L’émergence de l’Afrique dans l’œuvre de Michel Leiris témoigne de sa volonté de connaître l’autre et de se réévaluer par la rencontre de l’autre. Leiris sillonne l’Afrique d’Ouest en Est au cours de la mission Dakar/Djibouti de 1931 à 1933 en tant que secrétaire archiviste de la mission ethnographique et linguistique dirigée par Marcel Griaule. Cette mission est une occasion pour Leiris de rentrer en contact aves les Africains et de s’éloigner pour un moment de l’Europe. Le séjour à Sanga, lui permet de pénétrer dans l’univers sacré des Dogon et d’analyser la symbolique des masques. De même son séjour en Abyssinie le met en contact avec les possédés et les génies zar. L’Éthiopie est le dernier pays visité par Leiris et le pays qui le marque le plus fortement. Les Noirs ne font aucune différence entre Leiris et les autres colons blancs à cette époque de la colonisation. De son contact avec l’Afrique naissent plusieurs ouvrages dont L’Afrique fantôme et La Langue secrète des Dogon de Sanga. Leiris espère par son voyage en Afrique trouver une thérapie à ses maux. Dans cette vaste entreprise, il verra se briser au contact des Africains le mythe du voyage régénérateur et ne parviendra pas à se défaire de ses obsessions. L’Afrique fantôme apporte un témoignage sur la position ambiguë de l’ethnologie de cette époque. En toute objectivité, il essaie de tout dire sur lui et sur ce qu’il ressent en Afrique. Il fait de l’altérité sa principale préoccupation ; de l’Afrique aux Antilles, il s’intéresse aux cultures des Noirs tout en ayant souvent un avis critique à leur egard. Il devient l’ethnologue de lui-même, interrogeant le monde à partir de l’échantillon de catégorie humaine qu’il est, se faisant témoin extérieur, en quelque sorte, de ce qui se déroule en lui et autour de lui. L’Afrique reste un fantôme pour Leiris à l’image d’Emawayish, la Gondarienne d’Éthiopie dont il tombe amoureux pendant son séjour en Abyssinie. / The emergence of Africa in the work of Michel Leiris testifies his willingness to know the other and at the same time to re-evaluate his own self through the encounter with the other. Leiris travels through Africa from the west to the east during the Dakar/Djibouti mission from 1931 to 1933 as the recording archivist of the ethnographic and linguistic mission headed by Marcel Griaule. This mission becomes an occasion for Leiris to get in touch with Africans and to be away from Europe for a moment. His stay in Sanga allows him to enter the sacred universe of Dogon people and to analyse the significance of the masks. As far as that goes, his stay in Abyssinia also gives him the opportunity to be in direct contact with the possessed people and the Zar spirits. Ethiopia is the last country visited by Leiris and it is the country which touches him the most. Blacks do not make any difference between Leiris and the other white colonialists during this particular period of colonisation. His encounter with Africa gives birth to several pieces of work such as Ghost Africa and The Secret Language of Sanga’s Dogons. Leiris hopes that his travel to Africa will help him find a therapy to his problems. In this vast enterprise, he will see the myth of a regenerative travel broken and will not be able to get rid of his obsessions. Ghost Africa is a testimony on the ambiguous position of ethnology of this particular period. Objectively; he tries to say everything on his own self and on what he feels while in Africa. The other becomes his main concern, from Africa to the West Indies; he is interested in the cultures of the black people with often a critical comment on them. He becomes ethnologist himself, questioning the world from the sample of human category that he is, as an external witness somehow, of what is happening in his own self and around him. Africa remains a ghost for Leiris because of the image of Emawayish, the Gondarian of Ethiopia with whom he falls in love during his stay in Abyssinia.

Made available in DSpace on 2017-07-10T18:17:56Z (GMT). No. of bitstreams: 1 Micheli Aparecida de Oliveira.pdf: 2402924 bytes, checksum: 9e60730ee3afb679d59dcc1580ed4fb6 (MD5) Previous issue date: 2016-01-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The object study of this research deals with the social and environmental implications on Sanga Pinheirinho in Toledo City PR. The goal was to understand to what extent the preservation of Sanga Pinheirinho and the population's quality life may be compromised as a result of its use by the residents of their surroundings and how is representation thereof on the theme. The methodology was qualitative, with the completion of bibliographic and documentary research on the environmental and socio-environmental issues, aspects regarding life quality and municipality characteristics information and neighborhood, as well as the representation of residents on the proposed topic, if scored, also questions the professional social work and its performance. Collected socioeconomic data were used by the Unified Register of the Toledo City PR and the Central Social Assistance Reference of the Santa Clara IV districtand further data obtained through interviews with neighborhood residents. Therefore, guiding questions in semi-open interview which was held in place of choice of the interviewee were used. In final analysis, it was related data and information obtained in fieldwork with the theoretical framework used as input for the study. / O objeto de estudo dessa pesquisa versa sobre as implicações socioambientais na Sanga Pinheirinho em Toledo PR. A problemática da pesquisa centra-se na questão: em que medida o uso da Sanga Pinheirinho pelos moradores de seu entorno interfere diretamente na preservação do meio ambiente. Sendo seu objetivo geral compreender como a preservação da Sanga Pinheirinho e a qualidade de vida da população podem ser comprometidas em decorrência do seu uso pelos moradores de seu entorno. E como objetivos específicos abordar pobreza, meio ambiente e suas aproximações ao serviço social; compreender o movimento de construção do Município de Toledo e levantar junto aos moradores do Bairro Santa Clara IV suas representações acerca do uso da sanga e as implicações socioambientais oriundas. A metodologia adotada foi a qualitativa, com a realização de pesquisa bibliográfica e documental relativa às questões ambientais e socioambientais, aspectos acerca da qualidade de vida e informações características do município e bairro, bem como a representação dos moradores sobre o tema proposto. Foram utilizados dados socioeconômicos coletados junto ao Cadastro Único do Município de Toledo PR bem como do Centro de Referencia de Assistência Social do Bairro Santa Clara IV e ainda dados obtidos através das entrevistas realizadas com os moradores do bairro. Para tanto, foram utilizadas questões norteadoras em entrevista semiaberta realizada em local de escolha do entrevistado. Por fim, foram relacionados os dados e informações obtidos no trabalho de campo com o referencial teórico utilizado como subsídio para o estudo.

Thesis (MScAgric)--Stellenbosch University, 2008. / ENGLISH ABSTRACT: Research conducted on beef cattle in Botswana investigated both growth and reproduction. These studies however, did not specifically determine the influence of the different environmental factors on growth in the Tswana and Composite beef cattle breeds. The establishment of a national beef herd recording and performance testing scheme requires knowledge on the appropriate adjustment methods of field data for the fixed effects such as sex of calf and age of dam. A fair comparison of birth and weaning weights between male and female calves, and calves born from young, mature and old dams will be derived from these adjustment factors. There is no information on adjustment factors for the Tswana and Composite cattle breeds in the country. Genetic parameters for growth traits in these breeds are not known and are needed for the implementation of the performance scheme in Botswana. The Composite breed resulted from a controlled crossbreeding programme using the Simmental, Brahman, Tswana, Tuli and the Bonsmara breeds. The Tswana animals are indigenous to the country and were sourced locally at the beginning of the growth evaluation trial in the two breeds. The objectives of the study were to use data collected from Tswana and Composite cattle breeds to estimate the influence of non-genetic factors on growth traits in the two breeds; to develop adjustment factors for the effects of sex of calf and age of dam; and to estimate genetic parameters (heritabilities and genetic correlations) for future genetic evaluations in both breeds. Data were collected over the period 1988 to 2006. A total of 2 257 records for the Composite breed and 5 923 records for the Tswana breed were available for analyses. Growth characteristics of interest in this study were birth weight (BW), weaning weight (WW), pre-weaning average daily gain (ADG1), 18 months weight (18MW) and post-weaning average daily gain (ADG2). Study 1 indicated that non-genetic effects of breed of calf, sex of calf, month and year of birth, previous parous state, weight of cow at parturition, age of dam, and age of calf at weaning significantly affected BW, WW, 18MW, ADG1 and ADG2 in both breeds. The Composite breed had higher BW, ADG1 and WW whereas the Tswana had higher ADG2 and 18MW. Pre-weaning growth rate increased with an increase in the age of the dam, reaching a peak in mature (5-12 years) cows and declined in cows 13 years and older. Conversely, post-weaning growth rates declined as age of dam advanced but increased in old (13 years and older) dams. Male calves were heavier than female calves for all the growth traits. Birth weight increased as calving season progressed whilst a decrease in WW was observed over the same period. Heifers gave birth to lighter calves when compared to mature multiparous dams. The Composite breed can therefore be considered for weaner production under ranch conditions while the Tswana can be reared under extensive systems due to its adaptability to the environment. Additive correction factors for effects of sex of calf and age of dam on BW and WW were studied separately for the Tswana and Composite in study 2. The least squares means procedure was used to derive age groups and the adjustment factors. The three age groups were young (4 years and below) dams, mature (5-12 years) dams and older (13 years and above) dams. Male calves were heavier than their female counterparts. The sex of calf adjustments for BW and WW were 2.75 and 8.21 kg in the Tswana, and corresponding values for the Composite 2.84 and 10.11 kg, respectively. Birth weight and WW increased as age of dam increased, reached maximum in mature dams and declined in older dams. Age of dam adjustment factors for BW in the 3, 4 and 13+ years age groups for the Tswana were 1.74, 0.96 and 1.87 kg, respectively. The corresponding values for the Composite were 2.28, 0.94 and 2.06 kg, respectively. Age of dam adjustment factors for weaning weight in the Tswana were 10.36 and 5.46 kg for age groups 3-4 and 13+ years, respectively. Adjustment factors for WW in the Composite were 13.84, 3.20 and 9.58 kg for age groups 3, 4 and 13+ years. The differences in adjustment factors obtained between the two breeds emphasize the need to compute and apply these factors within breed. Study 3 involved the estimation of genetic parameters for BW, WW, ADG1, 18MW and ADG2. Single-trait and multi-trait analyses were used in the estimation of (co)variance components by fitting an individual animal model (AM) and the animal maternal model (AMM) for the two breeds. Direct heritabilities for BW, WW, ADG1, 18MW and ADG2 in the Tswana were 0.45, 0.32, 0.37, 0.31 and 0.31, respectively from a single-trait AM analysis. Fitting the AMM resulted in direct heritabilities of 0.31, 0.20 and 0.16 for BW, WW and ADG1, respectively, while the maternal heritabilities were 0.11, 0.15 and 0.21, respectively. For the Composite the direct heritabilities for BW, WW and ADG1 were 0.58, 0.32 and 0.30, respectively with single-trait AM. Partitioning using the AMM resulted in the direct heritabilities for BW, WW and ADG1 of 0.55, 0.17 and 0.14, respectively, while corresponding maternal effects were 0.09, 0.15 and 0.15, respectively. The genetic correlations between direct and maternal effects were positive and ranged from 0.20 to 0.89. When using the multi-trait analysis and fitting the AM, the direct heritabilities for the Tswana were 0.45, 0.37, 0.34, 0.39 and 0.31 for BW, WW, ADG1, 18MW and ADG2, respectively. Genetic correlations between the growth traits ranged from 0.16 to 0.97. Direct (and maternal) heritabilities for BW, WW and ADG1 were 0.31(0.11), 0.19(0.15) and 0.14(0.17), respectively, in the Tswana. Correlations between direct heritabilities for BW, WW and ADG1 ranged from 0.45 to 0.95, while maternal effects ranged from 0.12 to 0.99. The magnitude of the heritabilities indicates an existence of the opportunity to make genetic progress through selection in both breeds. Selection based on WW seems to be the ideal procedure to bring genetic improvement in the Tswana without detrimental long term effects. / AFRIKAANSE OPSOMMING: Navorsing wat op die vleisbeesrasse in Botswana gedoen is, het hoofsaaklik op beide groei en reproduksie gehandel. Hierdie studies het egter nie spesifieke gefokus op die bepaling van die invloed wat verskillende omgewingsfaktore op die groei van saamgestelde (d.i. Composite) en die Tswana vleisbeesrasse het nie. Die bepaling van ʼn nasionale vleisbees rekordhouding- en prestasietoetsskema verg kennis van die mees gepaste metode om velddata vir vaste effekte soos geslag van die kalf en ouderdom van die moeder aan te pas. Hierdie aanpassingsmetodes sal lei tot die regverdige vergelyking van geboorte- en speengewigte tussen manlike en vroulike diere, sowel as van kalwers gebore van jong, volwasse of ou moeders. Tans is daar geen inligting oor aanpassingfaktore vir die Tswana en saamgestelde vleisbeesrasse in Botswana bekend nie. Geen genetiese parameters vir groei-eienskappe vir geeneen van die rasse is beskikbaar nie en word benodig vir die implementering van die prestasie skema in Botswana. Die saamgestelde ras is die produk van ʼn beheerde kruisteeltprogram, wat onderskeidelik die Simmental, Brahman, Tswana, Tuli en die Bonsmara beesrasse ingesluit het. Die Tswana ras is inheems aan Botswana en vanaf plaaslike bronne vir die groei evaluasie studie bekom. Die doelwitte van die studie was eerstens die analisering van data wat van beide die Tswana en saamgestelde rasse ingesamel is, om die invloed van nie-genetiese faktore op die groei eienskappe te bepaal om ten einde aanpassingsfaktore vir die effek van geslag van die kalf en ouderdom van die moederdier te ontwikkel. ʼn Tweede doelwit was die bepaling van genetiese parameters (oorerflikhede en genetiese korrelasies) vir die gebruik in toekomstige genetiese evaluering van beide rasse. Data is vanaf 1988 tot 2006 ingesamel. ʼn Totaal van 2 257 waarnemings vir die saamgestelde ras en 5 923 waarnemings vir die Tswana ras is ontleed. Groei eienskappe wat in die studie ondersoek is, het geboortegewig (BW), speengewig (WW), voorspeen gemiddelde daaglikse toename (ADG1), 18-maand gewig (18MW) en naspeense gemiddelde daaglikse toename (ADG2) ingesluit. Studie een het aangedui dat nie-genetiese effekte van die ras van die kalf, die geslag van die kalf, maand en jaar van geboorte, vorige dragtigheidsstatus, koei se gewig met geboorte van kalf, ouderdom van die moederdier en die speenouderdom van die kalf het ʼn betekenisvolle invloed op BW, WW, 18MW, ADG1 en ADG2 van beide rasse gehad. Die saamgestelde ras het hoër waardes vir BW, ADG1 en WW gehad, terwyl die Tswana ras hoër waardes vir ADG2 en 18MW geopenbaar het. Voorspeense groeitempo het toegeneem met ʼn toename in die ouderdom van die moederdier, met ʼn piek in volwasse (d.i. 5-12 jaar ouderdom) moeders en ʼn afname in koeie 13 jaar en ouer. Omgekeerd het naspeen groeitempo afgeneem met ʼn toename in die ouderdom van die moederdier en weer begin toeneem vir ou (d.i. 13 jaar en ouer) koeie. Geboortegewig het toegeneem met die verloop van die kalfseisoen, terwyl ʼn afname in WW vir dieselfde periode aangeteken is. Verse het, wanneer hulle met volwasse koeie vergelyk is, het geboorte aan ligter kalwers gegee. Die saamgestelde ras kan dus oorweeg word vir die produksie van speenkalwers onder kommersiële intensiewe toestande, terwyl die Tswana ras, op grond van sy beter aanpassing by ekstensiewe omstandighede waar die moederlike invloed nie voorkom nie, vir produksie onder ekstensiewe omstandighede gebruik kan word. In studie 2 is die additiewe korreksie faktore vir die invloed van geslag van die kalf en moederouderdom op BW en WW apart vir die twee rasse bestudeer. Die geslag van die kalf x ouderdom van die moederdier interaksie was nie betekenisvol vir enige van die rasse nie. Dus kan geen aanpassing vir die ouderdom van die moeder binne geslagte vir enige van die twee rasse gemaak word nie. Die kleinste kwadraat gemiddeldes metode is gebruik om die ouderdomsgroepe en aanpassingsfaktore te bepaal. Die drie ouderdomsgroepe was jong (d.i. 4 jaar en jonger) koeie, volwasse (d.i. 5-12 jaar ouderdom) en ouer (d.i. 13 jaar en ouer) koeie. Daar is gevind dat manlike kalwers swaarders as hulle vroulike eweknieë is. Die aanpassingswaarde vir die geslag van die kalf vir BW en WW was 2.75 kg en 8.21 kg in die Tswana en 2.84 kg en 10.11kg vir die saamgestelde ras. Geboortegewig en WW het toegeneem met ʼn toename in die ouderdom van die moeder. Dit het ʼn maksimum bereik in volwasse koeie en afgeneem vir koeie ouer as 13 jaar. Die aanpassingsfaktore vir die ouderdom van die moederdier vir BW in die 3, 4 and 13+ jarige ouderdomsgroepe vir die Tswana ras was onderskeidelik 1.74 kg, 0.96 kg en 1.87 kg. Die ooreenstemmende waardes vir die saamgestelde ras was onderskeidelik 2.28 kg, 0.94 kg en 2.06 kg. Aanpassingsfaktore vir WW vir die Tswana ras was 10.36 kg en 5.46 kg vir onderskeidelik die 3-4 jaar en 13+ jaar en ouer ouderdomsgroepe. Aanpassingsfaktore vir WW in die Composite ras was 13.84 kg, 3.20 kg en 9.58 kg vir onderskeidelik die 3 jaar, 4 jaar en 13 jaar en ouer ouderdomsgroepe. Verskille in die onderskeie parameters vir die twee rasse beklemtoon die noodsaaklikheid vir die berekening en toepassing van die onderskeie aanpassingfaktore vir en binne elke ras. Studie 3 het die bepaling van die genetiese parameters vir BW, WW, ADG1, 18MW en ADG2 behels. Enkel- en multivariaat analises is gebruik vir die skatting van die (ko)variansie komponente deur ʼn direkte diermodel (AM) en ʼn dier-maternale model (AMM) vir die twee rasse te pas. Direkte oorerflikhede vir BW, WW, ADG1, 18MW en ADG2 vir die Tswana ras was onderskeidelik 0.45, 0.32, 0.37, 0.31 en 0.31, vir ʼn enkelvariaat AM analise. Die pas van ʼn AMM het direkte oorerflikhede van 0.31, 0.20 en 0.16 vir onderskeidelik BW, WW and ADG1 gegee, terwyl die maternale oorerflikhede onderskeidelik 0.11, 0.15 en 0.21 was. Vir die saamgestelde ras was die direkte oorerflikhede vir BW, WW en ADG1 onderskeidelik 0.58, 0.32 en 0.30 vir die enkelvariaat AM analise. Verdeling (partisie) van die AMM het direkte oorerflikhede vir BW, WW en ADG1 van onderskeidelik 0.55, 0.17 en 0.14 gegee, terwyl die ooreenstemmende maternale effekte onderskeidelik 0.09, 0.15 en 0.15 was. Die genetiese korrelasies tussen die drekte en maternale effekte was positief en tussen 0.20 en 0.89. Met die multivariaat analise en die pas van die AM, is direkte oorerflikhede van 0.45, 0.37, 0.34, 0.39 en 0.31 vir onderskeidelik BW, WW, ADG1, 18MW en ADG2, vir die Tswana ras bereken. Genetiese korrelasies tussen die groei eienskappe het gewissel tussen 0.16 tot 0.97. Direkte (en maternale) oorerflikhede vir BW, WW en ADG1 was onderskeidelik 0.31(0.11), 0.19(0.15) en 0.14(0.17), vir die Tswana ras. Korrelasies tussen die direkte oorerflikhede vir BW, WW en ADG1 het gewissel tussen 0.45 en 0.95, terwyl die maternale effekte tussen 0.12 en 0.99 gewissel het. Die grootte van die oorerflikhede dui op die moontlikheid van genetiese vordering wat deur seleksie in beide rasse gemaak kan word. Seleksie op grond van WW blyk die mees gepaste wyse te wees waarmee genetiese vordering binne die Tswana ras gemaak kan word, sonder enige langtermyn nadelige effekte.

Esta dissertação faz parte de um projeto que tem como objetivo investigar a origem e evolução do magmatismo de arco e pós-colisional do Escudo Sul-rio-grandense (ESRG), caracterizando a partir de estudos geoquímicos, estruturais e petrográficos os Granitóides Sanga do Areal (GSA), localizados na região de Quitéria, porção leste do Escudo Sul-rio-grandense. Estes granitóides consistem de dois corpos principais, alongados na direção NE-SW, com aproximadamente 14 km de extensão e 2 km de largura, e também de diversas intrusões menores, posicionadas, preferencialmente, na porção mediana de alta deformação cisalhante do Complexo Arroio dos Ratos. Estão em contato na porção NW com metatonalitos, metagranodioritos e gnaisses tonalíticos a dioríticos de idade paleoproterozóica do referido complexo e com horblenda-biotita granodioritos da unidade neoproterozóica Granodiorito Cruzeiro do Sul. Na porção SE o contato se dá com tonalitos a dioritos relacionados aos Granitóides Arroio Divisa de idade neoproterozóica. Os GSA são biotita monzogranitos de textura porfirítica em seu termo principal, com cerca de 30% de megacristais de até 5 cm de comprimento de plagioclásio e K-feldspato. A matriz heterogranular média a grossa é composta por quartzo fitado, feldspato parcialmente recristalizado e biotita. Subordinadamente, observam-se corpos de espessura centimétrica a métrica de biotita granodiorito equigranular médio, com fenocristais esparsos de feldspatos alinhados na foliação. Raramente ocorrem enclaves microgranulares máficos. A foliação milonítica é bem marcada pela orientação da biotita, dos megacristais lenticulares e do quartzo fitado e tem direção E-W, com alto ângulo de mergulho para N e para S, contendo lineação de estiramento direcional, com baixo caimento para W a SW. A foliação ígnea primária, concordante a sub-concordante com a foliação milonítica, tem ocorrência restrita e é marcada pela orientação dos megacristais não deformados e das lamelas de biotita. Estruturas S-C, caudas assimétricas em porfiroclastos de feldspatos, biotita fish e fitas assimétricas de quartzo são consistentes e indicam movimento transcorrente sinistral. Os Granitóides Sanga do Areal têm afinidade sub-alcalina médio a alto K, provavelmente toleítica, compatível com ambiente pós-colisional, onde foram deformados e controlados por zonas de cisalhamento transcorrente sub-verticais. Foi obtida uma idade U-Pb em zircão dos granitóides de 626,6±4,9 Ma (MSWD=2.2), coerente com as relações de campo. / This research investigates the evolution of arc to post-collisional magmatism in the Sul-rio-grandense Shield (ESGR), using geochemistry, structural and petrographic studies of the Sanga do Areal Granitoids (GSA). These granitoids are located in the Quitéria region, east of ESRG. The GSA form two main, NE-striking intrusions, and several other small ones, mainly within the shear zone croscutting the central portion of the Arroio dos Ratos Complex. The two main bodies are about 14 km long and 2 km wide. To the northwest, the GSA rocks are in contact with Paleoproterozoic metatonalites, metagranodiorites, tonalitic to dioritic gneisses of the Complex, and Neoproterozoic horblende-biotite granodiorites of the Cruzeiro do Sul unit. To the southeast, they are surrounded by tonalitic to dioritic rocks, related to the Neoproterozoic Arroio da Divisa Granitoids. The GSA rocks are composed mainly of porphyritic biotite monzogranites, with about 30% megacrysts of plagioclase and 5 cm long K-feldspar. The medium to coarse grained heterogranular groundmass is composed of microcrystalline ribbon quartz, partially re-crystallized feldspar and biotite. Medium-grained equigranular granodiorite occurs as centimeter to meter- thick bodies, with sparse feldspar megacrysts aligned on the foliation plane. Microgranular mafic enclaves are rarely observed within the GSA rocks. The mylonitic foliation is well-developed and marked by biotite, oriented lenticular megacrysts, as well as quartz ribbons. It strikes E-W and dips at high angles either N or S. The stretching lineation within the foliation shows shallow plunges, preferentially W-SW. A primary igneous foliation is sometimes observed, and it is concordant or sub-concordant with the mylonitic one, and marked by orientation of igneous megacrysts and biotite lamellae. S-C structures, asymetric tails in feldspar porphyroclasts, biotite fish, and asymetric quartz ribbons indicate transcurrent movement with consistent sinistral shear sense. The Sanga do Areal Granitoids show subalkaline medium- to high-K affinity, probably tholeiitic, and trace element composition consistent with sources related to post-collisional settings, which were deformed and controlled by E-NE and NE sub-vertical transcurrent shear zones. A U-Pb age in zircon grains from Sanga do Areal Granitoids of 626.6 ± 4.6Ma ((MSWD=2.2) was obtained and considered coherent with stratigraphic relations.

Esta dissertação faz parte de um projeto que tem como objetivo investigar a origem e evolução do magmatismo de arco e pós-colisional do Escudo Sul-rio-grandense (ESRG), caracterizando a partir de estudos geoquímicos, estruturais e petrográficos os Granitóides Sanga do Areal (GSA), localizados na região de Quitéria, porção leste do Escudo Sul-rio-grandense. Estes granitóides consistem de dois corpos principais, alongados na direção NE-SW, com aproximadamente 14 km de extensão e 2 km de largura, e também de diversas intrusões menores, posicionadas, preferencialmente, na porção mediana de alta deformação cisalhante do Complexo Arroio dos Ratos. Estão em contato na porção NW com metatonalitos, metagranodioritos e gnaisses tonalíticos a dioríticos de idade paleoproterozóica do referido complexo e com horblenda-biotita granodioritos da unidade neoproterozóica Granodiorito Cruzeiro do Sul. Na porção SE o contato se dá com tonalitos a dioritos relacionados aos Granitóides Arroio Divisa de idade neoproterozóica. Os GSA são biotita monzogranitos de textura porfirítica em seu termo principal, com cerca de 30% de megacristais de até 5 cm de comprimento de plagioclásio e K-feldspato. A matriz heterogranular média a grossa é composta por quartzo fitado, feldspato parcialmente recristalizado e biotita. Subordinadamente, observam-se corpos de espessura centimétrica a métrica de biotita granodiorito equigranular médio, com fenocristais esparsos de feldspatos alinhados na foliação. Raramente ocorrem enclaves microgranulares máficos. A foliação milonítica é bem marcada pela orientação da biotita, dos megacristais lenticulares e do quartzo fitado e tem direção E-W, com alto ângulo de mergulho para N e para S, contendo lineação de estiramento direcional, com baixo caimento para W a SW. A foliação ígnea primária, concordante a sub-concordante com a foliação milonítica, tem ocorrência restrita e é marcada pela orientação dos megacristais não deformados e das lamelas de biotita. Estruturas S-C, caudas assimétricas em porfiroclastos de feldspatos, biotita fish e fitas assimétricas de quartzo são consistentes e indicam movimento transcorrente sinistral. Os Granitóides Sanga do Areal têm afinidade sub-alcalina médio a alto K, provavelmente toleítica, compatível com ambiente pós-colisional, onde foram deformados e controlados por zonas de cisalhamento transcorrente sub-verticais. Foi obtida uma idade U-Pb em zircão dos granitóides de 626,6±4,9 Ma (MSWD=2.2), coerente com as relações de campo. / This research investigates the evolution of arc to post-collisional magmatism in the Sul-rio-grandense Shield (ESGR), using geochemistry, structural and petrographic studies of the Sanga do Areal Granitoids (GSA). These granitoids are located in the Quitéria region, east of ESRG. The GSA form two main, NE-striking intrusions, and several other small ones, mainly within the shear zone croscutting the central portion of the Arroio dos Ratos Complex. The two main bodies are about 14 km long and 2 km wide. To the northwest, the GSA rocks are in contact with Paleoproterozoic metatonalites, metagranodiorites, tonalitic to dioritic gneisses of the Complex, and Neoproterozoic horblende-biotite granodiorites of the Cruzeiro do Sul unit. To the southeast, they are surrounded by tonalitic to dioritic rocks, related to the Neoproterozoic Arroio da Divisa Granitoids. The GSA rocks are composed mainly of porphyritic biotite monzogranites, with about 30% megacrysts of plagioclase and 5 cm long K-feldspar. The medium to coarse grained heterogranular groundmass is composed of microcrystalline ribbon quartz, partially re-crystallized feldspar and biotite. Medium-grained equigranular granodiorite occurs as centimeter to meter- thick bodies, with sparse feldspar megacrysts aligned on the foliation plane. Microgranular mafic enclaves are rarely observed within the GSA rocks. The mylonitic foliation is well-developed and marked by biotite, oriented lenticular megacrysts, as well as quartz ribbons. It strikes E-W and dips at high angles either N or S. The stretching lineation within the foliation shows shallow plunges, preferentially W-SW. A primary igneous foliation is sometimes observed, and it is concordant or sub-concordant with the mylonitic one, and marked by orientation of igneous megacrysts and biotite lamellae. S-C structures, asymetric tails in feldspar porphyroclasts, biotite fish, and asymetric quartz ribbons indicate transcurrent movement with consistent sinistral shear sense. The Sanga do Areal Granitoids show subalkaline medium- to high-K affinity, probably tholeiitic, and trace element composition consistent with sources related to post-collisional settings, which were deformed and controlled by E-NE and NE sub-vertical transcurrent shear zones. A U-Pb age in zircon grains from Sanga do Areal Granitoids of 626.6 ± 4.6Ma ((MSWD=2.2) was obtained and considered coherent with stratigraphic relations.

Esta dissertação faz parte de um projeto que tem como objetivo investigar a origem e evolução do magmatismo de arco e pós-colisional do Escudo Sul-rio-grandense (ESRG), caracterizando a partir de estudos geoquímicos, estruturais e petrográficos os Granitóides Sanga do Areal (GSA), localizados na região de Quitéria, porção leste do Escudo Sul-rio-grandense. Estes granitóides consistem de dois corpos principais, alongados na direção NE-SW, com aproximadamente 14 km de extensão e 2 km de largura, e também de diversas intrusões menores, posicionadas, preferencialmente, na porção mediana de alta deformação cisalhante do Complexo Arroio dos Ratos. Estão em contato na porção NW com metatonalitos, metagranodioritos e gnaisses tonalíticos a dioríticos de idade paleoproterozóica do referido complexo e com horblenda-biotita granodioritos da unidade neoproterozóica Granodiorito Cruzeiro do Sul. Na porção SE o contato se dá com tonalitos a dioritos relacionados aos Granitóides Arroio Divisa de idade neoproterozóica. Os GSA são biotita monzogranitos de textura porfirítica em seu termo principal, com cerca de 30% de megacristais de até 5 cm de comprimento de plagioclásio e K-feldspato. A matriz heterogranular média a grossa é composta por quartzo fitado, feldspato parcialmente recristalizado e biotita. Subordinadamente, observam-se corpos de espessura centimétrica a métrica de biotita granodiorito equigranular médio, com fenocristais esparsos de feldspatos alinhados na foliação. Raramente ocorrem enclaves microgranulares máficos. A foliação milonítica é bem marcada pela orientação da biotita, dos megacristais lenticulares e do quartzo fitado e tem direção E-W, com alto ângulo de mergulho para N e para S, contendo lineação de estiramento direcional, com baixo caimento para W a SW. A foliação ígnea primária, concordante a sub-concordante com a foliação milonítica, tem ocorrência restrita e é marcada pela orientação dos megacristais não deformados e das lamelas de biotita. Estruturas S-C, caudas assimétricas em porfiroclastos de feldspatos, biotita fish e fitas assimétricas de quartzo são consistentes e indicam movimento transcorrente sinistral. Os Granitóides Sanga do Areal têm afinidade sub-alcalina médio a alto K, provavelmente toleítica, compatível com ambiente pós-colisional, onde foram deformados e controlados por zonas de cisalhamento transcorrente sub-verticais. Foi obtida uma idade U-Pb em zircão dos granitóides de 626,6±4,9 Ma (MSWD=2.2), coerente com as relações de campo. / This research investigates the evolution of arc to post-collisional magmatism in the Sul-rio-grandense Shield (ESGR), using geochemistry, structural and petrographic studies of the Sanga do Areal Granitoids (GSA). These granitoids are located in the Quitéria region, east of ESRG. The GSA form two main, NE-striking intrusions, and several other small ones, mainly within the shear zone croscutting the central portion of the Arroio dos Ratos Complex. The two main bodies are about 14 km long and 2 km wide. To the northwest, the GSA rocks are in contact with Paleoproterozoic metatonalites, metagranodiorites, tonalitic to dioritic gneisses of the Complex, and Neoproterozoic horblende-biotite granodiorites of the Cruzeiro do Sul unit. To the southeast, they are surrounded by tonalitic to dioritic rocks, related to the Neoproterozoic Arroio da Divisa Granitoids. The GSA rocks are composed mainly of porphyritic biotite monzogranites, with about 30% megacrysts of plagioclase and 5 cm long K-feldspar. The medium to coarse grained heterogranular groundmass is composed of microcrystalline ribbon quartz, partially re-crystallized feldspar and biotite. Medium-grained equigranular granodiorite occurs as centimeter to meter- thick bodies, with sparse feldspar megacrysts aligned on the foliation plane. Microgranular mafic enclaves are rarely observed within the GSA rocks. The mylonitic foliation is well-developed and marked by biotite, oriented lenticular megacrysts, as well as quartz ribbons. It strikes E-W and dips at high angles either N or S. The stretching lineation within the foliation shows shallow plunges, preferentially W-SW. A primary igneous foliation is sometimes observed, and it is concordant or sub-concordant with the mylonitic one, and marked by orientation of igneous megacrysts and biotite lamellae. S-C structures, asymetric tails in feldspar porphyroclasts, biotite fish, and asymetric quartz ribbons indicate transcurrent movement with consistent sinistral shear sense. The Sanga do Areal Granitoids show subalkaline medium- to high-K affinity, probably tholeiitic, and trace element composition consistent with sources related to post-collisional settings, which were deformed and controlled by E-NE and NE sub-vertical transcurrent shear zones. A U-Pb age in zircon grains from Sanga do Areal Granitoids of 626.6 ± 4.6Ma ((MSWD=2.2) was obtained and considered coherent with stratigraphic relations.