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‣ Conflicting structural and geochronological data from the Ibituruna quartz-syenite (SE Brazil): Effect of protracted ""hot"" orogeny and slow cooling rate?

PETITGIRARD, Sylvain; VAUCHEZ, Alain; Egydio da Silva, Marcos; BRUGUIER, Olivier; CAMPS, Pierre; MONIE, Patrick; Babinski, Marly; MONDOU, Mathieu
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
Português
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The Ibituruna quartz-syenite was emplaced as a sill in the Ribeira-Aracuai Neoproterozoic belt (Southeastern Brazil) during the last stages of the Gondwana supercontinent amalgamation. We have measured the Anisotropy of Magnetic Susceptibility (AMS) in samples from the Ibituruna sill to unravel its magnetic fabric that is regarded as a proxy for its magmatic fabric. A large magnetic anisotropy, dominantly due to magnetite, and a consistent magnetic fabric have been determined over the entire Ibituruna massif. The magmatic foliation and lineation are strikingly parallel to the solid-state mylonitic foliation and lineation measured in the country-rock. Altogether, these observations suggest that the Ibituruna sill was emplaced during the high temperature (similar to 750 degrees C) regional deformation and was deformed before full solidification coherently with its country-rock. Unexpectedly, geochronological data suggest a rather different conclusion. LA-ICP-MS and SHRIMP ages of zircons from the Ibituruna quartz-syenite are in the range 530-535 Ma and LA-ICP-MS ages of zircons and monazites from synkinematic leucocratic veins in the country-rocks suggest a crystallization at similar to 570-580 Ma, i.e., an HT deformation >35My older than the emplacement of the Ibituruna quartz-syenite. Conclusions from the structural and the geochronological studies are therefore conflicting. A possible explanation arises from (40)Ar-(39)Ar thermochronology. We have dated amphiboles from the quartz-syenite...

‣ Evolução magmática do Sill de Limeira: petrografia e geoquímica; Magmatica evolution of the Limeira Sill: petrography and chemistry

Faria, Camila Antenor
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 19/11/2008 Português
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O Sill de Limeira possui variação composicional ampla e aparentemente contínua, no intervalo entre basalto nas bordas de resfriamento e quartzo monzodiorito grosso na parte mais central exposta até agora nas pedreiras onde é explorado. Abaixo da borda basáltica do topo encontra-se uma camada bastante rica em amígdalas, preenchidas por minerais de origem hidrotermal, seguida pela ocorrência de ocelos de composição quartzo monzonítica. Por toda extensão do sill ocorrem veios riolíticos (em menor proporção, quartzo monzoníticos), de direção preferencial perpendicular às bordas de resfriamento. As rochas são compostas essencialmente por plagioclásio, clinopiroxênio (augita ± pigeonita) e/ou anfibólio, Ti-magnetita, illmenita, além de quartzo e feldspato alcalino (nos termos mais diferenciados). Os minerais acessórios são apatita, filossilicatos, zircão, badeleíta, esfalerita, pirita e allanita; minerais de alteração hidrotermal são zeólitas, calcita, apofilita. Augita tem composição variada entre Fs~20, nas rochas mais primitivas e Fs40 nas mais diferenciadas (quartzo monzodiorito até riolito). O plagioclásio varia desde labradorita até oligoclásio, com predomínio de andesina An50-30 nas rochas mais abundantes. A química de rocha total revela um trend de diferenciação contínuo de composições entre o basalto de borda (~48% SiO2) e o quartzo monzodiorito (~61% SiO2); um hiato entre quartzo monzodiorito e riolito é identificado no intervalo 61-69% SiO2...

‣ Associações metamórficas de alta pressão: nappes neoproterozóicas a sul do Cráton São Francisco

Garcia, Maria da Gloria Motta
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 05/04/2001 Português
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A área estudada é caracterizada por um conjunto de unidades estruturalmente relacionadas transportadas grosseiramente para E-NE em direção à borda sul do Cráton São Francisco. A Nappe Socorro-Guaxupé (NSG), a oeste, representa a unidade mais superior, sendo composta por assembléias minerais nas facies anfibolito e granulito que mostram uma trajetória P-T compatível com uma evolução metamórfica inicial envolvendo magmatismo na base da crosta antes e durante seu soterramento. Este gradiente térmico anômalo foi responsável pela geração de metamorfismo granulítico anidro, sugestão corroborada pela heterogeneidade das composições isotópicas de oxigênio. As unidades subjacentes ocorrem como uma grande pilha metassedimentar organizada como uma nappe superior formada por Ky/Sill granulitos (Nappe Três Pontas-Varginha - NTPV), na qual um padrão metamórfico invertido foi reconhecido, e uma nappe inferior constiruída por Ky xistos e gnaisses (Nappe Carmo Cachoeira - NCC), separados por uma descontinuidade tectônica. Na NTPV, trajetórias P-T tipo IBC horárias, típicas de ambientes colisionais, foram definidas para os Ky e Sill granulitos. Os Ky granulitos basais mostram uma trajetória no campo de estabilidade da Ky...

‣ O tráfego de máquinas agrícolas e as propriedades físicas, hídricas e mecânicas de um Latossolo dos Cerrados

Silva, Reginaldo Barboza da; Dias Junior, M. S.; Silva, Francisca Alcivania de Melo; Fole, S. M.
Fonte: Sociedade Brasileira de Ciência do Solo Publicador: Sociedade Brasileira de Ciência do Solo
Tipo: Artigo de Revista Científica Formato: 973-983
Português
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No Brasil, o tráfego contínuo e inadequado de rodados de máquinas e a ação da soleira dos implementos sobre áreas agrícolas na região dos Cerrados têm provocado alterações dos atributos físicos e mecânicos dos solos. Com este entendimento, este estudo teve por objetivo avaliar a influência do rodado traseiro e da soleira de implementos agrícolas, usualmente utilizados na região dos Cerrados, sobre a compressibilidade de um Latossolo Vermelho distrófico típico. Os ensaios foram realizados em parcelas preparadas com arado de discos, arado de aivecas, grade aradora e semeadora/adubadora, que, desde novembro de 1994 até à data da amostragem, novembro de 1999, estiveram sob o sistema plantio direto. As alterações na compressibilidade foram avaliadas pela quantificação das pressões de preconsolidação, assim como por algumas propriedades físicas e hídricas (densidade do solo, porosidade e condutividade hidráulica do solo saturado) no momento do preparo e depois da colheita. No momento do preparo, logo depois da passada do rodado e antes que o implemento mobilizasse o solo, o solo foi avaliado em superfície (SP - 0,00 a 0,05 m) e na profundidade média de trabalho (PMT - 0,24 a 0,27 m). A influência da soleira dos implementos foi avaliada logo depois do corte...

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

Seixas, Adriano da Rosa
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Dissertação de Mestrado Formato: 79 f. : gráfs., il., tabs.
Português
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Pós-graduação em Geologia Regional - IGCE; The magnetometry is an important tool in geological mapping, especially in studies of basic rocks in the context of sedimentary basin. There are few geophysical works directly related to Sills, therefore, the purpose of this study is to characterize the geological subsurface structure of the Sill diabase in the Paraná Magmatic Province exposed beneath sandstones in the Itararé group, located near the city of Limeira, in the east-central region of São Paulo state. In this study, we present maps illustrating the results of ground magnetometry as well as corrections, stages processing, and interpretation of geophysical data. The magnetometric method served as an important tool in the characterization of physical properties of the contrast generated between the Sill diabase and the sandstone rocks (Itararé group). According to previous works, the bodies of the Sill diabase in Limeira should present a subsurface lateral continuity. However, the magnetometric method performed in this study allowed us to define that the area of the Limeira Sill comprises several independent diabase bodies, in the shape of Sills, which do not exhibit subsurface lateral continuity. The average radial power spectrum allowed determines the wave number cut-off value suitable for the components separation in shallow and deep sources. Spectral analysis showed that the structures with depths exceeding 100 m were related to the structure of the diabase bodies...

‣ Desempenho acústico de diferentes tipologias de peitoris ventilados; Acoustic performances of various types of windows ventilated sills

Maria Lúcia Gondim da Rosa Oiticica
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 05/07/2010 Português
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t: Com a crise energética na década de 60, varias discussões foram levantadas com o propósito de estimular as edificações a estarem inseridas em um contexto sustentável. As edificações, por serem grandes consumidoras dos recursos naturais, buscam ser mais eficientes energeticamente que outras quando estas proporcionam as mesmas condições ambientais com menor consumo energético. Para tal, a bioclimatologia que relaciona o estudo do clima aplicado à arquitetura, quando focada nas decisões arquitetônicas, torna-se uma excelente ferramenta para se obter valores de consumo energéticos mais baixos. Nas regiões de clima quente úmido, a utilização do peitoril ventilado como estratégia de projeto bioclimático, é uma ferramenta de projeto muito bem aplicada dentro deste conceito. O peitoril ventilado é um dispositivo geralmente executado em concreto, em formato geralmente em “L” invertido, sobreposto a uma abertura localizada no peitoril abaixo das janelas, que tem por finalidade atuar como fonte complementar do movimento de ar proporcionado pelas aberturas. A presença deste elemento nas aberturas das edificações pode proporcionar uma redução do consumo de energia, uma vez que estimula a climatização natural...

‣ Magnetic studies of the Late Cretaceous magmatism in Portugal:from Iberian plate kinematics to magnetic fabrics

Neres, Marta Maria de Almeida, 1984-
Fonte: Universidade de Lisboa Publicador: Universidade de Lisboa
Tipo: Tese de Doutorado
Publicado em //2014 Português
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Tese de doutoramento (co-tutela), Ciências Geofísicas e da Geoinformação (Geofísica), Université de Toulouse, Universidade de Lisboa, 2013; The Jurassic-Cretaceous Iberian kinematics is still not well understood, mainly due to limitations on reconstructions based on marine magnetic anomalies (uncertainties about the nature of the crust and presence of the Cretaceous Normal Superchron) and on paleomagnetic data (insu cient and sometimes low-quality data, low age resolution, tectonic in uences and remagnetizations). In this thesis, we rst provide new high-quality paleomagnetic poles for the Late Cretaceous of Iberia, calculated from two ma c sills (Foz da Fonte, 88 Ma et Pa co de Ilhas, 94 Ma), which enable better calibrating the Iberian apparent polar wander path (APWP) at the Late Cretaceous. A detailed study of magnetic mineralogy and microscopic observations (electronic and optic) con rm a primary magnetization carried by titanomagnetite. We then present a new compilation of the published paleomagnetic data for the Late Jurassic-Cretaceous of Iberia from which we calculate mean poles for six time periods. By rotating these mean poles to the African frame using Euler rotation poles from kinematic models we evaluate their position with respect to the global APWP in African coordinates. We verify that while post-rift mean poles (from 70 to 120 Ma) are in agreement with the APWP...

‣ Evolution of the soil surface roughness using geostatistical analysis

Vázquez,Eva Vidal; Bertol,Ildegardis; Siqueira,Glécio Machado; Paz-Ferreiro,Jorge; Dafonte,Jorge Dafonte
Fonte: Instituto Agronômico de Campinas Publicador: Instituto Agronômico de Campinas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2010 Português
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The objective of this work was to investigate the decay of initial surface roughness induced by simulated rainfall under different soil residue cover and to compare classical statistical indices with geostatistical parameters. A conventionally tilled loamy soil with low structure stability, thus prone to crusting was placed at 1 m² microplots. Each microplot received three successive rainfall events which bring about cumulative 25 mm, 50 mm and 75 mm at 65 mm h-1 intensity. Five treatments without replication were tested with different corn straw quantities (0, 1, 2, 3 and 4 Mg ha"1). Soil surface microrelief was measured at the initial stage and after each simulated rainfall event. Five treatments and four surface stages were monitored, resulting in 20 data sets. Point elevation data were taken at 0.03 m intervals using a pinmeter. Digital elevation models were generated and analysed using semivariograms. All data sets showed spatial dependence and spherical models were fitted to experimental semivariograms. A very significant relationship was found between the random roughness index, RR, and the sill of the semivariogram (C0+C1). All the treatments showed a clear trend to sill value reduction with increasing precipitation. However...

‣ Response of Euphausia pacifica to small-scale shear in turbulent flow over a sill in a fjord

Ianson, Debby; Allen, Susan E.; Mackas, David L.; Trevorrow, Mark V.; Benfield, Mark C.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
Português
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Zooplankton in the ocean respond to visual and hydro-mechanical cues such as small-scale shear in turbulent flow. In addition, they form strong aggregations where currents intersect sloping bottoms. Strong and predictable tidal currents over a sill in Knight Inlet, Canada, make it an ideal location to investigate biological behaviour in turbulent cross-isobath flow. We examine acoustic data (38, 120 and 200 kHz) collected there during the daylight hours, when the dominant zooplankters, Euphausia pacifica have descended into low light levels at ∼90 m. As expected, these data reveal strong aggregations at the sill. However, they occur consistently 10–20 m below the preferred light depth of the animals. We have constructed a simple model of the flow to investigate this phenomenon. Tracks of individual animals are traced in the flow and a variety of zooplankton behaviours tested. Our results indicate that the euphausiids must actively swim downward when they encounter the bottom boundary layer (bbl) to reproduce the observed downward shift in aggregation patterns. We suggest that this behaviour is cued by the small-scale shear in the bbl. Furthermore, this behaviour is likely to enhance aggregations found in strong flows at sills and on continental shelves.

‣ Effects of Igneous Intrusion on Microporosity and Gas Adsorption Capacity of Coals in the Haizi Mine, China

Jiang, Jingyu; Cheng, Yuanping
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
Publicado em 26/02/2014 Português
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This paper describes the effects of igneous intrusions on pore structure and adsorption capacity of the Permian coals in the Huaibei Coalfield, China. Twelve coal samples were obtained at different distances from a ~120 m extremely thick sill. Comparisons were made between unaltered and heat-affected coals using geochemical data, pore-fracture characteristics, and adsorption properties. Thermal alteration occurs down to ~1.3 × sill thickness. Approaching the sill, the vitrinite reflectance (Ro) increased from 2.30% to 2.78%, forming devolatilization vacuoles and a fine mosaic texture. Volatile matter (VM) decreased from 17.6% to 10.0% and the moisture decreased from 3.0% to 1.6%. With decreasing distance to the sill, the micropore volumes initially increased from 0.0054 cm3/g to a maximum of 0.0146 cm3/g and then decreased to 0.0079 cm3/g. The results show that the thermal evolution of the sill obviously changed the coal geochemistry and increased the micropore volume and adsorption capacity of heat-affected coal (60–160 m from the sill) compared with the unaltered coals. The trap effect of the sill prevented the high-pressure gas from being released, forming gas pocket. Mining activities near the sill created a low pressure zone leading to the rapid accumulation of methane and gas outbursts in the Haizi Mine.

‣ Isotopic and geochemical studies of four volcano-tectonic provinces in continental margins: the Franciscan Subduction Complex, California, the Palisade Sill, New York-New Jersey, the Afar Triple Junction, Ethiopia, and the Rajmahal-Sylhet Traps, Northeast India

Ghatak, Arundhuti (1981 - ); Basu, Asish (1944 - )
Fonte: Universidade de Rochester Publicador: Universidade de Rochester
Tipo: Tese de Doutorado Formato: Number of Pages:xxiv, 457 leaves
Português
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Thesis (Ph. D.)--University of Rochester. Dept. of Earth and Environmental Sciences, 2010; This study examines petrological-geochemical characteristics of rocks from different plate-tectonic settings in three different continents that include the Mesozoic Franciscan Subduction Complex of coastal California (Part I), and three continental margin igneous provinces from the Mesozoic to recent times (Part II). The three igneous provinces, related to three large flood basalt eruptions, include the Afar triple junction volcanics in Ethiopia, the Palisade sill of New York-New Jersey, and the Rajmahal-Sylhet Traps in Northeastern India. Although disparate, studies of these three igneous provinces at continental margins provide insights for magma-tectonic processes during stretching and rupturing of continental lithosphere. PART – I Sr-, Nd-, Pb-isotopic ratios and major and trace element studies of the high-grade tectonic blocks of the Franciscan Subduction Complex indicate that the protoliths of these rocks were nascent arc tholeiites with no detrital continental crustal component. The tectonic model developed from geochemical data implies that these arc tholeiites had formed in a subduction zone different from the Franciscan subduction and were the first to be subducted when the Franciscan subduction was initiated some 175 My ago. Major and trace element concentration and Nd-Pb isotopic data of high and low-grade rocks from the Franciscan Subduction Complex and the Feather River ultramafic belt imply that the metavolcanic rocks...

‣ Section of the sill east of Door 2-1 in Room 2 on the second floor of the Peña-Peck House during restoration

Fonte: St. Augustine Restoration, Inc.; St. Augustine Restoration, Inc. Publicador: St. Augustine Restoration, Inc.; St. Augustine Restoration, Inc.
Tipo: mixed material
Publicado em //11/1/1968 Português
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Spanish Treasury; Section of sill east of door 2-1, Room 2-2; 1953

‣ Using 3D seismic data and geochemistry to model magma ascent pathways in the Otway Basin.

Holt, S. J.
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2012 Português
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Modern studies have challenged the traditional view point that magma rises through the lithosphere via dykes and high-angle faults. These studies have suggested that horizontal structures such as inter-connected saucer-shaped sills play a large part in magma transport and result in large horizontal offsets between the source and eruption point of the magma. The South Australian Quaternary Basalts (SAQB) are found in the S.E. of South Australia and are the result of the most recent volcanic activity on the Australian continent and have undergone little alteration. As a result, the SAQB represent a superb natural laboratory to be used as a field area to conduct geochemical and 3D seismic modelling in order to discriminate between competing hypotheses for magma transport through the Earth’s crust. Geochemical modelling suggests that the magma that fed the SAQB was generated by decompressional melting of a secondary mantle plume at 42, 33 and 28 kbar for the Northern Group, Mt. Schank and Mt. Gambier respectively. During ascent the magma underwent between 34 and 41% fractional crystallisation, cooled approximately 200°C and resided in the crust for a time period in the order of days to weeks. 3D seismic modelling and volume visualisation of the Balnaves Seismic Survey revealed a saucer-shaped sill with an unusual and previously undescribed morphology...

‣ Biogeochemical patterns in the Atlantic Inflow through the Strait of Gibraltar

RAMIREZ-ROMERO Eduardo; MACIAS MOY DIEGO; GARCIA Carlos; BRUNO Miguel
Fonte: PERGAMON-ELSEVIER SCIENCE LTD Publicador: PERGAMON-ELSEVIER SCIENCE LTD
Tipo: Articles in Journals Formato: Online
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The effects of tidal forcing on the biogeochemical patterns of surface water masses flowing through the Strait of Gibraltar are studied by monitoring the Atlantic Inflow (AI) during both spring and neap tides. Three main phenomena were defined depending on the strength of the outflowing phase predicted over the Camarinal Sill: non-wave events (a very frequent phenomenon during the whole year); type I Internal wave events (a very energetic event, occurring during spring tides); and type II Internal wave events (less intense, occurring during neap tides). During neap tides, a non-wave event comprising oligotrophic open-ocean water from the Gulf of Cádiz is the most frequent and clearly dominant flow through the Strait. In this tidal condition, the inflow of North Atlantic Central Water (NACW) provides the main nutrient input to the surface layer of the Alboran Sea, supplying almost 70% of total annual nitrate transport to the Mediterranean basin. A low percentage of active and large phytoplankton cells and low average concentrations of chlorophyll (0.3-0.4 mg m-3 ) were found in this tidal phase. Around 50% of total annual phytoplankton biomass transport into the Mediterranean Sea through the Strait presents these oligotrophic characteristics. In contrast...

‣ Effect of coastal-trapped waves and wind on currents and transport in the Gulf of California

Guti errez, Manuel O.; L opez, Manuel; Candela, Julio; Castro, Ruben; Mascarenhas, Affonso; Collins, Curtis A.
Fonte: Escola de Pós-Graduação Naval Publicador: Escola de Pós-Graduação Naval
Tipo: Artigo de Revista Científica
Português
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The article of record as published may be located at http://dx.doi.org/10.1002/2013JC009538; Subsurface pressure (SsP) observations from stations inside and outside of the Gulf of California (GC) are used to analyze the relationship between low-frequency currents, temperature, and transport inside the GC and intraseasonal coastal-trapped waves (CTWs), which propagate poleward along the coast toward the GC. Correlation functions and coherences of SsP stations were consistent with intraseasonal CTWs splitting in two at the mouth of the gulf: one part enters the gulf, propagates around the gulf, and eventually, toward the mouth, and another part that appears to ‘‘jump’’ the mouth of the gulf and travels poleward along the west coast of the peninsula. The correlation and coherence estimates of SsP at Manzanillo with currents showed that downwelling CTWs generated along-gulf current anomalies toward the head of the gulf at the mainland shelf of the mouth, whereas at Ballenas Channel sill (San Lorenzo sill) these waves generated current anomalies toward the mouth near the surface (bottom). At the San Lorenzo (SL) sill, downwelling CTWs increased the near-bottom ( 400 m) temperature and reduced the bottom transport of deep...

‣ Nitrate to silicate ratio variability and the composition of micro-phytoplankton blooms in the inner-fjord of Seno Ballena (Strait of Magellan, 54 degrees S)

Reid, Brian; Blanco, José Luis; Pizarro, Gemita; Maureira, Constanza; Valle Levinson, Arnoldo; Montecino, Vivian; Frangópulos, Máximo; Hamamé, Madeleine; Torres, Rodrigo
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo de revista
Português
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Artículo de publicación ISI; The along-fjord variability of nitrate and dissolved silicate was studied in a silled fjord, Seno Ballena, in the Strait of Magellan during flood and ebb tidal phases in December 2007. The spatial and temporal variability of both nitrate and dissolved silicate were consistent with the dynamics of a tidal intrusion front previously described for this fjord by Valle-Levinson et al. (2006). During flood, maximum nitrate values were found seaward and close to the sill due to the upwelling of dense, nutrient-rich water by means of Bernoulli aspiration. Conversely, a sharp drop in surface nitrate landward of the sill was consistent with the sinking of saltier, nitrate-rich, dissolved silicate-poor upwelled waters under relatively less dense, nitrate-poor, dissolved silicate-rich surface waters after flowing landward over the shallow sill. The waters flooding over the sill were particularly enriched in nitrate but poor in dissolved silicate, (NO(3)(-):Si(OH)(4) ratio similar to 5). The ratio tended to decrease landward of the sill, particularly during the ebb tide (NO(3)(-):Si(OH)(4) ratio < 2), but the absolute Si(OH)(4) concentration values were still very low, normally ranging between 2 and 3 mu M Si(OH)(4). Consistent with the low availability of dissolved silicate (DSi)...

‣ Magma flow and thermal contraction fabric in tabular intrusions inferred from AMS analysis. A case study in a late-Variscan folded sill of the Albarracin Massif (southeastern Iberian Chain, Spain)

Gil-Imaz, A.; Rillo, Conrado; Guerrero, E.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 24576 bytes; application/msword
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13 pages, 8 figures, 2 tables.-- et al.; The effects of different petrological processes on the rock fabric of a folded sill from the Albarracin Massif (southeastern Iberian Chain, Spain) were studied by means of the anisotropy of magnetic susceptibility (AMS) technique. The most outstanding feature of the sill at outcrop-scale is a network of joints linked to thermal contraction, which define polygonal columns. The analysis of the magnetic fabric, taking the orientation of sill walls and column axes as a reference and using the ‘restored’ directional data corresponding to the whole of K3 susceptibility axes, has revealed magnetic fabrics related to two processes: (a) magma flow with a SW-trending flow vector characterized by a curved geometry of the magma foliations and (b) thermal contraction coeval to lava cooling. Early magnetite crystals, grown in a relatively high viscosity calc-alkaline magma, are the main carriers involved in the AMS fabric. Passive rotation of the early magnetic mineralogy within a medium-viscosity magma explains the magnetic fabric linked to both magma flow and near-solidus thermal contraction of the magma. Late-Variscan folding of the sill produced the rigid-body reorientation of the magnetic fabric.; Measurements of AMS and IRM data were carried out at the Institute of Earth Sciences ‘Jaume Almera’...

‣ Daylighting and solar shading performances of an innovative automated reflective louver system

Hashemi, Arman
Fonte: Elsevier Publicador: Elsevier
Tipo: Article; accepted version
Português
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This is the author accepted manuscript. The final version is available from Elsevier via http://www.sciencedirect.com/science/article/pii/S0378778814006355.; Traditional windows, as the major source of daylight, have a common problem which is uneven distribution of daylight in the room. Several innovative daylighting systems such as light shelves, fixed and movable reflective louvres, reflective sills, prismatic glazing, light pipes, etc., have been developed to address this problem. This paper reports on a research programme that investigates retrofitted solutions to uneven distribution of daylight in deep-plan office buildings. The work presented here follows initial investigations into the design and applicability of an automated retrofitted panel thermal shutters which can also act as a sunshade and daylighting system. The system has a patented function which allows each shutter/louvre to be controlled and placed separately from other louvres. This study evaluates the effectiveness of the system when acting as a sunshade, light shelf, reflective louvre, and reflective sill under clear, overcast, and sunny sky conditions. According to the results, the system significantly improved daylight distribution and reduced the need for artificial lighting by 60%.

‣ Effects of Altered Shorelines on Macrofauna and Diel-Cycling Hypoxia in Tidal Tributaries of Delaware Bay and Delaware Coastal Bays

Balouskus, Richard
Fonte: University of Delaware Publicador: University of Delaware
Tipo: Tese de Doutorado
Português
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Targett, Timothy; The physical structure of estuarine habitats has been, and continues to be modified by human activity. Understanding how the biophysical structure of shoreline affects the functional value and habitat quality of estuaries for shore-zone biota is important in determining impacts of shoreline modification on estuarine systems. The Mid-Atlantic region has seen a decrease in the area of Spartina alterniflora (smooth cordgrass) within estuaries during the past few decades, while invasive Phragmites australis (common reed) and several types of shoreline hardening including bulkhead, riprap and riprap-sill structures have become more common. These hardened shorelines and invasive grass species have caused a change in the ecological character of the intertidal zone, particularly in urbanized watersheds. This research seeks to understand how changes in shoreline structure affect the ecological character of tidal marsh creeks and basins along Delaware Bay and Delaware Coastal Bays through estuarine fish and crab assemblages, tributary water quality, and fish spawning activity. In the first part of this study, I used quantitative sampling to examine the spatiotemporal use of estuarine systems by fish and blue crabs in association with environmental characteristics of the habitat...

‣ Hydraulic fracturing as a possible mechanism of dyke-sill transitions and horizontal discordant intrusions in trachytic tabular bodies of Arraial do Cabo, State of Rio de Janeiro, Brazil

Motoki,A; Sichel,S.E.
Fonte: Instituto de Geofísica, UNAM Publicador: Instituto de Geofísica, UNAM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2008 Português
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This paper presents some field descriptions and genetic considerations about dyke-sill transitions and horizontal-discordant intrusions of the early Tertiary felsic alkaline dyke swarm at Arraial do Cabo, State of Rio de Janeiro, Brazil. Two examples show the entire process of dyke-sill transition. Near sea level they are vertical-discordant; at middle height, oblique-concordant; at the top of the cliff, horizontal-discordant. The latter process cannot be explained by a traditional model of magma intrusion along weaknesses in the host body. It can be accounted for by hydraulic fracturing: magma pressure creates a new fracture normal to σ3, regardless of whether old fracture systems exist. The dyke-sill transition takes place at a depth such that σa3 changes direction from horizontal to vertical. In the specific case described here, the stress change could be caused by intrusion and volume expansion of the Cabo Frio Island syenitic body.