965 resultados para sedimentologia,micropaleontologia,foraminiferi,mfs,facies


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O Maciço Sararé ocorre no sudoeste de Mato Grosso, intrusivo no Domínio Jauru, e encontra-se controlado por trend tectônico NW-SE ligado a tectônica regional transcorrente e, tardiamente, por feições tectônicas rúpteis NE-SW. É constituído por três fácies petrográficas principais denominadas biotita-monzogranito, muscovita-monzogranito e monzogranito, que apresentam contatos transicionais. São rochas leucocráticas, de cor vermelha a rosada, isotrópicas e eqüi/ineqüigranulares a localmente porfiríticas. Os dados geoquímicos as classificam como rochas do tipo S, peraluminosas, alto K, quimicamente restritas e evoluídas em relação a SiO2 alcançando teores em torno de 75%. Os valores de REE apresentam-se dispostos em três curvas assimétricas, evidenciando fácies distintas e mostrando uma redução destes valores e das anomalias de Eu para a fase final. O maciço representa intrusões diferenciadas, geradas a partir da fusão de material da crosta superior em ambiente de colisão continental no final do evento Aguapeí-Sunsás.

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A Bacia de Taubaté é caracterizada pela heterogeneidade geológica, herança da tectônica do tipo rifte, que dividiu a bacia em compartimentos e condicionou a sedimentação, constituída por depósitos de leques aluviais associados à planície aluvial e sedimentos lacustres do tipo playa-lake. A distribuição dos arenitos na bacia foi estudada com a interpolação 3D da fácies arenito, identificada através das informações dos perfis de poços. A interpolação não apenas distingue, em subsuperfície, os depósitos relacionados às formações Resende e Tremembé, como também constata zonalidades locais nos compartimentos. Ao relacionar as feições estruturais do rifte com a interpolação realizada para os arenitos, foi possível inferir a distribuição dos arenitos entre três grupos. O primeiro grupo relacionado à fase rifte, o segundo a um evento de transição bem representado no Compartimento São José dos Campos e o terceiro grupo aos sedimentos depositados durante o Neógeno até o Recente.

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Pós-graduação em Zootecnia - FCAV

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The Triunfo Member, from Rio Bonito Formation, is a potential reservoir for hydrocarbons and water, and contains coal deposits in the northern state of Paraná. On the eastern edge of the Paraná Basin, the Triunfo Member has two depocenters in Santa Catarina and offlap to the North of Paraná; here in two adjacent areas characterized his final lapout. These areas have a number of wells core/logged with the initials MA and NF, Monte Alegre and Figueira North, which were drilled by the Companhia de Pesquisa e Recursos Minerais (CPRM), in order to research for coal in the Rio Bonito Formation. In this study, three wells in the MA area, and they were MA-4, MA-6 and MA-7 was subjected to vertical facies analysis (1D), from the description of wells and processing of data, so that later it was possible to chronocorrelate thereof, together with MA-5 well, through cycles facies (2D). This is a thesis which has never been developed in these wells mentioned above, it was possible to observe the development of part of the Member Taciba (top) and the Member Triunfo as a whole, can be determined three cycles facies to the latter, as well as their depositional environments. Finally, the chronocorrelate showed that there is a tabular architecture between the wells studied, this occurred because of subsidence uniform

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The Cu-Au mine of Chapada is located in the municipality of Alto Horizonte, in the northwestern portion of Goiás state and is inserted in the geological context of the Brasilia Belt, specifically the Mara Rosa Magmatic Arc, which hosts important deposits of Au and Cu-Au. The rocks found in the study area belong mainly to the Volcano-Sedimentary Sequence of Mara Rosa and are composed of basic to acidic metavolcanic rocks, psammiticpellitic metasedimentary rocks, chemical rocks and also hydrothermal products. Late intrusions occur and are represented by pegmatitic dikes and tonalitic bodies. The ore deposit of the Chapada mine is formed predominantly by the chalcopyrite-pyritemagnetite association, where pyrite is the most abundant mineral. Through the structural mapping of the mining fronts, it was able to recognize three deformational phases (Dn, Dn +1, Dn +2). During the Dn phase, isoclinal recumbent folds were formed, in association with amphibolites facies metamorphism. Later, in phase Dn +1, there was formation of drag folds and intrafolial folds in association with retrograde metamorphism in the greenschist facies. The deformational phase Dn +2, in its turn, was responsible for late symmetrical folding of the foliation, with NS and EW axes, resulting in an interference pattern of the dome-and-basin type

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The study area is located in the southern portion of Rio Itapicuru Greenstone Belt, Bahia, where were found rocks that belongs to the Canto Sequence, that comprises felsics and intermediary rocks, beyond metasediments. The studied maps and drill holes help to recognized stratigraphy column that was divided in three mains domains, from the base to the top: andesitics to felsics lavas domain, carbonaceous and metasedimentary domains. The data obtained in mapping and petrography analysis allows classify the area in three deformational phases, Dn, Dn+1, Dn+2. The metamorphism recognized according to the mineralogical associations permitted to classify a progressive regional metamorphism (lower to medium greenchist facies) till biotite zone, falling until chlorite zone due to retrometamorphism. The auriferous mineralizations are mainly related to hydrothermal veins included in the different lithologies, mainly in carbonaceous schists

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The Rio Claro Formation, Tertiary-Quaternary age, is composed of unconsolidated sediments deposited by fluvial systems. In Paulínia (SP) region geological studies comprising sedimentological, structural and geomorphological aspects indicate that the Rio Claro Formation is constituted by deposits of a meandering fluvial system. Data from SPT drillings were used to obtain sedimentary textural information in order to generate stochastic stratigraphic models. Particle size analysis was carried with the core samples which resulted in the distinction of five litofacies, three of which can be grouped into only one mudstone unit. The other two facies represent channel belt facies, being clayey sands and medium to coarse sands. Geostatistical modeling of the stratigraphic architecture followed together with correlation of analogue outcrop data and conceptual models for this type of depositional system. 100 models were generated with the SPT drillings and 50 models were generated with data from an analogue outcrop, which allowed constraining of both simulation sets to the depositional model given for the region. T-PROGS methodology has good applicability in simulating stratigraphic frameworks and its inherent limitations may be approached with parallel studies, such as stochastic modeling of analogue outcrops or geophysical methods

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The main purpose of this work is to evaluate the chemical composition of the groundwaters from Guarani Aquifer System and Serra Geral Aquifer System in the Rio Pardo basin, located at the southwestern of São Paulo state. To the hydrochemical characterization, physicalchemical analyses from 32 sampled wells were used. These results were plotted in Piper diagrams allowing the classification of groundwater as calcium or calcium-magnesium bicarbonate type and sodium bicarbonate type for both aquifer systems. Distribution of hydrochemical facies over the study area was obtained using Stiff diagrams. The groundwater can be classified, representing in this sequence its hydrochemical evolution. The recognized mechanisms responsible for groundwater evolution are dissolution of minerals magnesium, such as olivine, present in the basalt, dissolution of feldspars and removal of the carbonate cement of the sandstones mineral framework. Ionic exchange may represent an important processes in the groundwater evolution, responsible for the increase in the sodium concentration and decrease of calcium

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The detailed study of the Brazilian continental margin basins became possible with the advancement of geophysical tools, with emphasis on seismic reflection. Characterizing the structural and stratigraphic elements of Brazil’s marginal basins they realized that there was a relationship with structures present on the adjacent continental basement. So many works began to be made to understand this relationship and know the major factors that influenced the evolution of the continental margin. The study area of this work includes the northern portion of the Campos Basin and the continental outcropping adjacent areas, which corresponds to the northern of Rio de Janeiro state and the southern of Espirito Santo state. This area stands an important structural feature of NW-SE direction with a projection to the Campos Basin called Lineamento de Piúma. The outcropping basement rocks belongs to the Ribeira Belt which was bonded to other mobile bands forming the continent Western Gondwana during the Brasiliano Cycle, which later fragmented giving rise to the Atlantic Ocean. The opening of the ocean results on the formation of the marginal basins of Brazil. These basins have continental, transitional and marine facies. On Campos Basin the continental phase resulted on the formation of horsts and grabens bounded by synthetic and antithetic faults. Continuing rifting formed the saline lakes that deposited siliciclastic and carbonate sediments. The transitional phase resulted on thick packages consist of evaporites (halite and anhydrite) that was deposited in lagoon environment, tectonically quiet arid and semi-arid. The marine phase it deposited siliciclastic and carbonate in the Campos Basin resulting in shales, marls, limestones, ritmito, turbidites, sandstones and others. The objective of this study is to investigate the possible continuation... (Complete abstract click electronic access below)

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The carbonatic rocks have great importance in petroleum geology, since most hydrocarbons reservoirs in the world are associated to this kind of rock. The new giant petroleum fields discovered in the Brazilian southeast Atlantic margin are directly connected to calcareous rocks, which are subjacent to the Aptian evaporite pack. This demand an increase in the number of geologists able to study such deposits. The Aptian carbonatic platform is completely exposed only in the Sergipe-Alagoas Basin. Therefore, it works as a natural laboratory to the study and understanding of this kind of rock. The Sergipe Basin is situated in the east Brazilian coast, and has its evolutional history is intimately related to the formation of the South Atlantic Ocean, through the break-up of the Gondwana supercontinent. The marine sequence of the Brazilian marginal basins is of Albian age and is marked by the development of carbonatic platforms. In doing so, this paper aims to analyze the Albian limestones from Riachuelo Formation of the Sergipe Basin. The project gave to the student the opportunity to increase his knowledge in carbonates, due to the laboratory and outdoor activities. The studied deposits, within a regional outline, were petrografically described, allowing interpretations about the evolution of the former South Atlantic Ocean. Ten points were visited where samples were collected for making of thin sheets. In this work several carbonatic facies were identified totaling 116 laminates described.

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The Itararé Group is the record of one of the most significant glaciation events of the Gondwana. Of neocarboniferous-eopermian age, this unit has facies associations interpreted as resulted from shallow marine settings with glacial and deglacial water influence. The role of glaciers on the tectonic-sedimentary processes of the Itararé Group is striking, as typical facies such as diamictites, tilites, shales and rhythmites with dropstones are generated, besides the existence of glacially striated and polished surfaces. This work had as main goal to contribute to the geological knowledge of the Itararé Group in the central eastern portion of São Paulo State, using as basis outcrops from Itu, Salto and Porto Feliz, and also pertinent bibliographic data and well profiles located in the surrounding areas. About the stratigraphic framework, genetic association and paleogeography of these deposits, this work concludes that the area studied comprises the basal section of the Itararé Group. The stacking of the facies recognized during the field work begins with the striated and polished surfaces of the basement, described in Salto, superposed by tilites and diamictites with glacial movement features. Over these are the turbidites from Itu, associated with the glacier retreat. The outcrops of Porto Feliz are at the top of this succession, with deposits generated by flows with lateral and vertical variations, sometimes with prevalence of tractive conditions, and sometimes with sediments transported largely by suspension. Paleocurrent measurements show main flow directions towards NW, the same as glacial striae, suggesting the influence of reworking of sediments by the meltwater during deglacial periods

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The Pirambóia Formation is a lithostratigraphic unit of the Paraná Basin, positioned between the Corumbataí (lower) and Botucatu (upper) Formations on the eastern edge of the basin. This unit is focused by many studies due to its great importance as an essential component in the Guarani Aquifer System (SAG) and the petroleum system “Irati-Pirambóia”, as excellent reservoirs. The Pirambóia Formation is historically the subject of several controversies on issues like age, contact relationships with the upper unit and depositional paleoenvironment. Despite these aspects, the Pirambóia Formation is commonly taken to be of Triassic age and is considered a product of wet aeolian systems, with plenty of wet interdunes and subordinate fluvial facies. In this work, by using techniques such as facies analysis, depositional architecture and facies association, facies of this unit were characterized and their depositional paleoenvironment was inferred particularly in Jundu Mining, region of Descalvado in northeastern São Paulo. Techniques such as grain size and petrographic analyses, aimed to characterize this unit as a potential reservoir rock. Five facies were described for the Pirambóia Formation in the studied region: St, Sh, Sm, Sr and Gt facies, generated by sedimentary processes of the bottom load type, mostly under low flow regime (with exception for the Sh facies, which is formed by upper flow regime processes). In addition to that, four facies associations were recognized from the architectural elements, primarily contained within the main channel: complex channel bars, composed by foreset macroforms (FM), sandy bedforms (SB) and gravel bars and bedforms (GB); flood deposits, constituted by laminated sand sheets (LS); deposits of hyperconcentrated flows and eolian deposits. It was interpreted that the Pirambóia Formation in Descalvado (SP) is the record of the sedimentation of braided rivers, with dunes and interdunes deposits...

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A wedge facies cycle it‟s a body of sedimentary rock, bounded above and below by unconformity and which represents a transgressive-regressive cycle of deposition. This cycle is formed by the following succession of facies: non-marine (N), transitional-coarse texture, and marine-fine texture; The objective of this study have been members of the sandstones and Triumph Siderópolis, seconded by rare calcareous sandstones and very thin limb Paraguaçu. Through analysis of facies in wells testified by CPRM, it was possible to group on facies successions and set the standard stacking. The Triunfo Member consists of three cycles of facies, lithology whose standard indicates a vertical arrangement ''type'' tuning up, other words, a component sandy bottom in the form of '' box'', followed by components sandy-clayey and clayey-carbonaceous (1st and 2nd cycle) and / or shale and limestone (3rd cycle), represented by the base member Paraguaçu. The first cycle only occurs on NF-5 wells and NF-6 in the form of Onlap channel dug in post-Itararé group. The cycle II also reaches wells NF-4 and NF-3 to the north, while the cycle III reaches the southern area, well NF-9. The member Paraguaçu, well PP-25 is predominantly clay-síltico, also stand out limestones and sandstones. The limestones are not coastal marine organisms probably connected with the algae and cyanobacteria, the sandstones are fine-textured, very thin and coastal deposition environment. The member Siderópolis, well NF-2 consists of a sandstone fluvial-estuarine deployed in the valley section, and succeeded by sandstones and siltstones bioturbed, they have linked the transgression of the Fm. Palermo

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The study area is located in the geological parameters of the Pilar de Goiás Greenstone Belt (GO), it is part of the Pilar de Goias Group’s meta-volcano-sedimentary sequence. This is a homoclinal package constituted by terrigenous metassediments containing intercalations of meta-ultramafic rocks and iron formations. The units that were informally named in this work, are interpreted as belongs to the Serra do Moinho Formation. Through mineralogical associations the area’s metamorphism were classified as high greenschist facies garnet zone. Prior to this work were detected in the area, through soil samples, some auriferous anomalies. One of the objectives of this work is the detection of possibles hidrotermal alterations related to these anomalies presents in the study area

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)