Geologia, petrografia e geoquímica das associações leucograníticas e TTG arqueanos da área de Nova Canadá (PA) Domínio Carajás

O mapeamento geológico realizado na área de Nova Canadá, porção sul do Domínio Carajás, aliado aos estudos petrográficos e geoquímicos, permitiram a caracterização de pelo menos três novas unidades que antes estavam inseridas no contexto geológico do Complexo Xingu. São elas: (i) Leucogranodiorito Nova Canadá, que é constituído por rochas leucogranodioríticas mais enriquecidas em Al₂O₃, CaO, Na₂O, Ba, Sr e na razão Sr/Y, que mostram fortes afinidades geoquímicas com a Suíte Guarantã do Domínio Rio Maria, as quais também podem ser correlacionadas aos TTGs Transicionais do Cráton Yilgarn. Estas rochas apresentam padrão ETR levemente fracionado, mostram baixas razões (La/Yb)N e anomalias negativas de Eu ausentes ou discretas; (ii) Leucogranito Velha Canadá, caracterizado pelos conteúdos mais elevados de SiO₂, Fe₂O₃, TiO₂, K₂O, Rb, HFSE (Zr, Y e Nb), das razões K₂O/Na₂O, FeOt/(FeOt+MgO), Ba/Sr e Rb/Sr. Apresentam dois padrões distintos de ETR: (a) baixas à moderadas razões (La/Yb)N com anomalias negativas de Eu acentuadas; e (b) moderadas à altas razões (La/Yb)N, com anomalias negativas de Eu discretas e um padrão côncavo dos ETRP. Em diversos aspectos, as rochas do granito Velha Canadá mostram fortes afinidades com os leucogranitos potássicos tipo Xinguara e Mata Surrão do Domínio Rio Maria, assim como aqueles da região da Canaã dos Carajás e mais discretamente com os granitos de baixo Ca do Cráton Yilgarn. Para a origem das rochas do Leucogranodiorito Nova Canadá é admitida a hipótese de cristalização fracionada a partir de líquidos com afinidade sanukitóide, seguido por processos de mistura entre estes e líquidos de composição trondhjemítica, enquanto que para aquelas de alto K do Leucogranito Velha Canadá, acreditase na fusão parcial de metatonalitos tipo TTG em diferentes níveis crustais, para gerar líquidos com tais características; e (iii) associações trondhjemíticas com afinidade TTG de alto Al₂O₃, Na₂O e baixo K₂O, compatíveis com os granitoides arqueanos da série cálcioalcalina tonalítica-trondhjemítica de baixo potássio. Foram distinguidas duas variedades: (a) biotita-trondhjemito com estruturação marcada pelo desenvolvimento de feições que indicam atuação de pelo menos dois eventos deformacionais em estágios sin- a pós-magmáticos, como bandamentos composicionais, dobras e indícios de migmatização; e (b) muscovita ± biotita trondhjemito que é distinguido da variedade anterior pela presença da muscovita, saussuritização do plagioclásio, textura equigranular média e atuação discreta da deformação com o desenvolvimento de uma foliação E-W de baixo angulo. A primeira variedade destes litotipos, que ocorre predominantemente na porção norte, tem ocorrência restrita. Com intensa deformação e prováveis feições de anatexia (migmatitos) podem indicar que estas rochas tenham sido afetadas por um retrabalhamento crustal, ligado à geração dos leucogranitos dominantemente descritos na área. Os trondhjemitos do sul da área são mais enriquecidos em Fe₂O₃, MgO, TiO₂, CaO, Zr, Rb, e na razão Rb/Sr em relação aos trondhjemitos da porção norte da área. Estas exibem ainda padrões fracionados de ETR, com variações nos conteúdos de ETRP, além da ausência de anomalias de Eu e Sr, e baixos conteúdos de Y e Yb. Tais feições são tipicamente atribuídas à magmas gerados por fusão parcial de uma fonte máfica em diferentes profundidades, com aumento da influência da granada no resíduo e a falta de plagioclásio tanto na fase residual como na fracionante. Em uma análise geral, a disposição dos trends geoquímicos evolutivos de ambas as variedades sugere que estas unidades não são comagmáticas. As afinidades geoquímicas entre as rochas da área de Nova Canadá com aquelas do Domínio Mesoarqueano Rio Maria, poderiam nos levar a entender a região de Nova Canadá como uma extensão do Rio Maria para norte, enquanto que para aquelas do Leucogranito Velha Canadá, que são mais jovens e geradas já no Neoarqueano, se descarta a idéia de associação com os mesmos eventos tectono-magmáticos que atuaram em Rio Maria.

Geology, petrology and geochronology (Pb-Pb) of the Serra da Bocaina Formation: evidence of an Orosirian Amoguijá Magmatic Arc in the Rio Apa Terrane, south of the Amazonian Craton

Neste trabalho apresentam-se os resultados do mapeamento geológico e caracterização petrológica da Formação Serra da Bocaina, pertencente ao Arco Magmático Amoguijá do Terreno Rio Apa, sul do Cráton Amazônico. A Formação Serra da Bocaina, na serra da homônima, consiste de rochas vulcânicas paleoproterozoicas de composição intermediária a predominantemente ácida, classificadas como andesito e riolitos, subdivididas em cinco fácies petrográficas sendo quatro piroclásticas e uma efusiva, que mantêm contato tectônico, a leste, com o Granito Carandá. Nas rochas estudadas estruturas tectônicas são formadas em duas fases deformacionais compressivas de natureza dúctil e dúctil-rúptil, respectivamente. A primeira fase, mais intensa, é observada ao longo de toda a área estudada e é responsável pela Zona de Cisalhamento Santa Rosa enquanto a segunda fase é mais discreta e localizada. O tratamento geoquímico indica que essas rochas foram geradas num ambiente de arco-vulcânico a partir de um magmatismo calcioalcalino de médio a alto-K, peraluminoso. Estas rochas retratam um evento magmático extrusivo, de natureza explosiva, relacionado à evolução do Arco Magmático Amoguijá, conforme resultado Pb-Pb em zircão de 1877,3 ± 3,9 Ma., interpretada como idade de cristalização destas rochas.

Mapeamento geológico - estrutural do astroblema de cerro do Jarau - RS Brasil

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

Análise de métodos de mapeamento de perigo: uma proposta de elaboração de mapeamento de perigo de escorregamento planar de solo via utilização do método participativo

This final assignment aimed to promote a critical analysis of methods of preparation mappings danger of landslide and presentation of proposed development from the use of participative method, as an instrument to facilitate the identification of adverse geological processes. There search was executed from literature review about concept associated with geological dangers theme and the typology and characteristics of gravitational mass movements. We analyzed particularly the so-called methods of mapping danger tradicional/classic and alternative. It is believed, that integrating the work of specialists with the participation of involvedagents (local community and stake holders). This literature review and proposed work do noted in itself. You need the continuing advance in the discussion, debates and research on this topic as well as public policies that act on problems identified more concretely

Mapeamento geológico e petrografia do alvo T-578 - Greenstone Belt Pilar de Goiás (Pilar de Goiás - GO)

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

Caracterização metamórfica do Greenstone Belt de Guarinos - GO

The study area comprises Guarinos Greenstone Belt which is located in the centralwest state of Goias and has an approximate size of 280 km2. The present work has as main objective to characterize the metamorphism of the greenstone belt and the relationship between the tectonic events and the metamorphism. For the execution of the work we used data collected in the course Geological Mapping of Crystalline Area of the geology course of UNESP, classes 2009 and 2010, the data collected by Alex Choupina Joaquim Andrade Silva in his master's thesis and the information collected in field in the study area. This compilation of data allows approximately 200 thin sections have been evaluated and allowed the construction of the metamorphic map in scale 1:125.000, also allowed the preparation of the geological map in scale 1:125.000 greestone belt, based on 1:25.000 scale maps performed by students of UNESP and the mapping conducted by Silva (2011). The study area was divided into two tectonic compartments depending on the Shear Zone Engenho Velho that longitudinally crosses study area, with direction approximately NW-SE. The west compartment is bordered by granite-gneiss complex and the east compartment, seems thicker to the south and narrows gradually towards the north and its structure is seen in general as a great monoclinal with NW-SE direction with trim to SW, this way your stack was considered as a package of rocks at the base and metaultramafic metamafic the top, with a second package in tectonic contact, which is composed of detrital and chemical metasedimentary rocks. The east compartment is represented by the intrusion of a large granitic body surrounded by amphibolites and metasediments, is bounded on the east by a granite-gneiss complexes through thrust fault, and is bounded on the west by the other compartment. The structure of the compartment is seen as a major axis oriented roughly... (Completo abstract click electronic access below)

Análise de dados pedogeoquímicos de multielementos visando o refinamento de mapeamento geológico de detalhe em alvos de Pb-Zn nos municípios de Adrianópolis, Cerro Azul e Tunas do Paraná (Vale do Ribeira, PR)

In order to to research, the region of Perau, base metal mineralization, Grupo Votorantim Metals conducted a soil sampling on targets predetermined holding its chemical analysis. These reviews have been provided by the company for this work was to evaluate the potential use of these data pedogeochemical multi-element for refinement of the work of geological mapping. We selected six targets: Varginha, Salvador, Guararema Taquara Lisa and Coffin of Mendes, in the municipalities of Adrianople, Cerro Azul and Tunas do Paraná, located in Vale do Ribeira (PR). Both have about 10 km2 and situated in the geological context of the Fold Belt Terrane and the Massif de Joinville. The main rock types are present metasedimentary rocks of low to medium grade metamorphic, interspersed the amphibolites ortoderivados, both belonging to the Complex Perau, gneisses and migmatitic Complex. Applied to the geochemical data descriptive statistical techniques (variogram, kriging and histogram). From the correlation between the distributions of elements with the geological data, we could assess the potential of the proposed methodology.

Caracterização geológica da terminação norte do Domo de Ambrósio - Bahia

The Ambrósio dome is a granodioritic batholiths of elliptical geometry, 40km length in the N-S direction and variable width of up to 8 km, has a weakly deformed nucleus with intensely deformed margins, in its northern portion is intruded in orthogneiss that belong to the Archean basement, and its southern part comes in direct contact with the volcano-sedimentary sequence of Paleoproterozoic Rio Itapicuru Greenstone Belt (RIGB), Bahia. From geological mapping on 1:25:000 scale were recognized two structural domains, termed West Domain and East Domain. From investigation of these domains was identified a major shear zone, which puts in contact two distinct stratigraphic sequences, one west, consisting primarily of metavulcanic and metapyroclastic rocks with records of low-grade regional metamorphism, and east discontinuity a metassedimentary domain, with record of gradational contact metamorphism, deformation and compression generated from the rise of Ambrosio Pluton. Such records put into question the structural and stratigraphic models in the literature so far

Geologia do platô N6 - província mineral de Carajás (SP)

The N6 Plateau presents an iron-ore occurence in Carajás Mineral Province, standing near to actually operating deposits. Geological mapping in 1:10,000 scale and integration of geochemical, geophysical, petrography and drilling turns possible interpretation of his geological evolution. The mapped area has lithotypes from Archean Grão Pará Group, comprising very lowgrade metamorphic basic rocks and iron formation and an Proterozoic sedimentary association of conglomeratic sandstones called as Caninana Unity. The structural geology in given by a regional scale homoclinal, where the Grão Pará Group strata dips towards SW, as a part of the Northern Limb of the Carajás Fold. Subsequent deformation associated to the installation of the Carajás Shear Zone presents as E-W fold axis. Geochemical evidence permits to consider de Parauapebas Formation as the rocks which has been hydrothermally-altered to outsourcing fluids responsible to deposition of iron formations in the oceanic system, including different signatures which can be interpreted as possible sub-embayments in the Carajás Basin. The iron ore in the area occurs in subsurface as very fine friable hematite generated by supergenous enrichment of the iron formation. The conceived geologic model differs from the current academic proposal on the fact that hydrothermal alteration has been involved on the jaspelite enrichment. Metamorphism on the Parauapebas Formation presents paragenesis considered as ocean-floor metamorphism which precedes de deformation insofar as the rocks show no tectonic fabric referring to shallow crust evolution. Geophysical methods such as magnetometry and gravimetry presents excellent results for structural interpretation in uneven exposed terrain

Geologia da região da Fazenda Salobo, Vazante - MG

Important deposits of Zn-Pb associated with the Vazante Group, and Au in Group Canastra occur in the Vazante-Paracatu region (MG). They are located in the Brasília Fold Belt, which was generated from a convergent tectonic in the Brasiliano cycle, forming a complex system of imbricated nappes and faults. This study aims to characterize stratigraphic, structural and metamorphic aspects of an area, located in the Salobo’s farm region. A geological mapping in 1:20,000 scale was executed in order to identify the outcropping lithotypes and to collect structural measures. Drill holes were described to support the surface data and samples were selected for the preparation of thin and polished sections. In this context, the occurrence of rock types and hydrothermal processes that had not been previously described were found, for example layers of phosphatic quartzite in the Serra do Poço Verde Formation (SPV), hydrothermal hematites from martitization magnetite in contact by detachment of the Serra do Garrote Formation and SPV in the Vazante Group and layers of microbanded iron formations in Paracatu Formation (Canastra Group). In the area, four deformational phases were recognized, occurring progressively, in which two of them are related to convergent tectonic, with the development of thrust faults, one is associated to tectonic escape and/or reactivation of basement faults and the last has a distensive character, representing the post-convergence relaxation. The metamorphism in the area was subgreenschist facies, reaching lower greenschist, with temperatures up to 350°C

Mapeamento geológico-estrutural e potencialidade econômica dos arredores de Jacutinga - MG

This monograph presents the data of geological mapping, structural and economic research of an area of about 230 km², in the outskirts of Jacutinga / MG, south of Minas Gerais State and adjacent areas of the northeastern state of São Paulo, in compliance with the discipline of Graduation Course of Geology at the Institute of Geosciences and Exact Sciences. It consists of Socorro-Guaxupé Nappe, developed in response to the collision of cratons Parana and Sao Francisco (630 Ma ago), with mass transit to the east, affected by the coexistence of a system pushes later, with convergence to Northwest, giving rise to the intricate area of interference of the two provinces. Locally there metasedimentary rocks of molasse basin of Proterozoic- Phanerozoic transition called Eleutério; Intrusive, equigranular and porphyroid granits, polyphase, and predominantly granodioritic migmatites Anatexia of structures with different neossomas predominantly granodioritic to granitic in Group Amparo, paragneisses arcosianos, greywacke, aluminous , calc-silicate, mica schists and migmatites of the aluminous migmatites and Itapira Anatexia of multi-phase, with neossomas predominantly granodiorite, with intercalations orthogneissic homogeneous granitic to tonalitic porphyroid composition of the Amparo. We tried to draw a geological map, semi-structural detail of the area in focus, with location of mineral occurrences economically viable operation. Furthermore, this study aims to train students in basic and applied geology, using techniques learned during the undergraduate course.

Mapeamento geológico, caracterização litoquímica e potencial econômico do corpo de cromitito de Cedrolina, Santa Terezinha de Goiás - GO

Studies of mafic-ultramafic bodies have been carried out through the years due to their great use on the interpretation of geochemical and geotectonic processes that took place in Earth's history. Amongst them, chromitites are notably recognized for being excellent indicators of their parental magma chemistry and of different geotectonic environments, as well for frequently containing associated noble metals mineralization. Thus the investigation of one of this ultramafic bodies that occurs inside the Pilar de Goiás Greenstone Belt was proposed, resulting in a detailed map of the chromitites and country rocks, as well as innumerous new data on the chemistry of chromite and associated matrix and accessory minerals. These studies were based upon geological field observations, optic and Scanning Electron Microscope (SEM), besides electron microprobe and cathodoluminescence analysis performed at the “Eugen F. Stumpfl Laboratory” of the Montanuniversität Institute of Resource Mineralogy, University of Leoben - Leoben, Austria. The chromitites are composed of 40-70% in volume of chromite (~50% on average), 14-55% of talc (~30% on average), 3-60% of chromium rich chlorite (~20% on average), traces to 4% of iron hydroxides and traces to 3% of rutile (1,5% on average). The chromite occurs as large spherical aggregates or as fine grained subhedral crystals disseminated in the matrix. This aggregates have diameters of 0.3-1.5 cm (1 cm on average) and are extremely well rounded, massive to intensively fractured, and commonly deformed to ellipsoids. When observed under the microscope, these aggregates show well rounded to slightly irregular borders, but on their interiors, these structures are represented by fine to medium grained euhedral to subhedral chromite crystals that have sharp contacts between themselves. The rock's matrix is basically made of chlorite and talc that define a metamorphic foliation (Sn), being the talc an alteration product ...

Modelo petrofísico 3D do Arenito Namorado no Campo de Namorado - Bacia de Campos, RJ

The Namorado Oil Field represents the beginning of the oil exploration in Brazil, in the 70s, and it is still a subject of researches because the importance of this turbidite sandstone in the brazilian oil production. The Namorado’s production level was denominated “Namorado sandstone”, it is composed by turbidite sandstone deposited during the Albian-Cenomanian. In order to define the structural geometry of the main reservoir, geological and geophysical tools like RECON and Geographix (Prizm – Seisvision) softwares were used, and its application was focused on geological facies analysis, for that propose well logs, seismic interpretation and petrophysical calculations were applied. Along this work 15 vertical wells were used and the facies reservoirs were mapped of along the oil field; it is important to mentioned that the all the facies were calibrated by the correlation rock vs log profile, and 12 reservoir-levels (NA-1, NA-2, NA-3, NA-4, NA-5, NA-6, NA-7, NA-8, NA-9, NA-10, NA-11 e NA-12) were recognized and interpreted. Stratigraphic sections (NE-SW and NW-SE) were also built based on stratigraphic well correlation of each interpreted level, and seismic interpretation (pseudo-3D seismic data) on the southeastern portion of the oil field. As results it was interpreted on two- and three-dimensional maps that the deposition reservoir’s levels are hight controlled by normal faults systems. This research also shows attribute maps interpretation and its relationship with the selection of the reservoir attribute represented on it. Finally the data integration of stratigraphic, geophysical and petrophysical calculations lets us the possibility of obtain a detail geological/petrophysical 3D model of the main reservoir levels of “Namorado sandstone” inside the oil/gás field

Caracterização magnetométrica de Sill de diabásio na região de Limeira - SP

Pós-graduação em Geologia Regional - IGCE

Prospecção geológica e geofísica com ênfase em formações ferríferas na faixa meridional do Quadrilátero Ferrífero do Supergrupo Minas Indiviso

Pós-graduação em Geociências e Meio Ambiente - IGCE