Geochemical variation among small eruptive centers in the central SVZ of the Andes: An evaluation of subduction, mantle and crustal influences

Subduction zone magmatism is an important and extensively studied topic in igneous geochemistry. Recent studies focus on from where arc magmas are generated, how subduction components (fluids or melts) are fluxed into the source of the magmas, and whether or how the subduction components affect partial melting processes beneath volcanic arcs at convergent boundaries. ^ At 39.5°S in the Central Southern Volcanic Zone of the Andes, Volcano Villarrica is surrounded by a suite of Small Eruptive Centers (SEC). The SECs are located mostly to the east and northeast of the stratovolcano and aligned along the Liquine-Ofqui Fault Zone, the major fracture system in this area. Former studies observed the geochemical patterns of the SECs differ distinctively from those of V. Villarrica and suggested there may be a relationship between the compositions of the volcanic units and their edifice sizes. This work is a comprehensive geochemical study on the SECs near V. Villarrica, using a variety of geochemical tracers and tools including major, trace and REE elements, Li-Be-B elements, Sr-Nd-Pb isotopes and short-lived isotopes such as U-series and 10Be. In this work, systematic differences between the elemental and isotopic compositions of the SECs and those of V. Villarrica are revealed and more importantly, modeled in terms of magmatic processes occurring at continental arc margins. Detailed modeling calculations in this work reconstruct chemical compositions of the primary magmas, source compositions, compositions and percentages of different subduction endmembers mixed into the source, degrees of partial melting and different time scales of the SECs and V. Villarrica, respectively. Geochemical characteristics and possible origins of the two special SECs—andesitic Llizan, with crustal signatures, and Rucapillan, to the northwest toward the trench, are also discussed in this work. ^

Isotopic studies of the Guerrero composite terrane, west-central Mexico: Implications for provenance of crustal rocks and genesis of ore metals

A variety of world-class mineral deposits occur in Mesozoic and Tertiary rocks of the Guerrero terrane. New Pb isotope analyses of various crustal units and ores from distinct subterranes of the Guerrero terrane are presented to trace metal sources in these deposits and infer source reservoirs. New Sr and Nd isotope results are provided to gain insight into the provenance of the crustal rocks from the Guerrero terrane. Triassic schist samples from the Arteaga Complex and Triassic-Jurassic phyllite and slate samples from the Tejupilco metamorphic suite contain radiogenic Pb (206Pb/204Pb = 18.701–19.256) relative to bulk earth models. Cretaceous sedimentary rocks of the Zihuatanejo Sequence are more radiogenic (206Pb/204Pb = 18.763–19.437) than samples from the Huetamo Sequence (206Pb/204Pb = 18.630–18.998). Tertiary intrusive rocks from La Verde, Inguaran, La Esmeralda, and El Malacate plot to the right of the average Pb crust evolution curve of Stacey and Kramers (206Pb/204Pb = 18.705–19.033). Ores from the La Verde and La Esmeralda porphyry copper deposits yield isotopic ratios (206Pb/204Pb = 18.678–18.723) that are generally less radiogenic than the host igneous rocks, but plot within the field defined by the sedimentary rocks from the Huetamo Sequence. Tertiary intrusive rocks from the Zimapan and La Negra districts in the Sierra Madre terrane plot above and to the right of the Stacey-Kramers reference line (206Pb/204Pb = 18.804–18.972). Lead isotope ratios of ore minerals from the Zimapan and La Negra skarn mines ( 206Pb/204Pb = 18.775–18.975) resemble those of the associated igneous rocks, implying a magmatic Pb input in the skarn deposits. New Sr and Nd isotope data on metamorphic rocks (87Sr/ 86Sr = 0.707757–0.726494 and 143Nd/144 Nd = 0.512109–0.512653) suggest that the basement of the Guerrero terrane originated from sources that had been derived from an old cratonic area. The narrow ranges and generally low 87Sr/86Sr ratios (0.704860–0.705755) and 143Nd/144Nd values (0.512765–0.512772) above that of bulk earth for igneous rocks from Inguaran, El Malacate, and La Esmeralda suggest a relatively low degree of crustal contamination. However, the isotopic values for the La Verde site (87Sr/86Sr = 0.708784 and 143Nd/144Nd = 0.512640) may indicate the involvement of a more evolved crustal component.

A geochemical study of crustal plutonic rocks from the southern Mariana Trench forearc: Relationship to volcanic rocks erupted during subduction initiation

Two suites of intermediate-felsic plutonic rocks were recovered by dredges RD63 and RD64 (R/V KK81-06-26) from the northern wall of the Mariana trench near Guam, which is located in the southern part of the Izu-Bonin-Mariana (IBM) island arc system. The locations of the dredges are significant as the area contains volcanic rocks (forearc basalts and boninites) that have been pivotal in explaining processes that occur when one lithospheric plate initially begins to subduct beneath another. The plutonic rocks have been classified based on petrologic and geochemical analyses, which provides insight to their origin and evolution in context of the surrounding Mariana trench. Based on whole rock geochemistry, these rocks (SiO2: 49-78 wt%) have island arc trace element signatures (Ba, Sr, Rb enrichment, Nb-Ta negative anomalies, U/Th enrichment), consistent with the adjacent IBM volcanics. Depletion of rare earth elements (REEs) relative to primitive mantle and excess Zr and Hf compared to the middle REEs indicate that the source of the plutonic rocks is similar to boninites and transitional boninites. Early IBM volcanic rocks define isotopic fields (Sr, Pb, Nd and Hf-isotopes) that represent different aspects of the subduction process (e.g., sediment influence, mantle provenance). The southern Mariana plutonic rocks overlap these fields, but show a clear distinction between RD63 and RD64. Modeling of the REEs, Zr and Hf shows that the plutonic suites formed via melting of boninite crust or by crystallization from a boninite-like magma rather than other sources that are found in the IBM system. The data presented support the hypothesis that the plutonic rocks from RD63 and RD64 are products of subduction initiation and are likely pieces of middle crust in the forearc exposed at the surface by faulting and serpentine mudvolcanoes. Their existence shows that intermediate-felsic crust may form very early in the history of an intra-oceanic island arc system. Plutonic rocks with similar formation histories may exist in obducted suprasubduction zone ophiolites and would be evidence that felsic-intermediate forearc plutonics are eventually accreted to the continents.

Petrologic and geochemical study of crustal xenoliths from Calbuco Volcano, Chile (latitude 41°20ʹS)

Twenty Four samples of xenoliths and country rocks from the 1961 lava flow of Calbuco volcano have been studied. Fourteen samples have been analyzed for major elements and P, Ni, Ba, Cr, V, Zr, Sc, Y, and Sr. Five of these samples were further analyzed for Sm, Nd, Sr, and Pb isotope ratios. Seventeen samples were studied under the microscope and three samples were analyzed by microprobe for their pyroxene compositions. Based on petrographic studies xenoliths were divided into three groups. Fine grained xenoliths (groups I and II) probably formed from metamorphosed MORB-like basalts, whereas coarse grained xenoliths (group III) were apparently derived from cumulate minerals that crystallized from the Calbuco magma. The fine grained xenoliths were probably entrained in magma at intermediate levels of the crust, near the stability limit of amphibole to form pyroxene and plagioclase. In the coarse grained xenoliths amphibole that formed at depth dehydrated as the xenoliths were brought to the surface. The country rocks are apparently unrelated to the xenoliths.

Cultura da representação de arquitetura: concursos de projeto, Brasil 2008-2011

This thesis deepens the issues pointed out in our master's dissertation (2009) and the following texts about architectural projects representation presented in architectural competitions. It aims to identify the representation culture of projects from architectural competitions. Were there common ways to argue among successful architects? Which were them? How extent the various arguments are consistent or what is the discursive coherent? Which interlocutors were privileged in argumentation, the requesting ones or those that evaluate the proposals? To answer these questions, we began from a correlation suggested by TOSTRUP (1999) among some drawings – plans, sections, façades, perspective, details or texts - and emphasized aspects in a project argumentation (place, zoning, environmental comfort, energy efficiency, etc.). On the top of this, we add functions that DURAND (2003) indicates relevant to architectural representations: conception, communication or seduction and execution. Other writers, such as COLLINS (1971), COLLYER (2004), MOON (2005), BANDEIRA (2007), and OXMAN (2008) in different ways, offered us subsidies to relate kinds of architectural representations with specific functions or strategies of persuasion. Thus, for 08 Brazilian competitions, occurred between 2008 – 2011, we analyzed the requests from the brief of the official announcement, the evaluations of the jurors, and the boards of the winning designs – graphical and textual representations. That allowed us to observe a representation culture predominantly based on perspectives and plans, even been articulated in different arguments. This may emphasize since objective aspects as building execution to appeals of mere visual seduction. In what regards to the audience, even when the official announcement resembled to one another, the winners’ argumentation were different, suggesting a possible jury’s privilege as an interlocutor.

Implementação de uma arquitetura fuzzy neural em hardware com treinamento online

Computational Intelligence Methods have been expanding to industrial applications motivated by their ability to solve problems in engineering. Therefore, the embedded systems follow the same idea of using computational intelligence tools embedded on machines. There are several works in the area of embedded systems and intelligent systems. However, there are a few papers that have joined both areas. The aim of this study was to implement an adaptive fuzzy neural hardware with online training embedded on Field Programmable Gate Array – FPGA. The system adaptation can occur during the execution of a given application, aiming online performance improvement. The proposed system architecture is modular, allowing different configurations of fuzzy neural network topologies with online training. The proposed system was applied to: mathematical function interpolation, pattern classification and selfcompensation of industrial sensors. The proposed system achieves satisfactory performance in both tasks. The experiments results shows the advantages and disadvantages of online training in hardware when performed in parallel and sequentially ways. The sequentially training method provides economy in FPGA area, however, increases the complexity of architecture actions. The parallel training method achieves high performance and reduced processing time, the pipeline technique is used to increase the proposed architecture performance. The study development was based on available tools for FPGA circuits.

Arquitetura escolar Infantil modulada e flexível

For many y ears, the federal government policy is to use project for in order to speed up the work for decreasing the elementary education deficit vacancy . In Natal municipality the schoolhouses for children, from 0 to 6 years of age are denom inated Muinicipality Centre for Elementary Education. The federal government provides capital for the news edifications by the program of government named PROINFÂNCIA. This program embraces three types of projects. Type “A” must be furnished by the interes ted municipality and approved by Education and Cultura Ministry. The type “B” is standard plan with capability to 120 schoolchildren in full - time or 240 in two turns and ground plot measuring 40 x 70m and the “type C” also a standart projects to 60 schoolc hildren in full - time or 120 in two turns and ground plot measuring 35 x 45m. Sometimes , due to scarcity of bigger ground plot s is the “type C” instead of “type B”, referring to offering vacancies. In this meaning, this study intend s to present the draft - project to elementary schoolhouse, modulated and flexible, emphasizing the children needs . Therefore, it was studied concept, school architecture, construction technology, reference study and visiting to MCEE Fernanda Jales (PROINFÂNC IA “tipo B”). However, the proposal synthesizes the draft - project by module, implanting in its totality or in parts, according to its necessity and lot cha racteristic.

Arquitetura bioclimática para instituição de ensino fundamental em São Gonçalo do Amarante/RN

In the design of a building process must consider climatic variations in the region, the external conditions and the use of available resources in nature, like the sun, vegetation, rain and winds, to provide a built environment with comfort and environment reduced energy expenditure. However, increasing urbanization, often with an occupancy of disordered ground comes disregarding this knowledge and disregarding local characteristics, drastically reducing the green areas. This disordered occupation associated with the reduction of green spaces, is modifying aspects of climate and thus, damaging the thermal comfort of users. Given this situation was born the question: What projetuais strategies can bring better thermal conditions to an educational building located in a region of hot and humid weather? Thus, faced with two important issues , education and environmental comfort , the research is justified by the fact that there is a large national demand for expansions and renovations in its public schools , but not in most areas provides students with quality for good learning development. This paper aims to draw up a project for establishment of Primary Education with the application of the concepts of bioclimatic, highlighting the use of vegetation as a regulatory element of the climate. Initially we carried out a literature search; we analyzed architectural solutions and set up the site. The next phases, called understanding, were raised with the laws, rules and environmental restrictions. Subsequently, the program needs and the development of architectural design was defined. The conclusion of this paper presents the definition of criteria and solutions for the use of vegetation to design of bioclimatic architecture in hot and humid climates and contributes a catalog of plant species for schools in the metropolitan region of Natal, RN.

Ícones urbanos na cidade de Natal: arquitetura e desenvolvimento urbano na cidade do sol e mar

Natal has come through major changes in the last 150 years, since the actions of city beautification, in the 19th century, until the present day, when such transformations start to have the objective of including the city in the competition for the attraction of the capital flows and consumption, domestically and in a foreign sense. It is thought that the first initiatives aimed at increasing tourism in Natal occurred in the 1960s, however, it became apparent that only from the 1980s was there a significant increase in tourist activities in Natal and the Metropolitan Region, especially on the east coast of the state of Rio Grande do Norte, leading to an expansion of the labour market, the significant increase of foreign investment, territorial changes of great impact and the production of buildings primarily intended for the hotel industry and second residence for European tourists. Since then, the incentives for tourist activity in the state have been maintained and even increased, based on tourism aimed at natural beauties, local cuisine and events, which transformed the tourist activity in one of the main sources of foreign exchange for the city of Natal. In the early 21st century, the construction of high-rise condominiums, monuments (including the designer ones), such as the Parque da Cidade, designed by Oscar Niemeyer, were already established. Also, shopping centers and, in order to host the World Cup, the new football stadium, the Arena das Dunas, among others, which were aimed at local and foreign consumers, especially European, stood out in the city. It is understood that these new buildings, monuments and also renovations and restorations that were deployed in the city of Natal aimed at constructing a new identity for the city, within the process of capitalist development and urban spectacle. It is considered that the monuments and the iconic buildings are attributes of the cities aimed at selling locations as goods, establishing a new urban environment, a new role as cities, which aimed at seeking greater autonomy from the nation-state. In this research, it was sought to analyze the architectural object, that is, buildings and monuments built or restored in Natal and its relevance to the city marketing promoted by the city itself. It was found that, indeed, such buildings and monuments are inserted in contemporary architectural production as a basis for increasing the competitive nature of Natal. In addition, they reveal a capitalist mode of production, supported by public resources, operating in the production of urban space with a view to repeating the hegemonic model of a competitive city

Avaliação da usabilidade e da arquitetura da informação do site do Instituto do Cérebro da UFRN: um estudo de caso com base nas opiniões dos usuários da instituição

The objective of the current piece of research presents was draw up a list of recommendations for the site of the Instituto do Cérebro da Universidade Federal do Rio Grande do Norte, with an emphasis on fault identification in usability and information architecture, through the application of design techniques with users of the institution. From the use of the following techniques: Cardsorting, applied to a group of six people as target public, such as professor, administrative technicians and graduate student of the institution; Interviews, carried out with the director of the Instituto do Cérebro, secretaries of the undergraduate and graduate courses; Cooperative Evaluation applied in two ways: in group and individually. The evaluation in group was fulfilled in four sessions that occurred with a group composed of six people who are part of the technical staff of the Instituto do Cérebro. In the Individual Cooperative Evaluation, eight users (graduate students and administrative technicians of the Instituto do Cérebro da UFRN) performed tasks which are frequently fulfilled by users from the public target in the site of the Instituto do Cérebro. After each session of the Individual Cooperative Evaluation, a questionnaire of the user´s satisfaction was used about his or her perception in regard to the site usability and utility of the mentioned institute site. Therefore, it was concluded that, by means of the analysis of the results and the triangulation of the obtained data in each one of the techniques applied with the users, in the present piece of research, problems were verified, among others; all related to the unsuitable use of the interface elements, navigation, labeling of some menu terms, and still, the lack of search space and integration with the social networks – besides the lack, positioning and inappropriate formatting of information that would be of high relevance to the users. Finally, a list of recommendations is presented and this can be used in a future interface redesign with the goal to improve the information architecture and the usability of the site of the Instituto do Cérebro da Universidade Federal do Rio Grande do Norte.