas. Análises geocronológicas U-Pb (SHRIMP) e K-Ar embora não decisivos em quanto à determinação da idade da mineralização, revelaram a idade de ~2.7 Ga. como o limite temporal para a deposição das rochas hospedeiras. No contexto geológico aplicado se estabelece a potencialidade para a prospecção aurífera que apresentam as rochas metapelíticas do topo do Greenstone Belt Rio das Velas associadas a camadas bandadas de ferro com ouro, e que os alvos mais relevantes seriam zonas com falhas inversas e cisalhamentos transcorrentes. / The Quadrilátero Ferrífero is an important geotectonic unit of the São Francisco Craton that host iron and gold deposits within the vulcanosedimentary rocks of the greenstone belt Rio das Velhas. The geodynamic evolution of this greenstone includes several tectonometamorphic events. Gold deposits were formed by epithermal fluids, remobilized during the Proterozoic orogenic processes, are associated whit the banded iron formations and are sporadically disseminate in metapelitic rocks within the top of the greenstone sequence. In the ores is common the crystallization of iron sulfide minerals during diverse stages. Gold deposits have an important structural control by folds, reverse faults and strike-slip shearing zones, and are commons several hydrothermal alteration processes like sericitization, chloritization and carbonate usually related to the deformation. The Córrego do Sítio gold deposit is hosted in turbiditic siliciclastic rocks that are metamorphosed in the greenschist facies. The gold is associated with the iron sulfide arsenopyrite and pyrite, which are disseminated in metapelitic rocks and quartz-carbonate veins. The mineralization includes vary stages of crystallization, (1) pyrite and pyrrotite (2) arsenopyrite, pyrrotite and fine pyrite, (3) arsenopyrite whit pyrrotite and sulphosalts in quartz vein, and (4) pervasive pyrite. An integrated Pb, Sr e Nd, isotopic study of the Córrego do Sítio deposit allowed to identify that sources of the mineralizing fluids was the host rocks, that in the policiclic evolution the gold mineralizaton had participation events of metamorphism and hidrothermalism to age 2.2, 2.0 and 0.6 Ga. respectively the wich induced the hydrothermal circulation processes in the study area. The isotopic character of this deposit and its comparison with similar ones, suggest that the gold and its metals associated it is deposited in Córrego do Sítio to age 2.2 Ga. and that metals were derived from the banded iron formations, and remobilized by hidrothermal fluids across reverse faults. Although U-Pb (SHRIMP) and K-Ar geochronologic data were not conclusive to constrain the age of the mineralization, they provide to age ~2.7 Ga. that a good limit for the sedimentation of the host rock. It is suggest that there is a potential for gold prospection within the metapellitic rocks associated with banded iron formation of the Greenstone Rio das Velhas, and that the more relevant targets include areas with inverse and strike-slip fault.

O receptor scavenger classe B tipo I (SR-BI) media a captação seletiva do colesterol da lipoproteina de alta densidade (HDL) e participa no effluxo do colesterol livre para aceptores lipoprotéicos. A HDL tem um importante rol aterogênico associado com sua participação no transporte reverso do colesterol. Polimorfismos no gene que codifica para o SR-BI (SCARB1) foram relacionados com alterações do perfil lipídico sérico e outros fatores de risco associados com doença cardiovascular. As estatinas são inibidores da síntese do colesterol utilizados no tratamento da dislipidemia. Vários polimorfismos em genes envolvidos no metabolismo intermediario de lipideos foram relacionados com diferenças na resposta a hipolipemiantes. Com a finalidade de avaliar o efeito de polimorfismos do SCARB1 sobre o perfil lipídico sérico, expressão gênica e a resposta a estatinas, foram selecionados 185 indivíduos normolipidêmicos (NL) e 147 pacientes hipercolesterolêmicos (HC). Os pacientes HC foram tratados com atorvastatina (10 mg/dia/4 semanas). DNA e RNA foram extraídos de amostras de sangue periférico. Os polimorfismos de nucleotídeo único (SNP) G4A, In5C>T e Ex8C>T foram detectados por PCR-RFLP. A expressão de RNAm do SCARB1 em células mononucleares de sangue periférico (CMSP) foi analisada por PCR em tempo real usando o gene da Ubiquitina c (UBC) como referência endógena. Nos indivíduos HC, as freqüências dos alelos raros G4A (12%), In5C>T (7%) e Ex8C>T (40%), no grupo HC, foram similares às encontradas no grupo NL (4A: 15%, In5T: 7%, e Ex8T: 35%, p>0,05). O alelo SCARB1 4A (genótipos GA + AA) foi associado com valores diminuídos de apoAI no grupo NL. O alelo In5T foi associado com maior concentração LDL-C sérico (p=0,029), em NL, e com apoB e razão apoB/apoAI elevadas (p>0,05) no grupo HC. O SNP SCARB1 Ex8C>T não foi relacionado com o perfil lipídico sérico basal, embora os portadores do genótipo Ex8CC foram associados com resposta reduzida ao tratamento com atorvastatina mostrando menor variação de colesterol total, LDL-C, apoB e razão apoB/apoAI. O SNP Ex8C>T foi associado com maior probabilidade (OR=3,1; 95% IC: 1,00-9,5; p=0,044) de ter uma resposta à atorvastatina diminuída. Os SNPs SCARB1 In5C>T e Ex8C>T estão em desequilíbrio de ligação. O haplótipo G1C5C8/G1T5C8 foi associado com concentrações basais elevadas de triglicérides e VLDL-C em NL e diminuídas de HDL-C e apoAI em HC. Os haplótipos G1C5C8/A1C5C8 e C5C8/C5C8 tiveram variação diminuída da apoB quando comparados com os outros haplótipos, G1C5C8/A1C5C8 e o diplótipo C5C8/C5C8 também apresentou uma variação reduzida da razão apoB/apoAI. Os SNPs G4A e In5C>T estão associados com diminuição da expressão gênica do SCARB1 em NL. O tratamento com atorvastatina não modifica a expressão de RNAm do SCARB1 em CMSP nos HC. Esses resultados são sugestivos de que os polimorfismos no SCARB1 estão associados com valores basais do perfil lipídico sérico e de expressão de RNAm do SCARB1, assim como de resposta à atorvastatina. / The scavenger receptor class B type I (SR-BI) mediates the selective uptake of the high density lipoprotein (HDL) cholesterol and it participates in the free cholesterol efflux to lipoprotein acceptors. HDL has an important antiatherogenic role associated with important activity in the cholesterol reverse transport. Polymorphisms in the SR-BI gene (SCARB1) have been related to variations on plasma lipoprotein profile and other risk factors for cardiovascular disease. Statins are potent inhibitors of cholesterol synthesis prescribed for treatment of the dislipidemia. Several polymorphisms in genes involved in intermediary metabolism of lipids have been related to differences in response to lowering-cholesterol drugs. In order to evaluate the effect of SCARB1 polymorphisms on serum lipids, gene expression and lipid-lowering response to atorvastatin, 185 normolipidemic (NL) and 147 hypercholesterolemic (HC) individuals were selected. HC individuals were treated with atorvastatin (10 mg/day/4 weeks). DNA and RNA were extracted from peripheric blood mononuclear cells (PBMC). SCARB1 mRNA expression was analyzed by real time PCR using ubiquitin c gene (UBC) as endogenous reference. The frequencies of the rare alleles in HC group (G4A: 12%; In5C>T: 7%, and ExC>T: 39%) were similar to those found in NL individuals (4A: 15%, In5T: 7%, and Ex8T: 35%, p>0.05). The SCARB1 4A allele (GA+AA genotypes) was associated with lower apoAI concentration in NL. The In5T allele was associated with higher serum LDL-C (p=0,029) in NL individuals, and with higher apoB and apoB/apoAI ratio (p>0,05) in HC group. SCARB1 Ex8C>T SNP was not related to serum lipids profile, however Ex8CC genotype carriers had lower variation of total cholesterol, LDL-C, apoB and apoB/apoAI ratio in response to atorvastatin. SCARB1 Ex8C>T was associated with higher chance to have a lower atorvastatin response (OR=3.1, 95% CI: 1.00-9.5; p=0.044). SCARB1 In5C>T and ExC>T were in linkage disequilibrium. G1C5C8/G1T5C8 SCARB1 haplotype was associated with higher level of triglycerides and VLDL-C in NL and lower HDL-C and apoAI levels in HC individuals. G1C5C8/A1C5C8 haplotype and C5C8/C5C8 diplotype had lower variations on apoB than the other haplotypes, and G1C5C8/A1C5C8 had also lower variation on apoB/apoAI ratio. G4A and In5C>T SNPs are associated with lower SCARB1 mRNA expression in PBMC of NL individuals. Atorvastatin therapy did not modify the expression level of the SCARB1 transcript in HC. Our results suggest that SCARB1 polymorphisms are associated with basal serum lipids profile, mRNA SCARB1 expression and atorvastatin response.

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