O problema do Hiker Dice em tabuleiro compacto: um estudo algorítmico

The Hiker Dice was a game recently proposed in a software designed by Mara Kuzmich and Leonardo Goldbarg. In the game a dice is responsible for building a trail on an n x m board. As the dice waits upon a cell on the board, it prints the side that touches the surface. The game shows the Hamiltonian Path Problem Simple Maximum Hiker Dice (Hidi-CHS) in trays Compact Nth , this problem is then characterized by looking for a Hamiltonian Path that maximize the sum of marked sides on the board. The research now related, models the problem through Graphs, and proposes two classes of solution algorithms. The first class, belonging to the exact algorithms, is formed by a backtracking algorithm planed with a return through logical rules and limiting the best found solution. The second class of algorithms is composed by metaheuristics type Evolutionary Computing, Local Ramdomized search and GRASP (Greed Randomized Adaptative Search). Three specific operators for the algorithms were created as follows: restructuring, recombination with two solutions and random greedy constructive.The exact algorithm was teste on 4x4 to 8x8 boards exhausting the possibility of higher computational treatment of cases due to the explosion in processing time. The heuristics algorithms were tested on 5x5 to 14x14 boards. According to the applied methodology for evaluation, the results acheived by the heuristics algorithms suggests a better performance for the GRASP algorithm

Renderizações não fotorealísticas para estilização de imagens e vídeos usando areia colorida

Non-Photorealisitc Rendering (NPR) is a class of techniques that aims to reproduce artistic techniques, trying to express feelings and moods on the rendered scenes, giving an aspect of that they had been made "by hand". Another way of defining NPR is that it is the processing of scenes, images or videos into artwork, generating scenes, images or videos that can have the visual appeal of pieces of art, expressing the visual and emotional characteristics of artistic styles. This dissertation presents a new method of NPR for stylization of images and videos, based on a typical artistic expression of the Northeast region of Brazil, that uses colored sand to compose landscape images on the inner surface of glass bottles. This method is comprised by one technique for generating 2D procedural textures of sand, and two techniques that mimic effects created by the artists using their tools. It also presents a method for generating 21 2D animations in sandbox from the stylized video. The temporal coherence within these stylized videos can be enforced on individual objects with the aid of a video segmentation algorithm. The present techniques in this work were used on stylization of synthetic and real videos, something close to impossible to be produced by artist in real life

O Gênero Cyathus haller: pers. (Agaricales, Basidiomycota) em áreas de caatinga do Nordeste brasileiro

Fungi of the family Nidulariaceae or bird s nest fungi present a vase-shaped basidiomata with the wall surface smooth or striated lengthwise and internal structures resembling small bird eggs in a nest, the peridioles. Among the five genera that comprise the group, the more representative is Cyathus Haller: Pers. The Brazilian Northeast region shows major importance for the world s diversity by containing a Brazilian unique and exclusively phytoecological domain, the Caatinga, which lacks particular attention regarding macrofungi. Although the gradual growth of knowledge in recent years, studies are still insipient in the Caatinga domain. Between their various vegetal formations are the Brejos de Altitude , described as islands with moist perennial vegetation, low soil fertility and annual precipitation of 900 1.300 mm. This study aimed to evaluate the taxonomic richness of Nidulariaceae fungi in Caatinga s areas of Northeastern Brazil, describing and identifying species, as well as expanding the collection of Herbarium UFRN Fungos. For description of Nidulariaceae fungi was followed the proposed by specialized literature in the group. We have found and described 10 species of the genus Cyathus, namely: C. earlei Lloyd, C. gayanus Tul. & C. Tul., C. gracilis H.J. Brodie, C. intermedius (Mont.) Tul. & C. Tul., C. limbatus Tul. & C. Tul., C. montagnei Tul. & C. Tul., C. pallidus Berk. & M.A. Curtis, C. poeppigii Tul. & C. Tul., C. striatus (Huds.) Willd. and C. tríplex Lloyd. Beyond these have been described four new species to science: Cyathus calvescens R. Cruz & Baseia sp. nov., C. hortum R. Cruz & Baseia sp. nov., C. magnomuralis R. Cruz & Baseia sp. nov. and C. parvocinereus R. Cruz & Baseia sp. nov. Two samples were identified only to genus level. No member of Mycocalia J.T. Palmer, Nidula V.S. White, Nidularia Fr. and Crucibulum Tul. & C. Tul. has been found, however the results were extremely valuable for being an unprecedented work in Caatinga, and importante tool for implementation of conservation projects and sustainable utilization of this domain

Caracterização geológico-geofísica do meio aqüífero fissural : uma contribuição aos modelos de fluxo e armazenamento de água subterrânea

Northeastern Brazil is mainly formed by crystalline terrains (around 60% in area). Moreover, this region presents a semi-arid climate so that it is periodically subject to drought seasons. Furthermore, ground water quality extracted fromwells usually presents poor quality because of their high salinity contents. Nevertheless, ground water is still a very important source of water for human and animal consumption in this region. Well sitting in hard rocks terrains in Northeastern Brazil offers a mean success index of aboul 60%, given that a successful siting is defined by a well producing at least 0.5 m³/h. This low index reveals lack of knowledga about the true conditions of storage and percolation of ground water in crystalline rocks. Two models for structures storing and producing ground water in crystalline rocks in Northeastem Brazil have been proposed in the literature. The first model,tradnionally used for well sitting since the sixties are controlled by faults or fractures zones. This model is commonly referred, in Brazilian hydrogeological literature, as the "creek-crack" model (riacho-fenda in Portuguese). Sites appearing to present dense drainage network are preferred for water well siting - particularly at points where the drainages cross-cul each other. Field follow up work is usually based only on geological criteria. The second model is the "eluvio-alluvial through" (calha eluvio-aluvionar in Portuguese); it is also described in the literature but it is not yet incorporated in well sitting practice. This model is based on the hypothesis that reclilinear drainages can also be controlled by the folietion of the rock. Eventually, depending upon the degree of weathering, a through-shaped structure filled with sediments (alluvium and regolith) can be developed which can store and water can be produced from. Using severalfield case studies, this Thesis presents a thorough analysis ofthe two above cited models and proposes a new model. The analysis is based on an integrated methodological approach using geophysics and structural geology. Both land (Resitiviy and Ground Penetrating Radar- GPR) and aerogeophysical (magnetics and frequency domain eletromagnetics) surveys were used. Slructural analysis emphasized neolectonic aspects; in general, itwas found that fractures in the E-W direction are relatively open, as compared to fracturas inthe N-S direction, probably because E-W fractures were opened by the neotectonic stress regime in Northeastern Brazil, which is controlled by E-W compression and N-S extension. The riacho-fenda model is valid where drainages are controlled by fractures. The degree of fracturing and associated weathering dictale the hydrogeological potential of the structure. Field work in structural analogues reveals that subvertical fractures show consistent directions both in outcrop and aerophotograph scales. Geophysical surveys reveal subvertical conductive anomalies associated to the fracture network controlling the drainage; one of the borders of the conductive anomaly usually coincide wih the drainage. An aspect of particular importance to the validation of fracture control are the possible presence of relalively deep conductive anomalies wihoul continuation or propagalion to the surface. The conductive nature of lhe anomaly is due to the presence of wealhered rock and sedirnenls (alluvium and/or regolilh) storing ground waler which occur associated to the fracture network. Magnetic surveys are not very sensisnive to these structures.lf soil or covering sedirnents are resislive (> 100 Ohm.m), GPR can ba used to image precisely lhe fracture network. A major limialion of riacho-fenda model, revealed by GPR images, is associated to the fact thal subhorizontal fractures do play a very important role in connecting the fracture network, besides connect shallow recharge zones to relalively deep subvertical frecture zones. Iffractures play just a secondary control on the drainage, however, r/acho-fenda model may have a very limiled validny; in these cases, large portions oflhe drainage do nol coincide wilh frectures and mosl oflhewells localed in lhe drainage surrounding would resull dry. Usually, a secondary conlrol on lhe drainage by Ihefraclure networkcan be revealed only wilh detailed geophysical survey. The calha elClv1o-aluvlonarmodel is valid where drainages are conlrolled by folialion. The degree 01 wealhering 01 lhe lolialion planes dictales lhe hydrogeological polenlial 01 lhe slruclure. Outcrop analysis reveals Ihal lolialion and drainage direclions are parallel and Ihal no Iraclures, orfraclures wilh diflerent directions 01 lhe drainage direclion occur. Geophysical surveys reveal conduclive anomalies in a slab lorm associaled 10 lhe Ihrough 01 lhe wealhered rock and sedimenls (alluvium and/or regolith). Magnelic surveys can ofler a very good conlrol on lolialion direclion. An importanl aspect 10 validale lolialion conlrol are lhe presence 01 conductive anomalies showing shallow and deep portions area which are linked. Illhere is an exlensive soil cover, r/acho-fenda and calha eIClv1o-aluv/onar conlrols can be easily misinlerpreled in lhe absence 01 geophysical conlrol. Certainly, Ihis lacl could explain at leasl a part of lhe failure index in well sitting. The model wealhering sack (bolsllo de Intempertsmo in Portuguese) is proposed to explain cases where a very inlensive wealhering occur over lhe crystalline rock so Ihal a secondary inlerslilial porosity is crealed. The waler is Ihen stored in lhe porous of lhe regolilh in a similar mannerlo sedimentary rocks. A possible example ofthis model was delecled by using land geophysical survey where a relalivelyvery deep isolaled conduclive anomaly, in a slab form, was delected. Iflhis structure does store ground waler, certainly Ihere must be a link 01 lhe deep slructure wilh lhe surface in orderlo provide walerfeeding. This model mighl explain anomalous waler yields as greal as 50 m³/h Ihalsomelimescan occur in crystalline rocks in Northeaslern Brazil

Litoestratigrafia e deformação cenzóica na região de Icapuí, Ceará, e implicações para a estruturação de campos de petróleo na borda ocidental da bacia Potiguar(NE do Brasil)

This thesis deals with the sedimentological/stratigraphic and structural evolution of the sedimentary rocks that occur in the NW continental border of the Potiguar Basin. These rocks are well exposed along coastal cliffs between the localities of Lagoa do Mato and Icapuí, Ceará State (NE Brazil). The sedimentological/stratigraphic study involved, at the outcrop scale, detailed facies descriptions, profile mapping of the vertical succession of different beds, and columnar sections displaying inferred lateral relationships. The approach was complemented by granulometric and petrographic analyses, including the characterization of heavy mineral assemblages. The data set allowed to recognize two kinds of lithological units, a carbonate one of very restricted occurrence at the base of the cliffs, and three younger, distinct siliciclastic units, that predominate along the cliffs, in vertical and lateral extent. The carbonate rocks were correlated to the late Cretaceous Jandaíra Formation, which is covered by the siliciclastic Barreiras Formation. The Barreiras Formation occurs in two distinct structural settings, the usual one with nondeformed, subhorizontal strata, or as tilted beds, affected by strong deformation. Two lithofacies were recognized, vertically arranged or in fault contacts. The lower facies is characterized by silty-argillaceous sandstones with low-angle cross bedding; the upper facies comprises medium to coarse grained sandstones, with conglomeratic layers. The Tibau Formation (medium to coarse-grained sandstones with argillite intercalations) occurs at the NW side of the studied area, laterally interlayered with the Barreiras Formation. Eolic sediments correlated to the Potengi Formation overly the former units, either displaying an angular unconformity, or simply an erosional contact (stratigraphic unconformity). Outstanding structural features, identified in the Barreiras Formation, led to characterize a neocenozoic stress field, which generated faults and folds and/or reactivated older structures in the subjacent late cretaceous (to paleogene, in the offshore basin) section. The structures recognized in the Barreiras Formation comprise two distinct assemblages, namely a main extensional deformation between the localities of Ponta Grossa and Redonda, and a contractional style (succeeded by oblique extensional structures) at Vila Nova. In the first case, the structural assemblage is dominated by N-S (N±20°Az) steep to gently-dipping extensional faults, displaying a domino-style or listric geometry with associated roll-over structures. This deformation pattern is explained by an E-W/WNW extension, contemporaneous with deposition of the upper facies of the Barreiras Formation, during the time interval Miocene to Pleistocene. Strong rotation of blocks and faults generated low-angle distensional faults and, locally, subvertical bedding, allowing to estimate very high strain states, with extension estimates varying between 40% up to 200%. Numerous detachment zones, parallel to bedding, help to acommodate this intense deformation. The detachment surfaces and a large number of faults display mesoscopic features analoguous to the ones of ductile shear zones, with development of S-C fabrics, shear bands, sigmoidal clasts and others, pointing to a hydroplastic deformation regime in these cases. Local occurrences of the Jandaíra limestone are controled by extensional faults that exhume the pre-Barreiras section, including an earlier event with N-S extension. Finally, WNWtrending extensional shear zones and faults are compatible with the Holocene stress field along the present continental margin. In the Vila Nova region, close to Icapuí, gentle normal folds with fold hinges shallowly pluging to SSW affect the lower facies of the Barreiras Formation, displaying an incipient dissolution cleavage associated with an extension lineation at high rake (a S>L fabric). Deposition of the upper facies siliciclastics is controlled by pull-apart graben structures, bordered by N-NE-trending sinistral-normal shear zones and faults, characterizing an structural inversion. Microstructures are compatible with tectonic deformation of the sedimentary pile, burried at shallow depths. The observed features point to high pore fluid pressures during deformation of the sediments, producing hydroplastic structures through mechanisms of granular flow. Such structures are overprinted by microfractures and microfaults (an essentially brittle regime), tracking the change to microfracturing and frictional shear mechanisms accompanying progressive dewatering and sediment lithification. Correlation of the structures observed at the surface with those present at depth was tested through geophysical data (Ground Penetrating Radar, seismics and a magnetic map). EW and NE-trending lineaments are observed in the magnetic map. The seismic sections display several examples of positive flower structures which affect the base of the cretaceous sediments; at higher stratigraphic levels, normal components/slips are compatible with the negative structural inversion characterized at the surface. Such correlations assisted in proposing a structural model compatible with the regional tectonic framework. The strong neogenepleistocene deformation is necessarily propagated in the subsurface, affecting the late cretaceous section (Açu and Jandaíra formations), wich host the hydrocarbon reservoirs in this portion of the Potiguar Basin. The proposed structural model is related to the dextral transcurrent/transform deformation along the Equatorial Margin, associated with transpressive terminations of E-W fault zones, or at their intersections with NE-trending lineaments, such as the Ponta Grossa-Fazenda Belém one (the LPGFB, itself controlled by a Brasiliano-age strike-slip shear zone). In a first step (and possibly during the late Cretaceous to Paleogene), this lineament was activated under a sinistral transpressional regime (antithetic to the main dextral deformation in the E-W zones), giving way to the folds in the lower facies of the Barreiras Formation, as well as the positive flower structures mapped through the seismic sections, at depth. This stage was succeeded (or was penecontemporaneous) by the extensional structures related to a (also sinistral) transtensional movement stage, associated to volcanism (Macau, Messejana) and thermal doming processes during the Neogene-Pleistocene time interval. This structural model has direct implications to hydrocarbon exploration and exploitation activities at this sector of the Potiguar Basin and its offshore continuation. The structure of the reservoirs at depth (Açu Formation sandstones of the post-rift section) may be controlled (or at least, strongly influenced) by the deformation geometry and kinematics characterized at the surface. In addition, the deformation event recognized in the Barreiras Formation has an age close to the one postulated for the oil maturation and migration in the basin, between the Oligocene to the Miocene. In this way, the described structural cenario represents a valid model to understand the conditions of hydrocarbon transport and acummulation through space openings, trap formation and destruction. This model is potentially applicable to the NW region of the Potiguar Basin and other sectors with a similar structural setting, along the brazilian Equatorial Atlantic Margin

Análise de uso e cobertura do solo no município de Parelhas/RN

The human interference in the semiarid region of Seridó Potiguar has promoted the increase of degraded areas. The economic dynamic that was established in the Seridó territory, especially after the fall of the trinomial cattle-cotton-mining in the 70s and 80s of the 20th century as pillars of the regional economy, resulted in an accelerated process of erosion of natural resources. The municipalities of the Seridó region have been spatially reordered by this new economic dynamic, marked by the growth of existing enterprises, and the development of new agricultural practices. One of the municipalities in the region that restructured its territorial space with the emergence of new agro-industrial activities was the town of Parelhas. With the demise of the trinomial cattle-cotton-mining in the 1980s, other productive activities were intensified from the 1990s, amongst them, pottery, responsible for the vegetal extraction for use as energy source. This recent economic and spatial restructuring in the region, reflected in the Parelhense municipal territory, required new productive ingredients responsible for the modification of past production relations that were based on cattle, cotton and mining. By that a process of exploring the environment was unleashed, especially the native vegetation, in an uncontrolled manner. In this context, the objective of this study was to survey and detect deforestation in the areas of Caatinga vegetation, used indiscriminately as energy supply for new agricultural practices, using remote sensing techniques based on the quantification of the Normalized Difference Vegetation Index / NDVI, Soil-Adjusted Vegetation Index / SAVI, surface temperature and rainfall data in the years 1990 and 2010. The results indicated that SAVI values above 0.2 in 1990 and 2010 represent the areas with the highest density of vegetation that occur exclusively along the major drainages in the town and areas of higher elevations. The areas between the ranges of values from 0.5 to 0.15 SAVI are areas with poor vegetation. On the other hand the highest values of temperature are distributed in the western and southeastern parts of the township, usually in places where the soil is exposed or there is sparse vegetation. The areas of bare soil decreased in extension in 2010 at 11, 6% when related to 1990, this was caused by a higher rainfall intensity in the first half of 2010, but no regeneration of vegetation occurred in some places in the western and southeastern areas of the municipality today, due to the extraction of firewood to fuel the furnaces of industries in town

Análises clínicas, radiográfica e microscópica de molares permanentes sem ou com lesão de cárie na superfície oclusal

O presente trabalho, objetivou avaliar comparativamente o diagnóstico clínico, radiógráfico e histológico de molares permanentes humanos sem ou com lesão de cárie na superfície oclusa!. Vinte e quatro dentes que estavam armazenados em formalina a 10% foram selecionados e em seguida submetidos a um exame clínico, através da inspeção visual, onde foram separados em 3 grupos: grupo 1 (G1), formado por dentes hígidos; grupo 2(G2), por dentes com pigmento na superfície oclusal e grupo 3(G3), aqueles com lesão de cárie na oclusal. Este exame foi realizado com auxílio de luz artificial proveniente de um refletor odontológico, sem qualquer manipulação da superfície. Para cada dente foram realizados duas tomadas radiográficas com e sem tela milimetrada, no sentido vestibulo lingual por um dos avaliadores, simulando uma radiografia interproximal, onde o feixe incidiu perpendicular ao longo eixo do dente. Em seguida os dentes foram preparados histomorfologicamente para coloração com hematoxilina e eosina e análise microscópica. Pela avaliação dos resultados a partir da amostra de 100%, foi possível concluir: 1) Os dentes clinicamente considerados hígidos (G1) apresentaram radiograficamente 74,99% de ausência de imagem radiolúcida e em 25% presença desta imagem na Junção Amelo¬dentinária e microscopicamente ausência de cárie em 100%; 2) os dentes que clinicamente apresentaram fissura pigmentada' (G2) notou-se em 33,33%, ausência da imagem radiolúcida e em 66,66% presente esta imagem na junção amelodentinária, 100% de ausência de cárie através da análise microscópica; 3) clinicamente, os dentes que apresentaram lesão de cárie (G3), radiograficamente foram comprovados 100% de imagem radiolúcida sugestiva de cárie e microscopicamente dos 100% destas, foram considerados cáries rasa (16,66%), média (61,10%) e profunda (22,22%) respectivamente

Espectros fractais em sistemas nanoestruturados e cristais fotônicos

The study of the elementary excitations such as photons, phonons, plasmons, polaritons, polarons, excitons and magnons, in crystalline solids and nanostructures systems are nowdays important active field for research works in solid state physics as well as in statistical physics. With this aim in mind, this work has two distinct parts. In the first one, we investigate the propagation of excitons polaritons in nanostructured periodic and quasiperiodic multilayers, from the description of the behavior for bulk and surface modes in their individual constituents. Through analytical, as well as computational numerical calculation, we obtain the spectra for both surface and bulk exciton-polaritons modes in the superstructures. Besides, we investigate also how the quasiperiodicity modifies the band structure related to the periodic case, stressing their amazing self-similar behavior leaving to their fractal/multifractal aspects. Afterwards, we present our results related to the so-called photonic crystals, the eletromagnetic analogue of the electronic crystalline structure. We consider periodic and quasiperiodic structures, in which one of their component presents a negative refractive index. This unusual optic characteristic is obtained when the electric permissivity and the magnetic permeability µ are both negatives for the same range of angular frequency ω of the incident wave. The given curves show how the transmission of the photon waves is modified, with a striking self-similar profile. Moreover, we analyze the modification of the usual Planck´s thermal spectrum when we use a quasiperiodic fotonic superlattice as a filter.

Testes em modelos weibull na forma estendida de Marshall-Olkin

In survival analysis, the response is usually the time until the occurrence of an event of interest, called failure time. The main characteristic of survival data is the presence of censoring which is a partial observation of response. Associated with this information, some models occupy an important position by properly fit several practical situations, among which we can mention the Weibull model. Marshall-Olkin extended form distributions other a basic generalization that enables greater exibility in adjusting lifetime data. This paper presents a simulation study that compares the gradient test and the likelihood ratio test using the Marshall-Olkin extended form Weibull distribution. As a result, there is only a small advantage for the likelihood ratio test

Área e volume da esfera

In this dissertation, we present a study on the teaching of volume of the sphere and the area of spherical surface. On this topic, a quali-quantitative was taken survey with the objective of identifying how these topics are addressed. For this, we made 14 questions to 30 teachers of Natal and the results of this survey are presented and discussed. After that, we present alternative ways to derive the formulas of the volume of a sphere and the are of a spherical surface

Uso do GPR na geração de modelos estáticos 3D para o planejamento de lavra de minerais pesados depositados em dunas eólicas

This project was developed as a partnership between the Laboratory of Stratigraphical Analyses of the Geology Department of UFRN and the company Millennium Inorganic Chemicals Mineração Ltda. This company is located in the north end of the paraiban coast, in the municipal district of Mataraca. Millennium has as main prospected product, heavy minerals as ilmenita, rutilo and zircon presents in the sands of the dunes. These dunes are predominantly inactive, and overlap the superior portion of Barreiras Formation rocks. The mining happens with the use of a dredge that is emerged at an artificial lake on the dunes. This dredge removes sand dunes of the bottom lake (after it disassembles of the lake borders with water jets) and directs for the concentration plant, through piping where the minerals are then separate. The present work consisted in the acquisition external geometries of the dunes, where in the end a 3D Static Model could be set up of these sedimentary deposits with emphasis in the behavior of the structural top of Barreiras Formation rocks (inferior limit of the deposit). The knowledge of this surface is important in the phase of the plowing planning for the company, because a calculation mistake can do with that the dredge works too close of this limit, taking the risk that fragments can cause obstruction in the dredge generating a financial damage so much in the equipment repair as for the stopped days production. During the field stages (accomplished in 2006 and 2007) topographical techniques risings were used with Total Station and Geodesic GPS as well as shallow geophysical acquisitions with GPR (Ground Penetrating Radar). It was acquired almost 10,4km of topography and 10km of profiles GPR. The Geodesic GPS was used for the data geopositioning and topographical rising of a traverse line with 630m of extension in the stage of 2007. The GPR was shown a reliable method, ecologically clean, fast acquisition and with a low cost in relation to traditional methods as surveys. The main advantage of this equipment is obtain a continuous information to superior surface Barreiras Formation rocks. The static models 3D were elaborated starting from the obtained data being used two specific softwares for visualization 3D: GoCAD 2.0.8 and Datamine. The visualization 3D allows a better understanding of the Barreiras surface behavior as well as it makes possible the execution of several types of measurements, favoring like calculations and allowing that procedures used for mineral extraction is used with larger safety

Análises estratigráfica e estrutural da Seção Rifte (Valanginiano ao Barremiano) na área do levantamento sísmico 3D de baixo vermelho, Bacia Potiguar emersa

Baixo Vermelho area, situated on the northern portion of Umbuzeiro Graben (onshore Potiguar Basin), represents a typical example of a rift basin, characterized, in subsurface, by the sedimentary rift sequence, correlated to Pendência Formation (Valanginian-Barremian), and by the Carnaubais fault system. In this context, two main goals, the stratigraphic and the structural analysis, had guided the research. For this purpose, it was used the 3D seismic volume and eight wells located in the study area and adjacencies. The stratigraphic analysis of the Valanginian-Barremian interval was carried through in two distinct phases, 1D and 2D, in which the basic concepts of the sequence stratigraphy had been adapted. In these phases, the individual analysis of each well and the correlation between them, allowed to recognize the main lithofacies, to interpret the effective depositional systems and to identify the genetic units and key-surfaces of chronostratigraphic character. The analyzed lithofacies are represented predominantly by conglomerates, sandstones, siltites and shales, with carbonate rocks and marls occurring subordinately. According to these lithofacies associations, it is possible to interpret the following depositional systems: alluvial fan, fluvio-deltaic and lacustrine depositional systems. The alluvial fan system is mainly composed by conglomerates deposits, which had developed, preferentially in the south portion of the area, being directly associated to Carnaubais fault system. The fluvial-deltaic system, in turn, was mainly developed in the northwest portion of the area, at the flexural edge, being characterized by coarse sandstones with shales and siltites intercalated. On the other hand, the lacustrine system, the most dominant one in the study area, is formed mainly by shales that could occur intercalated with thin layers of fine to very fine sandstones, interpreted as turbidite deposits. The recognized sequence stratigraphy units in the wells are represented by parasequence sets, systems tracts and depositional sequences. The parasequence sets, which are progradational or retrogradational, had been grouped and related to the systems tracts. The predominance of the progradation parasequence sets (general trend with coarsening-upward) characterizes the Regressive Systems Tract, while the occurrence, more frequently, of the retrogradation parasequence sets (general trend with finning-upward) represents the Transgressive System Tract. In the seismic stratigraphic analysis, the lithofacies described in the wells had been related to chaotic, progradational and parallel/subparallel seismic facies, which are associated, frequently, to the alluvial fans, fluvial-deltaic and lacustrine depositional systems, respectively. In this analysis, it was possible to recognize fifteen seismic horizons that correspond to sequence boundaries and to maximum flooding surfaces, which separates Transgressive to Regressive systems tracts. The recognition of transgressive-regressive cycles allowed to identify nine, possibly, 3a order deposicional sequences, related to the tectonic-sedimentary cycles. The structural analysis, in turn, was done at Baixo Vermelho seismic volume, which shows, clearly, the structural complexity printed in the area, mainly related to Carnaubais fault system, acting as an important fault system of the rift edge. This fault system is characterized by a main arrangement of normal faults with trend NE-SO, where Carnaubais Fault represents the maximum expression of these lineations. Carnaubais Fault corresponds to a fault with typically listric geometry, with general trend N70°E, dipping to northwest. It is observed, throughout all the seismic volume, with variations in its surface, which had conditioned, in its evolutive stages, the formation of innumerable structural features that normally are identified in Pendencia Formation. In this unit, part of these features is related to the formation of longitudinal foldings (rollover structures and distentional folding associated), originated by the displacement of the main fault plan, propitiating variations in geometry and thickness of the adjacent layers, which had been deposited at the same time. Other structural features are related to the secondary faultings, which could be synthetic or antithetic to Carnaubais Fault. In a general way, these faults have limited lateral continuity, with listric planar format and, apparently, they play the role of the accomodation of the distentional deformation printed in the area. Thus, the interaction between the stratigraphic and structural analysis, based on an excellent quality of the used data, allowed to get one better agreement on the tectonicsedimentary evolution of the Valanginian-Barremian interval (Pendência Formation) in the studied area

Estudo geológico e geofísico da falha de carnaubais, Bacia Potiguar-RN, e implicações neotectônicas

The segment of Carnaubais Fault located in the southeasthern portion of Guamaré Graben (Potiguar Basin) was studied. Several structures were detected and some of them strongly suggest that the last movements in Carnaubais Fault are of Neotectonic age. The study comprises an integrated interpretation of geologic, geomorphologic and geophysical data (gravimetry, magnetometry, resistivity, and self potential methods). According to the size of the studied areas, two approaches were used in this research. The first approach is of a regional nature and was conducted in an area, hereafter named Regional Area, having approximately 6,000 km2 and localized in the northern portion of Rio Grande do Norte state, around Macau city. The second approach comprises detailled studies of two small areas inside the Regional Area: the Camurupim and São Bento areas. Gravimetric and topographic data were used in the Regional Area. A separation into regional and residual components were conducted both on gravimetric and topographic data. The interpretation of the residual component of the gravimetric data allows a precise mapping of the borders of the Guamaré Graben. The regional component features of the topographic data are controlled by the pair of conjugate faults composed by the Carnaubais Fault (NE direction) and the Afonso Bezerra Fault (NW direction). On the other hand, the residual component of the topographic data shows that river valleis of NW direction are sharply interrupted where they intersect Carnaubais Fault. This fact is interpreted as an evidency that the last significant moviments occured in the Carnaubais Fault. Geologic, geomorphologic and geophysical data (magnetometry, resistivity, and self potential methods) were used in the Camurupim Area. The geologic mapping allows to identify five lithophacies unities. The first two unities (from base to top) were interpreted as composing a marine (or transitional) depositional sequency while the other were interpreted is composing a continental depositional sequence. The two sequences are clearly separated of an erosional discordance. The unities grouped in the marine sequence are composed by calcarenites (Unity A) and mudstones (Unity B). Unity A was deposited in a shalow plataform while Unity B, in a tidal flat. The unities grouped in the continental sequence are composed of conglomerate (Unity C) and sandstones (Unities D and E). Unities C and D are fluvial deposits while unity E is an eolian deposit. Unities A and B can be stratigraphycally correlated with Guamaré Formation. Unities C and D present three possible correlations. They may be correlated with Tibau Formation; or with Barreiras Formation; or with a clastic sediment deposit, commonly found in some rivers of Rio Grande do Norte state, and statigraphycally positioned above Barreiras Formation. Based on the decrease of the grain sizes from base to top both on unities C and D, it is proposed that these unities are correlated with the clastic sediment above mentioned. In this case, these unities would have, at least, Pleistocenic age. Finally, it is proposed that Unity E represent an eolian deposit that sufferred recent changes (at least in the Quaternary). The integrated interpretation of hydrographic, morphologic and geophysical data from Camurupim Area shows that Carnaubais Fault is locally composed by a system of several paralel subvertical faults. The fault presenting the larger vertical slip controls the valley of Camurupim river and separates the area in two blocks; in the nothern block the top of the Jandaira limestone is deeper than in the southern block. In addition, at least one of the faults in the northern block is cutting the whole sedimentary section. Because unities C , D, and/or E may be of Quaternary age, tectonic moviments possibly occured in Carnaubais Fault during this period. Detailled geologic mapping were conducted in beachrocks found in São Bento Area. This area is located at the intersection of the coast line with the Carnaubais Fault. The detected structures in the beachrocks are very similar to those caused by fragile deformations. The structures mapped in the beachrocks are consistent with a stress field with maximun compressional stress in E-W direction and extensional stress in the N-S direction. Since the Carnaubais Fault has a NE direction, it is optimally positioned to suffer tectonic movements under the action of such stress field. In addition, the shape of the coastal line appear to be controlled by the Carnaubais Fault. Furthemore, the observed structures in Camurupim Área are consistent with this stress field. These facts are interpreted as evidences that Carnaubais Fault and beachrocks suffered coupled tectonic movements. These moviments are of Neotectonic age because the beachrocks present ages less than 16,000 years

As dunas eólicas de Natal/RN: datação e evolução

The main purpose of this study is to present complementary information on eolian systems that occur in the Center-South portion of the city of Natal, Rio Grande do Norte State, Brazil. The investigation focused on the identification of eolian units, absolute luminescence dating of eolian sediments, to geophysical analysis by Ground Penetrating Radar (GPR), as well as qualitative identification of the use and terrain occupation in the study area. A map was elaborated in order to separate eolian geological units, and describe their deposicional and erosional characteristics, by aerial photo-interpretation. The study lead to the identification of six main units: Unit I - Blowouts (BW), Unit II - Active dunes field (DA), Unit III - Fixed dunes field (DF), Unit IV - Parabolic dunes field (DP), Unit V - Red parabolic dunes field (DV) and Unit VI - Devastated dunes surface (SD). Were analised by Termoluminescense (TL) Method Eight samples from units I, III, IV and V. The largest number of samples with similar or close resulted yielded ages about 15,000 years. Two GPR profiles were obtained in areas of the Dunes Park, near the "Natal s Conventions Center". Results showed the migration a new dune generation over on older one, the geologic contact between dunes and the Formação Barreiras (FB), and the groundwater level inside the dune unit. The qualitative study on the use and terrain occupation of the soil in some dunes fields in the study area, it was possible identify some use and occupation, as the following ones: the construction of residential and commercial buildings, dunes fields cutted for construction to access road and garbage deposition

Petrologia do magmatismo tardi-brasiliano no Maciço São José de Campestre(RN/PB), com ênfase no Plúton Alcalino Caxexa

The area studied is located on the north-easternmost portion of the Borborema Province, on the so-called São José de Campestre Massif, States of RN and PB, Northeast Brazil. Field relations and petrographic, geochemical and isotope data permitted the separation of five suites of plutonic rocks: alkali-feldspar granite (Caxexa Pluton), which constitutes the main subject of this dissertation, amphibole-biotite granite (Cabeçudo Pluton), biotite microgranite, gabbronorite to monzonite (Basic to Intermediate Suite) and aluminous granitoid. The Caxexa Pluton is laterally associated to the Remígio Pocinhos Shear Zone, with its emplacement along the mylonitic contact between the gneissic basement and the micashists. This pluton corresponds to a syntectonic intrusion elongated in the N-S direction, with about 50 km2 of outcropping surface. It is composed exclusively of alkali-feldspar granites, having clinopyroxene (aegirine-augite and hedenbergite), andradite-rich garnet, sphene and magnetite. It is classified geochemically as high silica rocks (>70 % wt), metaluminous to slightly peraluminous (normative corindon < 1%), with high total alkalis (>10% wt), Sr, iron number (#Fe=90-98) and agpaitic index (0.86-1.00), and positive europium anomaly. The Cabeçudo Pluton is composed of porphyritic rocks, commonly containing basic to intermediate magmatic enclaves often with mingling and mixing textures. Petrographically, it presents k-feldspar and plagioclase phenocrysts as the essential minerals, besides the accessories amphibole, biotite, sphene and magnetite. It is metaluminous and shows characteristics transitional between the calc-alkaline and alkaline series (or monzonitic subalkaline). Its REE content is greater than those ones of the Caxexa Pluton and biotite microgranite, and all spectra have negative europium anomalies. The biotite microgranites occur mainly on the central and eastern portion of the mapped area, as dykes and sheets with decimetric thickness, hosted principally in orthogneisses and micashists. Their field relationships as regards the Caxexa and Cabeçudo plutons suggested that they are late-tectonic intrusions. They are typically biotite granites, having also sphene, amphibole, allanite, opaques and zircon in the accessory assemblage. Geochemically they can be distinguished from the porphyritic types because the biotite microgranites are more evolved, peraluminous, and have more fractionated REE spectra. The Basic to Intermediate rocks form a volumetrically expressive elliptical, kilometric scale body on the Southeast, as well as sheets in micashists. They are classified as gabbronorites to monzonites, with the two pyroxenes and biotite, besides subordinated amounts of amphibole, sphene, ilmenite and allanite. These rocks do not show a well-defined geochemical trend, however they may possibly represent a monzonitic (shoshonitic) series. Their REE spectra have negative europium anomalies and REE contents greater than the other suites. The aluminous granitoids are volumetrically restricted, and have been observed in close association with migmatised micashists bordering the gabbronorite pluton. They are composed of almandine-rich garnet, andalusite, biotite and muscovite, and are akin to the peraluminous suites. Rb-Sr (whole rock) and Sm-Nd (whole-rock and mineral) isotopes furnished a minimum estimate of the crystallization (578±14 Ma) and the final resetting age of the Rb-Sr system (536±4 Ma) in the Caxexa Pluton. The aluminous granitoid has a Sm-Nd garnet age similar to that one of the Caxexa Pluton, that is 574±67 Ma. The strong interaction of shear bands and pegmatite dykes favoured the opening of the Rb-Sr system for the Caxexa Pluton and biotite microgranite. The amphibole-plagioclase geothermometer and the Al-in amphibole geobarometer indicate minimum conditions of 560°C and 7 kbar for the Cabeçudo Pluton, 730°C and 6 kbar for the microgranite and 743°C and 5 kbar for the basic to intermediate suite. The Zr saturation geothermometer reveals temperatures of respectively 855°C, 812°C and 957°C for those suites, whereas the Caxexa Pluton shows temperatures of around 757°C. The Caxexa, Cabeçudo and microgranites suites crystallized under high fO2 (presence of magnetite). On the other hand, the occurrence of ilmenite suggests less oxidant conditions in the basic to intermediate suite. Field relations demonstrate the intrusive character of the granitoids into a tectonically relatively stable continental crust. This is corroborated by petrographic and geochemical data, which suggest a late- or post-collisional tectonic context. It follows that the generation and emplacement of those granitoid suites is related to the latest events of the Brasiliano orogeny. Finally, the relationships between eNd (600 Ma), TDM (Nd) and initial Sr isotope ratio (ISr) do not permit to define the precise sources of the granitoids. Nevertheless, trace element modelling and isotopic comparisons suggest the participation of the metasomatised mantle in the generation of these suites, probably modified by different degrees of crustal contamination. In this way, a metasomatised mantle would not be a particular characteristic of the Neoproterozoic lithosphere, but a remarkable feature of this portion of the Borborema Province since Archaean and Paleoproterozoic times.