bluuebunny/crossref_metadata_2025 huggingface dataset:
NEOTECTÔNICA DA PLATAFORMA BRASILEIRA: ESBOÇO E INTERPRETAÇÃO PRELIMINARES
Authors: Saadi Allaoua
Published: January 2016

A number of significant informations about the evidences and characteristics of a neotectonic activity in the Brazilian Platform have been gathered in the last year in different parts of the country. These permit the definition of main structural features due to reactivation of Precambrian geossutures: Crustal Descontinuity of the Two Brazils (CDTB), Crustal Descontinuity of the Right Amazonian Margin (DCMDA), Minas- Alagoas Crustal Descontinuity (DCMA), Tocantins-Araguari Crustal Descontinuity (DCTA), Crustal Descontinuity of the Upper São Francisco (DCASF), Crustal Descontinuity of the Upper Rio Grande(DCARG), Crustal Descontinuity of the Pernambuco Lineament (DCLP), Crustal Descontinuity of the Midle-Upper Paraná (DCMAP), Crustal Descontinuity of the Paraíba do Sul (DCPS).In many of them, continental rifts and individual sedimentary basins have been generated. Some were submitted to a younger compression, resulting in its tectonic inversion. These main discontinuities control the macrorelief and the regional drainage pattern, as well as the orientation and subdivision of the main hidrographic basins.Blocks limited by these discontinuities are fragmented by faults of different types and sizes resulting in a regional structure alternating subsidence and uplift.The western extremity of the Amazon Basin is partially disrupted by blind inverse faults related to the Andean Orogeny. The central and Eastern areas are cut by Riedel Shears due to E-W dextral shearing.The oriental coastal province displays different patterns from south to north. The southern and southeastern regions, are dominated by Cenozoic uplift with tilting of blocks to W and NW and domnwarping of the off-shore blocks. In the Northeastern region morphological doming is related to transpressive conditions due to E-W dextral shears.The geological and seismological data indicate horizontal, roughly NW-SE oriented compressive stresse at least in the N, NE and Center- SE areas. Gravimetric data confirm the morphotectonic interpretation.
O SUPERGRUPO RIO DAS VELHAS DA FAIXA MATEUS LEME-PITANGUI - PARTE MERIDIONAL DO CRÁTON DO SÃO FRANCISCO, MG – E SEU SISTEMA DE ALTERAÇÃO HIDROTERMAL
Authors: Romano Antônio Wilson
Published: January 2016

The studied area is located at the southern São Francisco Craton, between the northwest comer of the Quadrilátero Ferrífero and the Upper Proterozoic Bambui basin. The region comprises Archaean granite-gneisses and two supracrustal sequences: a) The Archaean Rio das Velhas Supergroup, which consists of a thick sequence of a greenstones associated with metamorphic felsic volcanites, volcano-clastic and sedimentary rocks; and b) the overlying Early Proterozoic Minas Supergroup with its widespread banded iron formations.Two major deformational events are present. The oldest Dn event can be detected only in the Rio das Velhas rocks and produced large folds with mainly E-W trending axis. The latter Dn+1 of Transamazonian age (±2,0 Ga) is a progressive deformational event, that has also affected the Minas Supergroup. It produces NW-SE to NE-SW folds associated to conspicuous planar and linear structures. This event envolved to a NW-vergent thurst system with the development of a strong stretch lineation. This event also produced strike-slip faults interpreted as tear-faults parallel to the direction of the thrusts.This paper deals with the large hydrothermal alteration which has affected the lower volcanoclastics rocks of the Rio das Velhas Supergroup. This alteration has been produced by a solfataric hydrothermal system in mesothermal P-T conditions. It produced a high aluminium mineralogical assemblage of corundum, kyanite (minor andaluzite) and muscovite. This mineralogy is latter retrograde altered to diaspore, pyrophyllite, kaolinite. Minor amounts of tourmaline, rutile, chloritoid are also present. A hydrothermal zoning with three major subdivisions is proposed as follows: high aluminium zone, sericitic (muscovitic) zone and propilitic zone. Some cristallochemical aspects of the mineralogical phases are discussed, and also the origin  of the protolite and the relationship between alteration and deformatiom. The hydrothermal system has evolved under pre to syn tectonic conditions during the Archean Dn tectonism.For this event, a model of collisional tectonics is also proposed for the area, as the Rio das Velhas Supergroup represents a former continental back-arc basin.
MAPEAMENTO GEOLÓGICO DA REGIÃO DA SERRA DOS TURVOS, CARATINGA (MG), SETOR SUL DO ORÓGENO ARAÇUAÍ
Authors: Queiroga Gláucia , Novo Tiago , Pedrosa-Soares A. C.
Published: January 2016

A área de estudo situa-se na parte sul do núcleo cristalino do Orógeno Araçuaí, próximo à fronteira com o Orógeno Ribeira. A característica fundamental da região é a abundância de rochas de alto grau metamórfico, na transição de fácies anfibolito-granulito. Uma cobertura metassedimentar neoproterozóica é a unidade dominante e está representada por paragnaisse migmatítico, bandado, com intercalações de quartzito, formação ferrífera micácea e formação ferrífera maciça. Corpos de anfibolito, pegmatito e charnockito também ocorrem na área. A principal estrutura dúctil é a foliação (Sn) regional, paralela ao bandamento composicional do granada-biotita paragnaisse. Fraturas são abundantes no quartzito e formação ferrífera maciça. As formações ferríferas são ricas em magnetita e formam corpos lenticulares com espessura decamétrica a centimétrica, concordantes com o bandamento composicional do granada-biotita paragnaisse. Preliminarmente, interpreta-se a gênese dessas formações ferríferas como sedimentar, durante a deposição dos protolitos areno-pelíticos do paragnaisse.Palavras-chave: metamorfismo de alto grau, formação ferrífera, Orógeno Araçuaí. ABSTRACT: GEOLOGICAL MAPPING OF THE SERRA DOS TURVOS REGION, CARATINGA (MG), SOUTHERN SECTION OF THE ARAÇUAÍ OROGEN. The study area is located in the southern part of the crystalline core of the Araçuaí orogen, close to the boundary with the Ribeira orogen. The main feature of the region is the abundance of high-grade metamorphic rocks of the amphibolite-granulite facies transition. A Neoproterozoic sedimentary cover is the dominant unit in the area and consists of migmatitic banded paragneiss with intercalations of quartzite, mica-bearing iron formation and massive iron formation. Amphibolite, pegmatite and charnockite bodies are also found in the area. The main ductile structure is the regional foliation (Sn) which is parallel to the compositional banding of the garnet-biotite paragneiss. Fractures are abundant in the quartzite and massive iron formation. The iron formations form lenticular bodies ranging in thickness from centimeters to decameters, which are concordant to the banding and foliation of the garnet-biotite paragneiss. Accordingly to field data, a sedimentary genesis can be suggested for the iron formations.Keywords: high grade metamorphism, iron formation, Araçuaí Orogen
ANÁLISE DE ELEMENTOS DA DIVERSIDADE NATURAL NA PROPOSIÇÃO DE CONECTIVIDADE DE HABITATS DA PORÇÃO SUDESTE DO QUADRILÁTERO FERRÍFERO, MINAS GERAIS
Authors: Campos Rachel Rodrigues de , Azevedo Úrsula Ruchkys de , Vasconcelos Marcelo Ferreira de
Published: January 2016

O Quadrilátero Ferrífero é internacionalmente conhecido por seus recursos minerais, principalmente, o ouro e o ferro e por suarica diversidade natural. As atividades minerárias, juntamente a expansão urbana, bem como outras atividades antrópicas, têm acentuadoe acelerado o processo de fragmentação de habitats nesta região. Neste contexto este estudo apresenta uma proposta para conexão deunidades de conservação na porção sudeste do Quadrilátero Ferrífero utilizando análise multicritério tendo como variáveis elementos dageodiversidade, como unidades geológicas e hidrografia, assim como da biodiversidade, incluindo fitofisionomias vegetais e áreas depossível ocorrência de três espécies de avifauna (Passeriformes) quase endêmicas de campos rupestres. Os resultados permitiram verificare comparar a importância dos elementos da biodiversidade e da geodiversidade na conectividade para a área de estudo.Palavras-chave: Diversidade natural. Biodiversidade. Geodiversidade. Conectividade. Quadrilátero Ferrífero. ABSTRACTANALYSIS OF ELEMENTS OF NATURAL DIVERSITY IN THE PROPOSITION OF HABITAT CONNECTIVITY OF THE SOUTHEASTERNPORTION OF THE QUADRILATERO FERRIFERO, MINAS GERAIS, BRAZIL. The Quadrilatero Ferrifero is internationally known for its mineralresources, primarily gold and iron and its rich natural diversity. The mining activities along with urban sprawl have led to fragmentation ofhabitat in this region. In this context, this paper presents a proposal for connecting protected areas in the southeastern portion of theQuadrilatero by using multicriteria analysis as variable elements of geodiversity as geological units and hydrology, and biodiversity,including plant vegetation types and areas of possible occurrence of three species of birds (Passeriformes) almost endemic from rockyfields of the region. The results allowed to showed the importance and compare the elements of biodiversity and geodiversity in theconnectivity for the study area.Keywords: Natural Diversity. Biodiversity. Geodiversity. Connectivity. Quadrilatero Ferrifero.
EVOLUÇÃO SEDIMENTAR DO SUPERGRUPO MINAS: 500 MA. DE REGISTRO GEOLÓGICO NO QUADRILÁTERO FERRÍFERO, MINAS GERAIS, BRASIL
Authors: Renger Friedrich E. , Noce Carlos M. , Romano Antônio W. , Machado Nuno
Published: January 2016

It is now possible to bracket the age of the Minas Supergroup with reasonable precision between about2580 Ma. (base of the Moeda Formation) and 2050 Ma. (top of the Sabará Formation) on the basis of precisezircon U-Pb age determinations from both granitic rocks of the basement and detrital zircons from quartzitesand graywackes of the Proterozoic metasedimentary sequences of the Quadrilátero Ferrífero.Three major unconformities subdivide the stratigraphic column into three sequences. The first sequencecomprises the Moeda, Batatal, Cauê and Gandarela Formations from 2580 to 2400 Ma.. The second sequencecomprises the Cercadinho, Fecho do Funil, Taboões and Barreiro Formations (the Piracicaba Group) datedat 2400 to 2150 Ma.. The third sequence contains only the synorogenic sediments of the Sabará Formation,deposited during the Transamazonian Event between 2150 and 2050 Ma.. This event folded andmetamorphosed the Minas Supergroup for the first time.The Sabará Formation of the Piracicaba Group has very different sedimentological characteristics fromthe other formations of this group and is exceptionally thick (about 3500 m), we therefore propose to upgradeit to the rank of a Group.Zircon age histograms of the Moeda quartzite (sample QF-1) and Sabará graywacke are similar, indicatinga common Archean source, i.e. the Belo Horizonte Complex north of the Quadrilátero Ferrífero. This impliesthat sedimentation of the Minas Supergroup in the western Quadrilátero Ferrífero is autochthonous.Periods of carbonate and Iron Formation platform sedimentation (Cauê, Gandarela and partly Fecho doFunil Formations) coincide with minor frequency of age plots of detrital zircons, indicating also a stabletectonic environment.Comparison of the Minas Supergroup with the Transvaal Sequence of South Africa revealscorrespondence not only in age but also in thickness, position of the major unconformities, lithologicalcompositions and in the position of gold and pyrite bearing quartz-pebble conglomerates.
PALINOLOGIA DE DEPÓSITOS RUDÁCEOS DA REGIÃO DE ITATIAIA, BACIA DE RESENDE – RJ
Authors: Lima Murilo Rodolfo de , Melo Mario Sergio de
Published: January 2016

The Resende Basin is associated with rifting processes which characterize the Cenozoic geologic evolutionof southeastern Brazil. Some palynological information is available from alluvial plain deposits of itssedimentary fill, the Resende Formation. Other associated deposits, having questionable relationships withthis unit, have also been mentioned in the literature. One of these consists of rudaceous deposits of alluvialfans, in which the clasts are chiefly of alkaline rocks from the Itatiaia massif. These deposits, of controversedage, include silty-sand layers, very rich in organic matter, whose palynological potential motivated the researchreported here.The palynological association suggests an Oligocene age for the deposition of the organic matter. Froma paleoecological point of view, this deposition took place under stagnant conditions, in a tropical to subtropicalclimate.Geologically, these results reinforce the idea of a close genetic relationship between the rudaceousalluvial fan deposits and the alluvial plain sediments of the Resende Formation. It is proposed here the nameof Itatiaia Formation for the alluvial fan deposits.
Editorial
Authors: Fernandes Maria Lourdes Souza
Published: January 2016

Algumas palavras sobre o Professor Correia Neves...
PROSPECÇÃO E ECONOMIA DO DIAMANTE DA SERRA DO ESPINHAÇO
Authors: Fleischer Ronald
Published: January 2016

Diamond occurs in the Espinhaço range both in alluvials and in Midproterozoic metaconglomerates.In the alluvials they are recovered by large bucket wheel dredges as well as by more artisanal hydraulicgravel-pump mining. The “Sopa” metaconglomerates were mined out in the past wherever they wereheavily weathered into very soft material amenable to artisanal hydraulic gravel pump mining.This short paper describes the main geologic features which should be considered in the study of amining project on deposits of one of these two types.An attempt is also made at giving an insight into the future of the region’s diamond mining activityconsidering that its alluvials will be exhausted in the next decade. The discovery of new deposits of thesoft metaconglomerate type - and for this sake of their kimberlitic sources - depends largely on whichgeologic model is adopted. Various models have been proposed by different authors including the riftmodel, put forward by the present author. each model will justify the adoption of a different explorationapproach.Finally, the possibility of reactivating the diamond mining industry in the region through the designof an appropriate treatment process for the recovery of the gem from the metaconglomerates of the hardsilicified facies, known as “massa gelada”, is also envisaged.
A GEOMORFOLOGIA DA SERRA DO ESPINHAÇO EM MINAS GERAIS E DE SUAS MARGENS
Authors: Saadi Allaoua
Published: January 2016

The geomorphological evolution of the Serra do Espinhaço is discussed based on: a) a critical analysisof previous papers about the geomorphology of the range, b) new interpretation based on own field data,c) regional interpretation, considering informations about the evolution of adjacent areas west and east ofthe range (São Francisco River, Doce River and Jeqitinhonha-Araçuaí Rivers Basins). The global contextis presented as a synthetical characterization of the main geological conditions, regional physiographyand drainage system organization and anomalies.The regional geomorphological organization is rigid controlled by the geology: a) the shape of therange reproduce the original collisional arc developed during the proterozoic orogeny, b) the existence oftwo strongly diferenciated plateaux (Planalto Meridional and Planalto Setentrional) reflect the litho-structuralcontrast between the southern and northern parts of the range, c) the morphology expresses the associationbetween lithological resistance to erosion and the tectonic organization in all scales.The morphology of the higher portions of the plateaux is characterized by relicts of two tertiaryplanation surfaces. They are probably peneplains resulting from erosion under tropical humid climaticconditions. During the Pleistocene, the valleys recorded the formation of several stepped terraces. thespacial variation on its dislevelments reflects the intensity of crustal uplifts and the position of the streamsin the drainage system hierarchy. The hillsides were, during the Upper Pleistocene, covered by two finecolluvial layers. In both cases, the cenozoic sediments register evidences of humid and hot paleoclimaticconditions.The Serra do Espinhaço acquired its present main physiography after the Miocene, which wascharacterized by tectonic stability. During the Pliocene, a strong compressional tectonic event reactivatedthe main precambrian thrust faults and detachment planes. As a consequence, the high scarp related to thewest thrust front was enhanced together with a eastward tilting of the plateaux. At the same time, in thePlanalto Setentrional, several valley heads of the São Francisco drainage basin were deviated and capturedby the Jequitinhonha Basin drainage system. In the Planalto Meridional, the geological conditions (porouslithology and anticline structure) favoured the capture of streams by the São Francisco Basin drainagesystem.As a consequence of the compressional forces that uplifted the range, an extensional stress fielddeveloped in the eastern border, generating grabens structures where the main rivers installed its valleys.The neotectonic activity is also recorded in several parts of the range and adjacent areas by normal, reverseand strike-slip faults in pleistocenic alluvial and colluvial deposits. Fault planes data analysis indicates ageneral NW-SE compressional stress field that remains up to the present time, as confirmed by results ofseismological data.(*)
A MINERAÇÃO EM MINAS GERAIS: PASSADO, PRESENTE E FUTURO
Authors: Silva Olintho Pereira da
Published: January 2016

The first Portuguese pioneers who entered the newly discovered Brazilian lands were not succesful inthe prospection of precious metals and stones. The primitive inhabitants were not enough cultivated toextract the metals from the rocks. They lived in the stone age yet. They became the sole valuable productof the “entradas” ventures. The mining in Brazil started when, in the end of the XVIII century, goldplacers were found in the lands which were later named Minas Gerais.The beginnings were terrible. The rich placers were depredated, the environment heavily spoiled byunskilled and thoughtless miners.The Portuguese royal authorities tried to recuperate the mining activities by sending to Minas Geraisthe German Metallurgical Technician, the baron W.L. von Eschwege who did a great effort to improve thegold and diamond mining works and to create alternative metallurgical undertakings.During the Imperial Times, several English ventures were organized to continue exploiting gold depositsin Minas Gerais. The majority failled being succesfull. English capital left Brazil when the South Africangold rush started in 1886.By 1910, American entrepreneurs tried to exploit the rich iron ore deposits found in the heart ofMinas Gerais state. Political controversy prevented the American from implanting the projected iron oreundertakings. Now, looking far back, some doubts remain about the feasibility of the proposed ventures.The year of 1934 marked important dates for the Brazilian mining legal structure. In 1942 werecreated the Companhia Vale do Rio Doce and the Companhia Siderúrgica Nacional.In the second half of the 1960 decade started the best times for the Brazilian mining, but by 1982 thepolitical and economical turmoils reverted the trend. Wild gold rush bursted out with great politicalsupport.In 1988 a constitutional assembly elaborated a new Charter in which foreign capital was forbidden tocontrol a mining company and the wild mining activities were deserved an encourageous treatment.Minas Gerais has always been in the heart of old mining history. This prominent position was affectedwhen the Carajás district came upon. Nobody may say this trend will be reverted.
SIGNIFICADO DA OCORRÊNCIA DE FOSFATOS E BORATOS DE ALUMÍNIO NO CONTATO ENTRE OS SUPERGRUPOS RIO PARAÚNA E ESPINHAÇO NA REGIÃO DE DIAMANTINA, MINAS GERAIS, BRASIL
Authors: Horn Adolf Heinrich , Morteani Giulio , Ackermand Dietrich
Published: January 2016

Within a muscovite-kyanite quartzite and/or muscovite-kyanite schist at the contact between the UpperArchean Barão de Guacuí Formation and the Bandeirinha Formation near Diamantina (State of MinasGerais, Brazil) five rock types defining mineral assemblages can be found: 1: lazulite, kyanite, 2: lazulite,augelite, kyanite; 3: lazulite, amblygonite, tourmaline; 4: lazulite, svanbergite, tourmaline, and 5:dumortierite, kyanite. Additional phases in all rock types are quartz and muscovite/sericite. The wholerock chemistry influences the chemical composition of the individual minerals.These ocurrences are interpreted as precipitation of aluminium, phosphorous and boron-rich sedimentaryrocks in highly alcaline lakes under sabka conditions in the Middle Proterozoic on the Archeanmetasediments of the Baraõ de Guacuí Formation.During the Brasiliano event (680-450Ma) a greenschist metamorphism and associated tectonism withthrusting the actual texture and foliation were formed. Mobilization of lazulite and its deposition intoquartz veins, cutting the over- and underlain units occurred, too.The aluminophosphate minerals get importance because they could help to define more precisely thecontact between the Rio Paraúna and Espinhaço supergroups.
COMPOSIÇÃO QUÍMICA DE CROMITAS EM CORPOS METAMÁFICO/ ULTRAMÁFICOS DA BORDA LESTE DO ESPINHAÇO MERIDIONAL, MINAS GERAIS
Authors: Angeli Nélson , Carvalho Sebastião Gomes de
Published: January 2016

The study of variation in chemical composition of chromites associated with mafic/ultramafic sequenceshas a growing in importance because presents a close relation to gold and platinum group elementsconcentration. The researched areas : Serro, Alvorada de Minas and Morro do Pilar present chromites(massive, disseminated and accessory), which show a strong zoning due to hydrotermal/metamorphicprocess. These zones reflect changes in chemical composition of crystals, which are related to neoformationof mineral paragenesis based mainly on leaving of the elements in chromites ( for example the origin ofkammererites).In chromitites from Serro and Alvorada de Minas, as well as in accessory chromites from Morro doPilar, the zoning of the grains was observed. They have a core composed by chromites (aluminous chromites)and a broad margin with ferriferous composition (chromium magnetites to magnetites). In same cases thechromite crystals have a core with primary chemical composition preserved. In the Rio Mata Cavalovolcano-sedimentary sequence a Ir-Pt alloy was found as inclusion in chromium-magnetite. In othersmafic/ultramafic complex of Minas Gerais and Ceará States, high relations of PGE and Au has beenrecorded, and they are associated with chromitites submitted to this alteration process.
EVOLUÇÃO CLIMÁTICA DO GONDWANA NA REGIÃO CENTRO-SUL DO BRASIL E SEUS REGISTROS GEOLÓGICOS CONTINENTAIS DURANTE O MESOZÓICO, ENFATIZANDO O ARCO DO PARANAÍBA, A BORDA NNE DA BACIA DO PARANÁ E A PORÇÃO MERIDIONAL DA BACIA SANFRASCISCANA, NO OESTE DO ESTADO D
Authors: Sgarbi Geraldo Norberto Chaves , Dardenne Marcel Auguste
Published: January 2016

Current theories suggest the the main cause of the temperature changes in Earth surface along thegeological time, seems to be, as a concensus, the anomalous concentration of CO2 , CH4 and other gasesin the terrestrial atmosphere. There are however divergences about the origin of these gases which are themain responsables for the greenhouse effect.This study discusses questions about the global climate changes in the geological past, commentingthe mass-extinction periods of the Permian-Triassic (P/Tr) and Cretaceous/Tertiary (C/T) boundaries. Therelationship between unusual high CO2 levels in the atmosphere and mass-extinction events is commented.The origin of the greenhouse gases are attributed to: a) extensive outgassing of volatiles through of largevolcanic events, or b) asteroid or cometary impact by bodies ranging up to 10 Km in diameters, or c)marine and terrestrial organic production by living organisms.Climatic changes have been detected in all the geological records, from Precambrian to Cenozoic.Tillites and varvites in Gondwana are features of Proterozoic and Paleozoic ice ages. The Mesozoic, onthe other hand, had a global warm climate, exhibiting generally high level sea and low thermal variationbetween the poles and the equator. The Mesozoic continental geologic records in Gondwana are consequenceof this arid climate, and the sedimentary rocks are mainly red-beds seguences or other related with arid/semi-arid environments.The relationship between the climate, geological records and paleogeographical aspects in the MesozoicCentral-South Gondwana are presented, focussing the NNE border of the Paraná and the SouthernSanfranciscana basins, which occur in the western part of Minas Gerais state. The Parecis Basin thatoccurs in Mato Grosso State is also mentioned.These basins show sequences of varied rock types -volcanicand sedimentary ones -, and exhibit ages ranging from early to late Cretaceous.Other important paleogeographic feature studied occurs as a strip of intensely deformed Precambrianrocks forming a NW-SE tectonic arch, preserved as a succession of thrust slices. This is known as Alto doParanaíba Arch or Alto do Paranaíba Anteclesis, (Ladeira et al. 1971, Grossi Sad et al 1971, respectively),a regional structure related with the emplacement of the Cretaceous Paraná and Sanfranciscana basins.
UM MODELO PARA A EVOLUÇÃO MICROESTRUTURAL DOS MINÉRIOS DE FERRO DO QUADRILÁTERO FERRÍFERO. PARTE II – TRAMA, TEXTURA E ANISOTROPIA DE SUSCEPTIBILIDADE MAGNÉTICA
Authors: Rosière C. A. , Quade H. , Siemes H. , Chemale Jr. F. , Souza E. M. Resende de
Published: January 2016

Low strain itabirite still displays primary features similar to jaspilites such as sedimentary layeringand a porous granoblastic fabric composed of martite with magnetite relics and hematite Due tosynmetamorphic deformation this mineralogy recrystallizes in specularite producing a variety of fabrics,textures and anisotropy of the magnetic susceptibility (AMS) depending mainly on the strain conditions.Folded ores usually display a foliation parallel to the banding due to flexural slip and an axial planeschistosity that results in a lepidogranoblastic fabric. The stereogram of the {11.0} texture is a singlemaximum parallel to the intersection lineation. The AMS is low and its ellipsoid is triaxial. Increasingstrain and shearing transposes and obliterates the primary banding, resulting in iron ore mylonites withlepidoblastic (S-tectonites) or nematoblastic (L-tectonites) fabrics probably depending on the shape of thestrain ellipsoid.The stereogram of the {11.0} texture of schistose ores is typically a girdle parallel to foliation. AMSintensity is high with oblate shape. Stereograms of the texture of lineated ores display a single maximumparallel to the stretch lineation. AMS is low to moderate with prolate shape. Secondary recrystallizationand grain growth does not affect the lattice preferred orientation.
O GRABEN DA FAZENDA RETIRO GRANDE E OUTROS ASPECTOS NEOTECTÔNICOS NA REGIÃO DA PRAIA DE REDONDA (CEARÁ)
Authors: Torquato Joaquim Raul , Torquato Ana Maria Pires , Moraes Roberto Mendonça de
Published: January 2016

This paper describes neotectonic characteristics on a shore area named Redonda, Icapuí county, in thenortheastern region of the State of Ceará. A moderate dimensioned graben (114m width and a maximunnet slip of 50m) was identified, including sediments of the Barreiras and Açu formations. Also, in all area,normal-, vertical-, some positive flower-faults, and conjugate fault systems, besides clastic dykes arespreaded out. A horizontal direction on the N80oW direction was identified that correponds to a maximumcompressive stress (s1)
THE ROLE OF NEOTECTONICS IN THE EVOLUTION OF THE BRAZILIAN COAST
Authors: Suguio Kenitiro , Martin Louis
Published: January 2016

Embora alguns trabalhos pioneiros sobre a neotectônica no Brasil tenham vindo a lume há mais de 40anos, o real interesse por este assunto foi despertado somente na década de 70 devido à construção denumerosas e gigantescas obras de engenharia civil, tais como as usinas hidrelétricas e termonucleares.O papel mais relevante da neotectônica na evolução do litoral brasileiro pode ser demonstrado, demaneira inquestionável, pelas bacias marginais, que são uma evidência de macro-escala (ou escalacontinental). Essas bacias foram mais ativas do Cretáceo ao Terciário, mas as falhas principais estão ativasaté hoje.O Rift Continental do Sudeste Brasileiro, compreendendo as bacias de Curitiba, São Paulo, Taubaté,Resende e Volta Redonda, representaria outro importante testemunho de meso-escala (ou escala regional)do papel da neotectônica na evolução da costa brasileira. Esta feição foi originada durante o Paleógeno econtinuou ativa durante o Neógeno e Quaternário até hoje, como uma manifestação tardia e mais interior daReativação Pós-paleozóica, cuja conseqüência mais importante foi a origem do Oceano Atlântico Sul,simultaneamente à formação das bacias marginais.Além disso, as origens das nítidas diferenciações entre as porções norte e sul da linha costeira paulista,bem como da zona deprimida do Gráben da Guanabara, ou as impressionantes feições do tipo-ria do NE dacosta do Pará e os afloramentos suspensos de rochas praiais do litoral norte-riograndense poderiam estarrelacionadas a movimentos neotectônicos de micro-escala (ou escala local), mas elas necessitam de estudosmais específicos e detalhados.Aparentemente não há dúvida sobre a relevância do papel desempenhado pela neotectônica na evoluçãodo litoral brasileiro, no entanto muitos setores desta costa ainda não foram suficientemente estudados. Poroutro lado, deve-se reconhecer que muitas dessas feições representam fenômeno de tectônica ressurgente,cuja origem remonta ao Pré-cambriano.
CADASTRO DAS ÁREAS NATURAIS PROTEGIDAS EM MINAS GERAIS
Authors: Camargos Regina M. F. , Lanna Mônica Torrent
Published: January 2016

The directory of Protected Natural Areas in the State of Minas Gerais presents data concerning thelegally protected areas at federal and state levels as well as the municipalities involved in each area, itsdimensions, especific laws and the institutions responsible for the management of these areas. These dataare basic references for the development of environmental licencing of projects and also for the definitionof aliquats of the Ecological State Taxe, regarding the protected areas. This study indicates the need forthe establishment of a State Plan for the preservation of natural areas.
DISTRIBUIÇÃO E ASPECTOS METALOGENÉTICOS DAS OCORRÊNCIAS DE SCHEELITA NO PRÉ-CAMBRIANO DO ESTADO DE MINAS GERAIS, BRASIL
Authors: Pereira Ronaldo Mello , Ávila Ciro Alexandre
Published: January 2016

This paper presents a general description of six scheelite mineralized areas in Minas Gerais State,southeastern Brazil:- Nazareno - São João Del Rei - Lagoa Dourada area where scheelite occurs confined to orthoamphibolitic rocks of the Barbacena Greenstone Belt;- Iron Quadrangle area where most scheelite occurrences are related to a auriferous shear zones of theNova Lima Group of the Rio das Velhas Greenstone Belt;Itinga - Coronel Murta - Rubelita area in the Araçuai Fold Belt where scheelite is present in calcsilicaterocks interlayered with metasedimentary schists of the Macaubas Group and in quartz vein withwolframite;- Galiléia-Mendes Pimentel area in Costeiro Fold Belt where scheelite mineralization occurs in calcsilicatelayers and quartz veins, in schists of the São Tomé Group;- Itamonte - Itanhandu area in the Ribeira Fold Belt where scheelite is related to greisen of leucocraticgranitoids cupolas;- Rio Manhuaçu - Mutum area in the Costeiro Folded Belt where the scheelite mineralization ispresent in calc-silicate xenoliths associated with granitic rocks of the Pocrane Complex.
EVOLUÇÃO DIAGENÉTICA DOS ARENITOS DA FORMAÇÃO MORRO DO CHAPÉU, GRUPO CHAPADA DIAMANTINA, NA REGIÃO DE MORRO DO CHAPÉU, BAHIA
Authors: Battilani Gislaine Amorés , Gomes Newton Sousa , Guerra Wilson José
Published: January 2016

The Mesoproterozoic Chapada Diamantina Group crops out in the central part of Bahia State, coveringthe São Francisco Craton. It is composed, from the base to the top, of the following formations: Tombador,Caboclo and Morro do Chapéu. The lower contact of the Chapada Diamantina Group is characterized byonlap with the Archean basement or by an unconformity with the Mesoproterozoic rocks of ParaguaçuGroup. The upper contact with the Una Group is unconformable and characterized by a depositional hiatus.A depositional model, a rock classification and a diagenetic evolution of the Morro do Chapéu Formation arehere presented based on stratigraphic profiles, outcrop description and microscopic studies in 45 thin sections.The rocks were deposited by transitional and fluvial systems. They show high mineralogical and texturalmaturities, and can be classified as quartz-arenites. Besides quartz and chert, which usually make up to 95 %of the rock framework, feldspars, micas, heavy minerals as well as mud and carbonate intraclasts also occur.The carbonate intraclasts are frequently silicified. The presence of these intraclasts, which come from theunderlying Caboclo Formation consists an important record of a depositional hiatus between both units.Nine diagenetic events could be recognized in the fluvial sandstones of the Morro do Chapéu Formation:mechanical compactation, mechanical clay infiltration, early hematite cementation, quartz overgrowths,pressure solution, secondary porosity generation, clay authigenesis, late diagenetic phases and telodiageneticprocesses. The transicional sandstones, display, aditionally, four other events: a second quartz overgrowthphase, an incipient dolomitization, antraxolite and gipsite authigenesis.
PADRÕES E DIREÇÕES DE DRENAGEM NA BACIA DO RIO SAPUCAÍ – SUL DE MINAS GERAIS
Authors: Magalhães Antônio Pereira , Diniz Ângela Andréa
Published: January 2016

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PRESERVAÇÃO DA ÁREA CÁRSTICA DE LAGOA SANTA – MG, ATRAVÉS DA EDUCAÇÃO AMBIENTAL
Authors: Deus José Antônio Souza de , Ferreira Claiston Cosme Damião , Rodrigues Ronan Silva
Published: January 2016

A peculiaridade do patrimônio cárstico da região de Lagoa Santa é reconhecida internacionalmente,bem como seus sítios espeleológicos e locais historicamente relevantes, com seu potencial turísticointrínseco. É necessária portanto sua preservação, buscando uma relação de custo-benefício positiva paraa comunidade local. Esse ecossistema cárstico é altamente vulnerável a depredações de carater por vezesirreversível. Neste sentido, vimos a necessidade da produção de materiais educativo-ambientais: o protótipode um “software” destinado essencialmente às escolas, e três protótipos de “folders”, destinados à populaçãolocal, turistas e empresários. Havendo interesse de instituições públicas ou privadas em patrocinar estematerial educativo-ambiental, ele poderá ser reproduzido e distribuído para a sociedade envolvente.Acreditamos que, a ação conjunta de todos os segmentos sociais, será capaz de garantir a preservaçãodesse patrimônio cárstico e promover o desenvolvimento econômico regional, de forma sustentável.
DISTINCTION DE DEUX FAMILLES THOLÉIITIQUES PARMI LES DOLÉRITES TARDI-PANAFRICAINES DU SIROUA (ANTI-ATLAS CENTRAL, MAROC)
Authors: Touil Ahmed , Bilal Essaid , El Boukhar Abdelmajid
Published: January 2016

Os granitos Neoproterozóicos do flanco oeste do maciço de Siroua (Anti-Atlas Central) sãocortados por filões de doleritos orientados N-S e E-W. Estes doleritos têm uma composição detoleritos continentais de acordo com a repartição de Cr, Ti e elementos incompatíveis; os doleritosse dividem em dois grupos químicos independente da espessura e/ou da orientação dos filões. Estes doleritos toleríticos, associados ao plutonismo subalcalino de Ida ou Iploum, são concordantes coma distensão regional que afeta o maciço de Siroia na parte norte do cráton oeste africano.ABSTRACT: The Upper Proterozoic granits of western side Siroua massif (Anti-Atlas central), are transectedby N-S and E-W doleritic dykes. These dykes have a feature of a continental tholeiites. According totheir content in Cr, Ti and their incompatible elements ratios, they can be distributed on twochemical groups unrelated of their strike and thickness. These tholeiitic dolerites combined with thesubalcalin plutonism of Ida ou Illoun are compliant with the regional distension that the Siroua massifhas undergone during the upper proterozoic.
VARIÁVEIS PLURI-DISCIPLINARES E TERMODINÂMICAS EM CONTEXTO COM ESTUDOS INTER- E TRANS-DISCIPLINARES.
Authors: Martins Jr. Paulo Pereira , Ferreira Omar Campos
Published: January 2016

This is the second paper in a series that intend to show the inter and transdisciplinary cartography.This view needs one especification of variable to be measured, studied and observed into Nature toanswer the main question about structure and function of the ecosystems. Essential means answerthe more fundamental questions about the morpho-functional condiction with the less cost. Here,will be showed in a short way the variables needed for this view. The biotic and abiotic variables areenphasized and the social-economic will be let for another study.
AVALIAÇÃO TEMPORAL E ESPACIAL DA REDE DE CIDADES DE MINAS GERAIS NO PERÍODO DE 1960 A 1991
Authors: Carvalho Aílton Mota de , Frederico Niffinegger Barbi
Published: January 2016

The paper describes and analyses the evolution in time and space, of the urban network of the State ofMinas Gerais, between 1960 e 1991, focusing on its distribution by city-size, and on the dynamics ofregional space.
GEOGRAFIA E PLANEJAMENTO: ENTRE O PURO E O APLICADO
Authors: Hissa Cássio Eduardo Viana
Published: January 2016

The objective of this study is to present some introductory ideas about concepts concerning planning.The text is meant to motivate discussions about preliminary notions referring to the concepts in question.Geography is taken as an area of knowledge which, traditionally, turns next to the practices related to theurban and regional planning. This paper also proposes a discussion about the nature of the relationshipsand boundaries stablished between what can be called pure ou applied. It is only a start point which can,later on, amplifly the improvement of the organization of criteria, priorities and strategies which surroundplanning practices.
MODELOS MORFOGENÉTICOS E TECTÔNICA GLOBAL: REFLEXÕES CONCILIATÓRIAS
Authors: Saadi Allaoua
Published: January 2016

The user of models of relief formation and evolution should be surrounded by precautions basedon the previous understanding of the theoretical assumptions that support them. The case of therelationship between geomorphological dynamics and tectonic activity in reviewed on the basis ofnew geotectonic concepts. Davis and Penck's models occurred when the paradigms of "GlobalTectonics" had not yet been enunciate. For that reason they are usually presented as antagonisticmodels. However, when analyzed in the expressions, they present some compatibility and/orcomplementarity. The differences in their formulations tend to express the regionally observeddifferences in terms of magnitude, rates, and frequencies of the morphotectonic phenomena. Thelatter, actually, result from specificities of the geotectonic contexts. A simple solution to theproblem of theoretical modeling in geomorphology would be to reason based on the notion of"rhythms" applied to the theree fundamental factors controling relief formation from regional tocontinental scale: Climate, Tectonic, and Sea Level.
TRATAMENTO GRÁFICO E MATEMÁTICO-ESTATÍSTICO DE DADOS MULTIVARIADOS: ANÁLISES DE AGRUPAMENTOS A PARTIR DAS TÉCNICAS MATRIZ ORDENÁVEL, COMPONENTES PRINCIPAIS, WARD E K-MÉDIAS
Authors: Santos Márcia M. Duarte dos , Sanchez Miguel C. , Mingoti Sueli Ap.
Published: January 2016

In this paper some methods commonly used in multivariate cluster analysis are discussed and compared byusing a specific data set. The main objective is to show that the graphical method is efficient and similar tothe Ward and K-Means methods which are based upon mathematical and statistical theories. Thesimilarityfound between the graphical and the statistical methods suggests that although it is more subjective thegraphical method is a valid technique that could be used to determine the clusters of a sample or a population.,
HOMENAGEM AO PROF. CORREIA NEVES
Authors: CPMTC-IGC-UFMG Diretor do
Published: January 2016

Este volume de Geonomos é dedicado ao cientista que pavimentou a estrada da pesquisa científica em Geologia no Instituto de Geociências da Universidade Federal de Minas Gerais, pregando a necessidade da permanente geração de conhecimento, estruturando equipes e realizando projetos, cavando recursos e formando pesquisadores criando o Centro de Pesquisa Professor Manoel Teixeira da Costa e o Curso de Mestrado em Geologia. Este cientista se chama Professor Correia Neves.[...]Prof.Antônio Carlos Pedrosa-SoaresDiretor do CPMTC-IGC-UFMG
DEPÓSITOS DE ALEXANDRITA DE MALACACHETA, MINAS GERAIS
Authors: Basílio Márcio Silva , Pedrosa-Soares Antônio Carlos , Jordt-Evangelista Hanna
Published: January 2016

Since 1975, alexandrite [Be(Al2-xCrx)2O4], the chromium-bearing crysoberyl variety, has been exploitedfrom alluvial and paleo-alluvial deposits in the Malacacheta region. The alluvial deposits consist ofresedimented gravel along the present drainage streams. The paleo-alluvial deposits are richer in alexandrite,and show well-developed soil horizons covering the alexandrite-bearing gravel layer. Alexandrite grainsshow angular shapes with very sharp edges, suggesting transport for short distances. The country rocks arequartz-mica schist and peraluminous mica schist (Salinas Formation), covered by alternating mica schistand quartzite layers (Capelinha Formation). Both formations are of Neoproterozoic age. They host tectonicslabs of metaultramafic rocks, and are cut by intrusive granites of Cambrian age. No alexandrite-bearingrock has been found in the area, probably due to the intense tropical weathering. However, some of themapped rocks are sources for Be (granites), Cr (metaultramafics) and Al (peraluminous schists), the essentialelements for alexandrite crystallization. We suggest a metasomatic system of Cambrian age for alexandritegenesis in the area, involving the interaction of granite-related Be-rich fluids with metaultramafic rocksand peraluminous schists.
Necessity of the Establishment of a Financial Derivatives Market in Bangladesh
Authors: Rahman Md. Habibur , Chandra Das Bijoy
Published: January 2016

Derivatives instruments have been a feature of modern financial markets for several decades. They play a pivotal role in managing the risk of underlying securities such as bonds, equity, equity indices, currency, and short-term interest rate asset or liability positions. With the development of Bangladesh’s market economy, it is now becomes very essential of the establishment of a financial derivatives market in this country. In our article is has been tried to explain in detail the theoretical framework of various types of derivatives and their potential usage in strengthening capital market, capital structure of commercial banks, against the fluctuation of major import(petroleum) and export(RMG) sectors, and thus turning Bangladesh’s economy into a strong global one. In the last part of our study, some strong recommendations with the suggestion of phase by phase establishment of a financial derivatives market are included.
Political Culture in Post-Communist Countries: Albanian Case
Authors: Malltezı Orinda
Published: January 2016

The goal of this article is to establish the degree of interrelation between state and society as well as the implications that come from this interrelation by focusing on the Albanian case. If the state is perceived in relation with the society, then what comes as a result of this relationship will be seen as Plexus. On the other hand, Nexus is the way the Albanian society perceives the relation between state and society mostly represented by the functioning of state, where the state is the central axis and the society has no influence on it. This derives mostly from the political culture which has been shaped during communism. Countries that experienced totalitarian regimes tend to have similar behavior and perception towards politics which is the product of political culture. In this regard, the political culture in post-totalitarian regimes shares similar elements such as: lacks of civic participation, lack of public on governments or politics, etc.
Cerebral Lateralization of the EEG During Perceptual-Motor Integration in Young Adults With Down Syndrome: A Descriptive Study
Authors: Chen Chih-Chia , Ringenbach Shannon D. R. , Biwer Arielle , Riekena Abbie
Published: January 2016

Background: This study was aimed at investigating cerebral laterality of perceptual-motor integration in persons with DS. Method: Fourteen persons with DS between the ages of 12-39 drummed with their dominant hand (e.g., right hand) following verbal (i.e., drumming to a voice saying "drum"), rhythm (i.e., drumming to the sound of a drum being hit) and melody (i.e., drumming to the loudest beat) instructions. Electroencephalogram (EEG) data at T3 (left hemisphere) and T4 (right hemisphere) was collected and computed as cerebral specialization coefficients during drumming performance. Results: It seems like that our results were consistent with the model of atypical hemisphere processing of verbal information in the right hemisphere in persons with DS, which is opposite to the typical population (Elliott et al., 1987). In addition, the results showed that melody instructions were right hemisphere specialized and rhythm instruction was left hemisphere specialized in persons with DS. Conclusions: This is the first study to systematically examine verbal, rhythm and melody processing in persons with DS. Rhythm and melody are two main components of music. Therefore, these results are promising for understanding mechanisms underlying cerebral processing as well as music therapy for persons with DS.
Detecting Fracture Growth Out of Zone by Use of Temperature Analysis
Authors: Ribeiro Priscila M. , Horne Roland N.
Published: January 2016

Hydraulic fracturing is a widely applied well-stimulation technique. Recently, the application of multiple hydraulic fractures along horizontal wells has made possible the exploitation of unconventional reservoirs, such as shale gas and shale oil. However, the process of horizontal-well fracturing is uncertain and it is not fully understood yet. There exist many questions about the number and position of created fractures and whether the fracture stays contained within the main reservoir thickness.

This work presents the modeling and analysis of temperature data during and after the creation of multiple fractures along a horizontal well. Our model accounts for fracture growth and closure, the well effects, and interaction between multiple fractures.

The interference between multiple fractures growing simultaneously and the presence of reservoir-permeability heterogeneity were investigated. Capabilities and limitations of information carried by temperature data are presented through different geometry analyses.

A special consideration of fracture growth out of zone was addressed. For this case, it was considered that one of the hydraulic fractures activates a pre-existing fault and interconnects the reservoir with other zones hundreds of feet away.

Our work shows the advantage of the use of continuous-distributed-temperature data in comparison with the traditional single-point-pressure analysis. The local characteristic of temperature allows us to identify not only which of the created hydraulic fractures has interconnected the main reservoir with a different zone, but also the location of this zone. We also account for the effect of the interconnection on the growth of the other hydraulic fractures along the horizontal wellbore.

The simultaneous multiple fracture growth shows that falloff-distributed-temperature data can predict the number of created fractures. More than that, in the presence of heterogeneity, the interaction between the contained fractures can be captured by the temperature analysis. Different from the pressure analysis, distributed-temperature data can differentiate between heterogeneity locations along the wellbore.

Throughout this study, we present a series of examples in which the temperature can provide information that would not be obtained from the traditional pressure analysis.