WorldWideScience

Sample records for belt brazil implications

  1. The Neoproterozoic-Cambrian Paraguay Belt, central Brazil: Part I - New structural data and a new approach on the regional implications

    Science.gov (United States)

    Silva, Luiz José Homem D'el-Rey; Walde, Detlef Hans-Gerd; Saldanha, Davi Oliveira

    2016-04-01

    Together with the Araguaia and Brasília belts, the Paraguay belt forms in central Brazil, the Tocantins Province that is one of the largest orogens of western Gondwana. The Corumbá area occupies the site where the northern and southern parts of the Paraguay belt form, together with the Chiquitos-Tucavaca aulacogen (stretching E-W in the adjacent Bolivian territory) an R-R-R basin system opened-filled in the ~ 700/650-540 Ma interval within the Amazon-Rio Apa paleo-continent. The sedimentary (volcanic) rocks of the Jacadigo and Corumbá Groups found around the Corumbá city record part of the Neoproterozoic-Cambrian passive margin precursor of the Paraguay belt. Our pioneer structural analysis reveals that these rocks experienced progressive deformation (phases D1-D2-D3) and low-grade metamorphism during the Brasiliano Cycle (540-513 Ma). The crystalline basement was also involved, according to structural data and K-Ar ages in the literature. The paleo-passive margin was thickened during the D1-D2 deformation and was lately shortened (D3) in two orthogonal directions, SE-NW (D3P) and SW-NE (D3T). Developed co-axially and verging to NW, D1-D2-D3P structures record the closure of the basin precursor of the Paraguay belt, whereas D3T structures seem related to the inversion of the aulacogen. Although the tectonic transport to NW, as observed in the Corumbá area, matches the reported transport of Paraguay belt's supracrustal rocks towards the eastern margin of the Rio Apa block and Araguaia belt's rocks towards the Amazon craton, the transport direction is opposite in other parts of the Paraguay belt. Our comprehensive discussion of these facts brings to light profound regional implications.

  2. Chloritites of the Tocantins Group, Araguaia fold belt, central-northern Brazil: Vestiges of basaltic magmatism and metallogenetic implications

    Science.gov (United States)

    Kotschoubey, Basile; Villas, Raimundo Netuno; Aires, Benevides

    2016-08-01

    Chloritites from different localities (Arapoema, Couto Magalhães Velho, Juarina, Morro Grande, Morro do Jabuti, Morro do Pau Ferrado, Morro do Salto, Serra do Jacu, Serra do Quatipuru, Serra do Tapa, Serrinha) of the Araguaia fold belt, Tocantins geotectonic province, central-northern Brazil, have been investigated. Based on field work and petrographic, diffractometric, geochemical and mineral chemistry data, these rocks, commonly associated with metacherts and banded iron formations, have been interpreted as products of ocean-floor exhalative-hydrothermal activity on MORB basalts. Distribution patterns of rare earth elements and diagrams of relatively immobile components in the hydrothermal environment highlight not only the genetic link between the chloritites and the basaltic rocks that occur in the region (Serra do Tapa and Morro do Agostinho), but also some peculiar characteristics of the submarine environment. The rock association and anomalous contents of Cu, Zn, Ni, As, and Au are suggestive that the region was favorable to the formation of volcanogenic massive sulfide deposits, what makes it a potential target for mineral exploration programs.

  3. The Bossoroca Complex, São Gabriel Terrane, Dom Feliciano Belt, southernmost Brazil: Usbnd Pb geochronology and tectonic implications for the neoproterozoic São Gabriel Arc

    Science.gov (United States)

    Gubert, Mauricio Lemos; Philipp, Ruy Paulo; Stipp Basei, Miguel Angelo

    2016-10-01

    Usbnd Pb LA-ICPMS geochronological analyses were carried out on zircon grains from metavolcanic rocks of the Bossoroca Complex and for one ash tuff of the Acampamento Velho Formation of the Camaquã Basin, in order to understand the evolution of the Neoproterozoic São Gabriel magmatic arc. A total of 42 analyses of igneous zircon grains were performed in three samples. The results yielded Usbnd Pb ages of 767.2 ± 2.9 Ma for the metavolcanic agglomerate (BOS-02); 765 ± 10 Ma for the metacrystal tuff (BOS-03) and 565.8 ± 4.8 Ma for the ash tuff (BOS-04). The Orogenic Cycle in Brazil is characterized by a set of orogenic belts consisting of petrotectonic associations juxtaposed by two collisional events that occurred at the end of the Neoproterozoic. In southern Brazil this orogeny formed the Dom Feliciano Belt, a unit composed of associations of rocks developed during two major orogenic events called São Gabriel (900-680 Ma) and Dom Feliciano (650-540 Ma). The main São Gabriel associations are tectonically juxtaposed as elongated strips according to the N20-30°E direction, bounded by ductile shear zones. The Bossoroca Complex comprises predominantly metavolcano-sedimentary rocks, characterized by medium-K calc-alkaline association generated in a cordillera-type magmatic arc. The volcanism occurred in sub-aerial environment, developing deposits generated by flow, resurgence and fall, sporadically interrupted by subaqueous epiclastic deposits, suggesting an arc related basin. The São Gabriel Terrane contains the petrotectonic units that represent the closure of the Charrua Ocean associated to the subduction period of the Brasiliano Orogenic Cycle in the Sul-rio-grandense Shield.

  4. Geochemistry of komatiites and basalts from the Rio das Velhas and Pitangui greenstone belts, São Francisco Craton, Brazil: Implications for the origin, evolution, and tectonic setting

    Science.gov (United States)

    Verma, Sanjeet K.; Oliveira, Elson P.; Silva, Paola M.; Moreno, Juan A.; Amaral, Wagner S.

    2017-07-01

    The Neoarchean Rio das Velhas and Pitangui greenstone belts are situated in the southern São Francisco Craton, Minas Gerais, Brazil. These greenstone belts were formed between ca. 2.79-2.73 Ga, and consist mostly of mafic to ultramafic volcanics and clastic sediments, with minor chemical sediments and felsic volcanics that were metamorphosed under greenschist facies. Komatiites are found only in the Rio das Velhas greenstone belt, which is composed of high-MgO volcanic rocks that have been identified as komatiites and high-Mg basalts, based on their distinctive geochemical characteristics. The Rio das Velhas komatiites are composed of tremolite + actinolite + serpentine + albite with a relict spinifex-texture. The Rio das Velhas komatiites have a high magnesium content ((MgO)adj ≥ 28 wt.%), an Al-undepleted Munro-type [(Al2O3/TiO2)adj and (CaO/Al2O3)adj] ratio ranging from 27 to 47 and 0.48 to 0.89, relatively low abundances of incompatible elements, a depletion of light rare earth elements (LREE), a pattern of non-fractionated heavy rare- earth elements (HREE), and a low (Gd/Yb)PM ratio (≤ 1.0). Negative Ce anomalies suggest that alteration occurred during greenschist facies metamorphism for the komatiites and high-Mg basalts. The low [(Gd/Yb)PM 18] and high HREE, Y, and Zr content suggest that the Rio das Velhas komatiites were derived from the shallow upper mantle without garnet involvement in the residue. The chemical compositions [(Al2O3/TiO2)adj, (FeO)adj, (MgO)adj, (CaO/Al2O3)adj, Na, Th, Ta, Ni, Cr, Zr, Y, Hf, and REE] indicate that the formation of the komatiites, high-Mg basalts and basalts occurred at different depths and temperatures in a heterogeneous mantle. The komatiites and high-Mg basalts melted at liquidus temperatures of 1450-1550 °C. The Pitangui basalts are enriched in the highly incompatible LILE (large-ion lithophile elements) relative to the moderately incompatible HFS (high field strength) elements. The Zr/Th ratio ranging from 76 to

  5. The Caldas Novas dome, central Brazil: structural evolution and implications for the evolution of the Neoproterozoic Brası´lia belt

    Science.gov (United States)

    D'el-Rey Silva, Luiz José Homem; Wolf Klein, Percy Boris; Walde, Detlef Hans-Gert

    2004-10-01

    The Caldas Novas dome (Goiaás state, central Brazil) lies in the southern segment of the Neoproterozoic Brası´lia belt (center of the Tocantins Province) between the Goiás magmatic arc and the margin of the ancient São Francisco plate. The core of the dome comprises rocks of the Meso-Neoproterozoic Paranoá group (passive margin psamitic-pelitic sediments and subgreenschist facies) covered by a nappe of the Neoproterozoic Araxá group (backarc basin pelitic-psamitic sediments and volcanics of greenschist facies, bitotite zone). Hot underground waters that emerge along fractures in the Paranoá quartzite and wells in the Araxá schist have made the Caldas Novas dome an international tourist attraction. A recent detailed structural analysis demonstrates that the dome area was affected by a D 1-D 3 Brasiliano cycle progressive deformation in the ˜750-600 Ma interval (published U-Pb and Sm-Nd data). During event D 1, a pervasive layer-parallel foliation developed coeval the regional metamorphism. Event D 2 (intense F 2 isoclinal folding) was responsible for the emplacement of the nappe. D 1 and D 2 record a regime of simple shear (top-to-SE relative regional movement) due to a WNW-ESE subhorizontal compression ( σ1). Event D 3 records a WSW-ENE compression, during which the dome rose as a large-scale F 3 fold, possibly associated with a duplex structure at depth. During the dome's uplift, the layers slid back and down in all directions, giving way to gravity-slide folds and an extensional crenulation cleavage. A set of brittle fractures and quartz veins constitutes the record of a late-stage D 4 event important for understanding the thermal water reservoir.

  6. The Mesoproterozoic volcano-sedimentary Serra do Itaberaba Group of the Central Ribeira Belt, Sao Paulo State, Brazil: implications for the age of the overlying Sao Roque Group

    Energy Technology Data Exchange (ETDEWEB)

    Juliani, Caetano [Sao Paulo Univ., SP (Brazil). Inst. de Geociencias]. E-mail: cjuliani@usp.br; Hackspacher, Peter; Fetter, Allen Hutchenson [UNESP, Rio Claro, SP (Brazil). Inst. de Geociencias e Ciencias Exatas]. E-mail: phack@rc.unesp.br; fetter@rc.unesp.br; Dantas, Elton Luiz [Brasilia Univ., DF (Brazil). Inst. de Geociencias]. E-mail: elton@unb.br

    2000-03-01

    One of the fundamental problems to understanding the evolution of volcano-sedimentary sequences in southeastern Brazil is constraining their depositional ages. Brasiliano tectonic and metamorphic either obscured or destroyed primary features, such as unconformities, as well as other geologic relationships. This problem is exemplified by the Serra do Itaberaba and Sao Roque groups, where the lack of data about the timing of their deposition has prevented resolution of proposed one-and two-stage geotectonic/depositional models. Recent U-Pb zircon data obtained from metavolcanic rocks in the Sao Roque Group indicate that it was deposited between 628 and 607 Ma. New U-Pb zircon data of 1395{+-} 10 Ma for a metandesite in the basal Morro da Pedra Preta Formation (Serra do Itaberaba Group) indicate the maximum age for the beginning of the deposition of the pelites overlying MORB-like basalt. A metarhyolite of the upper unit, the Nhangucu Formation, contains two zircon populations. One yielded an age of 619 {+-}3 Ma, which defines the crystallization age of the rock, and the other an age of 1449 {+-}3 Ma, interpreted as inherited xenocrystal grains from older units of the Serra do Itaberaba Group. The younger metarhyolite was affected only by the S{sub 2} foliation, generated during the Brasiliano orogenesis, whereas the Middle Proterozoic metavolcano-sedimentary sequence records additional metamorphic and deformational events, confirming the presence of two different geotectonic cycles. (author)

  7. Anomalous heat flow belt along the continental margin of Brazil

    Science.gov (United States)

    Hamza, Valiya M.; Vieira, Fabio P.; Silva, Raquel T. A.

    2017-06-01

    A comprehensive analysis of thermal gradient and heat flow data was carried out for sedimentary basins situated in the continental margin of Brazil (CMB). The results point to the existence of a narrow belt within CMB, where temperature gradients are higher than 30 °C/km and the heat flow is in excess of 70 mW/m2. This anomalous geothermal belt is confined between zones of relatively low to normal heat flow in the adjacent continental and oceanic regions. The width of the belt is somewhat variable, but most of it falls within the range of 100-300 km. The spatial extent is relatively large in the southern (in the basins of Pelotas, Santos and Campos) and northern (in the basins of Potiguar and Ceará) parts, when compared with those in the central parts (in the basins of South Bahia, Sergipe and Alagoas). The characteristics of heat flow anomalies appear to be compatible with those produced by thermal sources at depths in the lower crust. Hence, magma emplacement at the transition zone between lower crust and upper mantle is considered the likely mechanism producing such anomalies. Seismicity within the belt is relatively weak, with focal depths less than 10 km for most of the events. Such observations imply that "tectonic bonding" between continental and oceanic segments, at the transition zone of CMB, is relatively weak. Hence, it is proposed that passive margins like CMB be considered as constituting a type of plate boundary that is aseismic at sub-crustal levels, but allows for escape of significant amounts of earth's internal heat at shallow depths.

  8. Policy Implications from an Evaluation of Seat Belt Use Regulation.

    Science.gov (United States)

    Desai, Anand; You, Min-Bong

    1992-01-01

    Effects of Ohio's mandatory seat belt law on seat belt use, number of car accidents, and number of fatal and severe injuries were evaluated for January 1982 through March 1988. The monthly average number of accident victims was 2,002. Implications for public policy formulation and implementation are discussed. (SLD)

  9. Nd-Sr Isotopic Geochemistry and U-Pb Geochronology of the Fé Granitic Gneiss and Lajedo Granodiorite: Implications for Paleoproterozoic Evolution of the Mineiro Belt, Southern São Francisco Craton, Brazil

    Directory of Open Access Journals (Sweden)

    Wilson Teixeira

    2008-04-01

    Full Text Available The Fé granitic gneiss and Lajedo granodiorite belong to a voluminous felsic-mafic plutonism, tectonically linked toPaleoproterozoic magmatic evolution of the Mineiro Belt, southern portion of the São Francisco Craton, central-easternBrazil. The Fé pluton is located north of the Lenheiros shear zone and is intrusive with respect to the Rio das Mortesgreenstone belt and pyroxenite - gabbroic bodies, as indicated by xenoliths of gneiss and amphibolite, in the first case, andpyroxenite in the latter. The Lajedo granodiorite is located south of the Lenheiros shear zone and cuts the metamafic rocks ofthe Forro peridotite – pyroxenite and mafic and intermediate rocks of the Nazareno greenstone belt, as evidenced by xenolithsfrom the latter unit. The modal composition of the Fé granitic gneiss lies within the ranges of monzogranite and syenogranite.It is peraluminous and shows a large variation in K2O content, which implies a middle-K calc-alkaline to high-K calc-alkalinetendency. The Lajedo modal composition is consistent with granodioritic and tonalitic compositions. It indicates a predominantlyperaluminous composition and calc-alkaline character. The U-Pb zircon crystallization age of the Fé granitic gneiss is 2191± 9 Ma, whereas the Lajedo granodiorite yields 2208 ± 26 Ma. The Nd/Sr characteristics of the Fé and Lajedo plutons areconsistent with mixtures of enriched mantle (EMI-type, DMM and crustal components during magma genesis in a plutonicarc setting, while the low 87Sr/86Sri ratios point to contribution of mafic rock protoliths during magma genesis. This is also inaccordance with the characteristic xenoliths observed within the investigated plutons from the Nazareno and Rio das Mortesgreenstone belts. The Fé granitic gneiss and Lajedo granodiorite show tectonic characteristics which are comparable to thoseof nearby coeval plutons: Brito quartz-diorite (2221 ± 2 Ma, Brumado de Cima granodiorite (2219 ± 2 Ma, Brumado de

  10. Nd-Sr isotopic geochemistry and U-Pb geochronology of the Fe granitic gneiss and Lajedo Granodiorite: implications for paleoproterozoic evolution of the Mineiro Belt, southern Sao Francisco craton, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, Wilson [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Geociencias. Centro de Pesquisas Geocronologicas]. E-mail: wteixeir@usp.br; Avila, Ciro Alexandre [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Museu Nacional. Dept. de Geologia e Paleontologia]. E-mail: avila@mn.ufrj.br; Nunes, Luciana Cabral [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Geociencias]. E-mail: luciana@igc.usp.br

    2008-07-01

    The Fe granitic gneiss and Lajedo granodiorite belong to a voluminous felsic-mafic plutonism, tectonically linked to Paleoproterozoic magmatic evolution of the Mineiro Belt, southern portion of the Sao Francisco Craton, central-eastern Brazil. The Fe pluton is located north of the Lenheiros shear zone and is intrusive with respect to the Rio das Mortes greenstone belt and pyroxenite - gabbroic bodies, as indicated by xenoliths of gneiss and amphibolite, in the first case, and pyroxenite in the latter. The Lajedo granodiorite is located south of the Lenheiros shear zone and cuts the metamafic rocks of the Forro peridotite - pyroxenite and mafic and intermediate rocks of the Nazareno greenstone belt, as evidenced by xenoliths from the latter unit. The modal composition of the Fe granitic gneiss lies within the ranges of monzogranite and syenogranite. It is peraluminous and shows a large variation in K{sub 2}O content, which implies a middle-K calc-alkaline to high-K calc-alkaline tendency. The Lajedo modal composition is consistent with granodioritic and tonalitic compositions. It indicates a predominantly peraluminous composition and calc-alkaline character. The U-Pb zircon crystallization age of the Fe granitic gneiss is 2191 {+-} 9 Ma, whereas the Lajedo granodiorite yields 2208 {+-} 26 Ma. The Nd/Sr characteristics of the Fe and Lajedo plutons are consistent with mixtures of enriched mantle (EMI-type), DMM and crustal components during magma genesis in a plutonic arc setting, while the low {sup 87}Sr/{sup 86}Sri ratios point to contribution of mafic rock protoliths during magma genesis. This is also in accordance with the characteristic xenoliths observed within the investigated plutons from the Nazareno and Rio das Mortes greenstone belts. The Fe granitic gneiss and Lajedo granodiorite show tectonic characteristics which are comparable to those of nearby coeval plutons: Brito quartz-diorite (2221 +- 2 Ma), Brumado de Cima granodiorite (2219 {+-} 2 Ma), Brumado

  11. The atmospheric implications of radiation belt remediation

    Directory of Open Access Journals (Sweden)

    C. J. Rodger

    2006-08-01

    Full Text Available High altitude nuclear explosions (HANEs and geomagnetic storms can produce large scale injections of relativistic particles into the inner radiation belts. It is recognised that these large increases in >1 MeV trapped electron fluxes can shorten the operational lifetime of low Earth orbiting satellites, threatening a large, valuable population. Therefore, studies are being undertaken to bring about practical human control of the radiation belts, termed "Radiation Belt Remediation" (RBR. Here we consider the upper atmospheric consequences of an RBR system operating over either 1 or 10 days. The RBR-forced neutral chemistry changes, leading to NOx enhancements and Ox depletions, are significant during the timescale of the precipitation but are generally not long-lasting. The magnitudes, time-scales, and altitudes of these changes are no more significant than those observed during large solar proton events. In contrast, RBR-operation will lead to unusually intense HF blackouts for about the first half of the operation time, producing large scale disruptions to radio communication and navigation systems. While the neutral atmosphere changes are not particularly important, HF disruptions could be an important area for policy makers to consider, particularly for the remediation of natural injections.

  12. Algoma-type Neoproterozoic BIFs and related marbles in the Seridó Belt (NE Brazil)

    DEFF Research Database (Denmark)

    Sial, Alcides N.; Campos, Marcel S.; Gaucher, Claudio

    2015-01-01

    -itabirite and quartz-hematite itabirite) and iron ores, which are overlain by marbles of the Jucurutu Formation. Diamictites of uncertain stratigrahic position in the Seridó Belt exhibit gneiss and quartzite clasts up to 0.6 m long and a fine-grained metapelitic matrix. The C-isotope stratigraphic pathways......The Jucurutu Formation in the Seridó Belt, northeastern Brazil, encompasses fine-to coarse-grained amphibolite-facies marbles, locally with cross-bedding and stromatolites. Banded iron formations (BIF) at three localities in this belt comprise itabirites (actinolite- or cummingtonite...... for the Jucurutu Formation show negative δ13C values at the base of the formation followed upsection by positive values. At the Ferro do Bonito iron Mine, values as low as ˗12‰ in carbonates just above the contact with underlying BIF are followed by values of ca. ˗5‰ and by positive values up section (+4 to +10...

  13. Paleoproterozoic Greenstone-Granite Belts in Northern Brazil and the Former Guyana Shield - West African Craton Province

    Directory of Open Access Journals (Sweden)

    Ian McReath

    2006-03-01

    Full Text Available The mainly meta-volcano-sedimentary Vila Nova Group and associated granites constitute separate belts, which formpart of a large paleoproterozoic (mainly rhyacian province in the Guyana Shield of which northern Brazil forms a part, andthe West African Craton. In Brazil the southwestern Serra do Ipitinga and Serra Tumucumaque-Serra do Navio belts have noobvious geometrical extensions in the Guyanas or Venezuela, and may represent deposits formed at penecontemporaneouspassive continental margins and ocean floor spreading centres. To the Northeast the Serra Lombarda-Tartarugalzinho andOiapoque belts are continuations of Guianese belts. In the former the igneous rocks have geochemical characteristics ofsuprasubduction environments. Belts in the Guyana Shield and West African Craton have many similar features. Themegaprovince evolved in a number of stages, which may have started at about 2.3 Ga, and continued with diminished activityafter 2.11 Ga. Both major juvenile additions and (possibly minor reworking of earlier crust contributed to the growth of theprovince. The major transcurrent deformation, responsible for the present structure of the belts, probably occurred duringthe later stages of evolution of the province, but metamorphism and deformation are registered even in the oldest rocks.

  14. Aerial geophysics contribution to geology of Crixas Greenstone Belt , Brazil; Contribuicao aerogeofisica a geologia do 'greenstone belt' da Faixa Crixas, Goias, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Blum, Marcelo de Lawrence Bassay; Rosa, Cassio Thyone A. de; Carmelo, Adriana C.; Souza, Julio Coelho Ferreira de; Pires, Augusto C.B. [Brasilia Univ., DF (Brazil); Araujo, Albano A. de; Carvalho Junior, Osmar A. de [Infosat, XX, World Energy Council (WEC) (Austria)

    1993-07-01

    In this study we present the results obtained by interpreting geophysical data from the Crixas Greenstone Belt area. Magnetic and gamma-ray spectrometric profiles and maps were produced by reprocessing digital data belonging to the Brazil-Canada Geophysical project. Using the very detailed information revealed by the profiles processed in more adequate scale and the lateral continuity supplied by the maps, we obtained a more clear picture of the region. Despite of the strong correlation between profiles and maps with the presently known geology, observed discrepancies indicate targets for geological mapping and mineral exploration. (author)

  15. Earthquake source characteristics along the arcuate Himalayan belt: Geodynamic implications

    Indian Academy of Sciences (India)

    Prosanta Kumar Khan; Md Afroz Ansari; S Mohanty

    2014-07-01

    The occurrences of moderate to large magnitude earthquakes and associated subsurface geological processes were critically examined in the backdrop of Indian plate obliquity, stress obliquity, topography, and the late Tertiary regional tectonics for understanding the evolving dynamics and kinematics in the central part of the Himalayas. The higher topographic areas are likely associated with the zones of depressions, and the lower topographic areas are found around the ridges located in the frontal part of the orogen. A positive correlation between plate and stress obliquities is established for this diffuse plate boundary. We propose that the zone of sharp bending of the descending Indian lithosphere is the nodal area of major stress accumulation which is released occasionally in form of earthquakes. The lateral geometry of the Himalayas shows clusters of seismicity at an angle of ∼20° from the centre part of the arc. Such spatial distribution is interpreted in terms of compression across the arc and extension parallel to the arc. This biaxial deformation results in the development of dilational shear fractures, observed along the orogenic belt, at an angle of ∼20° from the principal compressive stress axis.

  16. Carbon and oxygen isotope geochemistry of Ediacaran outer platform carbonates, Paraguay Belt, central Brazil

    Directory of Open Access Journals (Sweden)

    Claudio Riccomini

    2007-09-01

    Full Text Available After the late Cryogenian glaciation the central region of Brazil was the site of extensive deposition of platformal carbonates of the Araras Group. This group includes a basal cap carbonate sequence succeeded by transgressive, deep platform deposits of bituminous lime mudstone and shale. Facies and stratigraphic data combined with carbon and oxygen isotopic analyses of the most complete section of the transgressive deposits, exposed in the Guia syncline, were used to evaluate the depositional paleoenvironment and to test the correlation of these deposits along the belt and with other units worldwide. The studied succession consists of 150 m thick tabular beds of black to grey lime mudstone and shale with predominantly negative delta13C PDB values around -2.5 to -1‰ . The delta13C PDB profile of Guia syncline shows a clear correlation with the upper portion of Guia Formation in the Cáceres region, about 200 km to the southwest. The delta13C PDB profile of the Araras Group is comparable with delta13C PDB profiles of Ediacaran units of the southern Paraguay Belt, western Canada, and the Congo and Kalahari cratons. Moreover, facies distribution, stratigraphy and the carbon isotopic profile of the Araras Group match the middle Tsumeb Subgroup in Namibia, which reinforces the Ediacaran age assigned to the Araras Group.Após a glaciação do final do Criogeniano, a região central do Brasil foi palco de extensa deposição de carbonatos plataformais do Grupo Araras. Este grupo inclui na sua base uma seqüência de capa carbonática sucedida por depósitos transgressivos de calcilutitos betuminosos e folhelhos de plataforma profunda. Dados de fácies e estratigráficos combinados com análises isotópicas de carbono e oxigênio da seção mais completa desses depósitos transgressivos, expostos no sinclinal da Guia, foram empregados para avaliar o paleambiente deposicional e para testar a correlação desses depósitos ao longo da faixa e tamb

  17. Microstructures and TitaniQ geothermometry in high - temperature dynamically recrystallized mylonites, Ribeira belt (SE Brazil)

    Science.gov (United States)

    Cavalcante, Carolina; Morales, Luiz

    2016-04-01

    The Ribeira belt (southern Brazil) was formed by the collision between the São Francisco and West Congo cratons at around 670 - 480 Ma, during the western Gondwana amalgamation. It consists of dextral strike-slip shear zones trending NE-SW to NNE-SSW. The ~20 km wide and ~120 km long Três Rios - Além Paraíba - Pádua shear zone is one these shear zones, in which quartzfeldspathic mylonites were formed at upper amphibolite to granulite conditions. The deformation of these rocks was accompanied by dynamic recrystallization and intense grain-size reduction that is reflected by the large amount of recrystallized grains with sizes >30 - 150 μm. Grain-size reduction is often pointed out as a process that promotes changes in the mechanical behavior of rocks, from grain-size insensitive (GSI) to grain-size sensitive (GSS) deformation mechanisms. However, it is still not clear if the switch from GSI to GSS deformation mechanisms may occur in coarsed grain recrystallized rocks. Furthermore, it is also not clear what is the effect of dynamic recrystallization on the titanium retention in quartz. Here we apply the TitaniQ geothermometer to coarse recrystallized quartz, coupled with detailed microstructural characterization to investigate thermal conditions and deformation mechanisms during recrystallization/deformation of quartz. Quartz grains show typically high temperature microstructure, such as irregular-lobate grain boundaries and subgrain walls. The average titanium contents are ~30 ppm for samples from the Três Rios region, 46 to 54 ppm for samples from Além Paraíba, and 74 to 86 ppm for samples from Santo Antônio de Pádua. The calculated temperatures are fairly homogenous at ~800 °C throughout the studied segments of the shear zone, which is compatible with the observed microstructures. The crystallographic orientation in these rocks is fairly weak, possibly due to static recovery and/or strong activity of such as diffusion processes due to the high

  18. Short-lived polyphase deformation during crustal thickening and exhumation of a collisional orogen (Ribeira Belt, Brazil)

    Science.gov (United States)

    Faleiros, F. M.; Campanha, G. A. C.; Pavan, M.; Almeida, V. V.; Rodrigues, S. W. O.; Araújo, B. P.

    2016-12-01

    The Ribeira Belt (Brazil) is a Neoproterozoic collisional-related feature that was located in a south-central position in West Gondwana. We present quantitative data on finite strain, flow vorticity and deformation temperatures for the Curitiba Terrane, a major segment of the southern Ribeira Belt. Six deformation phases (D1-D6) related with crustal thickening and exhumation were recognized. D1 and D2-related microstructures are preserved exclusively within porphyroblasts, in part grown during stages of high-pressure (∼9-12 kbar) isobaric heating after crustal thickening. D3 phase was active from peak metamorphism attained in contrasting crustal levels (810-400 °C), to the early stage of exhumation (500-400 °C), as indicated by petrological, microstructural and quartz c-axis fabric evidence. Kinematic vorticity results indicate that the SL3 mylonitic fabric resulted from a simple shear-dominated deformation related with westward thrusting. North-verging overturned D4 folds with E-W-trending subhorizontal axes derived from a pure shear-dominated deformation. Regional D5 open folds with subvertical axes and NNE-SSW-trending traces were produced by indentation tectonics. D6 phase comprises retrograde orogen-parallel transcurrent shear zones related with scape tectonics. Geochronological data indicate that D3-D6 phases occurred between 584 and 580 Ma, suggesting a fast exhumation rate of ∼8 mm/year for the deepest rocks from the southern Ribeira Belt.

  19. Distribution of the Iberian Calopteryx damselflies and its relation with bioclimatic belts: evolutionary and biogeographic implications.

    Science.gov (United States)

    Outomuro, David; Torralba-Burrial, Antonio; Ocharan, Francisco J

    2010-01-01

    Using bioclimatic belts as habitat and distribution predictors, the present study examines the implications of the potential distributions of the three Iberian damselflies, Calopteryx Leach (Odonata: Calopterygidae), with the aim of investigating the possible consequences in specific interactions among the species from a sexual selection perspective and of discussing biogeographical patterns. To obtain the known distributions, the literature on this genus was reviewed, relating the resulting distributions to bioclimatic belts. Specific patterns related to bioclimatic belts were clearly observed in the Mediterranean region. The potential distribution maps and relative frequencies might involve latitudinal differences in relative abundances, C. virgo meridionalis Sélys being the most abundant species in the Eurosiberian region, C. xanthostoma (Charpentier) in the northern half of the Mediterranean region and C. haemorrhoidalis (Vander Linden) in the rest of this region. These differences might explain some previously described latitudinal differences in secondary sexual traits in the three species. Changes in relative abundances may modulate interactions among these species in terms of sexual selection and may produce sexual character displacement in this genus. C. virgo meridionalis distribution and ecological requirements explain its paleobiogeography as a species which took refuge in Iberia during the Würm glaciation. Finally, possible consequences in species distributions and interactions are discussed within a global climate change context.

  20. Tectonic evolution of the Dom Feliciano Belt in Southern Brazil: Geological relationships and U-Pb geochronology

    Directory of Open Access Journals (Sweden)

    Ruy Paulo Philipp

    Full Text Available ABSTRACT: The Dom Feliciano Belt is an important Neoproterozoic to Cambrian orogenic complex, extending from eastern Uruguay to southern Brazil. It comprises a collage of oceanic domains and continental fragments developed between 900 and 540 Ma between the Rio de La Plata, Congo and Kalahari cratons. The integration of field and structural data with recent isotopic results has introduced new insights on the sources of the magmatism and sedimentary processes. This paper presents a review of the geochronological results combined with stratigraphic, structural and geochemical data. The evolution of the Dom Feliciano Belt involved three orogenic events known as the Passinho (0.89 - 0.86 Ga, São Gabriel (0.77 - 0.68 Ga and Dom Feliciano (0.65 - 0.54 Ga. The first two events involved the closure of the Charrua Ocean generating an intra-oceanic arc (Passinho and, subsequently, an active continental margin arc (São Gabriel. This ocean separated the continental areas represented by the Rio de la Plata Craton and the Nico Perez continental microplate. Closure of the Adamastor ocean resulted in an important collisional event between the Nico Perez Microplate/Rio de La Plata Craton and Kalahari and Congo cratons between 650 and 620 Ma, involving high T/intermediate P metamorphism. At this time of crustal thickening, the partition of the deformation controled the final evolution of the belt with important escape tectonics, responsible for nucleating crustal-scale transcurrent shear zones. These structures were deep and promoted the rise of mafic magmas, which, associated with high regional thermal gradient, lead to an important event of crustal reworking, responsible for the formation of the Pelotas Batholith. The orogenic collapse is represented by late magmatism of Pelotas Batholith and deposition of upper section of the Camaquã Basin.

  1. The tectonic evolution of the Neoproterozoic Brasília Belt, central Brazil: a geochronological and isotopic approach

    Directory of Open Access Journals (Sweden)

    Márcio Martins Pimentel

    Full Text Available ABSTRACT: The Brasília Belt is one of the most complete Neoproterozoic orogens in western Gondwana. Rapid progress on the understanding of the tectonic evolution of the belt was achieved due to new U-Pb data, combined with Sm-Nd and Lu-Hf analyses. The evolution of the Brasília orogen happened over a long period of time (900 - 600 Ma involving subduction, magmatism and terrain accretion, as a result of the consumption of the Goiás oceanic lithosphere. Provenance studies, based on U-Pb zircon data, indicate that the sedimentary rock units record different tectonic settings and stages of the evolution of the orogen. The Paranoá and Canastra groups represent passive margin sequences derived from the erosion of the São Francisco Craton. The Araxá and Ibiá groups, however, have dominant Neoproterozoic detrital zircon populations, as young as 650 Ma, suggesting derivation from the Goiás Magmatic Arc. The Goiás Magmatic Arc represents a composite arc terrain, formed by the accretion of older (ca. 0.9 - 0.8 Ga intraoceanic island arc(s, followed by more evolved continental arcs. It extends for several thousand kilometers, from SW Goiás, through NE Brazil and into Africa. Metamorphism took place between 650 - 630 Ma reflecting final closure of the Goiás Ocean and continental collision.

  2. Brasiliano-age granitoids in the Sergipana Fold Belt, NE Brazil: the Coronel João Sá Pluton

    Science.gov (United States)

    Mcreath, I.; Lafon, J. M.; Davison, I.; Chaves, J. M.; Conceiçāo, H.

    1998-01-01

    The Coronel João Sá pluton is a zoned Brasiliano-age, late- to post-tectonic intrusion in the Macururé schist domain of the Sergipana Foldbelt, Northeast Brazil. Biotite-hornblende granodiorite predominates, and flattened ultramafic to intermediate enclaves are present. Igneous orientations are present but fabrics produced by strong solid-state flattening are absent. Rb-Sr whole rock isochrons including enclaves and their host rocks yielded a probable intrusion age of 614 Ma which dates the waning phase of the dominant deformation which produced the F2 foliation of the Sergipana belt and is close to ages reported for late tectonic granites in other Brasiliano domains of Northeast Brazil. More radiogenic Sr (I Sr(614) = 0.71008 ± 52) is present in some felsic rocks, while less radiogenic Sr (I Sr(614) = 0.70814 ± 18) is mainly found in the more mafic core of the main body. Sr isotopic equilibrium between most enclaves and their host rocks was attained. Textural evidence, especially in the enclaves, shows that magma mixing occurred, but late biotite formation in the enclaves caused modifications of their chemical compositions. The geological, petrographical and isotopic evidence shows that the pluton was probably fed by a complex feeder system into the crust under extensional conditions. Variable upper crustal contamination was probably responsible for the isotopic heterogeneity of Sr.

  3. U-Pb (LA-ICP-MS of detrital zircon and whole rock Nd and geochemical constraints on the provenance, depositional age and tectonic setting of the metasedimentary Piriá Basin, northern Brazil: implications for the evolution of the Gurupi Belt

    Directory of Open Access Journals (Sweden)

    Elem Cristina dos Santos Lopes

    Full Text Available ABSTRACT: The Piriá Basin (Piriá Formation is a hemi-graben shaped basin that developed over Precambrian rocks of the Gurupi Belt. The lithological content comprises four interfingered lithofacies: (1 arkose and greywacke with pelite layers, (2 laminated siltstones and pelites, (3 arkose with hummocky stratification, and (4 oligomictic conglomerate. This sequence was formed in alluvial fans (conglomerate, and fluvial systems (arkose, greywacke, siltstones and pelites that were established and evolved during the migration of the subsidence. The sedimentary sequence underwent anquimetamorphism and very weak tectonic deformation. U-Pb analyses of detrital zircon set the maximum depositional age at 591 Ma and indicate several sediment sources, that range in age from the Neoproterozoic to the Archean. The main sources are from the Rhyacian, which is the main period of continental crust formation in the São Luís cratonic fragment and the basement of the Gurupi Belt. Neoproterozoic sources were important in the eastern segment of the basin. Ages from unknown sources in the region so far have also been recorded. Combined, the U-Pb zircon data, the whole-rock geochemical and Sm-Nd results, and the petrographic information revealed proximal felsic to intermediate provenance, in addition to recycled sedimentary sources. As a whole, our data suggest that the Piriá Formation was deposited in a post-orogenic basin related to the final stage of evolution of the Brasiliano cycle of orogenies, which built up the Gurupi Belt.

  4. Thermal implications of metamorphism in greenstone belts and the hot asthenosphere-thick continental lithoshere paradox

    Science.gov (United States)

    Morgan, P.

    1986-01-01

    From considerations of secular cooling of the Earth and the slow decay of radiogenic heat sources in the Earth with time, the conclusion that global heat loss must have been higher in the Archean than at present seems inescapable. The mechanism by which this additional heat was lost and the implications of higher heat low for crustal temperatures are fundamental unknowns in our current understanding of Archean tectonics and geological processes. Higher heat loss implies that the average global geothermal gradient was higher in the Archean than at present, and the restriction of ultramafic komatiites to the Archean and other considerations suggests that the average temperature of the mantle was several hundred degrees hotter during the Archean than today. In contrast, there is little petrologic evidence that the conditions of metamorphism or crustal thickness (including maximum crustal thickness under mountains) were different in archean continental crust from the Phanerozoic record. Additionally, Archean ages have recently been determined for inclusions in diamonds from Cretaceous kimeberlites in South Africa, indicating temperatures of 900 to 1300 at depths of 150 to 215 km (45 to 65 kbar) in the Archean mantle, again implying relatively low geothermal gradients at least locally in the Archean. The thermal implications of metamorphism are examined, with special reference to greenstone belts, and a new thermal model of the continental lithosphere is suggested which is consistent with thick continental lithosphere and high asthenosphere temperatures in the Archean.

  5. Stratigraphy and geochronlogy of the Guarinos greenstone belt, Goiás, Brazil

    Directory of Open Access Journals (Sweden)

    Hardy Jost

    2012-08-01

    Full Text Available The Guarinos greenstone belt is one of the three low metamorphic grade supracrustal rocks assemblage rimmed by orthogneissesof Central Brazil’s Archean Block northern limits. The investigation of the stratigraphy of those greenstone beltsstarted by the end of 1970’s and underwent improvements during the years as a result of detailed geological mapping. Thelatest and accepted stratigraphic model for the Guarinos greenstone belt refers its supracrustal rocks under the GuarinosGroup, which is subdivided into the Serra do Cotovelo (metakomatiites, Serra Azul (metabasalts, São Patricinho (maficmetaturbidites, Aimbé (BIF and Cabaçal (carbonaceous phyllites and impure metarenites formations. Detailed geologicmapping (1:10,000 and drill-cores during an exploration program by Yamana Desenvolvimento Mineral S.A. in the areaallowed a better definition of the metasedimentary package of the Cabaçal Formation, which is here formally proposed tobe subdivided into a Lower Member of carbonaceous phyllites with basalt lava flows and gondite lenses interlayers, anIntermediate Member of gondite, iron formation, metachert and massive barite lenses, and an Upper Member of carbonaceous phyllites with minor metachert lenses. The impure metarenites, formerly considered as part of the Cabaçal Formation, are proposedunder the Mata Preta Formation, which is laterally interfingered with the Cabaçal Formation. U-Pb LA-ICP-MS geochronologicaldata of detrital zircon grains from the São Patricinho mafic metaturbidites and the impure metarenites of the Mata Preta formationsindicate that the major source-area of the clastic load had a Siderian to Rhyacian age, with minor contribution from Archean rocks.From the rock assemblage of both units and their contact relationships it is concluded that the basin stage they represent evolved duringthe world-wide Anoxic Oceanic Event (AOE that took place during the 2.2 to 2.06 Ga, represented by the carbonaceous phyllites ofthe

  6. Augen gneisses versus Augen gneisses from the Jaguaribeana Belt, northeastern region from Brazil: stratigraphy, geochemistry and U-Pb ages; Augen gnaisses versus Augen gnaisses da faixa Jaguaribeana, NE do Brasil: estratigrafia, geoquimica e idades U-Pb

    Energy Technology Data Exchange (ETDEWEB)

    Sa, Jaziel Martins; Silva, Elvis Roberto da [Rio Grande do Norte Univ., Natal, RN (Brazil). Dept. de Geologia; Bertrand, Jean Michel [Savoie Univ., 73 - Chambery (France). Lab. de Geodynamique; Leterrier, Jacques [Centre National de la Recherche Scientifique (CNRS), 54 - Nancy (France). Centre de Recherches Petrographiques et Geochimiques

    1997-12-31

    The Jaguaribeana Belt is located at Borborema Province, Ceara State, Brazil and this study aims to present Uranium-Lead (U-Pb) data and the augen gneisses petrographic and geochemical study of the Jaguaribe Belt, and to realize comparisons between these and the augen gneisses from the Oros Belt. It describes the geological characteristics of this region, the augen gneisses petrography and geochemical data and the U-Pb method results for a discussion about the augen gneisses from the Oros and Jaguaribe Belt 10 refs., 6 figs.

  7. Timing of multiple hydrothermal events in the iron oxide-copper-gold deposits of the Southern Copper Belt, Carajás Province, Brazil

    Science.gov (United States)

    Moreto, Carolina P. N.; Monteiro, Lena V. S.; Xavier, Roberto P.; Creaser, Robert A.; DuFrane, S. Andrew; Melo, Gustavo H. C.; Delinardo da Silva, Marco A.; Tassinari, Colombo C. G.; Sato, Kei

    2015-06-01

    The Southern Copper Belt, Carajás Province, Brazil, hosts several iron oxide-copper-gold (IOCG) deposits, including Sossego, Cristalino, Alvo 118, Bacuri, Bacaba, Castanha, and Visconde. Mapping and U-Pb sensitive high-resolution ion microprobe (SHRIMP) IIe zircon geochronology allowed the characterization of the host rocks, situated within regional WNW-ESE shear zones. They encompass Mesoarchean (3.08-2.85 Ga) TTG orthogneiss, granites, and remains of greenstone belts, Neoarchean (ca. 2.74 Ga) granite, shallow-emplaced porphyries, and granophyric granite coeval with gabbro, and Paleoproterozoic (1.88 Ga) porphyry dykes. Extensive hydrothermal zones include albite-scapolite, biotite-scapolite-tourmaline-magnetite alteration, and proximal potassium feldspar, chlorite-epidote and chalcopyrite formation. U-Pb laser ablation multicollector inductively coupled mass spectrometry (LA-MC-ICP-MS) analysis of ore-related monazite and Re-Os NTIMS analysis of molybdenite suggest multiple Neoarchean (2.76 and 2.72-2.68 Ga) and Paleoproterozoic (2.06 Ga) hydrothermal events at the Bacaba and Bacuri deposits. These results, combined with available geochronological data from the literature, indicate recurrence of hydrothermal systems in the Southern Copper Belt, including 1.90-1.88-Ga ore formation in the Sossego-Curral ore bodies and the Alvo 118 deposit. Although early hydrothermal evolution at 2.76 Ga points to fluid migration coeval with the Carajás Basin formation, the main episode of IOCG genesis (2.72-2.68 Ga) is related to basin inversion coupled with Neoarchean (ca. 2.7 Ga) felsic magmatism. The data suggest that the IOCG deposits in the Southern Copper Belt and those in the Northern Copper Belt (2.57-Ga Salobo and Igarapé Bahia-Alemão deposits) do not share a common metallogenic evolution. Therefore, the association of all IOCG deposits of the Carajás Province with a single extensive hydrothermal system is precluded.

  8. The Fazenda Gavião granodiorite and associated potassic plutons as evidence for Palaeoproterozoic arc-continent collision in the Rio Itapicuru greenstone belt, Brazil

    Science.gov (United States)

    Costa, Felipe G.; Oliveira, Elson P.; McNaughton, Neal J.

    2011-08-01

    Several granitic plutons have intruded the Palaeoproterozoic Rio Itapicuru greenstone belt, São Francisco craton, Brazil, in the time interval 2163-2080 Ma, but their tectonic significance is poorly understood. The Fazenda Gavião granodiorite (FGG) is one of a set of plutons emplaced along the western boundary of the greenstone belt with Archaean migmatite-gneiss basement. The pluton is mostly composed of hornblende granodiorite, occasionally crosscut by syn-plutonic mafic dykes. The FGG is metaluminous, medium- to high-K calc-alkaline with relatively constant silica abundances (SiO2 ˜ 63-66 wt%), high Sr (900-800 ppm) and high Ba (1000-1500 ppm). The associated mafic dykes are ultrapotassic, with high abundances of Ba, Sr, MgO, Ni, Cr, and light rare earth elements, suggesting derivation from partial melts of an enriched mantle source. The FGG originated probably by fractional crystallization from a primitive K-rich mafic magma that interacted with crustal melts. Its zircon U-Pb SHRIMP age of 2106 ± 6 Ma indicates that the FGG is younger than the early (2163-2127 Ma) tonalite-trondhjemite-granodiorite (TTG) and calc-alkaline arc plutons of the greenstone belt, and is closely related in time and space with potassic to ultrapotassic plutons (ca. 2110-2105 Ma). The negative ɛNd(t) of FGG and coeval K-rich plutons of the Rio Itapicuru greenstone belt contrasts markedly with the positive ɛNd(t) of the older arc plutons, indicating a major change of isotope signatures in granites of the Rio Itapicuru greenstone belt with time. This isotope shift may be related to magma contamination with older continental material and/or derivation of the parental potassic magma from enriched lithospheric mantle sources. We suggest that the K-rich plutons were emplaced during or shortly after Palaeoproterozoic arc-continent collision.

  9. The Contraction/Expansion History of Charon with implication for its Planetary Scale Tectonic Belt

    CERN Document Server

    Malamud, Uri; Schubert, Gerald

    2016-01-01

    The New-Horizons mission to the Kuiper Belt has recently revealed intriguing features on the surface of Charon, including a network of chasmata, cutting across or around a series of high topography features, conjoining to form a belt. It is proposed that this tectonic belt is a consequence of contraction/expansion episodes in the moon's evolution associated particularly with compaction, differentiation and geophysical reactions of the interior. The proposed scenario involves no need for solidification of a vast subsurface ocean and/or a warm initial state. This scenario is based on a new, detailed thermo-physical evolution model of Charon that includes multiple processes. According to the model, Charon experiences two contraction/expansion episodes in its history that may provide the proper environment for the formation of the tectonic belt. This outcome remains qualitatively the same even if we assume a different initial composition and mass. Two alternative explanations for the precise localization and orie...

  10. Dynamical erosion of the asteroid belt and implications for large impacts in the inner solar system

    CERN Document Server

    Minton, David A

    2009-01-01

    The cumulative effects of weak resonant and secular perturbations by the major planets produce chaotic behavior of asteroids on long timescales. Dynamical chaos is the dominant loss mechanism for asteroids with diameters D > 10 km in the current asteroid belt. In a numerical analysis of the long term evolution of test particles in the main asteroid belt region, we find that the dynamical loss history of test particles from this region is well described with a logarithmic decay law. In our simulations the loss rate function that is established at t = 1 My persists with little deviation to at least t = 4 Gy. Our study indicates that the asteroid belt region has experienced a significant amount of depletion due to this dynamical erosion - having lost as much as ~50% of the large asteroids - since 1 My after the establishment of the current dynamical structure of the asteroid belt. Because the dynamical depletion of asteroids from the main belt is approximately logarithmic, an equal amount of depletion occurred i...

  11. Community food environment measures in the Alabama Black Belt: Implications for cancer risk reduction

    Directory of Open Access Journals (Sweden)

    Rebecca Gyawu

    2015-01-01

    Full Text Available In-store measures were utilized to evaluate the availability of healthy food choices and nutrition/health promotion messages for cancer risk reduction in the selected Alabama Black Belt counties/cities. Sixty one retail food outlets (RFOs were audited in 12 Alabama Black Belt cities. Store types included convenience stores (49.2%, restaurants (19.7%, fast food restaurants (16.4%, small supermarkets (8.2%, and large supermarket and farmers' markets (3.3 %, respectively. Although there were low numbers of farmers' markets/street stands and large supermarkets, these had significantly (p < 0.0001 higher health scores than the other store types. A few health promotion messages were highly visible or obscurely positioned in some RFOs. The Alabama Black Belt food environment had limited opportunities for healthy food choices.

  12. Community food environment measures in the Alabama Black Belt: Implications for cancer risk reduction.

    Science.gov (United States)

    Gyawu, Rebecca; Quansah, Joseph E; Fall, Souleymane; Gichuhi, Peter N; Bovell-Benjamin, Adelia C

    2015-01-01

    In-store measures were utilized to evaluate the availability of healthy food choices and nutrition/health promotion messages for cancer risk reduction in the selected Alabama Black Belt counties/cities. Sixty one retail food outlets (RFOs) were audited in 12 Alabama Black Belt cities. Store types included convenience stores (49.2%), restaurants (19.7%), fast food restaurants (16.4%), small supermarkets (8.2%), and large supermarket and farmers' markets (3.3 %), respectively. Although there were low numbers of farmers' markets/street stands and large supermarkets, these had significantly (p food environment had limited opportunities for healthy food choices.

  13. Implications Regarding the Energetics Of the Collisional Formation of Kuiper Belt Satellites

    CERN Document Server

    Stern, S A

    2002-01-01

    Recently, it has been discovered that at least 1% of Kuiper Belt Objects (KBOs) are accompanied by large satellites. Here we examine the energetics of KBO satellite formation via collisions, finding collisions require a dynamically excited Kuiper Belt. Further, even under optimistic assumptions (including perfect accretion of the satellites), we find that collisional processes cannot make KBO satellites at the observed frequency of occurrence unless KBO projectiles large enough to generate the observed satellites were \\~40 times more numerous in the ancient past, resulting in an increased collision rate with sufficiently large projectiles, or unless the fraction of impact energy estimated to be imparted to ejecta is of order unity. Neither alternative is very palatable. However, an easier to accept alternative also exists: KBO primary and/or KBO satellite surface albedos presently be underestimated by making the canonical assumption of 4% surface albedos; specifically, surface albedos of KBO primaries and/or ...

  14. Brazil's premier gold province. Part I: The tectonic, magmatic, and structural setting of the Archean Rio das Velhas greenstone belt, Quadrilátero Ferrífero

    Science.gov (United States)

    Lobato, Lydia; Ribeiro-Rodrigues, Luiz; Zucchetti, Márcia; Noce, Carlos; Baltazar, Orivaldo; da Silva, Luiz; Pinto, Claiton

    2001-07-01

    Rocks of the Rio das Velhas Supergroup comprise one of the most significant Archean greenstone-belt successions in Brazil, in both their appreciable mineral productivity and extensive mineral potential. A large part of this greenstone belt is contained within the Quadrilátero Ferrífero (Iron Quadrangle) region, Minas Gerais state, southeastern Brazil, which occupies the southernmost portion of the São Francisco craton. The Nova Lima Group rocks, at the base of the Rio das Velhas greenstone belt, host important orogenic gold deposits. The group contains lithological associations from bottom to top as follows: (1) mafic-ultramafic volcanic, (2) volcanic-chemical, (3) clastic-chemical, (4) volcaniclastic, and (5) resedimented rocks. Rocks of the resedimented, volcanic-chemical, and mafic-ultramafic volcanic associations mainly host the most important gold deposits. An early compressional deformation occurs in the rocks of the Rio das Velhas greenstone belt and basement gneisses, with tangential thrusting from the north to the south or southwest. Structures generated during a second, compressional deformation, encompass NW-striking thrust faults and SW-vergent, tight to isoclinal folds, inferring a general southwest transport direction. In the central portion of the Quadrilátero Ferrífero, the Paciência lineament, which strikes northwest and dips to the northeast in the south, or strikes northeast and dips to the southeast in the north, is a thrust-related, oblique ramp fault that hosts important gold deposits. The convergence of these two trends in the Nova Lima region is accommodated by roughly E-W-striking transcurrent faults, which are the most favored sites for large gold concentrations. Intracratonic extension in Late Archean to early Paleoproterozoic times and NW-vergent, Trans-Amazonian compressional deformation post-date gold deposition. Late extension during the Paleoproterozoic led to basin formation and the prominent dome-and-keel architecture of the

  15. Cambro-Ordovician magmatism in the Araçuaí Belt (SE Brazil): Snapshots from a post-collisional event

    Science.gov (United States)

    De Campos, Cristina P.; de Medeiros, Silvia R.; Mendes, Julio C.; Pedrosa-Soares, Antonio C.; Dussin, Ivo; Ludka, Isabel P.; Dantas, Elton L.

    2016-07-01

    The focus of the present work is the rebound of the magmatism at the late stages of orogenic collapse in the Araçuaí Belt, in Brazil. At the end of the orogen bimodal inversely zoned plutons were emplaced along a tectonic corridor following the Atlantic coast of Brazil. This event culminates around 500 Ma. We review geology, petrography, geochemistry and geochronology of these plutonic structures in the region of Espírito Santo. New geochemical modeling of trace element data together with new whole rock Sm-Nd and Rb-Sr isotopic data depict a gradual process of mantle contamination during different stages of the orogen. In the post-orogenic stage contamination reaches extreme values. Basic rocks reach εNd(0.5Ga) values below -10. Gabbros to peridotites are more enriched in Ba, Zr, LREE and Sr than the surrounding metasediments. Four new U-Pb data sets from determinations in zircon and monazite crystals, (central northern part of the belt) confirm peak magma production around 500 ± 15 Ma, ranging up to 525 ± 3 Ma in one of the structures. Based on the pictured data, we discuss the significance of this magmatism and present a possible model: a process of gradational delamination of the subcontinental lithospheric mantle and adjacent deep continental crust through underplating. As a consequence, an already enriched mantle was dramatically further contaminated. At the end of this event the intrusion of alkaline melts, with less negative εNd (-5) and further enrichment in incompatible elements, point towards a new input of deeper juvenile mantle magma. Our data suggest the possible onset of a hotspot due to the destabilization of the asthenospheric mantle after orogenic collapse.

  16. Mesozoic dinosaurs from Brazil and their biogeographic implications.

    Science.gov (United States)

    Bittencourt, Jonathas S; Langer, Max C

    2011-03-01

    The record of dinosaur body-fossils in the Brazilian Mesozoic is restricted to the Triassic of Rio Grande do Sul and Cretaceous of various parts of the country. This includes 21 named species, two of which were regarded as nomina dubia, and 19 consensually assigned to Dinosauria. Additional eight supraspecific taxa have been identified based on fragmentary specimens and numerous dinosaur footprints known in Brazil. In fact, most Brazilian specimens related to dinosaurs are composed of isolated teeth and vertebrae. Despite the increase of fieldwork during the last decade, there are still no dinosaur body-fossils of Jurassic age and the evidence of ornithischians in Brazil is very limited. Dinosaur faunas from this country are generally correlated with those from other parts of Gondwana throughout the Mesozoic. During the Late Triassic, there is a close correspondence to Argentina and other south-Pangaea areas. Mid-Cretaceous faunas of northeastern Brazil resemble those of coeval deposits of North Africa and Argentina. Southern hemisphere spinosaurids are restricted to Africa and Brazil, whereas abelisaurids are still unknown in the Early Cretaceous of the latter. Late Cretaceous dinosaur assemblages of south-central Brazil are endemic only to genus or, more conspicuously, to species level, sharing closely related taxa with Argentina, Madagascar, Indo-Pakistan and, to a lesser degree, continental Africa.

  17. Evolution of Migmatitic Granulite Complexes: implications from Lapland Granulite Belt, Part I: metamorphic geology

    Directory of Open Access Journals (Sweden)

    Pekka Tuisku

    2006-01-01

    Full Text Available The Palaeoproterozoic Lapland granulite belt was juxtaposed between Archaean and Proterozoic terrains in the NE part of the Fennoscandian Shield concurrently with the accretion of Svecofennian arc complexes at ~1.9 Ga. The belt consists mainly of aluminous migmatiticmetagreywackes. Abundant noritic to enderbitic magmas were intruded concordantly into the metasediments and were probably an important heat source for metamorphism, which took place during the crystallization of the magmas. This is supported by structural and contact relations of metasediments and igneous rocks, and by the lack progressive metamorphic reaction textures in the igneous rock series. The peak of metamorphism took place above the dehydration melting temperature of the biotite-sillimanite-plagioclase-quartz assemblageat 750−850°C and 5−8.5 kbar which lead to formation of a restitic palaeosome and peraluminous granitic melt in metapelites. Subsequently, the rocks were decompressed and cooled below the wet melting temperature of pelitic rocks (650°C under the stability field of andalusite coexisting with potassium feldspar (2−3 kbar. Cooling was accompanied by the crystallization of the neosomes, often carrying aluminium-rich phases. Postmetamorphic duplexing of the LGB is clearly seen in the distribution of calculated PT conditions.

  18. The Jugsaipatna Anorthosite Complex, Eastern Ghats Belt, India: Magmatic lineage and petrogenetic implications

    Science.gov (United States)

    Mahapatro, S. N.; Nanda, J. K.; Tripathy, A. K.

    2010-04-01

    The Jugsaipatna Anorthosite Complex (JAC) in the Eastern Ghats Mobile Belt (India) comprises a central anorthosite - leuconorite - troctolitic norite core mantled by a rim of high-Al gabbronorite (HAG). Small dykes of ferrodiorite occur in the core region of the JAC. A lensoidal body of eucritic gabbronorite occurs in contact with leuconorite and outer gabbronorite rim. Baring ferrodiorites, the mafic members such as HAG, troctolitic norite and eucritic gabbronorite are not known in other anorthosite complexes of this high grade belt. The HAG is characterised by high Al 2O 3 content (17 wt.%), enriched ΣREE and LREE, absence of 'Eu-anomaly' and negative Sr anomaly and is, therefore inferred to be the source melt for the JAC suite of rocks. The eucritic gabbronorite comprising An-rich plagioclase and high-Al pyroxenes has a komatiitic affinity with high Cr-Ni contents and primitive REE patterns. Troctolitic norite, leuconorite and anorthosite are interpreted to be cumulate rocks fractionated from the HAG. The ferrodiorite with enriched Fe, Ti, P, Zr and REE abundances and a prominent 'negative Eu' anomaly corresponds to the residual melt of the plagioclase (+pyroxene) dominated fractionates that comprise anorthosite-leuconorite.

  19. Local content in Brazil: conceptual framework and methodological implications

    Directory of Open Access Journals (Sweden)

    Tori Holmes

    2009-05-01

    Full Text Available This article presents work in progress from PhD research investigating the use of the internet in the favelas (shantytowns of Rio de Janeiro, Brazil, with a particular focus on the internet content produced and shared by those who live there. The research proposes to apply the concept of local content beyond the scope of digital inclusion policy and projects, to content generated in everyday practices of internet use. The article presents an overview of internet access in Brazil and discussion of the conceptual and methodological issues raised by the interest in local content, understood as "the expression of the locally owned and adapted knowledge of a community - where the community is defined by its location, culture, language, or area of interest" according to a definition proposed by Ballantyne (2002.

  20. Evolution of Migmatitic Granulite Complexes: implications from Lapland Granulite Belt, Part II: isotopic dating

    Directory of Open Access Journals (Sweden)

    Pekka Tuisku

    2006-01-01

    Full Text Available The migmatitic metapelites of the Lapland granulite belt (LGB in the NE part of the Fennoscandian Shield represent an arc-related greywacke basin metamorphosed in the granulite facies. Detrital zircons from migmatitic metapelites are derived from 1.94 - 2.9 Ga old acid source rocks (U-Pb SIMS ages. The clustering of detrital zircon ages between 1.97 and 2.2 Ga is problematic, because abundant felsic crust of this age is absent in the shield. The metasediments are characterized by Sm-Nd model ages of ca. 2.3 Ga. A younger, 1905-1880 Ma population of homogeneous zircons was formed during regional metamorphism. The peak high-grade metamorphism took place at ~1900 Ma and the latest chronological record from subsequent decompression and cooling phase is from ca. 1870 Ma. The norite-enderbite series of the LGB represents arc-magmas, which were intruded into the metasediments at ~1920-1905 Ma ago according to zircon U-Pb ages and were probably an important heat source for metamorphism. Older, zoned zircon grains in a quartz norite vein, initial εNd values of 0 to +1 and the continuous spectrum of LILE enrichment in the enderbite-series probably reflect assimilation of metasediments by magmas. Monazite U-Pb ages of migmatitic metasediments in the range 1906-1910±3 Ma overlap the late stage of enderbite intrusion and growth of early metamorphic zircons. Garnet-whole rock Sm-Nd ages from leucosomes in the range 1880-1886±7 Ma are concurrent with the growth of the youngest metamorphic zircons and probably indicate the crystallization of leucosomes of the influence of a fluid liberated from them. Isotopic and petrologic data reveal that the evolution of Lapland Granulite belt from the erosion of source rocks to the generation of a sedimentary basin, its burial, metamorphism and exhumation took place within ca. 60 Ma.

  1. Sources of granite magmatism in the Embu Terrane (Ribeira Belt, Brazil): Neoproterozoic crust recycling constrained by elemental and isotope (Sr-Nd-Pb) geochemistry

    Science.gov (United States)

    Alves, Adriana; Janasi, Valdecir de Assis; Campos Neto, Mario da Costa

    2016-07-01

    Whole rock elemental and Sr-Nd isotope geochemistry and in situ K-feldspar Pb isotope geochemistry were used to identify the sources involved in the genesis of Neoproterozoic granites from the Embu Terrane, Ribeira Belt, SE Brazil. Granite magmatism spanned over 200 Ma (810-580 Ma), and is dominated by crust-derived relatively low-T (850-750 °C, zircon saturation) biotite granites to biotite-muscovite granites. Two Cryogenian plutons show the least negative εNdt (-8 to -10) and highest mg# (30-40) of the whole set. Their compositions are strongly contrasted, implying distinct sources for the peraluminous (ASI ∼ 1.2) ∼660 Ma Serra do Quebra-Cangalha batholith (metasedimentary rocks from relatively young upper crust with high Rb/Sr and low Th/U) and the metaluminous (ASI = 0.96-1.00) ∼ 630 Ma Santa Catarina Granite. Although not typical, the geochemical signature of these granites may reflect a continental margin arc environment, and they could be products of a prolonged period of oceanic plate consumption started at ∼810 Ma. The predominant Ediacaran (595-580 Ma) plutons have a spread of compositions from biotite granites with SiO2 as low as ∼65% (e.g., Itapeti, Mauá, Sabaúna and Lagoinha granites) to fractionated muscovite granites (Mogi das Cruzes, Santa Branca and Guacuri granites; up to ∼75% SiO2). εNdT are characteristically negative (-12 to -18), with corresponding Nd TDM indicating sources with Paleoproterozoic mean crustal ages (2.0-2.5 Ga). The Guacuri and Santa Branca muscovite granites have the more negative εNdt, highest 87Sr/86Srt (0.714-0.717) and lowest 208Pb/206Pb and 207Pb/206Pb, consistent with an old metasedimentary source with low time-integrated Rb/Sr. However, a positive Nd-Sr isotope correlation is suggested by data from the other granites, and would be consistent with mixing between an older source predominant in the Mauá granite and a younger, high Rb/Sr source that is more abundant in the Lagoinha granite sample. The

  2. Mesozoic dinosaurs from Brazil and their biogeographic implications

    Directory of Open Access Journals (Sweden)

    Jonathas S. Bittencourt

    2011-03-01

    Full Text Available The record of dinosaur body-fossils in the Brazilian Mesozoic is restricted to the Triassic of Rio Grande do Sul and Cretaceous of various parts of the country. This includes 21 named species, two of which were regarded as nomina dubia, and 19 consensually assigned to Dinosauria. Additional eight supraspecific taxa have been identified based on fragmentary specimens and numerous dinosaur footprints known in Brazil. In fact, most Brazilian specimens related to dinosaurs are composed of isolated teeth and vertebrae. Despite the increase of fieldwork during the last decade, there are still no dinosaur body-fossils of Jurassic age and the evidence of ornithischians in Brazil is very limited. Dinosaur faunas from this country are generally correlated with those from other parts of Gondwana throughout the Mesozoic. During the Late Triassic, there is a close correspondence to Argentina and other south-Pangaea areas. Mid-Cretaceous faunas of northeastern Brazil resemble those of coeval deposits of North Africa and Argentina. Southern hemisphere spinosaurids are restricted to Africa and Brazil, whereas abelisaurids are still unknown in the Early Cretaceous of the latter. Late Cretaceous dinosaur assemblages of south-central Brazil are endemic only to genus or, more conspicuously, to species level, sharing closely related taxa with Argentina, Madagascar, Indo-Pakistan and, to a lesser degree, continental Africa.O registro osteológico de dinossauros no Mesozóico brasileiro está restrito a rochas triássicas do Rio Grande do Sul e estratos cretáceos de várias partes do país. Isto inclui 21 espécies nominais, sendo duas referidas como nomina dubia, e 19 consensualmente classificadas como dinossauros. Oito táxons supraespecíficos adicionais baseados em material fragmentado e diversas pegadas são conhecidos no Brasil. De fato, a maior parte dos espécimes é composta de dentes isolados e vértebras. Apesar do aumento em trabalhos de campo na última

  3. Paleomagnetic data from the Trans-Mexican Volcanic Belt: implications for tectonics and volcanic stratigraphy

    Science.gov (United States)

    Alva-Valdivia, L. M.; Goguitchaichvili, A.; Ferrari, L.; Rosas-Elguera, J.; Urrutia-Fucugauchi, J.; Zamorano-Orozco, J. J.

    2000-07-01

    We report a paleomagnetic and rock-magnetic study of Miocene volcanic rocks from the Trans-Mexican Volcanic Belt. A total of 32 sites (238 oriented samples) were collected from three localities: Queretaro, Guadalajara and Los Altos de Jalisco basaltic plateaux, which span from 11 to 7.5 Ma. Several rock-magnetic experiments were carried out in order to identify the magnetic carriers and to obtain information about their paleomagnetic stability. Microscopic observation of polished sections shows that the main magnetic mineral is Ti-poor titanomagnetite associated with exsolved ilmenite. Continuous susceptibility measurements with temperature yield in most cases reasonably reversible curves with Curie points close to that of magnetite. Judging from the ratios of hysteresis parameters, it seems that all samples fall in the pseudo-single domain (PSD) grain size region, probably indicating a mixture of multidomain (MD) and a significant amount of single domain (SD) grains. Based on our paleomagnetic and available radiometric data, it seems that the volcanic units have been emplaced during a relatively short time span of 1 to 2 My at each locality. The mean paleomagnetic directions obtained from each locality differ significantly from that expected for the Middle Miocene. The mean paleomagnetic direction calculated from 28 sites discarding those of intermediate polarity is I= 32.46°, D= 341.2°, k= 7.2 and a95= 11.6°. Comparison with the expected direction indicates some 20° anticlockwise tectonic rotations for the studied area, in accordance with the proposed left-lateral transtensional tectonic regime already proposed for this period.

  4. Study of Carbonaceous Material in cherts from Barberton Greenstone Belt and the Astrobiological Implications.

    Science.gov (United States)

    Rull, F.; Venegas, G.; Montero, O.; Medina, J.

    2012-04-01

    Carbonaceous matter is present in chert deposits of Barberton Greenstone Belt (BGB), South Africa. This is a famous place in the world for its Archean geology, wich represents around 3.5 billion years of earth's history. Therefore this area provides us the opportunity to study and understand an important part history of our planet, and also allow to compare with the geological history of other planets in our solar system [1]. Raman micro-spectroscopy has proved to be a very important and non-destructive powerful tool for distinguish micro-sized particles of C-polymorphs, as it is very sensitive to the nature of carbon bonding [2]. The connection between the Raman characterization of these carbonaceous phases with ancient biogenic activity it's of special interest. Cherts of BGB have been interpreted as precipitates or diagenetic replacements of preexisting sedimentary and pyroclastic deposits in a silica saturated Archean ocean [3]. Several layered Samples of cherts from BGB utility for the present study were collected during the expedition carried out in August 2010 sponsored by CNES and ESA. A detailed Raman spectral analysis of carbon C-C vibrations has been performed in the first (1200-1800 cm-1) and second (2500-3200 cm-1) order regions [4]. The results show important changes in the G-D bands in the layered structure of chert. Additionally a UPLC-ESI-QTOF-MS was carried out trying to introduce new insight in the Raman interpretation of the bands and in the possible assignments to particular molecular groups which could be related with biotic or abiotic origin of the carbonaceous material. Among the tentative compounds obtained from UPLC-ESI-QTOF-MS study it is worth to mention hydroxy-lycopene and the hydroxyl derivative of β-carotene (i.e. β-cryptoxanthin), which are carotenoids produced by cyanobacteria. These results are consistent with the presence of 22-Hopanol and Tetrahymanol, which are characteristic hopanoids of photosynthetic cyanobacteria and have

  5. Proterozoic Tectonic History of Borborema Province, NE Brazil: Implications For Assembly of West Gondwana

    Science.gov (United States)

    van Schmus, W. R.; Brito Neves, B. B.

    The Borborema Province of NE Brazil comprises the west-central part of a wide Pan- African - Brasiliano continental collision belt that formed during ca. 600 Ma assembly of West Gondwana. Our studies over the past decade, in collaboration with many other workers, demonstrate a complex Proterozoic history that created or modified crustal domains at 2.1, 1.7, 1.0, 0.8, and 0.6 Ga. Although NE Brazil contains a few small Archean domains included within early Paleoproterozoic orogens, the first major event was formation of extensive continental crust about 2.35 to 2.1 Ga, before and during the so-called Transamazonian orogeny. We believe that this occurred in conjunction with formation of a larger Paleoproterozoic continent about 2.05 Ga that included present-day West African, Amazonian, Congo, and São Francisco cratons. Incipient extension within this continent occurred in Brazil about 1.8 to 1.7 Ga, resulting in intracratonic sedimentation and bimodal volcanism, but equivalent rocks are less well known in Africa. A successful breakup occurred before or about 1.1 Ga, resulting in separation of parts of this continent into two major stable masses containing (a) the Amazon-West African craton, and (b) the São Francisco-Congo (SF/C) craton. The break-up also created many smaller fragments between these two large masses, particularly in the east (present-day NE Brazil and Saharan Africa) and including the Ceará-Rio Grande do Norte (CE/RN) craton in NE Brazil. About 1.0 Ga a magmatic arc more than 700 km long (Cariris Velhos orogen) developed in NE Brazil, possibly as a result of convergence between the CE/RN and SF/C cratons; eastward extension of the 1.0 Ga Cariris Velhos orogen into West Africa is presently unknown. About 850 to 700 Ma several extensional basins developed in NE Brazil, with intraplate bimodal volcanism and clastic sedimentation; coeval basins may have formed in west-central Africa. From 700 to 600 Ma plate convergence among the CE/RN craton, SF

  6. Southern Brasilia Belt (SE Brazil): tectonic discontinuities, K-Ar data and evolution during the Neoproterozoic Brasiliano orogeny

    Energy Technology Data Exchange (ETDEWEB)

    Valeriano, Claudio Morrison de [Universidade do Estado, Rio de Janeiro, RJ (Brazil)]. E-mail: cmval@uerj.br; Teixeira, Wilson [Sao Paulo Univ., SP (Brazil); Simoes, Luiz Sergio Amarante [UNESP, Sao Paulo, SP (Brazil); Heilbron, Monica [Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Brasilia, DF (Brazil)

    2000-03-01

    This paper focuses the tectonic evolution of the southern brasilia belt, with emphasis on the Furnas segment, along the 21 deg C S parallel. The uppermost structural unit (Passos Nappe - PN) comprises a highly deformed metasedimentary succession interpreted as a fragment of the Neoproterozoic passive margin of western Sao francisco craton. An inverted metamorphic gradient ranging from greensvhits to lower granulite facies of medium to high-pressure regime characterizes the PN as relict of a subduction zone. The External Domain display a complex imbrication of basement rocks (Archean Piumhi greenstones, a turbiditic gaywacke succession and a calc-alkaline granitoid suite) with undated siliciclast low-grade metasedimentary rocks. The Sao Francisco Craton (SFC) comprises pre-1.8 Ga basement rocks covered by anchimetamorphic Neoproterozoic carbonatic shallow marine platform deposits of the Bambui group. The Brasiliano thrust stacking generated a coarse clastic influx of molassic character on the foreland zone of Sao Francisco Craton, coeval with the exhumation of the External Domain thrust sheets. New K-Ar determinations on mineral separates are presented an interpreted among previous data. The SFC basement rocks display Paleo-to Meesoproterozoic cooling ages. The allochthonous units, in contrast, display K-Ar ages within the 560-675 Ma range. Brasiliano thrust stacking is therefore interpreted to have taken place onto a cold Sao Francisco craton foreland, in a thin-skinned style, as basement rocks were not heated enough to have their-K-ar systems reset during the allochthony. (author)

  7. Age constraints on felsic intrusions, metamorphism and gold mineralisation in the Palaeoproterozoic Rio Itapicuru greenstone belt, NE Bahia State, Brazil

    Science.gov (United States)

    Mello, E.F.; Xavier, R.P.; McNaughton, N.J.; Hagemann, S.G.; Fletcher, I.; Snee, L.

    2006-01-01

    U-Pb sensitive high resolution ion microprobe mass spectrometer (SHRIMP) ages of zircon, monazite and xenotime crystals from felsic intrusive rocks from the Rio Itapicuru greenstone belt show two development stages between 2,152 and 2,130 Ma, and between 2,130 and 2,080 Ma. The older intrusions yielded ages of 2,152??6 Ma in monazite crystals and 2,155??9 Ma in zircon crystals derived from the Trilhado granodiorite, and ages of 2,130??7 Ma and 2,128??8 Ma in zircon crystals derived from the Teofila??ndia tonalite. The emplacement age of the syntectonic Ambro??sio dome as indicated by a 2,080??2-Ma xenotime age for a granite dyke probably marks the end of the felsic magmatism. This age shows good agreement with the Ar-Ar plateau age of 2,080??5 Ma obtained in hornblendes from an amphibolite and with a U-Pb SHRIMP age of 2,076??10 Ma in detrital zircon crystals from a quartzite, interpreted as the age of the peak of the metamorphism. The predominance of inherited zircons in the syntectonic Ambro??sio dome suggests that the basement of the supracrustal rocks was composed of Archaean continental crust with components of 2,937??16, 3,111??13 and 3,162??13 Ma. Ar-Ar plateau ages of 2,050??4 Ma and 2,054??2 Ma on hydrothermal muscovite samples from the Fazenda Brasileiro gold deposit are interpreted as minimum ages for gold mineralisation and close to the true age of gold deposition. The Ar-Ar data indicate that the mineralisation must have occurred less than 30 million years after the peak of the metamorphism, or episodically between 2,080 Ma and 2,050 Ma, during uplift and exhumation of the orogen. ?? Springer-Verlag 2006.

  8. Brazil's premier gold province. Part II: geology and genesis of gold deposits in the Archean Rio das Velhas greenstone belt, Quadrilátero Ferrífero

    Science.gov (United States)

    Lobato, Lydia; Ribeiro-Rodrigues, Luiz; Vieira, Frederico

    2001-07-01

    Orogenic, gold deposits are hosted by rocks of the Archean Rio das Velhas greenstone belt in the Quadrilátero Ferrífero region, Minas Gerais state, Brazil, one of the major gold provinces in the world. The gold deposits occur at the base of the mafic-ultramafic succession, with the most important orebodies controlled by E-W-striking, strike-slip faults. The main mineralization styles are (1) structurally controlled, sulfide replacement zones in banded iron formation (BIF); (2) disseminated sulfide minerals and gold in hydrothermally altered rocks along shear zones; and (3) auriferous quartz-carbonate-sulfide veins and veinlets in mafic, ultramafic, and felsic volcanic rocks, and also in clastic sedimentary rocks. The most common host rocks for ore are metamorphosed oxide- and carbonate-facies banded iron (± iron-rich metachert) formations (e.g., the Cuiabá, São Bento and Raposos deposits) and the lapa seca unit, which is a local term for intensely carbonatized rock (e.g., the giant Morro Velho mine with >450 t of contained gold). Metabasalts host most of the remaining gold deposits. Mineralogical characteristics and fluid inclusion studies suggest variations in the H2O/CO2 ratio of a low-salinity, near-neutral, reducing, sulfur-bearing, ore fluid. The presence of abundant CH4-rich inclusions is related to reduction of the original H2O-CO2 fluid via interaction with carbonaceous matter in the wallrocks. Oxygen fugacity was close to that of graphite saturation, with variations likely to have been influenced by reaction with the carbonaceous matter. Carbon-rich phyllites and schists, which commonly bound ore-bearing horizons, seem to have played both a physical and chemical role in localizing hydrothermal mineral deposition. Microtextural studies indicate that gold deposition was mainly related to desulfidation reactions, and was paragenetically coeval with precipitation of arsenic-rich iron sulfide minerals. Carbon isotope data are compatible with dissolution of

  9. Cambro-Ordovician post-collisional granites of the Ribeira belt, SE-Brazil: A case of terminal magmatism of a hot orogen

    Science.gov (United States)

    Valeriano, Claudio de Morisson; Mendes, Julio Cezar; Tupinambá, Miguel; Bongiolo, Everton; Heilbron, Monica; Junho, Maria do Carmo Bustamante

    2016-07-01

    This work presents an overview of the geology and chemical composition of the Cambrian-Ordovician post-collisional (COPC) granites and associated rocks of Ribeira belt, SE-Brazil. These COPC granites make up some of the most picturesque and highest (>2000 m) rocky peaks and cliffs of Rio de Janeiro state, an accessible case of post-orogenic granitic magmatism associated with the terminal stages of a hot Ediacaran-Cambrian (Brasiliano-Panafrican) orogen. The COPC magmatism intruded tonalitic to granitic orthogneisses of the Rio Negro arc (∼790-600 Ma) and associated paragneisses of the São Fidelis Group. Post-collisional magmatism started ∼10 m.y. after the latest collisional event, the Buzios Orogeny, lasting discontinuously from ∼510 Ma until ∼470 Ma. The 15 largest intrusive bodies in Rio de Janeiro State are referred to in the literature as the Parati/Mangaratiba, Vila Dois Rios, Pedra Branca, Suruí, Silva Jardim, Favela, Andorinha, Teresópolis, Frade, Nova Friburgo, Conselheiro Paulino, São José do Ribeirão, Sana and Itaoca granites. They crop out as rounded/elliptical stocks or gently-dipping sheets, always with sharp contacts with the country rocks, along with pegmatite and aplitic veins and dykes. COPC granites are grey and pink undeformed medium-grained biotite monzogranites with (K-feldspar) porphyritic, mega-crystic, equigranular and serial textures. Magmatic flow foliation is frequently observed. Peripheric xenolith zones are common as well as isolated xenoliths from the country rocks. In a compilation of more than 100 chemical compositions, SiO2 contents display a major mode at 71wt%. The COPC magmatism generated high-K calc-alkaline granites and quartz monzonites with predominantly metaluminous granites. Meso to melanocratic gabbroic and dioritic enclaves also have calc-alkaline affinity and likely represent more resistant mafic xenoliths from the Rio Negro Arc.

  10. Further evidence of 777 Ma subduction-related continental arc magmatism in Eastern Dom Feliciano Belt, southern Brazil: The Chácara das Pedras Orthogneiss

    Science.gov (United States)

    Koester, E.; Porcher, C. C.; Pimentel, M. M.; Fernandes, L. A. D.; Vignol-Lelarge, M. L.; Oliveira, L. D.; Ramos, R. C.

    2016-07-01

    In this study new SHRIMP U-Pb zircon data for the Chácara das Pedras Gneiss in Porto Alegre, southern Brazil are presented. They represent a small exposure of the crust which was intruded by a large volume of orogenic to anorogenic granitoids at ca. 618-562 m.y. in the Eastern Domain of the Dom Feliciano Belt. The Chácara das Pedras tonalitic orthogneiss has geochemical similarities with subduction-related magmatic rocks of continental arcs. They present high Sr initial ratios (∼0.712), negative ɛNd(t = 777) values (∼-6), TDM varying from 1.8 to 2.0 Ga. The igneous protoliths of these orthogneisses were previously considered to be Paleoproterozoic based on an upper intercept age of discordant zircon analyses. In the present study these orthogneisses were re-sampled and re-analyzed in an attempt to obtain more concordant analytical data. The U-Pb zircon analyses were carried out using the SHRIMP IIe at the Laboratório de Geocronologia de Alta Resolução of the Universidade de São Paulo. The U-Pb concordia age obtained for igneous textural domains of the zircon grains is 777 ± 4 Ma. A few analyses on zircon overgrowths give poorly defined late Cryogenian ages of ca. 650 Ma. Older ages, mostly discordant, were obtained in a few zircon cores, showing an upper intercept age of ca. 1.9 Ga. One sample of the Três Figueiras Granodiorite, which crosscut the orthogneiss in the same outcrop, was also investigated. The zircons of this granodiorite are, however, mostly metamitic, preventing the determination of a reliable age. Some concordant analyses from a few grains define ages ranging in the interval between ca. 603 and 1022 Ma. The youngest (ca. 603 Ma) may represent a maximum age for the granodiorite crystallization. Older ages, with discordance Plata and Kalahari cratons.

  11. Brazil.

    Science.gov (United States)

    1985-09-01

    Brazil's population in 1985 was 135 million, with an annual growth rate (1982) of 2.3%. The infant mortality rate (1981) was 92/1000, and life expectancy stood at 62.8 years. 76% of the adult population was literate. Brazil is a federal republic which recognizes 5 political parties. 55% of the population is Portuguese, Italian, German, Japanese, African, or American Indian; 38% is white. Of the work force of 50 million, 35% are engaged in agriculture, 25% work in industry, and 40% are employed in services. Trade union membership totals 6 million. The agricultural sector accounts for 12% of the GDP and 40% of exports. Brazil is largely self-sufficient in terms of food. The GDP was US$218 billion in 1984, with an annual growth rate of 4%. Per capita GDP was US$1645. Brazil's power, transportation, and communications systems have improved greatly in recent years, providing a base for economic development. High inflation rates have been a persistent problem.

  12. Religion, spirituality and cardiovascular disease: research, clinical implications, and opportunities in Brazil.

    Science.gov (United States)

    Lucchese, Fernando A; Koenig, Harold G

    2013-03-01

    In this paper we comprehensively review published quantitative research on the relationship between religion, spirituality (R/S), and cardiovascular (CV) disease, discuss mechanisms that help explain the associations reported, examine the clinical implications of those findings, and explore future research needed in Brazil on this topic. First, we define the terms religion, spirituality, and secular humanism. Next, we review research examining the relationships between R/S and CV risk factors (smoking, alcohol/drug use, physical inactivity, poor diet, cholesterol, obesity, diabetes, blood pressure, and psychosocial stress). We then review research on R/S, cardiovascular functions (CV reactivity, heart rate variability, etc.), and inflammatory markers (IL-6, IFN-γ, CRP, fibrinogen, IL-4, IL-10). Next we examine research on R/S and coronary artery disease, hypertension, stroke, dementia, cardiac surgery outcomes, and mortality (CV mortality in particular). We then discuss mechanisms that help explain these relationships (focusing on psychological, social, and behavioral pathways) and present a theoretical causal model based on a Western religious perspective. Next we discuss the clinical applications of the research, and make practical suggestions on how cardiologists and cardiac surgeons can sensitively and sensibly address spiritual issues in clinical practice. Finally, we explore opportunities for future research. No research on R/S and cardiovascular disease has yet been published from Brazil, despite the tremendous interest and involvement of the population in R/S, making this an area of almost unlimited possibilities for researchers in Brazil.

  13. Subduction Contributions in the Trans-Mexican Volcanic Belt: Implications from Lava Chemistry and Hf-Nd-Pb Isotopes

    Science.gov (United States)

    Cai, Y.; Goldstein, S. L.; Langmuir, C. H.; Gómez-Tuena, A.; Lagatta, A.; Straub, S. M.; Martín Del Pozzo, A.

    2007-05-01

    Despite thick continental crust, near primitive lavas erupt throughout the Trans-Mexican Volcanic Belt (TMVB). In order to distinguish and better constrain subduction contributions and effects of crustal contamination, we analyzed samples representing subducting sediments from DSDP Site 487, and Quaternary lavas from stratovolcanoes and cinder cones, including alkaline "high-Nb" lavas from the Sierra Chichinautzin Volcanic Field (SCVF) showing negligible subduction signature in its trace element chemistry and representing melts of the mantle wedge. Our primary observations and implications are: (1) The high-Nb SCVF `intraplate' lavas define a linear trend along the "Nd-Hf mantle-crust array", defining the composition of the mantle wedge. (2) Popocatepetl and Nevado de Toluca stratovolcanoes show the highest Nd and Hf isotope ratios, higher than the `intraplate' lavas, indicating their sources are more "depleted mantle-like" than the regional mantle wedge. (3) The Popo and Toluca chemical and isotopic trends sharply contrast with Pico de Orizaba, which shows classic indications of crustal contamination (e.g. high 207Pb/204Pb, low Nd-Hf isotope ratios), consistent with contamination by local Precambrian crust. (4) Higher Nd-Hf isotopes in Popo and Toluca lavas also correlate with lower Pb isotope ratios, and lower Lu/Hf and Zr/Hf. Together, these data indicate contributions from subducted Pacific oceanic crust and hydrothermal sediment. (5) Popo and Toluca are also enriched in Th/LREE compared with `intraplate' lavas, reflecting subducted sediment contributions. (6) Nd-Hf isotope ratios of hydrothermal sediment from DSDP Site 487 lie on the "seawater array", with high Hf isotope ratios compared to the "mantle-crust array". Popo and Toluca Nd-Hf isotopes display a shallower slope than the "intraplate lava Nd-Hf array", reflecting contributions from hydrothermal sediment. Popocatepetl and Toluca lavas therefore avoid substantial crustal contamination of mantle wedge

  14. Fault Geometry beneath the Chittagong-Myanmar Fold and Thrust Belt, Bangladesh, and Implications for Earthquake Hazard

    Science.gov (United States)

    Burgi, P.; Hubbard, J.; Peterson, D. E.; Akhter, S. H.

    2016-12-01

    Bangladesh sits on the seismically active Chittagong-Myanmar Fold and Thrust Belt (CMFB), a partially exposed accretionary prism on the eastern margin of the India-Eurasia collision. Earthquakes on the basal décollement and emergent thrusts beneath and within the CMFB present a potential hazard to Bangladesh, one of the most densely populated countries in the world. Geodetic data suggest that the faults associated with the CMFB may be locked and accumulating 13 mm/yr of elastic strain (Steckler et al., 2016). However, accurate inversion of geodetic data requires data-constrained fault geometries to produce elastic loading models, particularly because of the shallow nature of these faults. In this study, we use both published and unpublished seismic reflection profiles and velocity data to locate the shallow décollement below east Bangladesh and the Indian state of Tripura. We then fit a surface to this data to constrain the overall geometry of the décollement. Seismic data reveal that the décollement is located at 9-10 km depth in northeast and southeast Bangladesh, but shallows to 5-6 km in the central portion of east Bangladesh. This shallow portion of the décollement is located in the region beneath the western-most exposed anticlines, as well as the northern extent of the Bay of Bengal. An important implication of this configuration is that the corrugated nature of this fault could act as a rupture barrier, were a large earthquake to occur on the basal décollement. The thrust faults that rise from the décollement and produce the anticlines within the CMFB may also be capable of slipping in earthquakes. The outermost folds in the CMFB appear to be detachment folds, whereas folds in the inner CMFB are cored by faults. This implies that deformation begins as distributed shearing and evolves into brittle deformation as the fold grows over time. Further efforts to invert geodetic data and model earthquakes on this large, subaerial fault system are necessary

  15. Geologic setting of the Central Alaskan Hot Springs Belt: Implications for geothermal resource capacity and sustainable energy production

    Science.gov (United States)

    Kolker, Amanda M.

    The Central Alaskan Hot Springs Belt (CAHSB) is a vast stretch of low-temperature hydrothermal systems that has the potential to be a geothermal energy resource for remote communities in Alaska. Little exploration has occurred in the CAHSB and the resource is poorly understood. A geothermal power plant was installed in 2006 at Chena Hot Springs (CHS), one of the 30-plus hot springs in the CAHSB. This, in addition to the multiple direct use projects at CHS, could serve as a model for geothermal development elsewhere in the CAHSB. This dissertation evaluates the geologic setting of the CAHSB and explores the implications for resource capacity and sustainable energy production. The local geology and geochemical characteristics of CHS are characterized, with a focus on identifying ultimate heat source responsible for the hot springs. A radiogenic heat source model is proposed and tested for the entire CAHSB, wherein the anomalously radioactive plutons that are associated with nearly every hot spring are providing the source of heat driving the geothermal activity. This model appears to be feasible mechanism for the observed heat transfer. This implies that CAHSB "reservoir" fluids are probably low-temperature. It also suggests that individual hydrothermal systems are small-scale and localized features, unlike the types of hydrothermal systems that are conventionally exploited for energy (i.e., those that derive their heat from magmatic or deep crustal sources, which have higher reservoir temperatures and larger spatial extent). In this context, the individual capacity of several CAHSB resources close to communities is assessed, and a preliminary evaluation of the sustainability of the power production scheme at CHS is given. As another approach to the question of sustainability, this dissertation explores the ways in which external benefits of geothermal energy can influence the economics of a project. In sum, producing geothermal energy from CAHSB resources is

  16. Temporal evolution of granitic magmas in the Luanchuan metallogenic belt, east Qinling Orogen, central China: Implications for Mo metallogenesis

    Science.gov (United States)

    Li, Dong; Han, Jiangwei; Zhang, Shouting; Yan, Changhai; Cao, Huawen; Song, Yaowu

    2015-11-01

    The Luanchuan metallogenic belt, located within the eastern part of the Qinling Orogen, central China, hosts a number of world-class Mo deposits that are closely related to small late Mesozoic granitic plutons. Zircon U-Pb dating of distinct plutons in the Luanchuan metallogenic belt has yielded ages of 153 ± 1, 154 ± 2, 152 ± 2, and 148 ± 1 Ma. Molybdenite Re-Os isotopic compositions of Yuku ore district in the southern part of Luanchuan metallogenic belt has yielded an isochron age of 146 ± 1 Ma, which is consistent with the large-scale mineralization ages in the northern part of the Luanchuan metallogenic belt. A combination of previous studies and new geochronological and isotopic data show a concordant temporal and genetic link between granitic magmatism and Mo mineralization in the Luanchuan metallogenic belt, suggesting that this mineralization episode formed the most extensive Mo mineralization belt in the east Qinling Orogen. Zircon grains from Mo-related granitic plutons show similar trace element distributions. High-precision Multi Collector-Inductively Coupled Plasma-Mass Spectrometry (MC-ICP-MS) Pb isotope analysis of K-feldspar megacrysts from mineralization-related granites suggest that they were derived from the lower crust. Similarly, the Pb isotopic compositions of pyrite coprecipitated with molybdenite also suggest that the metals were derived form the lower crust, with probably minor mantle contribution. A continuum mineralization model that describes the sourcing of Mo from an evolving granitic magma over successive differentiation events, possibly in separate but connected magma chambers, could explain the remarkable Mo enrichment in the Luanchuan metallogenic belt. The volatile- and Mo-bearing granitic magmas ascended as diapirs from the deep crust, and were emplaced as dikes in the upper crust. Lithological differences between these Mo-bearing granites may relate to different stages in the evolution of individual magmas. Finally, ore

  17. Mineralogical and textural evidences of melt transfer in a granulite from the Paleoproterozoic Itabuna-Salvador-Curaça belt (Salvador da Bahia, Brazil)

    Science.gov (United States)

    Goncalves, Philippe; Santos de Souza, Jailma; Barbosa, Johildo; Bourque, Hugo; Floess, David

    2014-05-01

    In pelitic rocks, the effect of melt transfer (loss and/or gain) on phase relations can be successfully predicted via phase equilibrium modeling and more particularly using pseudosections with bulk composition as a variable (e.g. White et al., 2001). One of the most obvious effect of melt loss is the dehydration of the rock that limits further melting and favors the preservation of peak metamorphic assemblage. However, in most cases, melt loss has a limited effect that can be hardly seen mineralogically. Indeed, composition of phases like garnet, cordierite or plagioclase, that are first-order metamorphic phase, will not be affected significantly by melt loss. Therefore, evidences of melt extraction must be evidenced texturally. The goal of this contribution is to present an example where both mineralogical and textural evidences of melt extraction have been inferred. The studied sample is a pelitic granulite from the Paleoproterozoic Itabuna-Salvador-Curaça belt (Salvador da Bahia, Brazil). It is located in the city of Salvador da Bahia, next to the Farol da Bara. Structurally, it is located in a steeply deeping high strain zone that could have play a major role on the segregation and transfer of melt. The gneissic foliation is marked by a compositional banding with centimer-wide quartzo-feldspathic leucosomes in a garnet-bearing granulite. Leucosomes are almost systematically surrounded by a darker layer that is quartz-undersaturated and enriched in spinel and primatic sillimanite. This silica undersaturation is interpreted as the effect of extreme melt extraction and was modeled using phase diagram section. An interesting feature of the rock is that garnet grain size decreases and the number of garnet grains increases in the melanosome away from the leucosome. Furthermore, the type, amount and shape of inclusions in garnet, chemical composition and zoning in garnet also varies greatly and continuously across the gneissic foliation. Texturally, the presence of

  18. Geochemical Characteristics and Implications of Eclogite Gravels from Mesozoic Strata at the Northern Margin of Dabie Orogenic Belt

    Institute of Scientific and Technical Information of China (English)

    李双应; 岳书仓; 王道轩; 刘因; 李任伟; 孟庆任; 金福全

    2004-01-01

    The eclogite gravels, which were found in the Mesozoic Fenghuangtai and Maotanchang formations on the northern margin of the Dabie orogenic belt, are rich in K2O ( 1.21% ), ∑REE (278μg/g), and LILE (such as Rb, Ba, K, Th, etc.), with high (La/Yb)N ratios ( 14.4 ), on the basis of the analyses of major elements, rare-earth elements (REE) and trace elements. Their enrichment in LILE, notable Nb-Ta depletion through, and depletion in HFSE relative to REE in comparison with the primitive mantle and N-MORB indicate that the protoliths of the eclogite gravels were formed in an island-arc setting. According to the Th-Hf-Ta discrimination diagram, the protoliths of the eclogite gravels are characterized by volcanic arc basalts. Trace element data indicate that the subducted marine sediments were assimilated in the magma chamber, resulting in the enrichment of LILE in the protoliths. Therefore, the protoliths of the eclogite gravels are considered to have been formed in an inland-arc setting, indicating that there had developed a paleo-inland arc before Triassic collision between the North and South China blocks in the Dabie orogenic belt. There is a marked difference between the eclogite gravels and the eclogites developed along the Dabie orogenic belt, solely based on their geochemical data, especially REE. Therefore, the eclogite gravels may not be derived from eclogite terrains preserved in the Dabie orogenic belt.

  19. Structure of the Edgeworth-Kuiper Belt (EKB) Dust Disk and Implications for Extrasolar Planet(s) epsilon Eridani

    Science.gov (United States)

    Liou, J. -C.; Zook, H. A.; Greaves, J. S.; Holland, W. S.; Boehnhardt, H.; Hahn, J. M.

    2000-01-01

    Numerical simulations of the orbital evolution of dust particles from Edgeworth-Kuiper Belt (EKB) objects show that the three giant planets, Neptune, Jupiter, and Saturn impose distinct and dramatic signatures on the overall distribution of EKB dust particles. The features are very similar to those observed in the dust disk around the nearby star Eridani. Numerical simulations of dust particles in the epsilon Eridani system show that planetary perturbations may be responsible for the observed features

  20. Considerations of the productive restructuring process in Brazil and its implications for workers and education

    Directory of Open Access Journals (Sweden)

    Karina Griggio Hotz

    2009-12-01

    Full Text Available This article aims to discuss the profile that is required of workers in current forms of production. This is done by considering the productive restructuring process that took place in Brazil since the 1990’s. This process presents implications to different social organizations, especially to the State and the institutions related to it, for example the schools. The analysis of the primary and secondary sources related to the basic education reforms implemented in the same decade reveals the valuing of work competencies such as flexibility and the capacity to adapt. The article presents reflections on the rhetoric used to justify educational reforms, pointing out its underlying ideology and the actions performed by the Brazilian State, as well as the structural limits of the capitalist system for the social inclusion of the whole population.

  1. The geology of the Morro Velho gold deposit in the Archean Rio das Velhas greenstone belt, Quadrilátero Ferrífero, Brazil

    Science.gov (United States)

    Vial, Diogenes Scipioni; DeWitt, Ed; Lobato, Lydia Maria; Thorman, Charles H.

    2007-01-01

    The Morro Velho gold deposit, Quadrilátero Ferrífero region, Minas Gerais, Brazil, is hosted by rocks at the base of the Archean Rio das Velhas greenstone belt. The deposit occurs within a thick carbonaceous phyllite package, containing intercalations of felsic and intermediate volcaniclastic rocks and dolomites. Considering the temporal and spatial association of the deposit with the Rio das Velhas orogeny, and location in close proximity to a major NNW-trending fault zone, it can be classified as an orogenic gold deposit. Hydrothermal activity was characterized by intense enrichment in alteration zones of carbonates, sulfides, chlorite, white mica±biotite, albite and quartz, as described in other Archean lode-type gold ores. Two types of ore occur in the deposit: dark gray quartz veins and sulfide-rich gold orebodies. The sulfide-rich orebodies range from disseminated concentrations of sulfide minerals to massive sulfide bodies. The sulfide assemblage comprises (by volume), on average, 74% pyrrhotite, 17% arsenopyrite, 8% pyrite and 1% chalcopyrite. The orebodies have a long axis parallel to the local stretching lineation, with continuity down the plunge of fold axis for at least 4.8 km. The group of rocks hosting the Morro Velho gold mineralization is locally referred to as lapa seca. These were isoclinally folded and metamorphosed prior to gold mineralization. The lapa seca and the orebodies it hosts are distributed in five main tight folds related to F1 (the best examples are the X, Main and South orebodies, in level 25), which are disrupted by NE- to E-striking shear zones. Textural features indicate that the sulfide mineralization postdated regional peak metamorphism, and that the massive sulfide ore has subsequently been neither metamorphosed nor deformed. Lead isotope ratios indicate a model age of 2.82 ± 0.05 Ga for both sulfide and gold mineralization. The lapa seca are interpreted as the results of a pre-gold alteration process and may be

  2. The dynamical evolution of dwarf planet (136108) Haumea's collisional family: General properties and implications for the trans-Neptunian belt

    CERN Document Server

    Lykawka, Patryk Sofia; Mukai, Tadashi; Nakamura, Akiko M

    2011-01-01

    Recently, the first collisional family was identified in the trans-Neptunian belt. The family consists of Haumea and at least ten other ~100km-sized trans-Neptunian objects (TNOs) located in the region a = 42 - 44.5 AU. In this work, we model the long-term orbital evolution of an ensemble of fragments representing hypothetical post-collision distributions at the time of the family's birth. We consider three distinct scenarios, in which the kinetic energy of dispersed particles were varied such that their mean ejection velocities (veje) were of order 200 m/s, 300 m/s and 400 m/s, respectively. Each simulation considered resulted in collisional families that reproduced that currently observed. The results suggest that 60-75% of the fragments created in the collision will remain in the trans-Neptunian belt, even after 4 Gyr of dynamical evolution. The surviving particles were typically concentrated in wide regions of orbital element space centred on the initial impact location, with their orbits spread across a ...

  3. The Central Iberian arc, an orocline centered in the Iberian Massif and some implications for the Variscan belt

    Science.gov (United States)

    Martínez Catalán, José R.

    2012-07-01

    An arcuate structure, comparable in size with the Ibero-Armorican arc, is delineated by Variscan folds and magnetic anomalies in the Central Iberian Zone of the Iberian Massif. Called the Central Iberian arc, its sense of curvature is opposite to that of the Ibero-Armorican arc, and its core is occupied by the Galicia-Trás-os-Montes Zone of NW Iberia, which includes the Rheic suture. Other zones of the Iberian Massif are bent by the arc, but the Ossa-Morena and South Portuguese zones are not involved. The arc formed during the Late Carboniferous, at final stages of thermal relaxation and collapse, and an origin related with right-lateral ductile transpression at the scale of the Variscan belt is proposed. The Central Iberian arc explains the width of the Central Iberian Zone, clarifies the position of the allochthonous terranes of NW Iberia, and opens new perspectives for correlations with the rest of the Variscan belt, in particular, with the Armorican Massif, whose central zone represents the continuation of the southwest branch of the arc detached by strike-slip tectonics.

  4. Deformation geometry and timing of theWupoer thrust belt in the NE Pamir and its tectonic implications

    Science.gov (United States)

    Cheng, Xiaogan; Chen, Hanlin; Lin, Xiubin; Yang, Shufeng; Chen, Shenqiang; Zhang, Fenfen; Li, Kang; Liu, Zelin

    2016-12-01

    The Pamir region, located to the northwest of the Tibetan Plateau, provides important information that can aid the understanding of the plateau's tectonic evolution. Here we present new findings on the deformation geometry and timing of the Wupoer thrust belt at the northeastern margin of Pamir. Field investigations and interpretations of seismic profiles indicate that the eastern portion of the Wupoer thrust belt is dominated by an underlying foreland basin and an overlying piggy-back basin. A regional unconformity occurs between the Pliocene (N2) and the underlying Miocene (N1) or Paleogene (Pg) strata associated with two other local unconformities between Lower Pleistocene (Q1) and N2 and between Middle Pleistocene (Q2-4) and Q1 strata. Results of structural restorations suggest that compressional deformation was initiated during the latest Miocene to earliest Pliocene, contributing a total shortening magnitude of 48.6 km with a total shortening rate of 48.12%, most of which occurred in the period from the latest Miocene to earliest Pliocene. These results, combined with previous studies on the Kongur and Tarshkorgan extensional system, suggest an interesting picture of strong piedmont compressional thrusting activity concurrent with interorogen extensional rifting. Combining these results with previously published work on the lithospheric architecture of the Pamir, we propose that gravitational collapse drove the formation of simultaneous extensional and compressional structures with a weak, ductile middle crustal layer acting as a décollement along which both the extensional and compressional faults merged.

  5. Deformation geometry and timing of theWupoer thrust belt in the NE Pamir and its tectonic implications

    Science.gov (United States)

    Cheng, Xiaogan; Chen, Hanlin; Lin, Xiubin; Yang, Shufeng; Chen, Shenqiang; Zhang, Fenfen; Li, Kang; Liu, Zelin

    2016-09-01

    The Pamir region, located to the northwest of the Tibetan Plateau, provides important information that can aid the understanding of the plateau's tectonic evolution. Here we present new findings on the deformation geometry and timing of the Wupoer thrust belt at the northeastern margin of Pamir. Field investigations and interpretations of seismic profiles indicate that the eastern portion of the Wupoer thrust belt is dominated by an underlying foreland basin and an overlying piggy-back basin. A regional unconformity occurs between the Pliocene (N2) and the underlying Miocene (N1) or Paleogene (Pg) strata associated with two other local unconformities between Lower Pleistocene (Q1) and N2 and between Middle Pleistocene (Q2-4) and Q1 strata. Results of structural restorations suggest that compressional deformation was initiated during the latest Miocene to earliest Pliocene, contributing a total shortening magnitude of 48.6 km with a total shortening rate of 48.12%, most of which occurred in the period from the latest Miocene to earliest Pliocene. These results, combined with previous studies on the Kongur and Tarshkorgan extensional system, suggest an interesting picture of strong piedmont compressional thrusting activity concurrent with interorogen extensional rifting. Combining these results with previously published work on the lithospheric architecture of the Pamir, we propose that gravitational collapse drove the formation of simultaneous extensional and compressional structures with a weak, ductile middle crustal layer acting as a décollement along which both the extensional and compressional faults merged.

  6. Geochemistry of the Serra das Melancias Pluton in the Serra da Aldeia Suite: a classic post-collisional high Ba-Sr granite in The Riacho do Pontal Fold Belt, NE Brazil

    Directory of Open Access Journals (Sweden)

    Marcela Paschoal Perpétuo

    Full Text Available ABSTRACT: The Serra da Aldeia Suite is composed by circular or oval-shaped plutons, intrusive in meta-sedimentary and meta-volcanosedimentary rocks in the Riacho do Pontal Fold Belt, NE Brazil. The Serra das Melancias Pluton, belonging to Serra da Aldeia Suite, is located southeastern of Piaui state, near Paulistana city. These plutons represent a major magmatic expression in this area and contain important information about the late magmatic/collisional geologic evolution of the Brasiliano Orogeny. Based on petrographic and geochemical data, three facies were defined in the Serra das Melancias Pluton: granites, syenites and quartz monzonites. The rocks display high-K and alkaline to shoshonitic affinities, are metaluminous and show ferrous character. They are enriched in Light Rare Earth Elements and Large Ion Lithophile Elements, with negative anomalies in Nb, Ta and Ti. Their high Ba, Sr, K/Rb, low Rb, relatively low U, Th, Nb to very low Heavy Rare Earth Elements and Y resemble those of typical high Ba-Sr granitoids. The geochemical data suggest the emplacement of Serra das Melancias Pluton in a transitional, late to post-orogenic setting in the Riacho do Pontal Fold Belt during the late Brasiliano-Pan African Orogeny.

  7. Societal impact of dengue outbreaks: Stakeholder perceptions and related implications. A qualitative study in Brazil, 2015

    Science.gov (United States)

    Rodrigues, Mariana; Davis, Ben; Besson, Marie-Hélène; Audureau, Etienne; Saba, Joseph

    2017-01-01

    Background The growing burden of dengue in many countries worldwide and the difficulty of preventing outbreaks have increased the urgency to identify alternative public health management strategies and effective approaches to control and prevent dengue outbreaks. The objectives of this study were to understand the impact of dengue outbreak on different stakeholders in Brazil, to explore their perceptions of approaches used by governmental authorities to control and prevent dengue outbreaks and to define the challenges and implications of preventing future outbreaks. Methods In 2015, a qualitative study was conducted in two urban states in Brazil: São Paulo, which was experiencing an outbreak in 2015, and Rio de Janeiro, which experienced outbreaks in 2011 and 2012. Face-to-face interviews using a semi-structured questionnaire were conducted with nine different categories of stakeholders: health workers (physicians, nurses), hospital administrators, municipal government representatives, community members and leaders, school administrators, business leaders and vector control managers. Interviews were focused on the following areas: impact of the dengue outbreak, perceptions of control measures implemented by governmental authorities during outbreaks and challenges in preventing future dengue outbreaks. Results A total of 40 stakeholders were included in the study. Health workers and community members reported longer waiting times at hospitals due to the increased number of patients receiving care for dengue-related symptoms. Health workers and hospital administrators reported that there were no major interruptions in access to care. Overall financial impact of dengue outbreaks on households was greatest for low-income families. Despite prevention and control campaigns implemented between outbreak periods, various stakeholders reported that dengue prevention and control efforts performed by municipal authorities remained insufficient, suggesting that efforts should

  8. Lightning-driven inner radiation belt energy deposition into the atmosphere: implications for ionisation-levels and neutral chemistry

    Directory of Open Access Journals (Sweden)

    C. J. Rodger

    2007-08-01

    Full Text Available Lightning-generated whistlers lead to coupling between the troposphere, the Van Allen radiation belts and the lower-ionosphere through Whistler-induced electron precipitation (WEP. Lightning produced whistlers interact with cyclotron resonant radiation belt electrons, leading to pitch-angle scattering into the bounce loss cone and precipitation into the atmosphere. Here we consider the relative significance of WEP to the lower ionosphere and atmosphere by contrasting WEP produced ionisation rate changes with those from Galactic Cosmic Radiation (GCR and solar photoionisation. During the day, WEP is never a significant source of ionisation in the lower ionosphere for any location or altitude. At nighttime, GCR is more significant than WEP at altitudes <68 km for all locations, above which WEP starts to dominate in North America and Central Europe. Between 75 and 80 km altitude WEP becomes more significant than GCR for the majority of spatial locations at which WEP deposits energy. The size of the regions in which WEP is the most important nighttime ionisation source peaks at ~80 km, depending on the relative contributions of WEP and nighttime solar Lyman-α. We also used the Sodankylä Ion Chemistry (SIC model to consider the atmospheric consequences of WEP, focusing on a case-study period. Previous studies have also shown that energetic particle precipitation can lead to large-scale changes in the chemical makeup of the neutral atmosphere by enhancing minor chemical species that play a key role in the ozone balance of the middle atmosphere. However, SIC modelling indicates that the neutral atmospheric changes driven by WEP are insignificant due to the short timescale of the WEP bursts. Overall we find that WEP is a significant energy input into some parts of the lower ionosphere, depending on the latitude/longitude and altitude, but does not play a significant role in the neutral chemistry of the mesosphere.

  9. Belt conveyer

    Energy Technology Data Exchange (ETDEWEB)

    Cwieczek, A.; Dembinski, C.

    1982-04-30

    The patented belt conveyor is distinguished by the fact that the rate of motion of the belt changes smoothly depending on the load: the greater the load the higher the rate. This makes it possible to prolong the service life of the belt, i.e., during idling of the conveyor it is exposed to deformation on the drive and tension drums a fewer number of times. The essence of the invention is based on the use for driving the drum of a friction transmission. One of the elements of this transmission is the drive drum of the conveyor, and the other is the drive wheel which is pressed to the inner (or outer) surface of the drum. Change in rotation velocity of the drum is reached by changing the diameter of the drive wheel. The rim of the latter has an elastic tire to which compressed air is fed. The diameter of the drive wheel depends on the quantity of air in the tire. It is set automatically by a regulating system depending on the conveyor load. Variants are patented for the belt conveyor which is distinguished by the design of the friction transmission. It contains 1, 2 or more drive wheels. It can have a cylindrical or conical inner surface of the drive drum, etc.

  10. Tattoos and transfusion-transmitted disease risk: implications for the screening of blood donors in Brazil

    Directory of Open Access Journals (Sweden)

    Sérgio de A. Nishioka

    2002-08-01

    Full Text Available Having a tattoo has been associated with serological evidence of hepatitis B and C viruses, as well as human immunodeficiency virus infections and syphilis; all of these are known to be transmissible by blood transfusion. These associations are of higher magnitude for individuals with nonprofessionally-applied tattoos and with two or more tattoos. Tattoos are common among drug addicts and prisoners, conditions that are also associated with transfusion-transmitted diseases. We examined the implications of these associations for the screening of blood donors in Brazil. Numbers of individuals who would be correctly or unnecessarily deferred from blood donation on the basis of the presence of tattoos, and on their number and type, were calculated for different prevalence situations based on published odds ratios. If having a tattoo was made a deferral criterion, cost savings (due to a reduced need for laboratory testing and subsequent follow-up would accrue at the expense of the deferral of appropriate donors. Restricting deferral to more `at-risk' sub-groups of tattooed individuals would correctly defer less individuals and would also reduce the numbers of potential donors unnecessarily deferred. Key factors in balancing cost savings and unnecessary deferrals include the magnitude of the pool of blood donors in the population, the prevalence of individuals with tattoos and the `culture' of tattoos in the population. Tattoos can therefore be an efficient criterion for the screening of blood donors in certain settings, a finding that requires corroboration from larger population-based studies.

  11. U-Pb ages related to uranium mineralization of Lagoa Real, Bahia - Brazil: tectonic implications

    Energy Technology Data Exchange (ETDEWEB)

    Chaves, Alexandre O.; Rios, Francisco J.; Oliveira, Lucilia A.R.; Alves, James V.; Fuzikawa, Kazuo; Neves, Jose M.C.; Chaves, Adriana M.D.V.; Prates, Sonia P. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)]. E-mail: aoc@cdtn.br; Tubrett, Michael [Memorial University of Newfoundland, NL (Canada). Inco Innovation Centre. MicroAnalysis Facility; Matos, Evando C. [Industrias Nucleares do Brasil S.A. (INB), Rio de Janeiro, RJ (Brazil)

    2007-07-01

    The uranium from Lagoa Real (Bahia/Brazil) is associated with syenitic magmatism (1904 {+-}44 Ma minimum age from upper intercept of zircon U-Pb discordia by LA-ICP-MS) belonging to a mafic/ felsic lithologic association linked to the final stages of 2.05-1.80 Ga Orosirian Orogeny, which acted in the Paramirim Block. These syenitic rocks are rich not only in albite, but also in U-rich titanite (source of uranium). In association with the development of the Orosirian ductile shear zones, the syenites were crystallized and deformed. The metamorphic reactions, which include intense recrystallization of magmatic minerals, led uraninite to precipitate (1868 {+-} 69 Ma; U-Pb by LA-ICP MS) under Redox control. A second population of uraninites was also generated by shear zones reactivation during 0.6-0.5 Ga Brasiliano Orogeny (605 {+-} 170 Ma; U-Pb by LA-ICP-MS). The geotectonic implications are: a) the importance of the Orosirian event in the Paramirim Block during paleoproterozoic Sao Francisco/Congo Craton edification and b) the influence of the Brasiliano event in the Paramirim Block during the West-Gondwana assembly processes, indicated by the 605 {+-} 170 Ma uraninite (second population) age and by the 483 {+-} 100 Ma lower intercept of the metamorphosed syenite U-Pb discordia. (author)

  12. Spinifex-textured komatiites in the south border of the Carajas ridge, Selva Greenstone belt, Carajás Province, Brazil

    Science.gov (United States)

    Siepierski, Lincoln; Ferreira Filho, Cesar Fonseca

    2016-03-01

    Spinifex-textured komatiites in the Selva greenstone belt are the first unequivocal examples of komatiites in the Transition Subdomain of the Carajás Mineral Province. Outcrops of spinifex-textured komatiites, located ∼1.5 km to the south of the Carajás ridge, were discovered during regional exploration for Ni-Cu-(PGE) sulfide deposits by VALE. They are associated with a 3.8 km long unit consisting of variable types of ultramafic rocks (talc schist, serpentinite and spinifex-textured komatiite). This ultramafic unit follows the steep dipping NW-SE trending Selva greenstone belt composed mainly by quartz-chlorite schists (interpreted as metasediments) and chlorite-actinolite schists (interpreted as metabasalts). Greenschist facies metamorphic parageneses characterize all rock types in the Selva greenstone belt. The komatiitic rocks in the Selva belt comprise a sequence of flows consisting of an upper spinifex-textured layer and a lower olivine cumulate layer. Although the spinifex and cumulus textures are well preserved in the field, the primary mineralogy of the komatiites has been completely replaced by greenschist facies metamorphic minerals. Platy olivine spinifex texture, consisting of an array of roughly parallel olivine plates, and random spinifex texture, consisting of randomly oriented olivine plates, are the most common primary volcanic textures in komatiites in the Selva greenstone belt. Platy and random spinifex texture is defined by former plates of olivine replaced by serpentine with minor actinolite, chlorite and magnetite, alternating with former matrix replaced by abundant actinolite and minor chlorite, talc, serpentine, and magnetite. The domains between olivine plates in both platy and random spinifex-textured rocks contain irregular arrays of fine-grained parallel crystals, representing primary fine-grained "quench" clinopyroxene crystals replaced by actinolite. Spinifex-textured komatiites have MgO contents bracket between 22.8 and 26.9 wt

  13. Middle Devonian Picrites of the Southern Margin of Altay Orogenic Belt and Implications for the Tectonic Setting and Petrogenesis

    Institute of Scientific and Technical Information of China (English)

    Zhang Zhaochong; Yan Shenghao; Chen Bailin; Zhou Gang; He Yongkang; Chai Fengmei; He Lixin

    2005-01-01

    The Altay orogenic belt of Xinjiang in NW China represents one of the important sites of juvenile crustal growth during the Phanerozoic. However, some important issues, e.g., tectonic evolution and petrogenesis, still remain controversial. The picrites in the south margin of the Altay orogenic belt were discovered in the lower part of marine volcanic-sedimentary sequences of the northwest-striking Middle Devonian Beitashan Formation (Fm.), which consists chiefly of intermediate-basic volcanic rocks intercalated minor carbonate, siltstone and siliceous rocks. The picrites are usually highly porphyritic, and contain abundant forsteritic olivine phenocrysts with minor clinopyroxene distributed in the groundmass, which consist of olivine, clinopyroxene and plagioclase with minor Fe-Ti oxides. The MgO contents of the picrites range from 14 wt% to 22 wt% with Mg# (atomic Mg/(Mg+Fe) ratio) of 0.75-0.80. They are characterized by slightly negative Ti anomalies, remarkably negative Nb and Ta anomalies and slightly positive P and Sm anomalies with the similar abundances of HFSE as MORB on the MORB-normalized trace element patterns, all of which characterize typical island arc magmas. In combing with the southwestward migration of the magmas of the Beitashan Fm., we propose that the magmas may result from the southwestward subduction of Junggar ocean plate. The Zr/Nb ratios (23-66) of both picrites and basalts resemble the MORB (10-66), suggesting that they were derived from the MORB-like sources. However, the basalts and picrites display some distinguishable element ratios and REE patterns, e.g., Ti/V (23-35) and Zr/Sm (18-23) ratios of basalts are higher than those of picrites (14-17 and 14-15 respectively), and the basalts display flat-type REE-chondrite patterns whereas the picrites are characterized by lower total REE concentrations ((26-34)×10-6) and slight enrichment of light REE. These distinguished geochemical characteristics could be interpreted by different

  14. Distribution, Microfabric, and Geochemical Characteristics of Siliceous Rocks in Central Orogenic Belt, China: Implications for a Hydrothermal Sedimentation Model

    Directory of Open Access Journals (Sweden)

    Hongzhong Li

    2014-01-01

    Full Text Available Marine siliceous rocks are widely distributed in the central orogenic belt (COB of China and have a close connection to the geological evolution and metallogenesis. They display periodic distributions from Mesoproterozoic to Jurassic with positive peaks in the Mesoproterozoic, Cambrian—Ordovician, and Carboniferous—Permian and their deposition is enhanced by the tensional geological settings. The compressional regimes during the Jinning, Caledonian, Hercynian, Indosinian, and Yanshanian orogenies resulted in sudden descent in their distribution. The siliceous rocks of the Bafangshan-Erlihe ore deposit include authigenic quartz, syn-depositional metal sulphides, and scattered carbonate minerals. Their SiO2 content (71.08–95.30%, Ba (42.45–503.0 ppm, and ΣREE (3.28–19.75 ppm suggest a hydrothermal sedimentation origin. As evidenced by the Al/(Al + Fe + Mn, Sc/Th, (La/YbN, and (La/CeN ratios and δCe values, the studied siliceous rocks were deposited in a marginal sea basin of a limited ocean. We suggest that the Bafangshan-Erlihe area experienced high- and low-temperature stages of hydrothermal activities. The hydrothermal sediments of the former stage include metal sulphides and silica, while the latter was mainly composed of silica. Despite the hydrothermal sedimentation of the siliceous rocks, minor terrigenous input, magmatism, and biological activity partly contributed to geochemical features deviating from the typical hydrothermal characteristics.

  15. The Glória quartz-monzodiorite: isotopic and chemical evidence of arc-related magmatism in the central part of the Paleoproterozoic Mineiro belt, Minas Gerais State, Brazil

    Directory of Open Access Journals (Sweden)

    Ciro A. Ávila

    2006-09-01

    Full Text Available The Glória quartz-monzodiorite, one of the mafic plutons of the Paleoproterozoic Mineiro belt, is intrusive into banded gneisses, amphibolites, schists and phyllites of the Rio das Mortes greenstone belt, in the southern portion of the São Francisco Craton, State of Minas Gerais, Brazil. The Glória quartz-monzodiorite yields a SHRIMP U-Pb zircon age of 2188 ± 29 Ma, suggesting a tectonic relationship with the pre-collisional phase of the Mineiro belt. According to the Nd isotopic evidence (epsilonNd(T = -3.4; T DM = 2.68 Ga the original magmas was formed by a mixture among Archean crustal material and Paleoproterozoic juvenile magma. The Glória quartz-monzodiorite shows metaluminous and calc-alkaline tendency with intermediate K content, comparable to that of volcanic-arc rocks. The primary mineralogical assemblage was partly modified by metamorphism, dated between 2131-2121 Ma in nearby coeval plutons. Such metamorphism is significantly older than the reported metamorphic episodes of the Mineiro belt in the Quadrilátero Ferrífero region (2059-2041 Ma in the eastern portion of the study area. This evidence, together with chemical and isotopic data from other mafic and felsic plutons coeval with the Glória quartz-monzodiorite, indicate a tectonic and magmatic migration within the Mineiro belt from west to east.O Quartzo Monzodiorito Glória é um corpo plutônicomáfico associado à evolução Paleoproterozóica do Cinturão Mineiro. Este é intrusivo em gnaisses bandados, anfibolitos, xistos e filitos do Greenstone Belt Rio das Mortes, na porção sudeste do Cráton São Francisco, Estado de Minas Gerais, Brasil. Este corpo possui idade de cristalização SHRIMP (em zircão de 2188 ± 29 Ma, enquanto os isótopos de Nd (épsilonNd(T = -3,4; T DM = 2,68 Ga apontam que sua fonte magmática envolveumaterial juvenil paleoproterozóico contaminada por protólitos arqueanos. As rochas do Quartzo Monzodiorito Glória são metaluminosas, c

  16. A Comparative Study of the Electrical Structure of Circum Tibetan Plateau Orogenic Belts and its Tectonic Implications

    Science.gov (United States)

    Jin, Sheng; Zhang, Letian; Wei, Wenbo; Ye, Gaofeng; Jing, Jianen; Dong, Hao; Xie, Chengliang; Yin, Yaotian

    2017-04-01

    The Tibetan Plateau, as known as "roof of the world", was created through the on-going continent-continent collision between the Indian and Eurasian plates since 55 Ma. As the process continues, the plateau is growing both vertically and horizontally. The horizontal expansion of the plateau is blocked by the Yangtze block in the east, the Tarim block in the north, and the Ordos block in the northeast, and consequently lead to the formation of the circum Tibetan plateau orogenic belts. To better understand the mechanism behind this process, we conducted a comparative study by collecting 7 magnetotelluric (MT) profiles over the margins of the Tibetan plateau, namely, the INDEPTH 100, 700 and 800 lines in the southern Tibet, the INDEPTH 4000 and 5000 lines across the Altyn Tagh fault on the northern margin of the plateau, as well as other two profiles across the Haiyuan fault and the Longmenshan fault on the northeastern and eastern margins of the plateau deployed under the framework of project SinoProbe. The electrical features of the stable blocks surrounding the Tibetan plateau are generally resistive, while crustal conductive layers are found to be wide spread within the plateau. The southern margin of the Tibetan plateau is characterized by large scale underthrust of the Indian lithosphere beneath the plateau. This intense converging process created the thrust fault system distributed along the southern margin of the Tibetan plateau over 1000 km. Crustal conductive layers discovered in southern Tibet are generally associated with the southward crustal flow that originated from the lower crust within the plateau and exhumed along the thrust belts in the Himalayas. On the eastern margin of the Tibetan plateau, the electrical structures suggest that the Yangtze block wedged into the Tibetan lithosphere and caused decoupling between the crust and upper mantel. Large scale conductors discovered beneath the Songpan-Ganze block reflect that the eastward crustal flow was

  17. Petrogenesis and tectonic implications of Upper Triassic appinite dykes in the East Kunlun orogenic belt, northern Tibetan Plateau

    Science.gov (United States)

    Liu, Bin; Ma, Chang-Qian; Huang, Jian; Wang, Lian-Xun; Zhao, Shao-Qing; Yan, Rong; Sun, Yang; Xiong, Fu-Hao

    2017-07-01

    This paper presents geochronological, mineralogical, geochemical, and Sr-Nd isotopic data for recently identified Upper Triassic appinite dyke swarms in the East Kunlun orogenic belt (EKOB), northern Tibetan Plateau. Zircon U-Pb isotopic analyses using SHRIMP and LA-ICP-MS techniques yield 206Pb/238U ages of 226.1 ± 1.9 Ma and 226.4 ± 3.5 Ma, which can be interpreted as the crystallization ages of the appinite dykes. All the samples are characterized by high Al2O3 contents, enrichments in light rare earth elements (LREEs) and large ion lithophile elements (LILEs) and strong depletions in Nb, Ta, Ti and P. These characteristics are comparable to those of subduction-related calc-alkaline high-Al basalts. Delayed plagioclase nucleation caused by relatively high-pressure conditions and high H2O contents is the most likely interpretation of the high Al contents. The geochemical and isotopic variations suggest that the appinite dykes were derived from partial melting of a mixed mantle source consisting of enriched lithospheric mantle and MORB-type asthenospheric mantle and had experienced some degree of crustal contamination during migration through continental crust. The appinite dykes are associated with previously documented, contemporaneous high-Ba-Sr and/or high-Sr/Y granites (225-223 Ma) derived from thickened mafic lower crust. These rocks provide important constraints on the compositional variations in the orogenic lithospheric mantle during the Late Triassic and provide evidence of a post-collisional environment associated with lithospheric delamination or slab break-off.

  18. Occurrence of Tourmaline in Metasedimentary Rocks of the Isua Supracrustal Belt, Greenland: Implications for Ribose Stabilization in Hadean Marine Sediments

    Science.gov (United States)

    Mishima, Shinpei; Ohtomo, Yoko; Kakegawa, Takeshi

    2016-06-01

    Abiotic formation of RNA was important for the emergence of terrestrial life, but the acknowledged difficulties of generating and stabilizing ribose have often raised questions regarding how the first RNA might have formed. Previous researchers have proposed that borate could have stabilized ribose; however, the availability of borate on the early Earth has been the subject of intense debate. In order to examine whether borate was available on the early Earth, this study examined metasedimentary rocks from the Isua Supracrustal Belt. Garnet, biotite, and quartz comprise the major constituents of the examined rocks. Field relationships and the chemical compositions of the examined rocks suggest sedimentary origin. The present study found that garnet crystals contain a number of inclusions of tourmaline (a type of borosilicate mineral). All tourmaline crystals are Fe-rich and categorized as schorl. Both garnet and tourmaline often contain graphite inclusions and this close association of tourmaline with garnet and graphite has not been recognized previously. Garnet-biotite and graphite geothermometers suggest that the tourmaline in garnet experienced peak metamorphic conditions (~500 °C and 5 kbar). The mineralogical characteristics of the tourmaline and the whole rock composition indicate that the tourmaline formed authigenically in the sediment during diagenesis and/or early metamorphism. Clay minerals in modern sediments have the capability to adsorb and concentrate borate, which could lead to boron enrichment during diagenesis, followed by tourmaline formation under metamorphic conditions. Clay minerals, deposited on the early Archean seafloor, were the precursors of the garnet and biotite in the examined samples. The studied tourmaline crystals were most likely formed in the same way as modern tourmaline in marine sediments. Therefore, boron enrichment by clays must have been possible even during the early Archean. Thus, similar enrichment could have been

  19. Sandbox modeling of evolving thrust wedges with different preexisting topographic relief: Implications for the Longmen Shan thrust belt, eastern Tibet

    Science.gov (United States)

    Sun, Chuang; Jia, Dong; Yin, Hongwei; Chen, Zhuxin; Li, Zhigang; Shen, Li; Wei, Dongtao; Li, Yiquan; Yan, Bin; Wang, Maomao; Fang, Shaozhi; Cui, Jian

    2016-06-01

    To understand the effects of substantial topographic relief on deformation localization in the seismically active mountains, like the Longmen Shan thrust belt in the eastern Tibet, sandbox experiments were performed based on the framework of the critical taper theory. First, a reference experiment revealed that the critical taper angle was 12° for our experimental materials. Subsequently, different proto wedges (subcritical (6° in taper angle), critical (12°), and supercritical (20°)) were introduced to cover the range of natural topographic relief, and we used two setups: setup A considered only across-strike topographic relief, whereas setup B investigated along-strike segmentation of topography, consist of two adjacent proto wedges. In all experiments, thrust wedges grew by in-sequence accretion of thrust sheets. Setup A revealed an alternating mode of slip partitioning on the accreted thrusts, with large-displacement thrust and small-displacement thrust developing in turn. And contrasting wedge evolutions occurred according to whether the proto wedge was subcritical or critical-supercritical. In setup B, the differential deformation along the strike produced transverse structures such as tear fault and lateral ramp during frontal accretion. The observed tear fault and its associated thrust system resemble the seismogenic fault system of the 2008 Mw7.9 Wenchuan earthquake. Our experimental results could also explain first-order deformation features observed in the Longmen Shan. Consequently, we conclude that topographic features, including topographic relief across the range and along-strike segmentation of topography, contribute significantly to the kinematics and deformation localization in such active mountains.

  20. Petrogenesis of Triassic granitoids in the East Kunlun Orogenic Belt, northern Tibetan Plateau and their tectonic implications

    Science.gov (United States)

    Shao, Fengli; Niu, Yaoling; Liu, Yi; Chen, Shuo; Kong, Juanjuan; Duan, Meng

    2017-06-01

    The East Kunlun Orogenic Belt (EKOB), an important part of the Greater Tibetan Plateau, is an ideal region for understanding the tectonic evolution of the Anyemaqen Ocean. Here, we present zircon U-Pb ages, bulk-rock major and trace element analyses and Sr-Nd-Hf isotope compositions on representative samples of the syn-collisional Dulan batholith at the eastern end of the EKOB. The zircon U-Pb age data indicate that the bulk of the Dulan batholith was emplaced at 240-235 Ma. The granitoids have high- to medium-K and metaluminous characteristics. They are enriched in large ion lithophile elements (LILEs) and light rare earth elements (LREEs) and depleted in some high field strength elements (HFSEs, e.g., Nb and Ta), while having a flat heavy REE (HREEs) pattern. The mafic magmatic enclaves (MMEs) share the same age, mineralogy and indistinguishable Sr-Nd-Hf isotopes with their granitoid hosts except for the higher HREE abundances. We show that the MMEs represent cumulate formed at earlier stages of the same magmatic system. The trace element data (e.g., Nb/Th, Ta/U) and inherited mantle isotopic characteristics of the Dulan batholith are also consistent with an origin via partial melting of the last fragments of underthrusting ocean crust. Simple mass balance calculations using the Sr-Nd-Hf isotopic data show that 85% Paleo-Tethys MORB and 15% mature crustal material (the Proterozoic gneiss of the study area) contribute to the source of the granitoids. The Dulan batholith shows compositional similarities to the bulk continental curst with inherited mantle isotopic signatures. The syn-collisional felsic magmatism must have contributed to the net continental crust growth in the EKOB. We infer that the Kunlun and Qinling orogens may actually be one single orogen offset later by the Wenquan fault system.

  1. Occurrence of Tourmaline in Metasedimentary Rocks of the Isua Supracrustal Belt, Greenland: Implications for Ribose Stabilization in Hadean Marine Sediments.

    Science.gov (United States)

    Mishima, Shinpei; Ohtomo, Yoko; Kakegawa, Takeshi

    2016-06-01

    Abiotic formation of RNA was important for the emergence of terrestrial life, but the acknowledged difficulties of generating and stabilizing ribose have often raised questions regarding how the first RNA might have formed. Previous researchers have proposed that borate could have stabilized ribose; however, the availability of borate on the early Earth has been the subject of intense debate. In order to examine whether borate was available on the early Earth, this study examined metasedimentary rocks from the Isua Supracrustal Belt. Garnet, biotite, and quartz comprise the major constituents of the examined rocks. Field relationships and the chemical compositions of the examined rocks suggest sedimentary origin. The present study found that garnet crystals contain a number of inclusions of tourmaline (a type of borosilicate mineral). All tourmaline crystals are Fe-rich and categorized as schorl. Both garnet and tourmaline often contain graphite inclusions and this close association of tourmaline with garnet and graphite has not been recognized previously. Garnet-biotite and graphite geothermometers suggest that the tourmaline in garnet experienced peak metamorphic conditions (~500 °C and 5 kbar). The mineralogical characteristics of the tourmaline and the whole rock composition indicate that the tourmaline formed authigenically in the sediment during diagenesis and/or early metamorphism. Clay minerals in modern sediments have the capability to adsorb and concentrate borate, which could lead to boron enrichment during diagenesis, followed by tourmaline formation under metamorphic conditions. Clay minerals, deposited on the early Archean seafloor, were the precursors of the garnet and biotite in the examined samples. The studied tourmaline crystals were most likely formed in the same way as modern tourmaline in marine sediments. Therefore, boron enrichment by clays must have been possible even during the early Archean. Thus, similar enrichment could have been

  2. Post-collisional multistage magmatism in the Ribeira mobile belt: geochemical and isotopic study of the Varzea Alegre intrusive complex, Espirito Santo, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, Silvia Regina de; Mendes, Julio Cezar [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Geociencias. Dept. de Geologia]. E-mail: medeiros@igeo.ufrj.br; Wiedemann-Leonardos, Cristina Maria [Brasilia Univ., DF (Brazil). Inst. de Geociencias]. E-mail: wiedeman@unb.br

    2000-03-01

    The Varzea Alegre Intrusive Complex (VAIC) corresponds to a post-collisional (late orogenic) pluton, related to the Brasiliano cycle, situated in the central part of the Espirito Santo State. It intrudes amphibolite to granulite facies metamorphic rocks of the Ribeira Belt. Two distinct domains were recognised in this zoned pluton: an inner domain with opx-gabbro, monzogabbro, diorite, quartz-diorite and megaporphyritic granite, and an outer one comprising an irregular and large ring of charnockitic rocks. Geochemical data from the former reveal medium to high-K calc-alkalic rocks, enriched in incompatible elements, mainly Ba, Sr, La, Ce and Pb and partially depleted in HFS elements. The charnockitic rocks show a high-K alkali-calcic signature; they are rich in Ba, K and some HFS elements, such a Zr, P and Nb. The incompatible element enrichment detected in the rocks of the VAIC has been reported for several intrusions from this part of the Ribeira Belt. A Rb-Sr isochronic age of 508{+-} 12 Ma was determined for the megaporphyritic granite. The T{sub DM} model age varies from 1.3 Ga (opx-gabbro) to ca. 1.67 Ga (charnockitic rocks), which can be related to an important Mesoproterozoic crustal event. The calculated T{sub CHUR} model ages of the cogenetic opx-gabbros and intermediary rocks is ca. 1.0 Ga, interpreted as the time when the basic magma was extracted from the source. (author)

  3. New geological framework for Western Amazonia (Brazil) and implications for biogeography and evolution

    Science.gov (United States)

    de Fátima Rossetti, Dilce; Mann de Toledo, Peter; Góes, Ana Maria

    2005-01-01

    Although many of the current hypotheses to explain the origin and distribution of the Amazon biodiversity has been based directly or indirectly on geological data, the reconstruction of the geological history of the Amazon region is still inadequate to analyze its relationship with the biodiversity. This work has the main goal to characterize the sedimentary successions formed in the Brazilian Amazon in the Neogene-Quaternary discussing the evolution of the depositional systems through time and analyzing their main controlling mechanisms in order to fill up this gap. Radar image interpretation, sedimentological studies, and radiocarbon dating allowed the mapping of Plio-Pleistocene to Holocene units along the Solimões-Amazonas River, Brazil. This integrated work led to the characterization of five sedimentary successions overlying Miocene deposits of the Solimões/Pebas Formation, which include the following: Içá Formation (Plio-Pleistocene), deposits Q1 (37,400-43,700 14C yr B.P.), deposits Q2 (27,200 14C yr B.P.), deposits Q3 (6730-2480 14C yr B.P.), and deposits Q4 (280-130 14C yr B.P.). These deposits occur mostly to the west of Manaus, forming NW-SE elongated belts that are progressively younger from SW to NE, indicating a subsiding basin with a depocenter that migrated to the NE. The reconstruction of the depositional history is consistent with significant changes in the landscapes. Hence, the closure of a large lake system at the end of the Miocene gave rise to the development of a Plio-Pleistocene fluvial system. This was yet very distinct from the modern drainage, with shallow, energetic, highly migrating, braided to anastomosed channels having an overall northeast outlet. This fluvial system formed probably under climatic conditions relatively drier than today's. During the early Pleistocene, there was pronounced erosion, followed by a renewed depositional phase ca. 40,000 14C yr B.P., with the development of prograding lobes and/or crevasse splays

  4. Debris avalanches and debris flows transformed from collapses in the Trans-Mexican Volcanic Belt, Mexico - behavior, and implications for hazard assessment

    Science.gov (United States)

    Capra, L.; Macías, J. L.; Scott, K. M.; Abrams, M.; Garduño-Monroy, V. H.

    2002-03-01

    Volcanoes of the Trans-Mexican Volcanic Belt (TMVB) have yielded numerous sector and flank collapses during Pleistocene and Holocene times. Sector collapses associated with magmatic activity have yielded debris avalanches with generally limited runout extent (e.g. Popocatépetl, Jocotitlán, and Colima volcanoes). In contrast, flank collapses (smaller failures not involving the volcano summit), both associated and unassociated with magmatic activity and correlating with intense hydrothermal alteration in ice-capped volcanoes, commonly have yielded highly mobile cohesive debris flows (e.g. Pico de Orizaba and Nevado de Toluca volcanoes). Collapse orientation in the TMVB is preferentially to the south and northeast, probably reflecting the tectonic regime of active E-W and NNW faults. The differing mobilities of the flows transformed from collapses have important implications for hazard assessment. Both sector and flank collapse can yield highly mobile debris flows, but this transformation is more common in the cases of the smaller failures. High mobility is related to factors such as water content and clay content of the failed material, the paleotopography, and the extent of entrainment of sediment during flow (bulking). The ratio of fall height to runout distance commonly used for hazard zonation of debris avalanches is not valid for debris flows, which are more effectively modeled with the relation inundated area to failure or flow volume coupled with the topography of the inundated area.

  5. The Dynamics Of Inner Solar System Bodies With 2.8 < Tj < 3.2 And The Implications For The Origin Of Main-Belt Comets

    Science.gov (United States)

    Haghighipour, Nader; Hsieh, Henry H.

    2014-05-01

    Main-belt comets (MBCs) have attracted a great deal of interest since their identification as a new class of bodies by Hsieh and Jewitt in 2006. Much of this interest is due to the implication that MBC activity is driven by the sublimation of volatile material (presumed to be water ice) presenting these bodies as probable candidates for the delivery of a significant fraction of the Earth’s water. An interesting characteristic of these objects is that while similar to comets, they have comae and dusty tails, they resemble asteroids, dynamically (i.e., their Tisserand numbers with respect to Jupiter, Tj, are larger than 3). The Tisserand parameter is a conserved quantity in the restricted three-body problem, and the Tisserand parameter with respect to Jupiter is frequently used to distinguish between asteroids (Tj>3), which are thought to be stable on Gyr timescales, and comets (Tjfact not as distinct as the common use of the Tisserand parameter would suggest. We studied the dynamical evolution of test particles with Tisserand numbers ranging from 2.8 to 3.2 to explore the behavior of solar system objects (such as MBCs) with Tj values close to the canonical asteroid-comet boundary of 3. We find, as expected, that Tj is not a hard boundary between asteroids and comets, and that we can expect to find objects that are dynamically stable (over the time period of integrations) with Tj3. Dynamical stability can be seen to be a function of not just Tj, but also other orbital elements such as the eccentricity and aphelion distance. We will report on the detailed findings of our analysis and discuss their implications for the origin of MBCs.

  6. Qualitative and semiquantitative interpretation of aeromagnetic data over the Lancinha Shear Zone, Southern Ribeira Belt, in Paraná State, Southern Brazil

    Directory of Open Access Journals (Sweden)

    Luís Gustavo de Castro

    2014-12-01

    Full Text Available The characterization of shear zones at the southern portion of the Ribeira Belt, PR, BR, as well as its recognition in depth is a major challenge. Despite the lack of subsurface information, the influence of such structures on the installation and evolution of the Paraná Basin during the Phanerozoic is widely accepted. Therefore, in this paper, are applied methods of anomaly enhancement (qualitative analysis and estimative of the sources depth (semiquantitative analysis, on the aeromagnetic coverage of the Lancinha Shear Zone area (LSZ in the Paraná state, in order to verify its spatial arrangement in subsurface. The processing resulted in the interpretation of magnetic-structural framework of the study area, which was validated by the depth estimative of the magnetic sources (Euler solutions. The results indicated the extension of the Lancinha, Morro Agudo and Itapirapuã shear zones under the Paraná Basin coverage.

  7. Structural evolution and U-Pb SHRIMP zircon ages of the Neoproterozoic Maria da Fé shear zone, central Ribeira Belt - SE Brazil

    Science.gov (United States)

    Zuquim, M. P. S.; Trouw, R. A. J.; Trouw, C. C.; Tohver, E.

    2011-03-01

    The Maria da Fé Shear Zone (MFSZ) is a sinistral strike-slip kilometric-scale structure developed in the late Neoproterozoic during the assembly of Gondwana. The MFSZ development is related to the NW-SE collision between the São Francisco Paleocontinent and the Rio Negro Magmatic Arc, which formed the Ribeira Belt. This paper describes the shear zone in detail, concluding that the orientation and age are consistent with NW-SE shortening during the afore mentioned collision. A U-Pb SHRIMP Concordia age of 586.9 ± 8.7 Ma is reported from zircon grains of a granitic dyke that crystallised synkinematically to the main tectonic activity of the shear zone. Another group of zircon grains from the same sample generated an upper intercept age of 2083 ± 43 Ma anchored in the younger Concordia age. These zircon grains are interpreted as relict grains of the basement from which the granite dyke was generated by partial melting. The temperature during mylonitization in the MFSZ was estimated in the range from 450 to 600 °C, based on microstructures in quartz and feldspar. An earlier collision in the same region, between 640 and 610 Ma, led to an extensive nappe-stack with tectonic transport to ENE, integrating the southern Brasilia Belt. One of the thrust zones between these nappes in the studied area is the Cristina Shear Zone with mylonites that were generated under upper amphibolite to granulite facies conditions. Brittle-ductile E-W metric-scale shear zones are superimposed on the MFSZ, which were active in similar, but probably slightly cooler, metamorphic conditions (≈500 °C).

  8. Gammaspectrometry identification covering Neoproterozoic supracrustal sequences in the Serido Belt , northeastern Brazil; Identificacao gamaespectrometrica de placeres rutilo-monaziticos neoproterozoicos no sul da Faixa Serido, nordeste do Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Sebastiao Milton P. da, E-mail: smpsilva@cchla.ufrn.br, E-mail: sebastiaomilton@gmail.com [Laboratorio de Geoprocessamento, Departamento de Geografia, Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil); Crosta, Alvaro P., E-mail: alvaro@ige.unicamp.br [Instituto de Geociencias, Universidade Estadual de Campinas (Unicamp), SP (Brazil); Ferreira, Francisco J.F., E-mail: francisco.ferreira@ufpr.br [Laboratorio de Pesquisas em Geofisica Aplicada- LPGA, Departamento de Geologia, Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil); Beurlen, Hartmut, E-mail: beurlen@terra.com.br [Programa de Pos-Graduacao em Geociencias, Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil); Silva, Adalene M., E-mail: adalene@unb.br [Laboratorio de Geofisica Aplicada, Instituto de Geociencias da Universidade de Brasilia (UnB), DF (Brazil); Silva, Marcelo R.R. da, E-mail: marcelor@ufpe.br [Departamento de Geologia, Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil)

    2010-01-15

    Aerial gamma-ray survey data covering Neoproterozoic supracrustal sequences in the Serido Belt were processed and analyzed together with ground gamma-ray data, air photos and geological data for lithogeophysical characterization and mapping of granitic rocks, related pegmatites fields and lithological units of Serido Group. Interpretation was based on individual and ternary images of the three radio-elements and the eU/eTh and eTh/K ratios, and allowed the discovery of thorium anomalies associated with coarse-grained metarenites and metaconglomerates facies intercalated with quartzites of the Equador Formation. High contents of iron oxides, ilmenite, monazite, rutile, titanite and zircon were identified by ore microscopy of polished sections in the metaconglomerate's matrix. Semiquantitative scanning electron microscopy (SEM) analyses in minerals of two samples revealed up to 79.4% of Th0{sub 2} and 87.7% of REE in monazites; up to 99.2% of Ti0{sub 2} in ilmenite and rutile and up to 1.81 % of HfO{sub 2} in zircon. Gamma-ray anomalies due to thorium were also identified in association with sediments of Cenozoic age in the region. (author)

  9. Seat belt reminders.

    NARCIS (Netherlands)

    2008-01-01

    Seat belts are an effective way of reducing the number or road deaths and severe road injuries in crashes. Seat belt reminders warn car drivers and passengers if the seat belt is not fastened. This can be done by a visual signal or an acoustic signal or by a combination of the two. Seat belt reminde

  10. Geochemical and isotopic evidence for the petrogenesis and emplacement tectonics of the Serra dos Órgãos batholith in the Ribeira belt, Rio de Janeiro, Brazil

    Science.gov (United States)

    Machado, Rômulo; Philipp, Ruy Paulo; McReath, Ian; Peucat, Jean Jacques

    2016-07-01

    The Serra dos Órgãos batholith in the State of Rio de Janeiro (Brazil) is a NE-SW-trending elongated body that occupies ca. 5000 km2 in plan view. It is a foliated intrusion, especially at its borders and is crosscut by syn-magmatic shear zones, with foliations that are moderately-to steeply-dipping to the northwest and moderately-to shallow-dipping in the center and to the southeast, in a configuration of a large laccolith. It was emplaced between 560 and 570 Ma, during an extensional episode that was part of a series of events that comprise the Brasiliano Orogeny in SE Brazil, and which includes deformation, metamorphism and granite intrusion during the interval between 630 and 480 Ma. The two main rock types in the batholith are biotite-hornblende monzogranite, and biotite leucogranite, with subordinate tonalite, granodiorite, diorite, quartz diorite (enclaves), aplite and pegmatite. Harker-type diagrams help show two rock groups with similar trends of evolution: a dioritic and a granitic. The first one is tholeiitic, whereas the second is calc-alkaline, with medium-to high-K calc-alkaline affinity and metaluminous to slightly peraluminous character. In both groups strong decrease in Al2O3, MgO, FeOT and CaO relative to silica contents are observed, which is compatible with trends of fractional crystallization involving clinopyroxene and/or hornblende, plagioclase, opaque minerals, apatite, microcline and biotite. The Sr and Nd isotopic data suggest recycling of a Paleoproterozoic crust as an important petrological process to generate the batholith rocks. Geothermometry (amphibole composition) and geobarometry (saturation in zircon and apatite) indicate that most of the batholith solidified at mid to lower crustal levels at about 750 °C and between 5 and 5.5 kbar. We consider that Serra dos Órgãos crustal protoliths underwent melting caused by the interaction with hotter mafic magma at the base of the crust. These two magmas, with distinct initial

  11. Belt attachment and system

    Science.gov (United States)

    Schneider, Abraham D.; Davidson, Erick M.

    2016-02-02

    Disclosed herein is a belt assembly including a flexible belt with an improved belt attachment. The belt attachment includes two crossbars spaced along the length of the belt. The crossbars retain bearings that allow predetermined movement in six degrees of freedom. The crossbars are connected by a rigid body that attaches to the bearings. Implements that are attached to the rigid body are simply supported but restrained in pitching rotation.

  12. Origin and evolution of the granitic intrusions in the Brusque Group of the Dom Feliciano Belt, south Brazil: Petrostructural analysis and whole-rock/isotope geochemistry

    Science.gov (United States)

    Hueck, Mathias; Basei, Miguel Angelo Stipp; Castro, Neivaldo Araújo de

    2016-08-01

    In the southern Brazilian state of Santa Catarina the Dom Feliciano Belt, formed by the tectonic juxtaposition of different crustal blocks during the Brasiliano-Pan African Orogenic cycle, can be divided into three domains. In the central domain, three granitic suites intrude the metavolcanosedimentary sequence of the Brusque Group: São João Batista (SJBS), Valsungana (VS) and Nova Trento (NTS), from the oldest to the youngest. This extensive magmatism, here referred to as granitic intrusions in the Brusqe Group (GIBG), is coeval with the thermal peak in the host metamorphic successions, but postdates its main foliation. A progressive deformation starting from the magmatic stage throughout the cooling history points to the influence of the late stages of deformation recorded in the Brusque Group. The SJBS consists of gray to white leucocratic, equigranular granites, with aluminous minerals such as muscovite, garnet and tourmaline. The porphyritic VS is the largest of the suites and is characterized by its cm-sized K-feldspar megacrysts in a coarse-grained biotite-rich matrix. The granites from the NTS are equigranular, light gray to pink in color and have biotite as the main mafic mineral, but magmatic muscovite, tourmaline and hornblende can occur as well. Geochemically, the GIBG are mildly peraluminous and show a calc-alkaline affinity. Most intrusions have a high REE fractionation, but some SJBS granites show a characteristic pattern with no fractionation and strong negative Eu anomalies ("seagull pattern"). Elevated Sr(i) values, between 0.707 and 0.735, and negative εNd values as low as -24 points to the melting of old evolved crust. The Nd (TDM) ages are scattered between 1.54 and 2.76 Ga, with a predominance of values around 2.0 Ga. The GIBG have a strong crustal signature that most closely connects, within the regional units, to that of the metasedimentary rocks of the Brusque Group and its crystalline basement, the Camboriú Complex. All three suites

  13. Decentralization, participation and deliberation in water governance: a case study of the implications for Guarulhos, Brazil

    NARCIS (Netherlands)

    F. van den Brandeler; M. Hordijk; K. von Schönfeld; J. Sydenstricker-Neto

    2014-01-01

    After the return to democracy in the late 1980s, Brazil developed a new system of water governance with a decentralization of responsibilities and the formation of participatory, deliberative institutions that characterized the governance reforms in general. Tripartite "water basin committees", with

  14. Detrital zircon analysis of Mesoproterozoic and neoproterozoic metasedimentary rocks of northcentral idaho: Implications for development of the Belt-Purcell basin

    Science.gov (United States)

    Lewis, R.S.; Vervoort, J.D.; Burmester, R.F.; Oswald, P.J.

    2010-01-01

    The authors analyzed detrital zircon grains from 10 metasedimentary rock samples of the Priest River complex and three other amphibolite-facies metamorphic sequences in north-central Idaho to test the previous assignment of these rocks to the Mesoproterozoic Belt-Purcell Supergroup. Zircon grains from two samples of the Prichard Formation (lower Belt) and one sample of Cambrian quartzite were also analyzed as controls with known depositional ages. U-Pb zircon analysis by laser ablation - inductively coupled plasma - mass spectrometry reveals that 6 of the 10 samples contain multiple age populations between 1900 and 1400 Ma and a scatter of older ages, similar to results reported from the Belt- Purcell Supergroup to the north and east. Results from the Priest River metamorphic complex confirm previous correlations with the Prichard Formation. Samples from the Golden and Elk City sequences have significant numbers of 1500-1380 Ma grains, which indicates that they do not predate the Belt. Rather, they are probably from a relatively young, southwestern part of the Belt Supergroup (Lemhi subbasin). Non-North American (1610-1490 Ma) grains are rare in these rocks. Three samples of quartzite from the Syringa metamorphic sequence northwest of the Idaho batholith contain zircon grains younger than the Belt Supergroup and support a Neoproterozoic age. A single Cambrian sample has abundant 1780 Ma grains and none younger than ~1750 Ma. These results indicate that the likely protoliths of many high-grade metamorphic rocks in northern Idaho were strata of the Belt-Purcell Supergroup or overlying rocks of the Neoproterozoic Windermere Supergroup and not basement rocks.

  15. Evidence for spreading in the lower Kam Group of the Yellowknife greenstone belt: Implications for Archaean basin evolution in the Slave Province

    Science.gov (United States)

    Helmstaedt, H.; Padgham, W. A.

    The Yellowknife greenstone belt is the western margin of an Archean turbidite-filled basin bordered on the east by the Cameron River and Beaulieu River volcanic belts (Henderson, 1981; Lambert, 1982). This model implies that rifting was entirely ensialic and did not proceed beyond the graben stage. Volcanism is assumed to have been restricted to the boundary faults, and the basin was floored by a downfaulted granitic basement. On the other hand, the enormous thickness of submarine volcanic rocks and the presence of a spreading complex at the base of the Kam Group suggest that volcanic rocks were much more widespread than indicated by their present distribution. Rather than resembling volcanic sequences in intracratonic graben structures, the Kam Group and its tectonic setting within the Yellowknife greenstone belt have greater affinities to the Rocas Verdes of southern Chile, Mesozoic ophiolites, that were formed in an arc-related marginal basin setting. The similarities of these ophiolites with some Archean volcanic sequences was previously recognized, and served as basis for their marginal-basin model of greenstone belts. The discovery of a multiple and sheeted dike complex in the Kam Group confirms that features typical of Phanerozoic ophiolites are indeed preserved in some greenstone belts and provides further field evidence in support of such a model.

  16. Magmatic garnet in the Cordilleran-type Galiléia granitoids of the Araçuaí belt (Brazil): Evidence for crystallization in the lower crust

    Science.gov (United States)

    Narduzzi, F.; Farina, F.; Stevens, G.; Lana, C.; Nalini, H. A.

    2017-06-01

    Magmatic garnet, together with epidote, is a rare mineral association in cordilleran-I-type granitoids and of special petrogenetic significance. The metaluminous to slightly peraluminous (ASI = 0.97-1.07) Galiléia batholith (Brazil) is a large (ca. 30,000 km2), Neoproterozoic (ca. 632-570 Ma) weakly foliated calc-alkaline granitoid body, characterized by the widespread occurrence of garnet (grossular 25-43 mol%) and epidote (pistacite 9.3-22.7 mol%). Field, petrographic and mineral chemical evidence indicates that garnet, epidote, biotite as well as white mica crystals (low-Si phengite), are magmatic. There is no difference in bulk rock major and trace element composition between the Galiléia granitoids and other garnet-free cordilleran-type granitoids worldwide. This evidence strongly suggests that the origin of the uncommon garnet + epidote parageneses is related to the conditions of magma crystallization, such as pressure, temperature and water content. Comparison between the mineral assemblages and mineral compositions from this study and those recorded in crystallization experiments on metaluminous calc-alkaline magmas, as well as within garnet-bearing metaluminous volcanic rocks and granitoids, indicates that the supersolidus coexistence of grossular-rich garnet, epidote and white mica is consistent with magma crystallization at pressures greater than 0.8 GPa (above 25 km depth) and at temperatures below 700 °C, i.e. near the water saturated solidus. Furthermore, resorption textures around garnet (plagioclase ± quartz coronas) and epidote suggest that these minerals have been partially consumed prior to complete crystallization. These findings demonstrate that at 630 Ma the crust underneath the Araçuaí Orogen was already at least 25-30 km thick and relatively cool. However, this contrasts with the marked high heat flow registered from the neighbour Carlos Chagas Batholith located 50 km to the east. In fact such granitoids record granulite

  17. Whistlers Observed Outside the Plasmasphere: Correlation to Plasmaspheric/Plasmapause Features and Implications for the Scattering of Radiation-Belt Electrons

    Science.gov (United States)

    Adrian, Mark L.; Gallagher, D. L.

    2007-01-01

    Magnetospherically reflected, lightning-generated whistler waves are an important potential contributor to pitch-angle scattering loss processes of the electron radiation belts. While lightning-generated whistlers are a common feature at, and just inside, the plasmapause, they are infrequently observed outside the plasmasphere. As such, their potential contribution to outer radiation belt loss processes is more tenuous. Recently, Platino et al. [2005] has reported on whistlers observed outside the plasmasphere by Cluster. Here, we present correlative global observations of the plasmasphere, for the reported periods of Cluster-observed whistlers outside the plasmasphere, using IMAGE-EUV data. The intent of this study is to seek the underlying mechanisms that result in whistlers outside the plasmasphere and consequently the anticipated morphology and significance these waves may have on radiation belt dynamics.

  18. Footprints of large theropod dinosaurs and implications on the age of Triassic biotas from Southern Brazil

    Science.gov (United States)

    da Silva, Rafael Costa; Barboni, Ronaldo; Dutra, Tânia; Godoy, Michel Marques; Binotto, Raquel Barros

    2012-11-01

    Dinosaur footprints found in an outcrop of the Caturrita Formation (Rio Grande do Sul State, Southern Brazil), associated with a diverse and well preserved record of fauna and flora, reopen the debate about its exclusive Triassic age. The studied footprints were identified as Eubrontes isp. and are interpreted as having been produced by large theropod dinosaurs. The morphological characteristics and dimensions of the footprints are more derived than those commonly found in the Carnian-Norian, and are more consistent with those found during the Rhaetian-Jurassic. The trackmaker does not correspond to any type of dinosaur yet known from Triassic rocks of Brazil. Recent studies with the paleofloristic content of this unit also support a more advanced Rhaetian or even Jurassic age for this unit.

  19. Phylogeographic implications for release of critically endangered manatee calves rescued in Northeast Brazil

    Science.gov (United States)

    Luna, Fábia O.; Bonde, Robert K.; Attademo, Fernanda L.N.; Saunders, Jonathan W.; Meigs-Friend, Gaia; Passavante, José Zanon O.; Hunter, Margaret E.

    2012-01-01

    1. The Antillean manatee (Trichechus manatus manatus), a subspecies of the West Indian manatee, is a large-bodied marine mammal found in fresh, brackish, and marine habitats throughout the Caribbean Islands and Central and South America. Antillean manatees in Brazil are classified as critically endangered, with a census size of approximately 500 individuals. The population in the Northeast region of Brazil is suspected to have approximately 300 manatees and is threatened by habitat alteration and incidental entanglement in fishing gear. 2. A high incidence of dependent calf strandings have been identified near areas of altered critical manatee habitat. The majority of the calves are neonates, discovered alive, with no potential mothers nearby. These calves typically require human intervention to survive.

  20. The role of pleistocene strike-slip tectonics in the neogene-quaternary evolution of the southern Apennine orogenic belt: implications for oil trap development

    Energy Technology Data Exchange (ETDEWEB)

    Monaco, C.; Tortorici, L.; Catalano, S. [Universita degli Studi di Catania (Italy). Dipt. di Scienze Geologiche; Paltrinieri, W.; Steel, N. [British Gas Rimi, Milan (Italy)

    2001-07-01

    The Southern Apennine orogenic belt is composed of allochthonous continental units derived from the African and European palaeo-margins of NeoTethys (the Adria and Corsica-Sardinia Blocks, respectively), together with oceanic units derived from the intervening NeoTethyan domain. The frontal part of the belt has been thrust over a foredeep-foreland system consisting of the Bradano Trough and Apulian Platform. The belt can be divided into two structural levels which are separated by a major detachment surface. The upper level consists of a multilayer complex made up of allochthonous NeoTethyan nappes; these were deformed during oceanic subduction, and are now emplaced on the Adria Block as a consequence of continent-continent collision. The lower structural level is characterised by large-scale duplexes involving the Mesozoic-Cenozoic sedimentary cover of the Adria Block which in recent years has formed an important target for oil exploration. On top of these allochthonous terranes, a series of small Plio-Pleistocene basins developed during the final phases of the thrust belt's migration into the foreland. During the last stages of orogenesis, thrust migration became locked as a result of collisional thickening of the continental crust, and deformation in the southern Apennines was taken up by strike-slip faults which now cut across the fold and thrust belt. In this paper, we describe the major Pleistocene strike-slip structures in the southern Apennines between the Pollino Mountains in the south and the Potenza region in the north, and investigate the role of wrench tectonics in the belt's Neogene-Quaternary evolution. The study combines field mapping with analyses of satellite images and aerial photographs. Sinistral WNW-ESE trending strike-slip faults are accommodated by thrusts and folds which cross-cut the preexisting tectonic layering, giving rise to an interference pattern in which culminations may act as structural traps suitable for oil and gas

  1. Reconstruction of P-T-t metamorphic conditions from symplectites: insights from Pouso Alegre mafic rocks (Brasília Belt, Brazil)

    Science.gov (United States)

    Tedeschi, Mahyra; Lanari, Pierre; Rubatto, Daniela; Hermann, Jörg; Pedrosa-Soares, Antônio Carlos; Dussin, Ivo; Aurélio Pinheiro, Marco; Bouvier, Anne-Sophie; Baumgartner, Lukas

    2017-04-01

    Reconstructing the metamorphic history of polycyclic tectono-metamorphic mafic rocks that preserve potential relicts of high-pressure metamorphism is challenging because such rocks are commonly retrogressed and rare in supercrustal sequences. However, pressure-temperature-time (P-T-t) information is required to obtain the paleo-geothermal gradients and thus to define those units as markers for suture zones. The mafic rocks from Pouso Alegre in the Meridional Brasília Orogen (SW-Brazil) outcrop as rare lenses within Sil-Grt gneisses, Amp-Grt orthogneisses and Bt granites. They are heavily weathered. They have previously been defined as "retro-eclogites", based on the characteristic symplectite texture and some mineralogical observations. They have been intepreted to mark the suture zone between the Paranapanema and São Francisco cratons, although no quantitative estimates of the pressure is available to support this conclusion. In this study we investigated in detail these samples to refine their P-T-t history. As commonly observed in retrogressed eclogites, the studied mafic rock shows symplectite and corona textures overprinting the former paragenesis of Garnet (Grt) - Clinopyroxene (Cpx) 1 - Amphibole (Amp) 1 - Rutile (Rt). Phase equilibrium modelling shows that this assemblage is stable at 690°C and 13.5 kbar, in line with Zr-in-rutile thermometry (720 ±30° C). Local compositions of the symplectite domains were used to retrieve the jadeite content of Cpx1. This low-Jd cpx is in line with the predictions of the model and confirms a maximum pressure of 14 kbar. The symplectite formed from the reaction Cpx1+Qz+H2O→Cpx2+Amp+Pl+Qz taking place at conditions of 600-750°C and <7 kbar. Zircon and monazite U-Th-Pb geochronology was performed for the mafic and surrounding rocks. Zircon core dates from the mafic rock spread along concordia from ca. 1.7 to 1.0 Ga with a cluster at 1520±17 Ma, which is interpreted as the protolith crystallization age. Zircon rim

  2. Lap belts and three-point belts.

    NARCIS (Netherlands)

    Kampen, L.T.B. van & Edelman, A.

    1975-01-01

    Results of the swov-accident investigation prove that if there are any differences in the effectiveness of lap belts and three-point belts, these are so small that they cannot form a basis for giving preference to one type over the other. Furthermore, in spite of the results of this investigation wh

  3. CURRICULUM MODEL LAW 5.692/1971 DURING MILITARY DICTATORSHIP FOR TRAVEL OF TEACHING AND ITS IMPLICATIONS IN TEACHER TRAINING IN BRAZIL AND SANTA CATARINA

    Directory of Open Access Journals (Sweden)

    Jéferson Silveira Dantas

    2015-10-01

    Full Text Available This paper discusses the pedagogical implications brought about by the implementation of the Law 5.692/1971 in the context of the military dictatorship in Brazil (1964-1985 and their effects on teacher training in Brazil and Santa Catarina, especially in the early grades of school fundamental, formerly of primary education. Furthermore, this study seeks to under-take an analysis of curricular reorganization in teaching 1st and 2nd grades in accordance with the restructuring of productive capital, counting on the support of certain organic intellectuals who supported the military regime.

  4. Petrology and provenance of the Neogene fluvial succession in Pishin Belt (Katawaz Basin) western Pakistan: Implications for sedimentation in peripheral forelands basins

    DEFF Research Database (Denmark)

    Kasi, Aimal Khan; Kassi, Aktar Muhammad; Friis, Henrik;

    2017-01-01

    FL and QmFLt diagrams show recycled and transitional recycled orogenic source for both the successions. The Dasht Murgha Group is rich in sedimentary and metamorphic lithics and poor in volcanic fragments (Lm35Lv18Ls47). The LmLvLs plot indicate that most of the samples lie in the fields of suture belts...

  5. Timing and sources of granite magmatism in the Ribeira Belt, SE Brazil: Insights from zircon in situ U-Pb dating and Hf isotope geochemistry in granites from the São Roque Domain

    Science.gov (United States)

    Janasi, Valdecir de Assis; Andrade, Sandra; Vasconcellos, Antonio Carlos B. C.; Henrique-Pinto, Renato; Ulbrich, Horstpeter H. G. J.

    2016-07-01

    Eight new in situ U-Pb zircon age determinations by SHRIMP and LA-MC-ICPMS reveal that the main granitic magmatism in the São Roque Domain, which is largely dominated by metaluminous high-K calc-alkaline monzogranites with subordinate peraluminous leucogranites, occurred between 604 ± 3 and 590 ± 4 Ma. This small temporal range is ca. 20-30 Ma younger than previously admitted based on U-Pb TIMS dates from literature, some of which obtained in the same occurrences now dated. The observed discrepancy seems related to the presence of small Paleoproterozoic inherited cores in part of the zircon populations used for TIMS multigrain dating, which could also respond for the unusually high (up to 10 Ma) uncertainty associated with most of these dates. The younger age range now identified for the São Roque granite magmatism has important implications for the evolution of the Ribeira Fold Belt. Whilst previously admitted ages ca. 620-630 Ma substantiated correlations with the widespread and intensely foliated high-K calc-alkaline granitoid rocks of the neighbor Socorro-Guaxupé Nappe (potentially associated with an accretionary continental margin), the ˜600-590 Ma interval seems more consistent with a late deformation tectonic setting. Strongly negative ɛHf(t) characterize the magmatic zircons from the São Roque Domain granites. An eastward increase from -22 in the São Roque Granite to -11 in the Cantareira Granite and neighboring stocks suggests an across-domain shift in granite sources. Such eastward younging of sources, also indicated by Sm-Nd isotope data from granites and supracrustal sequences in neighboring domains, is suggestive that some of the first-order limits and discontinuities in this belt are not defined by the strike-slip fault systems traditionally taken to separate distinct domains. Although the negative ɛHf(t) and ɛNd(t) indicate sources with long crustal residence for all studied granite plutons, the observed range is more radiogenic than the

  6. Ayahuasca and the process of regulation in Brazil and internationally: implications and challenges.

    Science.gov (United States)

    Labate, Beatriz Caiuby; Feeney, Kevin

    2012-03-01

    This paper provides a summary and analysis of the regulation of ayahuasca in Brazil, from its prohibition in the mid-eighties to the recent adoption of CONAD's (Conselho Nacional de Políticas sobre Drogas) 2010 Resolution, which established a set of rules, norms and ethical principles to be applied to religious and ritual uses of ayahuasca. Brazil's regulatory process is used as a starting point to explore emerging international regulatory themes as various nations respond to the global expansion of the Santo Daime and UDV (União do Vegetal) ayahuasca religions. The text reviews the primary legislative and court documents, academic literature, as well as solicited expert opinions. Three prominent themes have emerged internationally. The first concerns the scope of international treaties regarding plant-based psychoactive substances, as well as the responsibilities of individual nations to adhere to said treaties. The second concerns the scope of religious liberty and how to determine religious legitimacy. The final theme addresses the potential dangers of ayahuasca to health and public safety. Over the past 20 years the Brazilian ayahuasca religions have established a global presence, with congregations in the USA, Canada, Japan, South Africa, Australia, and throughout Europe and Latin America. As a result, many nations are faced with the predicament of balancing the interests of these religious minorities with the international "war on drugs." The regulatory process applied in Brazil exemplifies a progressive approach, one which considered issues of anthropology and involved representatives of ayahuasca religions, and which provided a degree of deference to the principle of religious liberty. The Brazilian process has influenced judicial and administrative decisions internationally, and stands as a model worthy of further consideration. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Detrital zircon U-Pb and Hf isotopic data from the Liuling Group in the South Qinling belt: Provenance and tectonic implications

    Science.gov (United States)

    Liao, Xiao-ying; Wang, Ya-wei; Liu, Liang; Wang, Chao; Santosh, M.

    2017-02-01

    The Liuling Group is exposed in the Northern part of the South Qinling orogenic belt. LA-ICP-MS U-Pb analysis of detrital zircons from the meta-sandstones in this Group yields ages ranging between 400 Ma and 3200 Ma, with three prominent age clusters at 500-400 Ma, 850-700 Ma and 1000-900 Ma. A few older zircon populations with U-Pb ages of 1750-1450 Ma, 2000 Ma and 2600-2400 Ma are also present. Age data integrated with cathodoluminescence, trace element data and εHf(t) values of zircon grains show that the Liuling sediments have a complex source. Source rocks mainly include Early Neoproterozoic and Early Paleozoic granitoids, together with minor ultra-high pressure/high pressure (HP-UHP) metamorphic rocks, and paragneiss in the North Qinling belt, and Middle-Late Neoproterozoic magmatic rocks in the South Qinling belt. The dominant population of detrital zircon grains with ages between 500 Ma and 400 Ma show the characteristics of both magmatic and metamorphic zircons. They show three age clusters at 497 Ma, 451 Ma, and ca. 420 Ma and show marked correlation with the three stages of Palaeozoic magmatism, as well as with the peak and retrograde HP-UHP metamorphic stages in the North Qinling belt. This correlation demonstrates that these Early Palaeozoic granitoids and HP-UHP metamorphic rocks in the North Qinling belt were already exhumed to the surface, underwent erosion prior to Middle Devonian time and were then deposited in an extensional basin. Based on the results from detrital zircon U-Pb dating, combined with geochemical data and the regional geology, the deposition of Liuling sediments is inferred to have occurred in a post-orogenic extensional basin, rather than a subduction-related fore-arc basin or a foreland basin formed during or after continental collision.

  8. Neoproterozoic granitic magmatism along the Ailao Shan-Red River belt: U-Pb zircon geochronology, Lu-Hf isotopes and tectonic implications

    Science.gov (United States)

    Chen, Xiaoyu; Liu, Junlai; Qi, Yinchuan; Fan, Wenkui; Burg, Jean-Pierre

    2017-04-01

    The Neoproterozoic tectonic characteristics of the high grade metamorphic massifs along the Ailao Shan-Red River belt are debated. Controversies are on 1) whether the massifs were parts of the Yangtze block to the northeast or 2) parts of the Indochina block to the southwest and 3) the magmatic rocks represent arc magmatism or rifting linked to break-up of the Rodinia supercontinent. This study presents new and precise LA-ICP-MS U-Pb age dating and geochemical and Hf isotopic analyses of granitic intrusions along the Ailao Shan-Red River belt in an attempt to elucidate the Neoproterozoic magmatic evolution of this belt. In general, zircon U-Pb ages of the studied granitic rocks are between 804 and 724Ma, with a weighted mean of ca. 770 Ma, thus confirming Neoproterozoic magmatism. All samples plot into the peraluminous domain, indicating a major crustal resource. In consistency with these conclusions, most of the Neoproterozoic granitoids show negative ɛHf (t) values near the chondrite line. A few samples possess low positiveɛ Hf (t) values, being signatures of mantle sources. It is therefore concluded that the Neoproterozoic magmatism along the ASRR belt originated from mantle sources with important contributions through anatexis of ancient lower crust. Discrimination diagrams of tectonic settings suggest continental arc magmatism. Neoproterozoic magmatism is widely reported along the margins of the Yangtze block, especially in the northern margin. However, there are fewer reports about Neoproterozoic magmatic activity along the southern and southwestern margins. The geochronology spectrum and geochemisty of the studied Neoproterozoic granitic rocks are similar to those along the western margin of the Yangtze block. The present study, combined with previous results, suggests that oceanic subduction contributed to the generation of the arc magmatisms along the western and southwestern margin of the Yangtze plate and along the ASRR belt (as part of the

  9. Late Paleozoic low-angle southward-dipping thrust in the Züünharaa area, Mongolia: tectonic implications for the geological structures in the Sayan-Baikal and Hangai-Daur belts

    Science.gov (United States)

    Onon, Gantumur; Tsukada, Kazuhiro

    2017-02-01

    The Central Asian Orogenic Belt (CAOB) is key to understanding the Paleozoic-Mesozoic geodynamics of Eurasian continent. The geological structure of the Middle-to-Late Paleozoic rock units in the North Mongolia-West Transbaikal region is critical in revealing development process of CAOB. The region is largely comprised of rocks from the continental affinity and accretionary complexes which form the Sayan-Baikal (SB) and Hangai-Daur (HD) belts. This paper describes the lithology, stratigraphy, geological structure, and U-Pb age of the rocks in the Züünharaa area, which is located within the Haraa terrane of the HD belt in Mongolia. We identified a regional low-angle southward-dipping thrust in this area. The tectonic implication of the low-angle south-dipping thrust is discussed within the North Mongolia-West Transbaikal region. The study area exposes metamorphosed clastic rocks of the Haraa Group intruded by Ordovician-Silurian granitic rocks, Devonian felsic volcanic rocks of the Ulaan Öndör Formation, and Visean clastic rocks of the Örmögtei Formation in ascending order. The Haraa Group, granitic rock, and Ulaan Öndör Formation are cut by the low-angle southward-dipping thrust throughout this area. The rocks along the thrust are fractured to form cataclasite zone up to 40 m wide. The thrust includes granite-rhyolite clast of 450-420 Ma, and is unconformably covered by Visean Örmögtei Formation. Therefore, thrusting occurred after Ordovician-Silurian and before Visean. Late Paleozoic low-angle southward-dipping thrusts, similar to the present study, are widely distributed in the Haraa terrane of the Hangai-Daur belt and in terranes of the Sayan-Baikal belt. Whereas, the contemporaneous southeast-verging composite folds and northward-dipping thrusts are developed in the accretionary complexes, which are exposed at south of the Haraa terrane. These contrasting structures suggest a couple of "landward-verging" and "oceanward-verging" structures and may

  10. Early Cambrian Post-collisional volcanosedimentary Rey Bouba greenstone belt in northern Cameroun: LA-MC-ICP-MS U-Pb geochronology and implications for the geodynamic evolution of the Central African Fold Belt (CAFB).

    Science.gov (United States)

    Bouyo, Merlain

    2014-05-01

    The Rey Bouba Greenstone Belt (RBGB) is a greenschist volcanosedimentary basin representing the youngest accretion event that characterized the geodynamic evolution of the CAFB of Northern Cameroon. LA-MC-ICP-MS U-Pb detrital zircon data indicate that both older PP to MP and younger NP to Early Cambrian sources from ca 2000 to ca 540 Ma, with main provenance being zircon grains from Cryogenian igneous rocks (between ca 850 and ca 650 Ma) were involved in the formation of the RBGB basin. Considering the age of metamorphism inferred from high pressure granulites at ca 600 Ma within the CAFB of northern Cameroon as the most direct evidence for the timing of continental collision, we conclude that the deformation associated with migmatites and post-collisional granites which fed the Rey Bouba basin mostly with NP zircon lasts until post 540 Ma, in correlation with the final amalgamation of the Gondwana Supercontinent during Latest Neoproterozoic-Earliest Cambrian. Therefore, the RBGB may represent the youngest post-collisional metavolcanosedimentary basin within the CAFB.

  11. Geothermal structure of the eastern Black Sea basin and the eastern Pontides orogenic belt: Implications for subduction polarity of Tethys oceanic lithosphere

    Directory of Open Access Journals (Sweden)

    Nafiz Maden

    2013-07-01

    Full Text Available The numerical results of thermal modeling studies indicate that the lithosphere is cold and strong beneath the Black Sea basin. The thermal lithospheric thickness increases southward from the eastern Pontides orogenic belt (49.4 km to Black Sea basin (152.2 km. The Moho temperature increases from 367 °C in the trench to 978 °C in the arc region. The heat flow values for the Moho surface change between 16.4 mW m−2 in the Black Sea basin and 56.9 mW m−2 in the eastern Pontides orogenic belt. Along the southern Black Sea coast, the trench region has a relatively low geothermal potential with respect to the arc and back-arc region. The numerical studies support the existence of southward subduction beneath the Pontides during the late Mesozoic–Cenozoic.

  12. The distribution, geochronology and geochemistry of early Paleozoic granitoid plutons in the North Altun orogenic belt, NW China: Implications for the petrogenesis and tectonic evolution

    Science.gov (United States)

    Meng, Ling-Tong; Chen, Bai-Lin; Zhao, Ni-Na; Wu, Yu; Zhang, Wen-Gao; He, Jiang-Tao; Wang, Bin; Han, Mei-Mei

    2017-01-01

    Abundant early Paleozoic granitoid plutons are widely distributed in the North Altun orogenic belt. These rocks provide clues to the tectonic evolution of the North Altun orogenic belt and adjacent areas. In this paper, we report an integrated study of petrological features, U-Pb zircon dating, in situ zircon Hf isotope and whole-rock geochemical compositions for the Abei, 4337 Highland and Kaladawan Plutons from north to south in the North Altun orogenic belt. The dating yielded magma crystallization ages of 514 Ma for the Abei Pluton, 494 Ma for the 4337 Highland Pluton and 480-460 Ma for the Kaladawan Pluton, suggesting that they are all products of oceanic slab subduction because of the age constraint. The Abei monzogranites derived from the recycle of Paleoproterozoic continental crust under low-pressure and high-temperature conditions are products of subduction initiation. The 4337 Highland granodiorites have some adakitic geochemical signatures and are sourced from partial melting of thickened mafic lower continental crust. The Kaladawan quartz diorites are produced by partial melting of mantle wedge according to the positive εHf(t) values, and the Kaladawan monzogranite-syenogranite are derived from partial melting of Neoproterozoic continental crust mixing the juvenile underplated mafic material from the depleted mantle. These results, together with existing data, provide significant information about the evolution history of oceanic crust subduction during the 520-460 Ma. The initiation of subduction occurred during 520-500 Ma with formation of Abei Pluton; subsequent transition from steep-angle to flat-slab subduction at ca.500 Ma due to the arrival of buoyant oceanic plateaus, which induces the formation of 4337 Highland Pluton. With ongoing subduction, the steep-angle subduction system is reestablished to cause the formation of 480-460 Ma Kaladawan Pluton. Meanwhile, it is this model that account for the temporal-spatial distribution of these early

  13. Endocrine disruptors and dental materials: health implications associated with their use in Brazil

    Directory of Open Access Journals (Sweden)

    Coelho Antonio Jorge Molinário

    2002-01-01

    Full Text Available This study analyzes international historical trends in the use of different types of materials in dental practice. The author describes the chemical properties of their ingredients and the potential and observed adverse effects in patients and dental technicians resulting from clinical or occupational exposure to various metals like beryllium, used to produce metal alloys. The growing use of various products (resin cements, ionomer cements, aesthetic restorative materials, resins, endodontal cements, and others based on the compound bisphenol-A, whose chemical structure is similar to that of estrogen. Considering the demographic and contemporary work force characteristics of those involved in dental practice in the Brazil, the study highlights the possible effect of the use of these materials in both male and female patients and all age strata, as well as in health professionals with occupational exposure to products containing bisphenol-A.

  14. Endocrine disruptors and dental materials: health implications associated with their use in Brazil

    Directory of Open Access Journals (Sweden)

    Antonio Jorge Molinário Coelho

    2002-04-01

    Full Text Available This study analyzes international historical trends in the use of different types of materials in dental practice. The author describes the chemical properties of their ingredients and the potential and observed adverse effects in patients and dental technicians resulting from clinical or occupational exposure to various metals like beryllium, used to produce metal alloys. The growing use of various products (resin cements, ionomer cements, aesthetic restorative materials, resins, endodontal cements, and others based on the compound bisphenol-A, whose chemical structure is similar to that of estrogen. Considering the demographic and contemporary work force characteristics of those involved in dental practice in the Brazil, the study highlights the possible effect of the use of these materials in both male and female patients and all age strata, as well as in health professionals with occupational exposure to products containing bisphenol-A.

  15. Habitat use by Collared Crescentchest (Melanopareia torquata) in a Cerrado in southeastern Brazil: implications for management.

    Science.gov (United States)

    Kanegae, M F; Levy, G; Freitas, S R

    2012-11-01

    The Collared Crescentchest (Melanopareia torquata) is a small insectivore endemic to the Cerrado. We examine the habitat use of this bird in a preserved Cerrado area in southeastern Brazil. Despite its occurrence in grassland with shrubs, the species used these areas less frequently than expected. The Collared Crescentchest mainly used areas of campo cerrado, but it was not recorded in a disturbed one. The common occurrence of exotic grass (U. decumbens) and cattle grazing may have brought about factors for its occurrence. However, the preference for native grasses may indicate an adverse indirect relationship against its occurence as there is competition between native and exotic grasses in the Cerrado. The presence of the Collared Crescentchest included the highest density of tall shrubs (>1 m) and native grasses. Conservation of the species should involve preserved areas of campo cerrado with a dominance of native grasses and tall shrubs.

  16. Habitat use by Collared Crescentchest (Melanopareia torquata in a Cerrado in southeastern Brazil: implications for management

    Directory of Open Access Journals (Sweden)

    MF. Kanegae

    Full Text Available The Collared Crescentchest (Melanopareia torquata is a small insectivore endemic to the Cerrado. We examine the habitat use of this bird in a preserved Cerrado area in southeastern Brazil. Despite its occurrence in grassland with shrubs, the species used these areas less frequently than expected. The Collared Crescentchest mainly used areas of campo cerrado, but it was not recorded in a disturbed one. The common occurrence of exotic grass (U. decumbens and cattle grazing may have brought about factors for its occurrence. However, the preference for native grasses may indicate an adverse indirect relationship against its occurence as there is competition between native and exotic grasses in the Cerrado. The presence of the Collared Crescentchest included the highest density of tall shrubs (>1 m and native grasses. Conservation of the species should involve preserved areas of campo cerrado with a dominance of native grasses and tall shrubs.

  17. An Ecological Comparison of Floristic Composition in Seasonal Semideciduous Forest in Southeast Brazil: Implications for Conservation

    Directory of Open Access Journals (Sweden)

    Sérgio de Faria Lopes

    2012-01-01

    Full Text Available We examined floristic patterns of ten seasonal semideciduous forest sites in southeastern Brazil and conducted a central sampling of one hectare for each site, where we took samples and identified all individual living trees with DBH (diameter at breast height, 1.30 m ≥4.8 cm. Arboreal flora totaled 242 species, 163 genera, and 58 families. Fabaceae (38 species and Myrtaceae (20 species were families with the largest number of species. Only Copaifera langsdorffii and Hymenaea courbaril occurred at all sites. Multivariate analysis (detrended correspondence analysis and cluster analysis using two-way indicator species analysis (TWINSPAN indicated the formation of a group containing seven fragments in which Siparuna guianensis was the indicator species. This analysis revealed that similarities between studied fragments were due mainly to the successional stage of the community.

  18. Geochemical constraints on komatiite volcanism from Sargur Group Nagamangala greenstone belt, western Dharwar craton, southern India: Implications for Mesoarchean mantle evolution and continental growth

    Directory of Open Access Journals (Sweden)

    Tushipokla

    2013-05-01

    Full Text Available We present field, petrographic, major and trace element data for komatiites and komatiite basalts from Sargur Group Nagamangala greenstone belt, western Dharwar craton. Field evidences such as crude pillow structure indicate their eruption in a marine environment whilst spinifex texture reveals their komatiite nature. Petrographic data suggest that the primary mineralogy has been completely altered during post-magmatic processes associated with metamorphism corresponding to greenschist to lower amphibolite facies conditions. The studied komatiites contain serpentine, talc, tremolite, actinolite and chlorite whilst tremolite, actinolite with minor plagioclase in komatiitic basalts. Based on the published Sm-Nd whole rock isochron ages of adjoining Banasandra komatiites (northern extension of Nagamangala belt and further northwest in Nuggihalli belt and Kalyadi belt we speculate ca. 3.2–3.15 Ga for komatiite eruption in Nagamangala belt. Trace element characteristics particularly HFSE and REE patterns suggest that most of the primary geochemical characteristics are preserved with minor influence of post-magmatic alteration and/or contamination. About 1/3 of studied komatiites show Al-depletion whilst remaining komatiites and komatiite basalts are Al-undepleted. Several samples despite high MgO, (Gd/YbN ratios show low CaO/Al2O3 ratios. Such anomalous values could be related to removal of CaO from komatiites during fluid-driven hydrothermal alteration, thus lowering CaO/Al2O3 ratios. The elemental characteristics of Al-depleted komatiites such as higher (Gd/YbN (>1.0, CaO/Al2O3 (>1.0, Al2O3/TiO2 (18 together with higher HREE, Y, Zr suggest their derivation from shallower upper mantle without garnet involvement in residue. The observed chemical characteristics (CaO/Al2O3, Al2O3/TiO2, MgO, Ni, Cr, Nb, Zr, Y, Hf, and REE indicate derivation of the komatiite and komatiite basalt magmas from heterogeneous mantle (depleted to primitive mantle at

  19. Present international patterns of foreign direct investment: underlying causes and some policy implications for Brazil

    Directory of Open Access Journals (Sweden)

    François Chesnais

    2013-12-01

    Full Text Available An important feature of the 1980s has been the substantial fall in the flow of foreign direct investment (FDI to the developing countries and also, with the limited exception of the Asian NIE (Korea, Taiwan, Malaysia, Singapore and China, to the newly industrialized countries, in particular those in Latin America. FDI has been concentrated more than ever among the advanced industrialized countries of OECD. The same period has witnessed a number of extremely important changes, both in the nature and location of basic or key technologies, the role of technology in industrial competitiveness; the most appropriate industrial management paradigm following the difficulties of the "Fordist" one; the nature of predominant international supply or market structures; and the relationships between productive and financial capital. Today a number of governments in developing countries and in NIC, among them the new government of Brazil, are again engaged in an attempt to attract FDI and to make foreign capital one of the major pillars of industrial revival and future growth. This paper argues that this policy objective is both fairly illusory and largely mistaken. It is fairly illusory in that it seriously underestimates the nature and strength of the structural factors which have been at work since the mid-1970s and seriously modified the strategies and investment priorities of the TNC which under took the brunt of the investment in developing countries and NICs in the earlier "golden age" of the 1960s and 1970s . The objective of luring foreign capital again to Brazil in ways and on a level similar to the 1960s is also largely mistaken in that it fails to recognize that the change in technological paradigms has modified the parameters of international technology transfers (cf. Ernst and O'Connor, 1989 and made indigenous and endogenous industrial growth dependent to a much higher degree than in the previous period (19601975 on factors which foreign capital

  20. The social adjustment of patients with schizophrenia: implications to the mental health policy in Brazil

    Directory of Open Access Journals (Sweden)

    Menezes Paulo R.

    1993-01-01

    Full Text Available A sample (n=124 of schizophrenic patients from a defined catchment area of the city os S.Paulo, Brazil, who had been consecutively admitted to hospital, was assessed for psychopathological status and social adjustment levels. Sociodemographic, socio-economic and occupational characteristics were recorded: almost 30% of the subjects had no occupation and received no social benefit, more than two-thirds had a monthly per capita income of US$ 100.00 or less. Sixty-five percent presented with Schneiderian firstrank symptoms. Nearly half the sample showed poor or very poor social adjustment in the month prior to admission. The most affected areas of social functioning were participation in the household activities, work and social withdrawal. The current mental health policy of promoting extra-mural care as an alternative to the previous hospital-based model will then mean the investment in a network of new community-based services, that give effective treatment and support to patients and their families. The need of further research into the current picture of mental disorders in the country is stressed.

  1. Economic implications of reducing carbon emissions from energy use and industrial processes in Brazil.

    Science.gov (United States)

    Chen, Y-H Henry; Timilsina, Govinda R; Landis, Florian

    2013-11-30

    This study assesses the economy-wide impacts of cutting CO2 emissions on the Brazilian economy. It finds that in 2040, the business-as-usual CO2 emissions from energy use and industrial processes would be almost three times as high as those in 2010 and would account for more than half of total national CO2 emissions. The current policy aims to reduce deforestation by 70 percent by 2017 and lower emissions intensity of the overall economy by 36-39 percent by 2020. If the policy were implemented as planned and continued to 2040, there would be no need to cut CO2 emissions from energy use and industrial processes until 2035, as emissions reduction through controlling deforestation would be enough to meet the voluntary carbon mitigation target of Brazil. The study also finds that using the carbon tax revenue to subsidize wind power can effectively increase the country's wind power output if that is the policy priority. Further, it finds evidence supporting the double dividend hypothesis, i.e., using revenue from a hypothetical carbon tax to finance a cut in labor income tax can significantly lower the GDP impacts of the carbon tax. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. PERFORMANCE OF REGULATORY AGENCIES IN ROAD CONCESSIONS IN BRAZIL: IMPLICATIONS OF THE AGENT-PRINCIPAL PROBLEM

    Directory of Open Access Journals (Sweden)

    Graciela Aparecida Profeta

    2016-05-01

    Full Text Available Public infrastructure services have been offered by private companies with state participation through sectoral regulatory agencies. However, due the existence of typical problems of Agent-Principal relationship that sign these arrangements, there are questions related to efficient performance of these agencies. In this sense, the objective was to present and discuss the intrinsic characteristics of the performance of the regulatory agencies, and how they are susceptible to political influence and capture problems. It was concluded that despite authorities with financial and administrative independence, there are important points of laxity in the agencies acting regime, especially those ones linked to the nomination / appointment of certain directors from their government and to budget subordination. These aspects indicate the possibility of capture and political influence, which can affect the efficiency in the sector. However, despite lack of reformulation and law enforcement, the performance of the agencies is important for ensuring efficiency because the highway concessions sector in Brazil is concentrated and this may allow the opportunistic behavior of firms and governments at the time of bidding.

  3. Electrical conductivity images across the Namibian passive margin: Implications for tectonic processes along the Kaoko Belt, the western Kongo Craton and the Walvis Ridge

    Science.gov (United States)

    Weckmann, Ute; Meqbel, Naser; Kapinos, Gerhard; Jegen-Kulcsar, Marion; Ritter, Oliver

    2014-05-01

    The Special Priority Programme SAMPLE of the German Science Foundation DFG is focussed on investigating processes related to the breakup of supercontinent Gondwana and the post breakup evolution of the passive continental margins of Africa and South America. Within this framework an amphibian magnetotelluric (MT) experiment was conducted at the Southern African passive continental margin, starting at the Walvis Ridge in the Atlantic Ocean and crossing onshore the entire Kaoko Belt and the western boundary of the Kongo Craton in Northern Namibia. High-quality MT data at 167 onshore and xx offshore sites show a strong variability within short distances and indicate complex subsurface structures in parts of the Kaoko Belt and along some of the major thrust and fault zones. To identify the main conductivity features and resolve their properties in more spatial detail we started our modelling procedure with 2D inversion for a sub-set of the data where the 3D effects are less dominant along the amphibian profile. However, to account for 3D effects in the MT data and to assess robustness of conductivity anomalies revealed in the 2D model we used the entire data set for the 3D inversion using ModEM. 2D and 3D inversion models show zones of high electrical conductivity that correlate with surface expressions of prominent faults such as the Purros Mylonite Zone and the Three Palm Mylonite Zone of the Kaoko Belt. Outcropping Etendeka flood basalts in the Western Kaoko Zones are imaged by 10-15km deep reaching zones of high resistivity. Additionally, the inversion models reveal a spatial correlation of resistive zones with the cratonic Northern Platform; however, the geologically defined onset of the Kongo Craton appears as an area of high conductivity. Compared with other craton boundaries in Southern Africa this is very untypical.

  4. Tourmaline from the Archean G.R.Halli gold deposit, Chitradurga greenstone belt, Dharwar craton (India): Implications for the gold metallogeny

    OpenAIRE

    Susmita Gupta; Jayananda, M.; Fareeduddin

    2014-01-01

    Tourmaline occurs as a minor but important mineral in the alteration zone of the Archean orogenic gold deposit of Guddadarangavanahalli (G.R.Halli) in the Chitradurga greenstone belt of the western Dharwar craton, southern India. It occurs in the distal alteration halo of the G.R.Halli gold deposit as (a) clusters of very fine grained aggregates which form a minor constituent in the matrix of the altered metabasalt (AMB tourmaline) and (b) in quartz-carbonate veins (vein tourmaline). The vein...

  5. Evolution of the Cretaceous magmatism in the Apuseni-Timok-Srednogorie metallogenic belt and implications for the geodynamic reconstructions: new insight from geochronology, geochemistry and isotope studies

    Science.gov (United States)

    von Quadt, A.; Peytcheva, I.; Heinrich, C. A.; Frank, M.; Cvetkovic, V.

    2003-04-01

    Most major Cu-Au (-PGE) deposits in the Carpathian Balkan orogen are related to a 1500 km long belt of Upper Cretaceous magmatism extending from southern Romania through Yugoslavia to Bulgaria, with a likely continuation southeast of the Black Sea into Turkey, known as the Apuseni Banat Timok Srednogorie (ABTS) belt (Popov et al., 2000). In the frame of ABTS belt a new investigation was started to reveal the relation between Cretaceous magmatism and the Cu-Au-PGE deposits across the belt in East Serbia (Yugoslavia) and the Panagyurishte district (Bulgaria). The Late Cretaceous (Palaeogene?) magmatism of East Serbia developed along the Timok Magmatic Complex (TMC) in the east and the Ridanj Krepoljin Zone (RKZ) in the west. High precision U-Pb single zircon dating and a combination of isotope tracing, geochronological data as well as petrological data were used to provide additional data for the geodynamic evolution. A maximum life span of 2.5 Ma could be calculated for the first phase of volcanic activity in TMC, starting with the Amf-andesites of Veliki Kravelj (86.29 ± 0.32 Ma) and finishing with the Timozites (84.66 ± 0.5 Ma). Ore bearing magmatism in a single deposit (Veliki Kravelj) extended a maximum of 0.6 Ma ("pre-ore": 86.29 ± 0.32 Ma, "post-ore": 86.17 ± 0.15 Ma). Preliminary data for the dacites (70.3 ± 3.5 Ma) outcropping near Krepoljin give evidence for a shifting of the volcanic activity from TMC to RKZ together with changing the ore-deposit type from Cu-Au-PGE (TMC) to Pb-Zn-Cu (RKZ). Isotope tracing give evidence for mantle dominated source with increasing of crustal contamination in the same direction: (87Sr/86Sr ratios: 0.70388 to 0.706050, e-Hf-zircon data: +12 in TMC to +4.5 in RKZ). The Panagyurishte district (Bulgaria) show a duration time of the magmatic activity of 14 Ma, starting in the north at 92 Ma and finishing in the south at 78 Ma. Ore-related magmatism becomes younger in the same direction but finishes with 86 Ma. Multiple short

  6. Geology and geochemistry of the Bingdaban ophiolitic mélange in the boundary fault zone on the northern Central Tianshan Belt, and its tectonic implications

    Institute of Scientific and Technical Information of China (English)

    DONG YunPeng; ZHANG GuoWei; ZHOU DingWu; LUO JinHai; ZHANG ChengLi; XIA LinQi; XU XueYi; LI XiangMin

    2007-01-01

    The properties and tectonic significance of the fault bound zone on the northern margin of the Central Tianshan belt are key issues to understand the tectonic framework and evolutionary history of the Tianshan Orogenic Belt. Based on the geological and geochemical studies in the Tianshan orogenic belt, it is suggested that the ophiolitic slices found in the Bingdaban area represent the remaining oceanic crust of the Early Paleozoic ocean between the Hazakstan and Zhungaer blocks. Mainly composed of basalts, gabbros and diabases, the ophiolites were overthrust onto the boundary fault between the Northern Tianshan and Central Tianshan belts. The major element geochemistry is characterized by high TiO2 (1.50%-2.25%) and MgO (6.64%-9.35%), low K2O (0.06%-0.41%) and P2O5 (0.1%-0.2%), and Na2O>K2O as well. Low ∑REE and depletion in LREE indicate that the original magma was derived from a depleted mantle source. Compared with a primitive mantle, the geochemistry of the basalts from the Bingdaban area is featureded by depletion in Th, U, Nb, La, Ce and Pr, and unfractionated in HFS elements. The ratios of Zr/Nb, Nb/La, Hf/Ta, Th/Yb and Hf/Th are similar to those of the typical N-MORB. It can be interpreted that the basalts in the Bingdaban area were derived from a depleted mantle source, and formed in a matured mid-oceanic ridge setting during the matured evolutionary stage of the Northern Tianshan ocean. In comparison with the basalts, the diabases from the Bingdaban area show higher contents of Al2O3, (REE and HFS elements as well as unfractionated incompatible elements except Cs, Rb and Ba, and about 10 times the values of the primitive mantle. Thus, the diabases are thought to be derived from a primitive mantle and similar to the typical E-MORB. The diabases also have slight Nb depletion accompanying no apparent Th enrichment compared with N-MORB. From studies of the regional geology and all above evidence, it can be suggested that the diabases from the Bingdaban

  7. Geology and geochemistry of the Bingdaban ophiolitic mélange in the boundary fault zone on the northern Central Tianshan Belt,and its tectonic implications

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The properties and tectonic significance of the fault bound zone on the northern margin of the Central Tianshan belt are key issues to understand the tectonic framework and evolutionary history of the Tianshan Orogenic Belt. Based on the geological and geochemical studies in the Tianshan orogenic belt, it is suggested that the ophiolitic slices found in the Bingdaban area represent the remaining oceanic crust of the Early Paleozoic ocean between the Hazakstan and Zhungaer blocks. Mainly com-posed of basalts, gabbros and diabases, the ophiolites were overthrust onto the boundary fault be-tween the Northern Tianshan and Central Tianshan belts. The major element geochemistry is charac-terized by high TiO2 (1.50%-2.25%) and MgO (6.64%-9.35%), low K2O (0.06%-0.41%) and P2O5 (0.1%-0.2%), and Na2O>K2O as well. Low ΣREE and depletion in LREE indicate that the original magma was derived from a depleted mantle source. Compared with a primitive mantle, the geochemistry of the basalts from the Bingdaban area is featureded by depletion in Th, U, Nb, La, Ce and Pr, and unfrac-tionated in HFS elements. The ratios of Zr/Nb, Nb/La, Hf/Ta, Th/Yb and Hf/Th are similar to those of the typical N-MORB. It can be interpreted that the basalts in the Bingdaban area were derived from a de-pleted mantle source, and formed in a matured mid-oceanic ridge setting during the matured evolu-tionary stage of the Northern Tianshan ocean. In comparison with the basalts, the diabases from the Bingdaban area show higher contents of Al2O3, ∑REE and HFS elements as well as unfractionated incompatible elements except Cs, Rb and Ba, and about 10 times the values of the primitive mantle. Thus, the diabases are thought to be derived from a primitive mantle and similar to the typical E-MORB. The diabases also have slight Nb depletion accompanying no apparent Th enrichment compared with N-MORB. From studies of the regional geology and all above evidence, it can be suggested that the diabases from the

  8. Origin and tectonic implications of the ∼200 Ma, collision-related Jerai pluton of the Western Granite Belt, Peninsular Malaysia

    Science.gov (United States)

    Jamil, Azmiah; Ghani, Azman A.; Zaw, Khin; Osman, Syamir; Quek, Long Xiang

    2016-09-01

    Triassic granitoids (∼200-225 Ma) are widespread in the Western Belt of Peninsular Malaysia. The Main Range granite is the biggest batholith in the Western Belt composed of peraluminous to metaluminous granite and granodiorite and displays typical ilmenite-series characteristics. Jerai granitic pluton occurs at the northwestern part of the Main Range granite batholith. The Jerai granite can be divided into three facies: (i) biotite-muscovite granite; (ii) tourmaline granite; and (iii) pegmatite and aplopegmatite. Biotite-muscovite granite accounts for 90% of the Jerai pluton, and the rest is tourmaline granite. Geochemical data reveal that pegmatite and tourmaline granite are more differentiated than biotite-muscovite granite. Both pegmatite and tourmaline granite have a higher SiO2 content (70.95-83.94% versus 69.45-73.35%) and a more pronounced peraluminous character. The U-Pb zircon geochronology of the Jerai granite gave an age ranging from 204 ± 4.3 Ma, 205 ± 4 Ma and 205 ± 2 Ma for pegmatite biotite-muscovite granite and tourmaline granite, respectively. The biotite-muscovite Jerai granites are similar to S-type Main Range granite, but the tourmaline granite has a signature of late-stage hydrothermal fluid interaction such as tourmaline quartz pods, the accumulation of large pegmatitic K-feldspar, pronounced peraluminous character, higher SiO2 content. Age evidence of these two granitic facies suggest that they are from the same magma.

  9. Zircon U-Pb ages, Hf isotope data, and tectonic implications of Early-Middle Triassic granitoids in the Ailaoshan high-grade metamorphic belt of Southeast Tibet

    Science.gov (United States)

    Wu, Wenbin; Liu, Junlai; Chen, Xiaoyu; Zhang, Lisheng

    2017-04-01

    The Ailaoshan tectonic belt, where the effects of the Paleo-Tethyan ocean evolution and Indian-Eurasian plate collision are superimposed, is one of the most significant geological discontinuities in western Yunnan province of southeast Tibet. An Ailaoshan micro-block within the belt is bounded by the Ailaoshan suture zone to the west and the Red River Fault to the east, and consists of low- and high-grade metamorphic belts. Late Permian-Middle Triassic granitoids that are widely distributed to the west of the Ailaoshan suture zone and within the Ailaoshan micro-block may yield significant information on the Tethyan tectonic evolution of the Ailaoshan tectonic belt. This study reports new LA-ICP-MS zircon U-Pb geochronology and Hf isotope data of four granitoids from the Ailaoshan high-grade metamorphic belt. Zircon grains from the Yinjie granitoid do not have inherited cores and yield a weighted mean U-Pb age of 247.1 ± 2.0 Ma. The zircon ɛ Hf( t) values range from 7.8 to 12.1, and Hf model ages from 775 to 546 Ma, indicating that the granitoid was derived from juvenile crust. The rims of zircons from the Majie and Yuanjiang granitoids yield weighted mean U-Pb ages of 239.5 ± 1.8 and 237.9 ± 2.6 Ma, respectively, whereas the cores yield ages of 1608-352 Ma. The ɛ Hf( t) values of zircon rims range from -20.4 to -5.3, yielding Hf model ages from 2557 to 1606 Ma and suggesting that the source magma of the Majie and Yuanjiang granitoids was derived from ancient crust. An additional granitoid located near the Majie Village yields a zircon U-Pb age of 241.2 ± 1.0 Ma. Based on our geochronological and geochemical data, combined with geological observations, we propose that the Ailaoshan micro-block was derived from the western margin of the Yangtze block, and is comparable to the Zhongzan and Nam Co micro-blocks. The presence of late Permian mafic rocks with rift-related geochemical characteristics within the Ailaoshan micro-block, together with granitoids derived

  10. Zircon U-Pb ages, Hf isotope data, and tectonic implications of Early-Middle Triassic granitoids in the Ailaoshan high-grade metamorphic belt of Southeast Tibet

    Science.gov (United States)

    Wu, Wenbin; Liu, Junlai; Chen, Xiaoyu; Zhang, Lisheng

    2016-05-01

    The Ailaoshan tectonic belt, where the effects of the Paleo-Tethyan ocean evolution and Indian-Eurasian plate collision are superimposed, is one of the most significant geological discontinuities in western Yunnan province of southeast Tibet. An Ailaoshan micro-block within the belt is bounded by the Ailaoshan suture zone to the west and the Red River Fault to the east, and consists of low- and high-grade metamorphic belts. Late Permian-Middle Triassic granitoids that are widely distributed to the west of the Ailaoshan suture zone and within the Ailaoshan micro-block may yield significant information on the Tethyan tectonic evolution of the Ailaoshan tectonic belt. This study reports new LA-ICP-MS zircon U-Pb geochronology and Hf isotope data of four granitoids from the Ailaoshan high-grade metamorphic belt. Zircon grains from the Yinjie granitoid do not have inherited cores and yield a weighted mean U-Pb age of 247.1 ± 2.0 Ma. The zircon ɛ Hf(t) values range from 7.8 to 12.1, and Hf model ages from 775 to 546 Ma, indicating that the granitoid was derived from juvenile crust. The rims of zircons from the Majie and Yuanjiang granitoids yield weighted mean U-Pb ages of 239.5 ± 1.8 and 237.9 ± 2.6 Ma, respectively, whereas the cores yield ages of 1608-352 Ma. The ɛ Hf(t) values of zircon rims range from -20.4 to -5.3, yielding Hf model ages from 2557 to 1606 Ma and suggesting that the source magma of the Majie and Yuanjiang granitoids was derived from ancient crust. An additional granitoid located near the Majie Village yields a zircon U-Pb age of 241.2 ± 1.0 Ma. Based on our geochronological and geochemical data, combined with geological observations, we propose that the Ailaoshan micro-block was derived from the western margin of the Yangtze block, and is comparable to the Zhongzan and Nam Co micro-blocks. The presence of late Permian mafic rocks with rift-related geochemical characteristics within the Ailaoshan micro-block, together with granitoids derived

  11. Tourmaline and Rutile as Indicators of a Magmatic-hydrothermal Origin for Tourmalinite Layers in the São José do Barreiro Area, NE Ribeira Belt, Southern Brazil

    Directory of Open Access Journals (Sweden)

    Gianna Maria Garda

    2010-10-01

    Full Text Available Tourmalines from tourmaline-rich layers intercalated with schists of the Rio Una Unit of the Embu Complex and fromcoarse-grained tourmalinite layers associated with quartzite from São José do Barreiro and Formoso (Central Ribeira Belt,São Paulo State, Brazil were analyzed for major, trace- and rare-earth elements and boron stable isotopes. Two main phasesof tourmaline formation were identified by mineral chemistry. The tourmalines from the schist-hosted tourmaline layers arecharacterized by relatively low MgO (from 4.7 to 6.5%, Na2O (1.5 to 2.1% and CaO (from 0.2 to 1.1% contents andhigh Al2O3 (from 32 to 35% and FeO (from 6.7 to 9.0% contents, and also by two (REECN patterns, one represented by(La/YbCN from 2.7 to 4.3 and positive Eu anomalies, and the other by (La/YbCN from 0.2 to 0.3 and practically no Euanomaly. The variations in major-element contents reflect the composition of the rock being metamorphosed and in whichtourmaline is crystallizing, whereas the (REECN patterns indicate the evolution of the metamorphic fluid in face of changingmetamorphic conditions. The tourmaline of the tourmalinite layers intercalated in quartzite is characterized by relatively highAl2O3 (from 32.3 to 33.92%, FeO (from 6.54 to 7.3% and Na2O (from 1.8 to 2.1% contents and very low total REE (3.5ppm contents, in particular of HREE. The (REECN pattern for this tourmaline is characterized by a positive Eu anomaly,indicating a high fluid/rock ratio. The δ11B values for this tourmaline fall in the -12.3 and -13.9‰ interval. On the other hand,the tourmaline of a massive tourmalinite also associated with quartzite has the highest MgO (from 7.3 to 9.7%, CaO (from0.8 to 2.5%, F, Th, U, Hf, Zr, Y, Sr and total REE (305 ppm contents and the lowest Al2O3 (from 28.6 to 31.8% and FeO(from 5.4 to 8.3% contents, when compared to the other tourmalines analyzed. Differing from all other (REECN patterns,the one that characterizes this tourmaline is LREE-enriched [(La

  12. Rapid Spread of Zika Virus in The Americas - Implications for Public Health Preparedness for Mass Gatherings at the 2016 Brazil Olympic Games

    Directory of Open Access Journals (Sweden)

    Eskild Petersen

    2016-03-01

    Full Text Available Mass gatherings at major international sporting events put millions of international travelers and local host-country residents at risk of acquiring infectious diseases, including locally endemic infectious diseases. The mosquito-borne Zika virus (ZIKV has recently aroused global attention due to its rapid spread since its first detection in May 2015 in Brazil to 22 other countries and other territories in the Americas. The ZIKV outbreak in Brazil, has also been associated with a significant rise in the number of babies born with microcephaly and neurological disorders, and has been declared a ‘Global Emergency by the World Health Organization. This explosive spread of ZIKV in Brazil poses challenges for public health preparedness and surveillance for the Olympics and Paralympics which are due to be held in Rio De Janeiro in August, 2016. We review the epidemiology and clinical features of the current ZIKV outbreak in Brazil, highlight knowledge gaps, and review the public health implications of the current ZIKV outbreak in the Americas. We highlight the urgent need for a coordinated collaborative response for prevention and spread of infectious diseases with epidemic potential at mass gatherings events.

  13. Rapid Spread of Zika Virus in The Americas--Implications for Public Health Preparedness for Mass Gatherings at the 2016 Brazil Olympic Games.

    Science.gov (United States)

    Petersen, Eskild; Wilson, Mary E; Touch, Sok; McCloskey, Brian; Mwaba, Peter; Bates, Matthew; Dar, Osman; Mattes, Frank; Kidd, Mike; Ippolito, Giuseppe; Azhar, Esam I; Zumla, Alimuddin

    2016-03-01

    Mass gatherings at major international sporting events put millions of international travelers and local host-country residents at risk of acquiring infectious diseases, including locally endemic infectious diseases. The mosquito-borne Zika virus (ZIKV) has recently aroused global attention due to its rapid spread since its first detection in May 2015 in Brazil to 22 other countries and other territories in the Americas. The ZIKV outbreak in Brazil, has also been associated with a significant rise in the number of babies born with microcephaly and neurological disorders, and has been declared a 'Global Emergency by the World Health Organization. This explosive spread of ZIKV in Brazil poses challenges for public health preparedness and surveillance for the Olympics and Paralympics which are due to be held in Rio De Janeiro in August, 2016. We review the epidemiology and clinical features of the current ZIKV outbreak in Brazil, highlight knowledge gaps, and review the public health implications of the current ZIKV outbreak in the Americas. We highlight the urgent need for a coordinated collaborative response for prevention and spread of infectious diseases with epidemic potential at mass gatherings events.

  14. Arboviruses emerging in Brazil: challenges for clinic and implications for public health

    Directory of Open Access Journals (Sweden)

    Maria Rita Donalisio

    Full Text Available ABSTRACT Arboviruses have been emerging in different parts of the world due to genetic changes in the virus, alteration of the host and vector population dynamics, or because of anthropogenic environmental factors. These viruses’ capacity for adaptation is notable, as well as the likelihood of their emergence and establishment in new geographic areas. In Brazilian epidemiologic scenario, the most common arboviruses are DENV, CHIKV, and ZIKV, although others may spread in the country. Little is yet known of the impact of viral co-circulation, which would theoretically result in more intense viremia or other immunological alterations that could trigger autoimmune diseases, such as Guillain-Barré syndrome. The impact on morbidity and mortality intensifies as extensive epidemics lead to a high number of affected individuals, severe cases, and implications for health services, mainly due to the absence of treatment, vaccines, and effective prevention and control measures.

  15. Eccentricity distribution in the main asteroid belt

    Science.gov (United States)

    Malhotra, Renu; Wang, Xianyu

    2017-03-01

    The observationally complete sample of the main belt asteroids now spans more than two orders of magnitude in size and numbers more than 64 000 (excluding collisional family members). We undertook an analysis of asteroids' eccentricities and their interpretation with simple physical models. We find that a century old conclusion that the asteroids' eccentricities follow a Rayleigh distribution holds for the osculating eccentricities of large asteroids, but the proper eccentricities deviate from a Rayleigh distribution; there is a deficit of eccentricities smaller than ∼0.1 and an excess of larger eccentricities. We further find that the proper eccentricities do not depend significantly on asteroid size but have strong dependence on heliocentric distance; the outer asteroid belt follows a Rayleigh distribution, but the inner belt is strikingly different. Eccentricities in the inner belt can be modelled as a vector sum of a primordial eccentricity vector of random orientation and magnitude drawn from a Rayleigh distribution of parameter ∼0.06, and an excitation of random phase and magnitude ∼0.13. These results imply that when a late dynamical excitation of the asteroids occurred, it was independent of asteroid size and was stronger in the inner belt than in the outer belt. We discuss implications for the primordial asteroid belt and suggest that the observationally complete sample size of main belt asteroids is large enough that more sophisticated model-fitting of the eccentricities is warranted and could serve to test alternative theoretical models of the dynamical excitation history of asteroids and its links to the migration history of the giant planets.

  16. Seat belt restraint system

    Science.gov (United States)

    Garavaglia, A.; Matsuhiro, D.

    1972-01-01

    Shoulder-harness and lap-belt restraint system was designed to be worn by individuals of widely different sizes and to permit normal body motion except under sudden deceleration. System is divided into two basic assemblies, lap belt and torso or shoulder harness. Inertia-activated reels immediately lock when seat experiences sudden deceleration.

  17. Electrical conductivity images across the Namibian passive margin: Tectonic implications for the evolution of the Kaoko Belt, the western Kongo Craton and the Walvis Ridge

    Science.gov (United States)

    Weckmann, U.; Meqbel, N. M.; Kapinos, G.; Ritter, O.; Jegen, M. D.

    2014-12-01

    High-quality magnetotelluric (MT) data were collected at 167 sites onshore in Northwestern Namibia within the framework of a project (SAMPLE) to investigate processes related to the breakup of Gondwana. The entire study area extents from the Walvis Ridge in the Atlantic Ocean and crosses onshore the Kaoko Belt and the western boundary of the Kongo Craton. The surface expressions of prominent faults such as the Purros Shear Zone and the Three Palm Mylonite Zone of the Kaoko Belt are expressed in 2D models as zones of high electrical conductivity. A region where the Etendeka flood basalts outcrop in the Western Kaoko Zone appears as a 10-15 km deep reaching highly resistive feature. However, dimensionality and strike direction analysis of the data exhibit 3D effects. The 3D inversion models reproduce the main structures obtained by 2D modelling but the spatial coherency of structures is better resolved. The Purros Shear Zone and the Three Palm Mylonite Zone appear in the 3D inversion models as zones of high electrical conductivity striking in NW-SE direction in the middle crust. Where the Walvis Ridge intersects with the continent, an upwelling of resistive structures indicates a modification of the middle crust, which seems be caused by a deeper anomaly which is not resolved with MT. The spatial extent and possible emplacement of the highly resistive material associated with the Etendeka flood basalts is more enigmatic as only a relatively confined region at upper- to mid-crustal levels seems to be affected. Most importantly, these Cretaceous flood basalt events did not affect or alter the high conductivity structures associated with the preexisting Proterozoic shear zones. Compared with other cratonic boundaries in Southern Africa and elsewhere the transition from the Kaoko Belt into the Kongo Craton is unusual as it is associated with an area of high conductivity at upper to mid crustal levels. As MT site coverage in this region is sparse, however, this

  18. Geochronology and geochemistry of Early Jurassic volcanic rocks in the Erguna Massif, northeast China: Petrogenesis and implications for the tectonic evolution of the Mongol-Okhotsk suture belt

    Science.gov (United States)

    Wang, Wei; Tang, Jie; Xu, Wen-Liang; Wang, Feng

    2015-03-01

    The Mongol-Okhotsk suture belt played an important role in the tectonic evolution of northeast Asia during the Mesozoic. However, few studies have examined the influence of this tectonic belt on the geological evolution of northeast China. In this paper, we present zircon U-Pb geochronology, major and trace element geochemistry, and zircon Hf-O isotopic data for Early Jurassic volcanic rocks in the Erguna Massif of northeast China, with the aim of constraining the evolution of the Mongol-Okhotsk suture belt and its influence on the tectonic history of China during the Early Jurassic. Zircon U-Pb dating indicates that the trachybasalt and basaltic andesite in the study area were erupted between 193 ± 5 Ma and 181 ± 9 Ma (i.e., in the Early Jurassic). These Early Jurassic volcanic rocks belong to the high-K calc-alkaline series and are enriched in large ion lithophile elements and light rare earth elements, as well as being depleted in heavy rare earth elements and high field strength elements such as Nb and Ta. The rocks show a small negative Eu anomaly. The zircon εHf (182 Ma) values of the volcanic rocks range from - 1.9 to + 5.1, corresponding to TDM1 values of 640-901 Ma and TDM2 values of 901-1345 Ma. Zircons from two volcanic rocks yield δ18O values of 7.2‰ ± 1.5‰ (n = 19) and 6.6‰ ± 0.7‰ (n = 35). Geochemically, these Early Jurassic volcanic rocks are similar to those from active continental margin settings, and their primary magmas could have been derived from the partial melting of a lithospheric mantle wedge modified by fluid from a subducted slab. The discovery of Early Jurassic calc-alkaline volcanic rocks in the Erguna Massif, together with the coeval porphyry Cu-Mo deposits, indicates that an active continental margin existed in the Erguna area during the Early Jurassic. Taken together, we conclude that southward subduction of the Mongol-Okhotsk oceanic plate took place beneath the Erguna Massif during the Early Jurassic.

  19. Age, tectonic setting, and metallogenic implication of Phanerozoic granitic magmatism at the eastern margin of the Xing'an-Mongolian Orogenic Belt, NE China

    Science.gov (United States)

    Chen, Cong; Ren, Yunsheng; Zhao, Hualei; Yang, Qun; Shang, Qingqing

    2017-08-01

    The eastern margin of the Xing'an-Mongolian Orogenic Belt is characterised by widespread Phanerozoic granitic magmatism, some of which is closely related to significant ore mineralisation. This paper presents new geochronological, petrogenetic, and tectonic data for selected intrusions. Zircon U-Pb geochronology for five granitoid plutons indicates they were emplaced during the middle-late Permian (264-255 Ma) and Cretaceous (106-94 Ma), and thus granitic magmatism occurred throughout the Phanerozoic, Permian (268-252 Ma), Early-Middle Triassic (248-240 Ma), Early Jurassic (183 Ma), and Cretaceous (112-94 Ma). The Permian granitoids consist of monzogranite, granodiorite, tonalite, and quartz diorite, characterised by enrichment in Na2O (3.60-4.72 wt.%), depletion in K2O (0.97-2.66 wt.%), and a negative correlation between P2O5 and SiO2. Together with the presence of hornblende, these geochemical features are indicative of an I-type affinity. The Permian granitic magmatism is associated with quartz-vein-type tungsten deposits (252 Ma; unpublished Sm-Nd isochron age), which formed in an active continental margin setting related to subduction of the Palaeo-Asian Ocean. The Cretaceous quartz diorites have an adakitic affinity, having relatively high Sr (374-502 ppm), low Yb (0.51-0.67 ppm) and Y (8.7-10.7 ppm), and high Sr/Y (39.4-46.8) and (La/Yb)N values (16.2-34.7), suggesting that they were related to the partial melting of subducted oceanic crust. In addition, they are associated with porphyry Au-Cu deposits. We conclude that the Cretaceous granitic rocks and associated porphyry Au-Cu mineralisation occurred in an extensional tectonic setting related to the subduction of the Palaeo-Pacific Plate beneath the Eurasian Plate. In addition, the large-scale Early-Middle Triassic syn-collisional granite belt at the eastern margin of the Xing'an-Mongolian Orogenic Belt extends from the middle of Jilin Province to the Wangqing-Hunchun region, constraining the timing of the

  20. Rapid Intensification of Agriculture in Brazil: Dynamics and Implications of Double Cropping

    Science.gov (United States)

    Spera, S. A.; Mustard, J. F.; Rudorff, B.; VanWey, L.; Risso, J.; Adami, M.

    2012-12-01

    Global food production and yield have increased substantially over the past 50 years to keep up with the demands of the world's growing population. At the forefront of some recent developments is Brazil, where Mato Grosso State has contributed to this increase in yield and production by both extensifying (converting forest to pasture or row crops) and intensifying (converting pasture to row crops or one-crop/growing year to two-crops/growing year) large areas of land. Our research reported here is focused on characterizing the land-cover and -use dynamics in this rapidly evolving region. We have developed a new algorithm to quantify both the conversion of land to mechanized agriculture and the character of those crop rotations. We use the systematic MODIS enhanced vegetation index (EVI) product (MODIS13Q1) aggregated from daily observations to a 16-day cloud free measurement. Each pixel's resulting 2000-2011 EVI time series is analyzed with a decision tree-like algorithm created in ENVI+IDL to determine not only the area of agricultural land for each of the past decade's growing seasons, but also the specific crop dynamic of that agricultural land: a soy or cotton single-cropping rotation or a soy/corn or soy/cotton double-cropping rotation. The algorithm is based on analysis of growing season EVI patterns of forest, pasture/cerrado, and annual crops. We define specific thresholds for the magnitude of EVI over the growing season to distinguish between natural vegetation, pasture, and cropland, and then use growing season length and crop calendars to separate specific crop types. Because the intra-annual EVI phenology of forest and pasture/cerrado is relatively constant but cropland shows a large dynamic range, the algorithm uses the standard deviation of a growing season's EVI time series to separate between forest and pasture/cerrado and agricultural land. For pixels identified as agricultural land, the algorithm then uses crop-specific growing season lengths and

  1. Predictive modeling of suitable habitats for threatened marine invertebrates and implications for conservation assessment in Brazil

    Directory of Open Access Journals (Sweden)

    Rafael A. Magris

    2010-01-01

    Full Text Available Spatial analysis and modeling tools were employed to predict suitable habitat distribution for threatened marine invertebrates and estimate the overlap between highly suitable areas for these species and the Brazilian marine protected areas (MPAs. Records of the occurrence of species were obtained from the collections included in the Ocean Biogeographic Information System (OBIS-Brazil, with additional records culled from the literature. The distribution data of 16 out of 33 threatened species, with at least ten occurrences in the available records, were selected for modeling by Maxent algorithm (Maximum Entropy Modeling based on environmental variables (temperature, salinity, bathymetry and their derivatives. The resulting maps were filtered with a fixed threshold of 0.5 (to distinguish only the highly suitable areas and superimposed on MPA digital maps. The algorithm produced reasonable predictions of the species' potential distributions, showing that the patterns predicted by the model are largely consistent with current knowledge of the species. The distribution of the highly suitable areas showed little overlapping with Brazilian MPAs. This study showed how the habitat suitability for threatened species can be assessed using GIS applications and modeling tools.Neste estudo foram utilizadas análises espaciais e ferramentas de modelagem para predizer a distribuição dos hábitats adequados aos invertebrados marinhos ameaçados e estimar a sobreposição destas áreas em relação às áreas marinhas protegidas existentes. Registros de ocorrência das espécies foram obtidos das coleções incluídas no Ocean Biogeographic Information System (OBIS-Brasil e de dados provenientes da literatura. Dados de distribuição de 16 das 33 espécies ameaçadas, com pelo menos 10 registros de ocorrência, foram selecionados para modelagem utilizando o algoritmo Maxent (Maximum Entropy Modeling e variáveis ambientais (temperatura, salinidade, batimetria

  2. The geodynamic characteristics of Cretaceous (Paleogene) magmatic belts between the southeastern coast of China and Japan: Implication from ductile deformations time and diagenetic manner

    Science.gov (United States)

    Mao, J.; Takahashi, Y.; Ye, H.; Zhao, X.; Li, Z.; Kee, W.; Liu, K.; Hu, Q.

    2011-12-01

    1.Introduction It is generally believed that the Yanshanian orogeny outlined the present-day geological configuration that has developed since the Jurassic (Li 2000), by which the Early Yanshanian (J3) dominated the Cathaysia interior, whereas the Late Yanshanian (K1) dominated the southeast coastal area. Basically, products of the early Cretaceous magmatism are more restricted in a NE-SW trending zone-the Southeast Coast of China Magmatic Belt (SECMB) in China. Previous investigations have revealed that volcano-intrusive rock assemblages are mainly shallow-level, calc-alkaline, I-type felsic rocks ranging from granodioritic to alkali feldspar granitic, and succeeding A-type granites(Chen et al. 2000). The Cretaceous to Paleogene volcano-intrusive complex rocks are extensively distributed in the WS Japan Magmatic Belt (WSJMB). Note that the majority of granitic intrusions were emplaced in the Cretaceous, and they intruded into the pre-Cretaceous accretionary complexes which include regional metamorphic rocks. The intrusive granitoids are associated with coeval gabbros, diorites, rhyolites and ignimbrites.The formation of the Japanese Islands has been taken as the classic model for accretionary orogeny and often serves as an example for understanding the crustal evolution of the CAOB and other accretionary orogens (Sengor and Natal'in, 1996; Condie, 2007; Cawood and others, 2009). 2. Correlation with two Cretaceous magmatic belts 2.1 The beginning and end times for magmatic activity as well as dynamics deformation time. 2.2 Beginning of high-Mg andesite and adakite produced by melting of subducting oceanic slab in Japan. 2.3 The finishing marks of magmatic activity. 2.4 Approximatively resembling diagenetic manner. 3. Geodynamic characteristics of two magmatic belts The WSJMB is a plutonic-metamorphic terrane that comprises unmetamorphosed pre-Cretaceous accretionary complexes with shallow-level, calc-alkaline, I-type granites-rhyolites, metasediments with

  3. Sr-Nd-Pb isotopes of the Early Paleozoic mafic-ultramafic dykes and basalts from South Qinling belt and their implications for mantle composition

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Late Early Paleozoic mafic-ultramafic dykes and volcanic rocks from the South Qinling belt are characterized by eNd( t ) = +3.28―+5.02, (87Sr/86Sr)i=0.70341―0.70555, (206Pb/204Pb)i = 17.256―18.993, (207Pb/204Pb)i= 15.505―15.642, (208Pb/204Pb)i=37.125―38.968, △8/4=21.18―774.43, △7/4=8.11―18.82. These charac- teristics suggest that they derived from a Middle Neoproterozoic mantle with isotopic compositions of mixed HIMU, EMII and minor EMI components. We interpret that these rocks were melting products of depleted mantle modified by subducted ancient oceanic crust and continental margin sediments along the northern margin of Yangtze block during Early Neoproterozoic.

  4. Geochronological, geochemical, and Nd-Hf isotopic studies of the Qinling Complex, central China: Implications for the evolutionary history of the North Qinling Orogenic Belt

    Directory of Open Access Journals (Sweden)

    Chunrong Diwu

    2014-07-01

    The available data indicate that the NQOB was an independent micro-continent at least prior to the Neoproterozoic, and included a portion of the Grenville orogenic belt during the period of 1.2–0.8 Ga. The NQOB has experienced a unique geological history, which is obviously different from that of the North China Craton (NCC and the Yangtze Craton during the Precambrian. The Neoproterozoic granitoids that intruded the Qinling Complex can be interpreted as the products of assembly of the supercontinent Rodinia. The NQOB was separated from Rodinia at ca. 830–740 Ma. Subsequently, the NQOB moved closer to the northern margin of the NCC, and the initial accretion or collision with the NCC occurred from the late Cambrian to the early Ordovician.

  5. 西南三江造山带火山岩-构造组合及其意义%Volcanic Petrotectonic Assemblages in Sanjiang Orogenic Belt,SW China and Implication for Tectonics

    Institute of Scientific and Technical Information of China (English)

    莫宣学; 邓晋福; 董方浏; 喻学惠; 王勇; 周肃; 杨伟光

    2001-01-01

    called it "post-collisional arc volcanic rocks" or "delayed arc volcanic rocks". Condie et al(1989), Aldrich et al(1986) reported similar cases in Kaapvaal of South Africa and in Rio Grande rift, respectively. A possible explanation for the delay of arc type volcanism and for the formation of post-collisional arc volcanic rocks was presented ( see Fig.8 in text). It is apparently that geotherm in the source region during the subduction was too low to reach the solidus of source rock. The subducted or collapsed slabs, however, might react with surrounding mantle and become a new source rock for magma generation afterwards. In post-collisional stage some kind of geological events such as upwelling, convection, intra-continental convergence/subduction might cause generation of magmas, which contained undoubtedly subduction zone components (SZC).   Other post-collisional volcanic assemblages in Sanjiang Orogenic Belt are those formed either in overlapping rifting basins within collision zone or in intra-continental rifting basins. The former is potentially valuable for prospecting of VMS-type base metal deposits.   Volcanic assemblages developed in relatively stable blocks within Sanjiang Orogenic Belt are helpful to understand the subcontinental mantle as a lithoprobe. They are composed of either tholeiites or alkali basalts with/without acidic volcanic rocks, formed in the period of time from the Carboniferous to the Triassic.   In addition, several aspects regarding to the application of petrotectonic assemblage approach to orogenic belts are also discussed, for instance, reconstruction of tectonic configuration from petrotectonic slices, comments on geochemical discrimination diagrams, and tectonic implication of coupled ophiolite zone and volcanic arc, of delayed arc volcanic rocks, and so on.

  6. Provenance of the Neoproterozoic high-grade metasedimentary rocks of the arc-related Oriental Terrane of the Ribeira belt: Implications for Gondwana amalgamation

    Science.gov (United States)

    Lobato, Marcela; Heilbron, Monica; Torós, Bernardo; Ragatky, Diana; Dantas, Elton

    2015-11-01

    The Costeiro domain integrates the Oriental terrane of the Ribeira belt, which encompasses arc-related orthogneisses of the Rio Negro complex (ca.790-605 Ma), with a well-documented subduction signature, and the high-grade metasedimentary rocks of the São Fidélis group. The arc-related rocks intruded the lower unit of the São Fidélis group, while both units are crosscut by syn-to late collision granitoids related to the development of different stages of the Brasiliano Orogeny (ca. 605-480 Ma). New U-Pb (LA-ICP-MS) data of detrital zircon grains from quartzites of the top unit of the São Fidélis group yielded a large spectrum of Mesoproterozoic and Paleoproterozoic ages, with subordinated Archean and Neoproterozoic ones. The largest age peaks occur at ca. 1.2 Ga and 2.2 Ga. The youngest detrital zircon of ca. 613 Ma, and metamorphic overprints, with ages varying from ca. 602 to 570 Ma bracket the age of sedimentation of the top unit. Two orthogneisses of the Rio Negro complex intruded within the basal unit of the São Fidélis Group rendered similar ages of ca.620 Ma. These orthogneisses and the basal unit of the São Fidélis group are interpreted as possible sources of the upper unit. The provenance pattern of the São Fidélis Group is similar to that of the Kaoko Belt, suggesting that the Angolan basement, where Mesoproterozoic ages are common, constitutes another important source area.

  7. Petrology and geochemistry of Abyssal Peridotites from the Manipur Ophiolite Complex, Indo-Myanmar Orogenic Belt, Northeast India: Implication for melt generation in mid-oceanic ridge environment

    Science.gov (United States)

    Krishnakanta Singh, A.

    2013-04-01

    The Manipur Ophiolite Complex (MOC) located in the Indo-Myanmar Orogenic Belt (IMOB) of Northeast India forms a section of the Tethyan Ophiolite Belt of the Alpine-Himalayan orogenic system. Whole rock compositions and mineral chemistry of mantle peridotites from the MOC show an affinity to the abyssal peridotites, characterized by high contents of Al2O3 (1.28-3.30 anhydrous wt.%); low Cr# of Cr-spinel (0.11-0.27); low Mg# of olivine (˜Fo90) and high Al2O3 in pyroxenes (3.71-6.35 wt.%). They have very low REE concentrations (∑REE = 0.48-2.14 ppb). Lherzolites display LREE-depleted patterns (LaN/SmN = 0.14-0.45) with a flat to slightly fractionated HREE segments (SmN/YbN = 0.30-0.65) whereas Cpx-harburgites have flat to upward-inflected LREE patterns (LaN/SmN = 0.13-1.23) with more fractionated HREE patterns (SmN/YbN = 0.13-0.65) than the lherzolite samples. Their platinum group elements (PGE) contents (<50 ppb) and distinct mantle-normalised PGE patterns with the Pd/Ir values (1.8-11.9) and Pt/Pt* values (0.2-1.1) show an affinity to the characteristic of the residual mantle material. Evaluation of mineralogical and petrological characteristics of these peridotites suggests that they represent the residues remaining after low degree of partial melting (˜2-12%) in the spinel stability field of a mid-oceanic ridge environment. The well-preserved mid-oceanic ridge characteristics of these peridotites further suggest that the mantle section was subsequently trapped in the forearc region of the subduction zone without undergoing significant modification in their chemistry by later subduction-related tectonic and petrological processes before its emplacement to the present crustal level.

  8. Petrogenesis of Middle-Late Triassic volcanic rocks from the Gangdese belt, southern Lhasa terrane: Implications for early subduction of Neo-Tethyan oceanic lithosphere

    Science.gov (United States)

    Wang, Chao; Ding, Lin; Zhang, Li-Yun; Kapp, Paul; Pullen, Alex; Yue, Ya-Hui

    2016-10-01

    The Gangdese belt is dominantly composed of igneous rocks that formed during the northward subduction of Neo-Tethyan oceanic lithosphere beneath the Lhasa terrane and has played a crucial role in understanding the pre-collisional evolution of southern Tibet. This paper presents new geochronological and geochemical (whole-rock major and trace element and Sr-Nd and zircon Hf isotope) data for recently identified volcanic rocks exposed in Changguo area, southernmost part of the Lhasa terrane. Zircon U-Pb dating from six samples yields consistent ages of 237.1 ± 1.1 Ma to 211.7 ± 1.5 Ma for magma emplacement through volcanic eruption, showing the Middle-Late Triassic magmatic activity in the southernmost Gangdese Belt. The Changguo volcanic rocks are mainly composed of basaltic and andesitic rocks and exhibit LILE enrichment and HFSE depletion. They also exhibit relatively uniform Nd-Hf isotopic compositions (εNd(t) = + 5.20 to + 7.74 and εHf(t)zircon = + 10.2 to + 15.9). The basaltic magmas were likely sourced from partial melting of sub-arc mantle wedge that was metasomatized by not only the aqueous fluid derived from subducting altered oceanic crust but also hydrous melt derived from subducting seafloor sediments, and subsequently experienced fractional crystallization and juvenile crustal contamination during ascent. The andesitic magmas were generated by partial melting of mafic-ultramafic metasomes through melt/fluid-peridotite reaction at slab-mantle interface. Taking into account the temporal and spatial distribution of the Early Mesozoic magmatic rocks and regional detrital zircon data, we further propose that the northward subduction of Neo-Tethyan oceanic lithosphere beneath the Lhasa terrane commenced by Middle Triassic.

  9. Geochronological, geochemical, and Nd-Hf isotopic studies of the Qinling Complex, central China:Implications for the evolutionary history of the North Qinling Orogenic Belt

    Institute of Scientific and Technical Information of China (English)

    Chunrong Diwu; Yong Sun; Yan Zhao; BingXiang Liu; Shaocong Lai

    2014-01-01

    The Qinling Complex of central China is thought to be the oldest rock unit and the inner core of the North Qinling Orogenic Belt (NQOB). Therefore, the Qinling Complex is the key to understanding the pre-Paleozoic evolution of the NQOB. The complex, which consists of metagraywackes and marbles, un-derwent regional amphibolite-facies metamorphism. In this study, we constrained the formation age of the Qinling Complex to the period between the late Mesoproterozoic and the early Neoproterozoic (ca. 1062e962 Ma), rather than the Paleoproterozoic as previously thought. The LA-ICP-MS data show two major metamorphic ages (ca. 499 and ca. 420e400 Ma) for the Qinling Complex. The former age is consistent with the peak metamorphic age of the high- and ultra-high pressure (HP-UHP) rocks in the Qinling Complex, indicating that both the HP-UHP rocks and their country rocks experienced intensive regional metamorphism during the Ordovician. The latter age may constrain the time of partial melting in the NQOB between the late Silurian and early Devonian. The Qinling Complex is mostly affiliated with subductioneaccretion processes along an active continental margin, and should contain detritus deposited in a forearc basin. The available data indicate that the NQOB was an independent micro-continent at least prior to the Neoproterozoic, and included a portion of the Grenville orogenic belt during the period of 1.2e0.8 Ga. The NQOB has experienced a unique geological history, which is obviously different from that of the North China Craton (NCC) and the Yangtze Craton during the Precambrian. The Neoproterozoic granitoids that intruded the Qinling Complex can be interpreted as the products of assembly of the supercontinent Rodinia. The NQOB was separated from Rodinia at ca. 830e740 Ma. Subsequently, the NQOB moved closer to the northern margin of the NCC, and the initial accretion or collision with the NCC occurred from the late Cambrian to the early Ordovician.

  10. Tectono-metamorphic evolution of the internal zone of the Pan-African Lufilian orogenic belt (Zambia): Implications for crustal reworking and syn-orogenic uranium mineralizations

    Science.gov (United States)

    Eglinger, Aurélien; Vanderhaeghe, Olivier; André-Mayer, Anne-Sylvie; Goncalves, Philippe; Zeh, Armin; Durand, Cyril; Deloule, Etienne

    2016-01-01

    The internal zone of the Pan-African Lufilian orogenic belt (Zambia) hosts a dozen uranium occurrences mostly located within kyanite micaschists in a shear zone marking the contact between metasedimentary rocks attributed to the Katanga Neoproterozoic sedimentary sequence and migmatites coring domes developed dominantly at the expense of the pre-Neoproterozoic basement. The P-T-t-d paths reconstructed for these rocks combining field observations, microstructural analysis, metamorphic petrology and thermobarometry and geochronology indicate that they have recorded burial and exhumation during the Pan-African orogeny. Both units of the Katanga metasedimentary sequence and pre-Katanga migmatitic basement have underwent minimum peak P-T conditions of ~ 9-11 kbar and ~ 640-660 °C, dated at ca. 530 Ma by garnet-whole rock Lu-Hf isochrons. This suggests that this entire continental segment has been buried up to a depth of 40-50 km with geothermal gradients of 15-20 °C.km- 1 during the Pan-African orogeny and the formation of the West Gondwana supercontinent. Syn-orogenic exhumation of the partially molten root of the Lufilian belt is attested by isothermal decompression under P-T conditions of ~ 6-8 kbar at ca. 530-500 Ma, witnessing an increase of the geothermal gradients to 25-30 °C·km- 1. Uranium mineralizations that consist of uraninite and brannerite took place at temperatures ranging from ~ 600 to 700 °C, and have been dated at ca. 540-530 Ma by U-Pb ages on uraninite. The main uranium deposition thus occurred at the transition from the syn-orogenic burial to the syn-orogenic exhumation stages and has been then partially transposed and locally remobilized during the post-orogenic exhumation accommodated by activation of low-angle extensional detachment.

  11. Sandbox modelling of sequential thrusting in a mechanically two-layered system and its implications in fold-and-thrust belts

    Science.gov (United States)

    Saha, Puspendu; Bose, Santanu; Mandal, Nibir

    2016-10-01

    Many fold-and-thrust belts display multi-storied thrust sequences, characterizing a composite architecture of the thrust wedges. Despite dramatic progress in sandbox modelling over the last three decades, our understanding of such composite thrust-wedge mechanics is limited and demands a re-visit to the problem of sequential thrusting in mechanically layered systems. This study offers a new approach to sandbox modelling, designed with a two-layered sandpack simulating a mechanically weak Coulomb layer, resting coherently upon a stronger Coulomb layer. Our experimental models reproduce strikingly similar styles of the multi-storied frontal thrust sequences observed in natural fold-and- thrust belts. The upper weak horizon undergoes sequential thrusting at a high spatial frequency, forming numerous, closely spaced frontal thrusts, whereas the lower strong horizon produces widely spaced thrusts with progressive horizontal shortening. This contrasting thrust progression behaviour gives rise to composite thrust architecture in the layered sandpack. We show the evolution of such composite thrust sequences as a function of frictional strength (μb) at the basal detachment and thickness ratio (Tr) between the weak and strong layers. For any given values of Tr and μb, the two thrust sequences progress at different rates; the closely-spaced, upper thrust sequence advances forelandward at a faster rate than the widely-spaced, lower thrust sequence. Basal friction (μb) has little effects on the vergence of thrusts in the upper weak layer; they verge always towards foreland, irrespective of Tr values. But, the lower strong layer develops back-vergent thrusts when μb is low (∼0.36). In our experiments, closely spaced thrusts in the upper sequence experience intense reactivation due to their interaction with widely spaced thrusts in the lower sequence. The interaction eventually affects the wedge topography, leading to two distinct parts: inner and outer wedges

  12. U-Pb geochronology of the Lagoa Real uranium district, Brazil: Implications for the age of the uranium mineralization

    Science.gov (United States)

    Lobato, Lydia Maria; Pimentel, Márcio Martins; Cruz, Simone C. P.; Machado, Nuno; Noce, Carlos Maurício; Alkmim, Fernando Flecha

    2015-03-01

    The Lagoa Real uranium district in Bahia, northeastern Brazil, is the most important uranium province in the country and presently produces this metal in an open-pit mine operated by Indústrias Nucleares do Brasil. Uranium-rich zones are associated with plagioclase (dominantly albite ± oligoclase) -rich rocks, albitites and metasomatized granitic-gneisses, distributed along NNW/SSE striking shear zones. We have used the ID-TIMS U-Pb method to date zircon and titanite grains from the São Timóteo granitoid, and albite-rich rocks from the Lagoa Real district in order to assess the age of granite emplacement, deformation/metamorphism and uranium mineralization. The isotopic data support the following sequence of events (i) 1746 ± 5 Ma - emplacement of the São Timóteo granitoid (U-Pb zircon age) in an extensional setting, coeval with the beginning of the sedimentation of the Espinhaço Supergroup; (ii) 956 ± 59 Ma hydrothermal alteration of the São Timóteo granitoid and emplacement of the uranium mineralization (U-Pb titanite age on an albite-rich sample); (iii) 480 Ma metamorphism, remobilization and Pb loss (U-Pb titanite age for the gneiss sample), during the nucleation of shear zones related to the collision between the São Francisco-Congo and Amazonia paleoplates. The 956 ± 59-Ma mineralization age is apparently associated with the evolution of the Macaúbas-Santo Onofre rift. This age bracket may bear an important exploration implication, and should be included in the diverse age scenario of uranium deposits worldwide.

  13. Mesozoic lacustrine system in the Parnaíba Basin, northeastern Brazil: Paleogeographic implications for west Gondwana

    Science.gov (United States)

    Cardoso, Alexandre Ribeiro; Nogueira, Afonso César Rodrigues; Abrantes, Francisco Romério; Rabelo, Cleber Eduardo Neri

    2017-03-01

    The fragmentation of the West Gondwana during Early Triassic to Cretaceous was marked by intense climatic changes, concomitant with the establishment of extensive desertic/lacustrine systems. These deposits succeeded the emplacement and extrusion of lava flows, related to the pre-rift phase and initial opening of the Equatorial Atlantic Ocean. The thermal phase is recorded in the Upper Jurassic-Lower Cretaceous Pastos Bons Formation, exposed mainly in southeast parts of the Parnaíba Basin, Northeastern Brazil. The sedimentary facies of this unit were grouped in two facies associations (FA), representative of a shallow lacustrine system, influenced by episodic hyperpycnal and oscillatory flows. Central lake facies association (FA1) is composed by laminated mudstone (Ml), sandstone/mudstone rhythmite (S/Mr) and sandstone with even-parallel lamination (Sel). Flysch-like delta front (FA2) consists in sandstones with wave structures (Sw), sandstones with even-parallel stratification (Ses), massive sandstones (Sm), sandstones with soft-sediment deformation structures (Sd) and laminated mudstones (Ml). FA1 was deposited in the deepest portions of the lake, characterized by low energy, episodically disturbed by siliciclastic influx. FA2 presents sandy deposits generated by unconfined flow, probably fed by ephemeral stream flows that generated thickening upward of tabular sandstone beds. The progressive filling of the lake resulted in recurrent shoaling up of the water level and reworking by wave action. The installation of Pastos Bons lakes was controlled by thermal subsidence, mainly in restricted depocenters. The siliciclastic fluvial inflow can be related to the adjacent humid desertic facies, formed under climatic attenuation, typical of post-Triassic period, with reduced biological activity. Smectite and abundant feldspars, in lacustrine facies, corroborate an arid climate, with incipient chemical weathering. The new facies and stratigraphic data present in this

  14. Arboviruses emerging in Brazil: challenges for clinic and implications for public health.

    Science.gov (United States)

    Donalisio, Maria Rita; Freitas, André Ricardo Ribas; Zuben, Andrea Paula Bruno Von

    2017-04-10

    Arboviruses have been emerging in different parts of the world due to genetic changes in the virus, alteration of the host and vector population dynamics, or because of anthropogenic environmental factors. These viruses' capacity for adaptation is notable, as well as the likelihood of their emergence and establishment in new geographic areas. In Brazilian epidemiologic scenario, the most common arboviruses are DENV, CHIKV, and ZIKV, although others may spread in the country. Little is yet known of the impact of viral co-circulation, which would theoretically result in more intense viremia or other immunological alterations that could trigger autoimmune diseases, such as Guillain-Barré syndrome. The impact on morbidity and mortality intensifies as extensive epidemics lead to a high number of affected individuals, severe cases, and implications for health services, mainly due to the absence of treatment, vaccines, and effective prevention and control measures. RESUMO Notifica-se a emergência de arboviroses em diferentes regiões do planeta em decorrência de mudanças genéticas no vírus, alteração da dinâmica populacional de hospedeiros e vetores ou por fatores ambientais de origem antropogênica. É notável a capacidade de adaptação desses vírus e a possibilidade de emergirem e se estabelecerem em novas áreas geográficas. No contexto epidemiológico brasileiro, os arbovírus de maior circulação são DENV, CHIKV e ZIKV, embora existam outros com potencial de disseminação no País. O impacto da cocirculação viral ainda é pouco conhecido, a qual teoricamente resultaria em viremias mais intensas ou outras alterações imunológicas que poderiam ser o gatilho para doenças autoimunes, como a síndrome de Guillain-Barré. O impacto na morbidade e mortalidade se intensifica à medida que extensas epidemias pressupõem grande número de indivíduos acometidos, casos graves e implicações sobre os serviços de saúde, principalmente diante da aus

  15. Radiation Belt Dynamics

    Science.gov (United States)

    2015-12-27

    Wygant, J. R., et al., “The Electric Field and Waves Instruments on the Radiation Belt Storm Probes Mission,” Space Sci. Rev., 179, 2013, pp. 183–220, doi...A. N., Li, X., Kanekal, S. G., Hudson, M. K., and Kress, B. T., “Observations of the Inner Radiation Belt: CRAND and Trapped Solar Protons,” J...1215–1228, doi:10.1002/2014JA020777. [27] Selesnick, R. S., “ Measurement of Inner Radiation Belt Electrons with Kinetic Energy Above 1 MeV,” J

  16. Geochemistry, geochronology and zircon Hf isotopic study of peralkaline-alkaline intrusions along the northern margin of the North China Craton and its tectonic implication for the southeastern Central Asian Orogenic Belt

    Science.gov (United States)

    Zhao, Pan; Jahn, Bor-ming; Xu, Bei; Liao, Wen; Wang, Yanyang

    2016-09-01

    A giant Permian alkaline magmatic belt has recently been identified in southern Inner Mongolia, along the northern margin of the North China Craton (NCC). This belt is mainly composed of syenite, quartz syenite, alkaline granite and mafic microgranular enclaves (MME)-bearing granodiorite. In order to study the petrogenesis and tectonic implications of these rocks, we undertook zircon U-Pb dating and geochemical analysis of two Permian alkaline plutons. The first Guangxingyuan Pluton occurs in the Hexigten area and is composed of MME-bearing tonalite, K-feldspar granite and syenite. The second Durenwuliji Pluton, located in the Xianghuangqi area, comprises syenite, quartz syenite and K-feldspar granite. Zircon U-Pb dating on tonalite, K-feldspar granite, syenite and quartz syenite from the two plutons yielded a tight range of ages from 259 to 267 Ma. The peralkaline-alkaline rocks show high abundance of total alkalis (K2O + Na2O = 7.9-12.9%) and K2O contents (3.9-8.0%), enrichment in large ion lithophile elements (LILE) and light rare earth element (LREE), and depletion of high field strength elements (HFSE). The associated tonalite and MMEs display I-type granitic geochemical affinity, with less total abundance of trace elements than the peralkaline-alkaline rocks. Zircon Hf isotopic analysis of the Guangxingyuan pluton yielded a large range of εHf(t) values from - 15.5 to + 6.7 and model ages (TDMC) from 781 to 2012 Ma. By contrast, the Hf isotopic data of the Durenwuliji pluton shows a small range of εHf(t) from + 6.2 to + 8.9 and TDMC from 667 to 816 Ma. The geochemical and Hf isotopic characteristics indicate that the parental magma was derived from a mixing of metasomatic mantle-derived mafic magma with different amount of crust-derived felsic magma, and followed by fractional crystallization. Considering previous tectonic studies in Inner Mongolia, a Permian post-orogenic extension was proposed to account for these peralkaline-alkaline intrusions following

  17. Field and Microstructure Study of Transpressive Jogdadi shear zone near Ambaji, Aravalli- Delhi Mobile Belt, NW India and its tectonic implication on the exhumation of granulites.

    Science.gov (United States)

    Tiwari, Sudheer Kumar; Biswal, Tapas Kumar

    2016-04-01

    Aravalli- Delhi mobile belt is situated in the northwestern part of Indian shield. It comprises tectono- magmatic histories from Archean to Neoproterozoic age. It possesses three tectono- magmatic metamorphic belts namely Bhilwara Supergroup (3000 Ma), Aravalli Supergorup (1800 Ma) and Delhi Supergroup (1100 -750Ma). The Delhi Supergroup is divided in two parts North Delhi and South Delhi; North Delhi (1100 Ma to 850 Ma) is older than South Delhi (850 Ma to 750 Ma). The study area falls in the South Delhi terrane; BKSK granulites are the major unit in this terrane. BKSK granulites comprise gabbro- norite-basic granulite, pelitic granulite, calcareous granulite and occur within the surrounding of low grade rocks as meta- rhyolite, quartzite, mica schist and amphibolites. The high grade and low grade terranes share a sheared margin. Granulites have undergone three phases of folding, intruded by three phases of granites and traversed by many shear zones. One of the shear zones is Jogdadi shear zone which consists of granitic mylonites and other sheared rocks. Jogdadi shear zone carries the evidence of both ductile as well as brittle shearing. It strikes NW- SE; the mylonitic foliation dip moderately to SW or NE and stretching lineations are oblique towards SE. The shear zone is folded and gabbro- norite - basic granulite occurs at the core. One limb of fold passes over coarse grained granite while other limb occurs over gabbro- norite- basic granulite. Presence of mylonitic foliation, asymmetric folding, S-C fabrics, porphyroclasts, mica fishes and book shelf- gliding are indicative of ductile deformation. Most of the porphyroclasts are sigmoidal and delta types but there are also some theta and phi type porphyroclasts. Book shelf-gliding structures are at low angle to the C plane. The shear zone successively shows protomylonite, mylonite and ultramylonites from margin to the centre. As the mylonitization increases recrystallized quartz grains appear. Porphyroclasts

  18. P- T- t constraints on the development of the Doi Inthanon metamorphic core complex domain and implications for the evolution of the western gneiss belt, northern Thailand

    Science.gov (United States)

    Macdonald, A. S.; Barr, S. M.; Miller, B. V.; Reynolds, P. H.; Rhodes, B. P.; Yokart, B.

    2010-01-01

    The western gneiss belt in northern Thailand is exposed within two overlapping Cenozoic structural domains: the extensional Doi Inthanon metamorphic core complex domain located west of the Chiang Mai basin, and the Mae Ping strike-slip fault domain located west of the Tak batholith. New P- T estimates and U-Pb and 40Ar/ 39Ar age determinations from the Doi Inthanon domain show that the gneiss there records a complex multi-stage history that can be represented by a clockwise P- T- t path. U-Pb zircon and titanite dating of mylonitic calc-silicate gneiss from the Mae Wang area of the complex indicates that the paragneissic sequence experienced high-grade, medium-pressure metamorphism (M1) in the Late Triassic - Early Jurassic (ca. 210 Ma), in good agreement with previously determined zircon ages from the underlying core orthogneiss exposed on Doi Inthanon. Late Cretaceous monazite ages of 84 and 72 Ma reported previously from the core orthogneiss are attributed to a thermal overprint (M2) to upper-amphibolite facies in the sillimanite field. U-Pb zircon and monazite dating of granitic mylonite from the Doi Suthep area of the complex provides an upper age limit of 40 Ma (Late Eocene) for the early stage(s) of development of the actual core complex, by initially ductile, low-angle extensional shearing under lower amphibolite-facies conditions (M3), accompanied by near-isothermal diapiric rise and decompression melting. 40Ar/ 39Ar laserprobe dating of muscovite from both Doi Suthep and Doi Inthanon provided Miocene ages of ca. 26-15 Ma, representing cooling through the ca. 350 °C isotherm and marking late-stage development of the core complex by detachment faulting of the cover rocks and isostatic uplift of the sheared core zone and mantling gneisses in the footwall. Similarities in the thermochronology of high-grade gneisses exposed in the core complex and shear zone domains in the western gneiss belt of northern Thailand (and also in northern Vietnam, Laos, Yunnan

  19. Toroidal, Counter-Toroidal, and Upwelling Flow in the Mantle Wedge of the Rivera and Cocos Plates: Implications for IOB Geochemistry in the Trans-Mexican Volcanic Belt

    Science.gov (United States)

    Neumann, Florian; Vásquez-Serrano, Alberto; Tolson, Gustavo; Negrete-Aranda, Raquel; Contreras, Juan

    2016-10-01

    We carried out analog laboratory modeling at a scale 1:4,000,000 and computer rendering of the flow patterns in a simulated western Middle American subduction zone. The scaled model consists of a transparent tank filled with corn syrup and housing two conveyor belts made of polyethylene strips. One of the strips dips 60° and moves at a velocity of 30 mm/min simulating the Rivera plate. The other one dips 45°, moves at 90 mm/min simulating the subduction of the Cocos plate. Our scaled subduction zone also includes a gap between the simulated slabs analogous to a tear recently observed in shear wave tomography studies. An acrylic plate 3 mm thick floats on the syrup in grazing contact with the polyethylene strips and simulates the overriding North America plate. Our experiments reveal a deep toroidal flow of asthenospheric mantle through the Cocos-Rivera separation. The flow is driven by a pressure gradient associated with the down-dip differential-motion of the slabs. Similarly, low pressure generated by the fast-moving Cocos plate creates a shallow counter-toroidal flow in the uppermost 100 km of the mantle wedge. The flow draws mantle beneath the western Trans-Mexican Volcanic Belt to the Jalisco block, then plunges into the deep mantle by the descending poloidal cell of the Cocos slab. Moreover, our model suggests a hydraulic jump causes an ~250 km asthenosphere upwelling around the area where intra-arc extensional systems converge in western Mexico. The upwelling eventually merges with the shallow counter-toroidal flow describing a motion in 3D space similar to an Archimedes' screw. Our results indicate the differential motion between subducting slabs drives mixing in the mantle wedge of the Rivera plate and allows the slab to steepen and retreat. Model results are in good agreement with seismic anisotropy studies and the geochemistry of lavas erupted in the Jalisco block. The model can explain the eruption of OIB lavas in the vicinity of the City of

  20. Geochemistry of Gneisses from Dabie Complex and Tongbai Complex in Qinling-Tongbai-Dabie Orogenic Belt: Implications for Location of Yangtze-Sino-Korean Suture

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The Dabie complex (DC) and the Tongbai complex (TBC) are separately distributed in the middle and eastern parts of the Qinling-Tongbai-Dabie orogenic belt. In this study, the Dabie complex can be divided into two units: one is the complex with no high pressure and ultrahigh pressure metamorphic rocks (DC1), and the other is the complex containing coesite-bearing eclogite lenses or boudins (DC2). Gneisses are predominant in the TBC, DC1 and DC2. Major and trace element data of gneisses in the TBC, DC1 and DC2 show them to be the orthogneisses. The gneisses in the DC1 have higher incompatible element contents and higher ratios of w(K2O)/w(Na2O) and w(La)n/w(Yb)n than those in the DC2. However, no obvious differences arise in other element contents and the ratios of w(La)/w( Nb), w(Nb)/w(Th), w(Nb)/w(Hf), w(Ba)/w(La), w(Sm)/w(Nd) and w(Th)/w(U) between the gneisses in the DC2 and those in the DC1. These observations suggest that the protoliths of the gneisses in the DC2 have affinities to those in the DC1. The difference between the DC1 and DC2 gneisses in incompat- ible element contents could reflect the difference in their partial melting extent. The TBC gneisses are geochemically similar to the DC1 gneisses, suggesting that the TBC and DC1 gneisses are the same lithologic unit in the Qinling-Tongbai-Dabie orogenic belt and that they have experienced similar formations and evolution histories. In the Qinling-Tongbai area, the TBC is part of the northern blocks of the Yangtze craton. Given the similarity of geochemical characteristics, the rock assemblage and the ages between the TBC and DC1 gneisses, we can infer that the Dabie complex also belongs to the northern blocks of the Yangtze craton. In terms of the distribution of eciogites and metamorphic facies, we propose that the collisionai suture in the Dabie area is distributed along the Xiaotian-Mozitan fault, at the contact with the Shang-Dan-Tongbai fault to the west.

  1. U-Pb, Re-Os and Ar-Ar dating of the Linghou polymetallic deposit, Southeastern China: Implications for metallogenesis of the Qingzhou-Hangzhou metallogenic belt

    Science.gov (United States)

    Tang, Yanwen; Xie, Yuling; Liu, Liang; Lan, Tingguan; Yang, Jianling; Sebastien, Meffre; Yin, Rongchao; Liang, Songsong; Zhou, Limin

    2017-04-01

    The Qingzhou-Hangzhou metallogenic belt (QHMB) in Southeastern China has gained increasingly attention in recent years. However, due to the lack of reliable ages on intrusions and associated deposits in this belt, the tectonic setting and metallogenesis of the QHMB have not been well understood. The Linghou polymetallic deposit in northwestern Zhejiang Province is one of the typical deposits of the QHMB. According to the field relationships, this deposit consists of the early Cu-Au-Ag and the late Pb-Zn-Cu mineralization stages. Molybdenite samples with a mineral assemblage of molybdenite-chalcopyrite-pyrite ± quartz are collected from the copper mining tunnel near the Cu-Au-Ag ore bodies. Six molybdenite samples give the Re-Os model ages varying from 160.3 to 164.1 Ma and yield a mean age of 162.2 ± 1.4 Ma for the Cu-Au-Ag mineralization. Hydrothermal muscovite gives a well-defined Ar-Ar isochron age of 160.2 ± 1.1 Ma for the Pb-Zn-Cu mineralization. Three phases of granodioritic porphyry have been distinguished in this deposit, and LA-ICP-MS zircon U-Pb dating shows that they have formed at 158.8 ± 2.4 Ma, 158.3 ± 1.9 Ma and 160.6 ± 2.1 Ma, comparable to the obtained ages of the Cu-Au-Ag and Pb-Zn-Cu mineralization. Therefore, these intrusive rocks have a close temporal and spatial relationship with the Cu-Au-Ag and Pb-Zn-Cu ore bodies. The presences of skarn minerals (e.g., garnet) and vein-type ores, together with the previous fluid inclusion and H-O-C-S-Pb isotopic data, clearly indicate that the Cu-Au-Ag and Pb-Zn-Cu mineralization are genetically related to these granodiorite porphyries. This conclusion excludes the possibility that this deposit is of ;SEDEX; type and formed in a sag basin of continental rifts setting as previously proposed. Instead, it is proposed that the Linghou polymetallic and other similar deposits in the QHMB, such as the 150-160 Ma Yongping porphyry-skarn Cu-Mo, Dongxiang porphyry? Cu, Shuikoushan/Kangjiawang skarn Pb

  2. Toroidal, Counter-Toroidal, and Upwelling Flow in the Mantle Wedge of the Rivera and Cocos Plates: Implications for IOB Geochemistry in the Trans-Mexican Volcanic Belt

    Science.gov (United States)

    Neumann, Florian; Vásquez-Serrano, Alberto; Tolson, Gustavo; Negrete-Aranda, Raquel; Contreras, Juan

    2015-12-01

    We carried out analog laboratory modeling at a scale 1:4,000,000 and computer rendering of the flow patterns in a simulated western Middle American subduction zone. The scaled model consists of a transparent tank filled with corn syrup and housing two conveyor belts made of polyethylene strips. One of the strips dips 60° and moves at a velocity of 30 mm/min simulating the Rivera plate. The other one dips 45°, moves at 90 mm/min simulating the subduction of the Cocos plate. Our scaled subduction zone also includes a gap between the simulated slabs analogous to a tear recently observed in shear wave tomography studies. An acrylic plate 3 mm thick floats on the syrup in grazing contact with the polyethylene strips and simulates the overriding North America plate. Our experiments reveal a deep toroidal flow of asthenospheric mantle through the Cocos-Rivera separation. The flow is driven by a pressure gradient associated with the down-dip differential-motion of the slabs. Similarly, low pressure generated by the fast-moving Cocos plate creates a shallow counter-toroidal flow in the uppermost 100 km of the mantle wedge. The flow draws mantle beneath the western Trans-Mexican Volcanic Belt to the Jalisco block, then plunges into the deep mantle by the descending poloidal cell of the Cocos slab. Moreover, our model suggests a hydraulic jump causes an ~250 km asthenosphere upwelling around the area where intra-arc extensional systems converge in western Mexico. The upwelling eventually merges with the shallow counter-toroidal flow describing a motion in 3D space similar to an Archimedes' screw. Our results indicate the differential motion between subducting slabs drives mixing in the mantle wedge of the Rivera plate and allows the slab to steepen and retreat. Model results are in good agreement with seismic anisotropy studies and the geochemistry of lavas erupted in the Jalisco block. The model can explain the eruption of OIB lavas in the vicinity of the City of

  3. Multiple edifice-collapse events in the Eastern Mexican Volcanic Belt: The role of sloping substrate and implications for hazard assessment

    Science.gov (United States)

    Carrasco-Nunez, Gerardo; Diaz-Castellon, Rodolfo; Siebert, L.; Hubbard, B.; Sheridan, M.F.; Rodriguez, Sergio R.

    2006-01-01

    Belt. However, critical pore water pressure from extraordinary amounts of rainfall associated with hurricanes or other meteorological perturbation cannot be ruled out, particularly for smaller volume collapses. There are examples in the area of small seismogenic debris flows that have occurred in historical times, showing that these processes are not uncommon. Assessing the stability conditions of major volcanic edifices that have experienced catastrophic sector collapses is crucial for forecasting future events. This is particularly true for the Eastern Mexican Volcanic Belt, where in many cases no magmatic activity was associated with the collapse. Therefore, edifice failure could occur again without any precursory warning. ?? 2006 Elsevier B.V. All rights reserved.

  4. Zircon Senstive High Resolution Ion Microprobe (SHRIMP) study of granitoid intrusions in Zhaoye Gold Belt of Shandong Province and its implication

    Institute of Scientific and Technical Information of China (English)

    苗来成; 罗镇宽; 黄佳展; 关康; N.J. McNaughton; D. I. Groves

    1997-01-01

    The zircon Sensitive High Resolution Ion Microprobe (SHRIMP) results show that granitoid intrusions in Zhaoyc Gold Belt were emplaced at two periods of Mesozoic: Linglong and Luanjiahe types of granitic intrusions were emplaced between 160 Ma and 150 Ma (late Jurassic); Guojialing type of granodioritic intrusions, 130 Ma and 126 Ma (early Cretaceous). All the three types contain at least two major generations of inherited zircons with Precambrian ( >650 Ma) and early Mesozoic ages (200-250 Ma), respectively. The former suggests that these plu-tonic rocks are of crustal origin and that Precambrian basement with component of sialic crust up to 3.4 Ga old ( Middle Archean) exists in the region. The presence of abundant inherited zircons with early Mesozoic age indicates that the Precambrian basement was affected by a major tectono-thermal event, that is the collision of the North and South China blocks, at 250 Ma to 200 Ma. SHRIMP results also indicate that the gold mineralization in the region took place

  5. Teleseismic P-wave tomography and the upper mantle structure of the Sulu orogenic belt (China): implications for Triassic collision and exhumation mechanism

    Science.gov (United States)

    Peng, Miao; Tan, Handong; Jiang, Mei; Xu, Zhiqin; Li, Zhonghai; Xu, Lehong

    2016-12-01

    As the largest ultrahigh-pressure (UHP) metamorphic tectonic unit outcropping in the world, the Dabie-Sulu UHP metamorphic belt is considered to be one of the best areas for studying the continental dynamics. However, their continental collision and exhumation mechanism are still debated. We performed a 3D teleseismic P-wave tomography beneath the Sulu orogen for the purpose of understanding the deep structure. The tomographic results show that there is a prominently near-SN-trending low-velocity zone (LVZ) close to the Tanlu fault (TLF), indicating a slab tear of the subducted Yangtze plate (YZP) during the initial Early Triassic collision. Our results also suggest that both the Yangze crustal slab and the North China lithospheric slab were dragged downwards by the subducted oceanic slab, which constituted a ‘two-sided’ subduction mode. A conceptual geodynamic model is proposed to explain the exhumation of Sulu high- to UHP rocks and imply a polyphase exhumation driven by buoyancy of continental materials at different depth and upward extrusion of crustal partial melting rocks to the surface at the later stage.

  6. Thermochronology of Mesozoic Sandstone from the Beipiao Basin and Its Implication to Meso-Cenozoic Tectonic Evolution of the Eastern Yan-Liao Orogenic Belt

    Institute of Scientific and Technical Information of China (English)

    YAN Yi; LIN Ge; XIA Bin; LI Zi'an; LI Zhongcheng

    2005-01-01

    Combining the single-grain low-temperature apatite fission track with high-temperature zircon U-Pb dating of sandstone can better reveal the temporal association between the source and depositional site, and identify both the age component of the source terrain and subsequent thermo-tectohic events after deposition. This paper introduces the singlegrain zircon U-Pb dating and fission track (FT) dating of sediments from the Beipiao basin in Northeast China. The U-Pb ages of 18 single zircon grains collected from the early Jurassic Beipiao Formation range from 194.3±2.9 to 233.8±4.2 Ma and most of apatite FI ages are about 30-40 Ma, indicating that the eastern part of the Yan-Liao orogenic belt experienced an obvious tectonic seesawing during Meso-Cenozoic time. The eastern part of Liaoning Province (the Liaodong block)uplifted in the early Mesozoic (230-190 Ma) and formed a geological landscape of high mountains, while the western part of the province (the Liaoxi area) subsided relatively and thousand-meter-scale sediments were deposited. During the Cenozoic (30-40 Ma), the Liaoxi area uplifted as a whole, and the Xialiaohe Basin sank intensively. The topographic landscape had a great change: high mountains in the west and east of Liaoning Province and low plains in the central area.

  7. Geochemistry of the Caledonian Basic Volcanic Rocks at the South Margin of the Qinling Orogenc Belt,and Its Tectonic Implications

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The geochemistry of the basic volcanic rocks at the south margin of the Qinling orogenic belt(SMQOB) suggests that they were formed in an intraplate tectonic setting.The REE distribution patterns show these rocks are strongly enriched in LREE with high ∑REE, and their trace elements geochemistry is similar to that of contimental flood basalt.All the above evidence suggests that the Caledonian basic volcanic rocks in the SMQOB were tholeiitic basalts formed in an intraplate spreading-initial rift tectonic setting.The characteristics of regional geology and geochemistry indicate that there was an intraplate spreading-rift tectonic setting between the South Qingling block and the Yangtze block in the Caledonian epoch.The dynamic spreading in this district began in the Early Caledonian and then the intraplate spreadinginitial rifts were formed in the Late Caledonian.As a result of spreading of the Tethys and geodynamic processes in deep mantle ,the Mianlue-Huashan oceanic basin was formed between the Qinling block and the Yangtze block in Devonian,and the Qinling microplate was separated from the northern part of the Yangtze plate.

  8. VERO cells harbor a poly-ADP-ribose belt partnering their epithelial adhesion belt

    Directory of Open Access Journals (Sweden)

    Laura Lafon-Hughes

    2014-10-01

    Full Text Available Poly-ADP-ribose (PAR is a polymer of up to 400 ADP-ribose units synthesized by poly-ADP-ribose-polymerases (PARPs and degraded by poly-ADP-ribose-glycohydrolase (PARG. Nuclear PAR modulates chromatin compaction, affecting nuclear functions (gene expression, DNA repair. Diverse defined PARP cytoplasmic allocation patterns contrast with the yet still imprecise PAR distribution and still unclear functions. Based on previous evidence from other models, we hypothesized that PAR could be present in epithelial cells where cadherin-based adherens junctions are linked with the actin cytoskeleton (constituting the adhesion belt. In the present work, we have examined through immunofluorescence and confocal microscopy, the subcellular localization of PAR in an epithelial monkey kidney cell line (VERO. PAR was distinguished colocalizing with actin and vinculin in the epithelial belt, a location that has not been previously reported. Actin filaments disruption with cytochalasin D was paralleled by PAR belt disruption. Conversely, PARP inhibitors 3-aminobenzamide, PJ34 or XAV 939, affected PAR belt synthesis, actin distribution, cell shape and adhesion. Extracellular calcium chelation displayed similar effects. Our results demonstrate the existence of PAR in a novel subcellular localization. An initial interpretation of all the available evidence points towards TNKS-1 as the most probable PAR belt architect, although TNKS-2 involvement cannot be discarded. Forthcoming research will test this hypothesis as well as explore the existence of the PAR belt in other epithelial cells and deepen into its functional implications.

  9. Reconstructing multiple arc-basin systems in the Altai-Junggar area (NW China): Implications for the architecture and evolution of the western Central Asian Orogenic Belt

    Science.gov (United States)

    Li, Di; He, Dengfa; Tang, Yong

    2016-05-01

    The Altai-Junggar area in northwestern China is a critical region to gain insights on the tectonic framework and geological evolution of the western Central Asian Orogenic Belt (CAOB). In this study, we report results from integrated geological, geochemical and geophysical investigations on the Wulungu Depression of the Junggar Basin to determine the basement nature of the basin and understand its amalgamation history with the Chinese Altai, within the broad tectonic evolution of the Altai-Junggar area. Based on borehole and seismic data, the Wulungu Depression is subdivided into two NW-trending tectonic units (Suosuoquan Sag and Hongyan High) by southward-vergent thrust faults. The Suosuoquan Sag consists of the Middle-Late Devonian basaltic andesite, andesite, dacite, tuff, tuffaceous sandstone and tuffite, and the overlying Early Carboniferous volcano-sedimentary sequence with lava flows and shallow marine sediments from a proximal juvenile provenance (zircon εHf(t) = 6.0-14.9), compared to the Late Carboniferous andesite and rhyolite in the Hongyan High. Zircon SIMS U-Pb ages for dacites and andesites indicate that these volcanics in the Suosuoquan Sag and Hongyan High erupted at 376.3 Ma and 313.4 Ma, respectively. The Middle-Late Devonian basaltic andesites from well LC1 are calc-alkaline and exhibit primitive magma-like MgO contents (7.9-8.6%) and Mg# values (66-68), with low initial 87Sr/86Sr (0.703269-0.704808) and positive εNd(t) values (6.6-7.6), and relatively high Zr abundance (98.2-116.0 ppm) and Zr/Y ratios (5.1-5.4), enrichment in LREEs and LILEs (e.g., Th and U) and depletion in Nb, Ta and Ti, suggesting that they were probably derived from a metasomatized depleted mantle in a retro-arc extensional setting. The well LC1 andesitic tuffs, well L8 dacites, well WL1 dacitic tuffs and well L5 andesites belong to calc-alkaline and metaluminous to peraluminous (A/CNK = 0.8-1.7) series, and display low Mg# values (35-46) and variably positive εNd(t) (4

  10. U-Pb SHRIMP and Sm-Nd geochronology of the Silvânia Volcanics and Jurubatuba Granite: juvenile Paleoproterozoic crust in the basement of the Neoproterozoic Brasília Belt, Goiás, central Brazil

    Directory of Open Access Journals (Sweden)

    FISCHEL DANIELLE P.

    2001-01-01

    Full Text Available U-Pb SHRIMP and Sm-Nd isotopic ages were determined for felsic metavolcanic rocks from the Silvânia Sequence and Jurubatuba Granite in the central part of the Brasília Belt. Zircon grains from a metavolcanic sample yielded 2115 ± 23 Ma and from the granite yielded 2089 ± 14 Ma, interpreted as crystallization ages of these rocks. Six metavolcanic samples of the Silvânia Sequence yielded a six-point whole-rock Sm-Nd isochron indicating a crystallization age of 2262 ± 110 Ma and positive epsilonNd(T = +3.0 interpreted as a juvenile magmatic event. Nd isotopic analyses on samples from the Jurubatuba Granite have Paleoproterozoic T DM model ages between 2.30 and 2.42 Ga and epsilonNd(T values vary between -0.22 and -0.58. The oldest T DM value refers to a sedimentary xenolith in the granite. These results suggest crystallization ages of Silvânia volcanics and Jurubatuba Granite are the first evidence of a ca. 2.14-2.08 juvenile magmatic event in the basement of the central part of the Brasília Belt that implies the presence of arc/suture hidden in reworked basement of the Brasília Belt.

  11. Crustal nature and origin of the Russian Altai: Implications for the continental evolution and growth of the Central Asian Orogenic Belt (CAOB)

    Science.gov (United States)

    Cai, Keda; Sun, Min; Buslov, M. M.; Jahn, Bor-ming; Xiao, Wenjiao; Long, Xiaoping; Chen, Huayong; Wan, Bo; Chen, Ming; Rubanova, E. S.; Kulikova, A. V.; Voytishek, E. E.

    2016-04-01

    The Central Asian Orogenic Belt is a gigantic tectonic collage of numerous accreted terranes. However, its geodynamic evolution has been hotly debated primarily due to incomplete knowledge on the nature of these enigmatic terranes. This work presents new detrital zircon U-Pb and Hf isotopic data to constrain the crustal nature and origin of the Russian Altai, a critical segment of Altai-Mongolian terrane. The youngest zircon 206Pb/238U ages of 470 Ma constrain that the Terekta Formation, previously envisaged as Precambrian basement, was actually deposited after the Middle Ordovician. As for the three more sedimentary sequences above the Terekta Formation, they have youngest zircon 206Pb/238U ages of 425 Ma, 440 Ma and 380 Ma, respectively, indicating their depositions likely in the Late Silurian to Devonian. From all analyses, it is noted that many zircon U-Pb ages cluster at ca. 520 Ma and ca. 800 Ma, and these zircons display oscillatory zoning and have subhedral to euhedral morphology, which, collectively, suggests that adjacent Neoproterozoic to Paleozoic igneous rocks were possibly dominant in the sedimentary provenance. Additionally, a few rounded Archean to Mesoproterozoic zircon grains are characterized by complex texture, which are interpreted as recycling materials probably derived from the Tuva-Mongolian microcontinent. Precambrian rocks have not been identified in the Russian Altai, Chinese Altai and Mongolian Altai so far, therefore, Precambrian basement may not exist in the Altai-Mongolian terrane, but this terrane probably represents a large subduction-accretion complex built on the margin of the Tuva-Mongolian microcontinent in the Early Paleozoic. Multiple episodes of ridge-trench interaction may have caused inputs of mantle-derived magmas to trigger partial melting of the newly accreted crustal materials, which contributed to the accretionary complex. During accretionary orogenesis of the CAOB, formation of such subduction-accretion complex is

  12. Microstructural analysis of a subhorizontal gold-quartz vein deposit at Donalda, Abitibi greenstone belt, Canada: Implications for hydrodynamic regime and fluid-structural relationship

    Directory of Open Access Journals (Sweden)

    Guoxiang Chi

    2011-10-01

    Full Text Available The Donalda gold deposit in the southern part of the Archean Abitibi greenstone belt consists mainly of a subhorizontal gold-quartz vein perpendicular to subvertical shear zones. The 0.3–0.5 m thick vein is characterized by vein-parallel banding structures indicating multiple episodes of fracture opening and mineral precipitation. Measurement of the c-axis of primary growth quartz indicates that quartz preferentially grew perpendicular to the fracture, suggesting open space filling and/or extensional nature of the fracture. Measurement of the orientations of microfractures, veinlets and fluid–inclusion planes (FIPs crosscutting primary growth quartz indicates that the vein minerals were subject to a vertical maximum principal stress (σ1, which is inconsistent with the subhorizontal σ1 inferred from the regional stress field with N–S shortening. This apparent discrepancy is explained by invoking episodic fluid pressure fluctuation between supralithostatic and hydrostatic regimes accompanied by episodic opening and closing of the subhorizontal fracture. When fluid pressure was higher than the lithostatic value, the fracture was opened and primary growth minerals were precipitated, whereas when fluid pressure decreased toward the hydrostatic value, the hanging wall of the fracture collapsed, causing collision of protruding primary growth minerals from both sides of the fracture and resulting in formation of vein-parallel deformation bands. The columns where the two facing sides of the fracture collided were subject to higher-than-lithostatic stress due to the bridging effect and reduced support surface area, explaining the development of vertical σ1. This hypothesis is consistent the fault-valve model, and explains the flipping of σ1 without having to change the regional stress field.

  13. Petrology, magnetostratigraphy and geochronology of the Miocene volcaniclastic Tepoztlán Formation: implications for the initiation of the Transmexican Volcanic Belt (Central Mexico)

    Science.gov (United States)

    Lenhardt, Nils; Böhnel, Harald; Wemmer, Klaus; Torres-Alvarado, Ignacio S.; Hornung, Jens; Hinderer, Matthias

    2010-09-01

    The volcaniclastic Tepoztlán Formation (TF) represents an important rock record to unravel the early evolution of the Transmexican Volcanic Belt (TMVB). Here, a depositional model together with a chronostratigraphy of this Formation is presented, based on detailed field observations together with new geochronological, paleomagnetic, and petrological data. The TF consists predominantly of deposits from pyroclastic density currents and extensive epiclastic products such as tuffaceous sandstones, conglomerates and breccias, originating from fluvial and mass flow processes, respectively. Within these sediments fall deposits and lavas are sparsely intercalated. The clastic material is almost exclusively of volcanic origin, ranging in composition from andesite to rhyolite. Thick gravity-driven deposits and large-scale alluvial fan environments document the buildup of steep volcanic edifices. K-Ar and Ar-Ar dates, in addition to eight magnetostratigraphic sections and lithological correlations served to construct a chronostratigraphy for the entire Tepoztlán Formation. Correlation of the 577 m composite magnetostratigraphic section with the Cande and Kent (1995) Geomagnetic Polarity Time Scale (GPTS) suggests that this section represents the time intervall 22.8-18.8 Ma (6Bn.1n-5Er; Aquitanian-Burdigalian, Lower Miocene). This correlation implies a deposition of the TF predating the extensive effusive activity in the TMVB at 12 Ma and is therefore interpreted to represent its initial phase with predominantly explosive activity. Additionally, three subdivisions of the TF were established, according to the dominant mode of deposition: (1) the fluvial dominated Malinalco Member (22.8-22.2 Ma), (2) the volcanic dominated San Andrés Member (22.2-21.3 Ma) and (3) the mass flow dominated Tepozteco Member (21.3-18.8 Ma).

  14. Flux rates for water and carbon during greenschist facies metamorphism: implications for the role of orogenic belts as a source/sink for atmospheric CO2

    Science.gov (United States)

    Skelton, A.

    2010-12-01

    The time-averaged flux rate for a CO2-bearing hydrous fluid during greenschist facies regional metamorphism was estimated to 10-10.2 ± 0.4 m3.m-2.s-1. This was evaluated by combining 1) Peclet numbers obtained by chromatographic analysis of the propagation of reaction fronts in 33 metamorphosed basaltic sills in the SW Scottish Highlands, 2) empirical diffusion rates for CO2 in water obtained by Wark & Watson (2003), and 3) calculated time-averaged metamorphic porosities. The latter were calculated using an expression obtained by combining estimated Peclet numbers with the empirical porosity - permeability relationships obtained by Wark and Watson (1998) and Price et al. (2006) and Darcy’s law. This approach yielded a time-averaged metamorphic porosity of 10-2.6 ± 0.2 for greenschist facies conditions. The corresponding timescale for metamorphic fluid flow was 103.6 ± 0.1 years. By using mineral assemblages to constrain fluid compositions, I further obtained a time-averaged annual flux rate for carbon of 0.5-7 mol-C.m-2.yr-1. This matches measured emission rates for metamorphic CO2 from orogenic hot springs. These fluxes significantly exceed estimated rates of CO2 drawdown by orogenic silicate weathering and therefore indicate that orogenic belts are a source rather than a sink of atmospheric CO2. Thin section in XPL showing replacement of amphibole by calcite recording syn-metamorphic carbonation of a metamorphosed basaltic sill in the SW Scottish Highlands.

  15. Polyphase deformation and metamorphism of the Cuiabá group in the Poconé region (MT, Paraguay Fold and Thrust Belt: kinematic and tectonic implications

    Directory of Open Access Journals (Sweden)

    Bruno Rodrigo Vasconcelos

    Full Text Available Several deformation models have been proposed for the Paraguay Belt, which primarily differ in the number of phases of deformation, direction of vergence and tectonic style. Structural features presented in this work indicate that the tectonics was dominated by low dip thrust sheets in an initial phase, followed by two progressive deformation phases. The first phase of deformation is characterized by a slate cleavage and axial plane of isoclinal recumbent folds with a NE axial direction, with a recrystallization of the minerals in the greenschist facies associated with horizontal shear zones with a top-to-the-SE sense of movement. The second stage shows vergence towards the NW, characterized by crenulation cleavage axial plane to F2 open folds over S0 and S1, locally associated with reverse faults. The third phase of deformation is characterized by subvertical faults and fractures with a NW direction showing sinistral movement, which are commonly filled by quartz veins. The collection of tectonic structures and metamorphic paragenesis described indicate that the most intense deformation at the deeper crustal level, greenschistfacies, occurred during F1, which accommodated significant crustal shortening through isoclinal recumbent folds and shear zones with low dip angles and hangwall movement to the SE, in a thin-skinned tectonic regime. The F2 deformation phase was less intense and had a brittle to ductile behavior that accommodated a slight shortening through normal open subvertical folds, and reverse faults developed in shallower crustal level, with vergence towards the Amazonian Craton. The third phase was less pervasive, and the shortening was accommodated by relief subvertical sinistral faults.

  16. The thrust contact between the Canastra and Vazante groups in the Southern Brasília Belt: structural evolution, white mica crystallinity and implications for the Brasiliano orogeny

    Directory of Open Access Journals (Sweden)

    Manuela de Oliveira Carvalho

    Full Text Available ABSTRACT: Two regional thrust-sheets of Neoproterozoic metasedimentary rocks occur in the Southern Brasília Belt, northwest Minas Gerais. The lower one comprises the Vazante Group, that is formed in the studied area, from base to top, by the Serra do Garrote (metapelites interlayered with carbonaceous phyllite, Serra do Poço Verde (beige to pink stromatolitic metadolomite with interlayered greenish slates, Morro do Calcário (gray stromatolitic metadolomite interlayered with gray slates and Serra da Lapa (phyllite with dolarenitic lenses interlayered with slates formations. The upper thrust sheet consists of the Canastra Group (Paracatu formation: laminated sericite phyllites and carbonaceous phyllites interlayered with quartzite. The Braziliano orogeny resulted in four phases of contractional deformation, associated with low-grade metamorphism. The first two (D1 and D2 are ductile, while the third and fourth ones (D3 and D4 are brittle-ductile. D1 developed a slaty S1 cleavage subparallel to the primary layering, with shallow to steep dips to NW. D2 developed a crenulation cleavage (S2 that dips moderately to NW and is associated with tight to isoclinal folds. D3 and D4 phases developed crenulations and open folds and kink bands. S3 dips steeply to NW, while S4 has moderate to steep dips to NE and SW. White mica crystallinity (Kübler index measurements in metapelites indicate that both the Canastra and Vazante groups reached anchizone/epizone conditions, and metamorphic discontinuities along thrusts indicate that the peak of metamorphism is pre or syn-thrusting.

  17. Thick-skinned tectonics within the intracontinental easternmost Atlas foreland-and-thrust belt (Tunisia): Meso-Cenozoic kinematics and implications for regional geodynamics

    Science.gov (United States)

    Belkhiria, W.; Boussiga, H.; Inoubli, M. H.

    2017-05-01

    The transition zone between western and central Mediterranean domains presents a key area to investigate kinematic interactions within the adjacent orogen systems such as the easternmost Atlas foreland-and-thrust belt. Gravity and seismic data revealed a highly structured basement, characterizing a series of structural highs and lows delimited by high-angle N-S, E-W, and NW-SE extensional faults. This basement architecture is inherited from successive extensional events related to the openings of the Triassic-Early Cretaceous Tethys oceans (i.e., Alpine Tethys, Ligurian Tethys, and Mesogea). Throughout this period, this mosaic of continental blocks significantly controlled the thickness and facies distributions. Early stages of diapirism took place along these basement faults and allowed maximum subsidence in minibasins revealed by the development of growth strata. In response to the Late Cretaceous-Eocene shortenings, these extensional faults have been reactivated as trasnpressional shear zones, giving rise to narrow pop-up structures. In addition, gravity modeling indicates crustal thinning and deep-rooted faults affecting the crust south of the Zaghouan Thrust and along E-W transfer zones. From the late Miocene, a drastic change in the stress regime is attributed to the effect of the adjacent Sicily channel on the study area. This promotes crustal thinning, basin subsidence, and channeling up of mantle-derived helium along lithospheric-scale weak zones. Our results give rise to new insights into the reactivation of inherited weakness zones of southern Tethys margin in response to the complex interaction between African and Eurasian plates accommodated by subduction, rollback, collision, and slab segmentation.

  18. Tourmaline from the Archean G.R.Halli gold deposit, Chitradurga greenstone belt, Dharwar craton (India):Implications for the gold metallogeny

    Institute of Scientific and Technical Information of China (English)

    Susmita Gupta; M. Jayananda; Fareeduddin

    2014-01-01

    Tourmaline occurs as a minor but important mineral in the alteration zone of the Archean orogenic gold deposit of Guddadarangavanahalli (G.R.Halli) in the Chitradurga greenstone belt of the western Dharwar craton, southern India. It occurs in the distal alteration halo of the G.R.Halli gold deposit as (a) clusters of very fine grained aggregates which form a minor constituent in the matrix of the altered metabasalt (AMB tourmaline) and (b) in quartz-carbonate veins (vein tourmaline). The vein tourmaline, based upon the association of specific carbonate minerals, is further grouped as (i) albite-tourmaline-ankerite-quartz veins (vein-1 tourmaline) and (ii) albite-tourmaline-calcite-quartz veins (vein-2 tourmaline). Both the AMB tourmaline and the vein tourmalines (vein-1 and vein-2) belong to the alkali group and are clas-sified under schorl-dravite series. Tourmalines occurring in the veins are zoned while the AMB tour-malines are unzoned. Mineral chemistry and discrimination diagrams reveal that cores and rims of the vein tourmalines are distinctly different. Core composition of the vein tourmalines is similar to the composition of the AMB tourmaline. The formation of the AMB tourmaline and cores of the vein tour-malines are proposed to be related to the regional D1 deformational event associated with the emplacement of the adjoining ca. 2.61 Ga Chitradurga granite whilst rims of the vein tourmalines vis-à-vis gold mineralization is spatially linked to the juvenile magmatic accretion (2.56e2.50 Ga) east of the studied area in the western part of the eastern Dharwar craton.

  19. LA-ICP-MS U-Pb Zircon Geochronology of Basic Dikes within Maxianshan Rock Group in the Central Qilian Orogenic Belt and Its Tectonic Implications

    Institute of Scientific and Technical Information of China (English)

    He Shiping; Wang Hongliang; Chen Junlu; Xu Xueyi; Zhang Hongfei; Ren Guangming; Yu Jiyuan

    2007-01-01

    A large number of basic dikes, which indicate an important tectonic-magmatic event in the eastern part of the Central Qilian (祁连) orogenic belt, were found from Maxianshan (马衔山) rock group, Yongjing (永靖) county, Gansu (甘肃) Province, China. According to the research on the characteristics of geology and petrology, the basic dike swarms, widely intruded in Maxianshan rock group,are divided into two phases by the authors. U-Pb isotope of zircons from the basic dikes above two phases is separately determined by LA-ICP-MS in the Key Laboratory of Continental Dynamics of Northwest University, China and the causes of formation of the zircons are studied using CL images.The formation age of the earlier phase of metagabbro dikes is (441.1±1.4) Ma (corresponding to the early stage of Early Silurian), and the age of the main metamorphic period is (414.3±1.2) Ma (corresponding to the early stage of Early Devonian). The formation age of the later phase of diabase dike swarms is (434±1.0) Ma (corresponding to the late stage of Early Silurian). The cap- tured-zircons from diabase dike swarms saved some information of material interfusion by Maxianshan rock group (207pb/206Pb apparent ages are (2325±3)-(2573±6) Ma), and some zircons from diabase dike swarms also saved impacted information by tectonic thermal event during the late period of Caledonian movement (206pb/238U apparent ages are (400±2)-(429±2) Ma). By combining the results of the related studies, the basic dikes within Maxianshan rock group were considered to be formed in the transfer period, from subductional orogeny towards collisional orogeny, which represents geological records of NW-SE extension during regional NE-SW towards intense compression in the Central Qilian block.

  20. Dynamic characteristics of conveyor belts

    Institute of Scientific and Technical Information of China (English)

    HOU You-fu; MENG Qing-rui

    2008-01-01

    The dynamic characteristics of a belt conveyor are determined to a large extent by the properties of the belt. This paper describes experiments designed to establish the dynamic properties of belting material. The dynamic elastic modulus, viscous damping and theological constants of the belt were measured. Several properties were studied as a function of the tensile loading on the belt. These included longitudinal vibration, the natural vibration frequency in the transverse direction and the response to an impulse excitation. Vibration response was observed under several different excitation frequencies. Most of these properties have not been tested previously under conditions appropriate for the ISO/DP9856 standard. Two types of belt were tested, a steel reinforced belt and a fabric reinforced belt. The test equipment was built to provide data appropriate for designing belt conveyors. It was observed that the stress wave propagation speed increased with tensile load and that tensile load was the main factor influencing longitudinal vibrations.

  1. The early Cretaceous orogen-scale Dabieshan metamorphic core complex: implications for extensional collapse of the Triassic HP-UHP orogenic belt in east-central China

    Science.gov (United States)

    Ji, Wenbin; Lin, Wei; Faure, Michel; Shi, Yonghong; Wang, Qingchen

    2016-03-01

    The Dabieshan massif is famous as a portion of the world's largest HP-UHP metamorphic belt in east-central China that was built by the Triassic North-South China collision. The central domain of the Dabieshan massif is occupied by a huge migmatite-cored dome [i.e., the central Dabieshan dome (CDD)]. Origin of this domal structure remains controversial. Synthesizing previous and our new structural and geochronological data, we define the Cretaceous Dabieshan as an orogen-scale metamorphic core complex (MCC) with a multistage history. Onset of lithospheric extension in the Dabieshan area occurred as early as the commencement of crustal anatexis at the earliest Cretaceous (ca. 145 Ma), which was followed by primary (early-stage) detachment during 142-130 Ma. The central Dabieshan complex in the footwall and surrounding detachment faults recorded a consistently top-to-the-NW shearing. It is thus inferred that the primary detachment was initiated from a flat-lying detachment zone at the middle crust level. Removal of the orogenic root by delamination at ca. 130 Ma came into the extensional climax, and subsequently isostatic rebound resulted in rapid doming. Along with exhumation of the footwall, the mid-crustal detachment zone had been warped as shear zones around the CDD. After 120 Ma, the detachment system probably experienced a migration accommodated to the crustal adjustment, which led to secondary (late-stage) detachment with localized ductile shearing at ca. 110 Ma. The migmatite-gneiss with HP/UHP relicts in the CDD (i.e., the central Dabieshan complex) was product of the Cretaceous crustal anatexis that consumed the deep-seated part of the HP-UHP slices and the underlying para-autochthonous basement. Compared with the contemporaneous MCCs widely developed along the eastern margin of the Eurasian continent, we proposed that occurrence of the Dabieshan MCC shares the same tectonic setting as the "destruction of the North China craton". However, geodynamic trigger

  2. Geochemistry and petrogenesis of high-K "sanukitoids" from the Bulai pluton, Central Limpopo Belt, South Africa: Implications for geodynamic changes at the Archaean-Proterozoic boundary

    Science.gov (United States)

    Laurent, Oscar; Martin, Hervé; Doucelance, Régis; Moyen, Jean-François; Paquette, Jean-Louis

    2011-04-01

    The Neoarchaean Bulai pluton is a magmatic complex intrusive in the Central Zone of the Limpopo Belt (Limpopo Province, South Africa). It is made up of large volumes of porphyritic granodiorites with subordinate enclaves and dykes of monzodioritic, enderbitic and granitic compositions. New U-Pb LA-ICP-MS dating on zircon yield pluton-emplacement ages ranging between 2.58 and 2.61 Ga. The whole pluton underwent a high-grade thermal overprint at ~ 2.0 Ga, which did not affect the whole-rock compositions for most of the major and trace-elements, as suggested by a Sm-Nd isochron built up with 16 samples and yielding an age consistent with U-Pb dating. The whole-rock major- and trace-element compositions evidence that the Bulai pluton belongs to a high-K, calc-alkaline to shoshonitic suite, as well as unequivocal affinities with "high-Ti" sanukitoids. Monzodioritic enclaves and enderbites have both "juvenile" affinities and a strongly enriched signature in terms of incompatible trace elements (LREE, HFSE and LILE), pointing to an enriched mantle source. Based on trace-element compositions, we propose the metasomatic agent at their origin to be a melt deriving from terrigenous sediments. We therefore suggest a two-step petrogenetic model for the Bulai pluton: (1) a liquid produced by melting of subducted terrigenous sediments is consumed by reactions with mantle peridotite, producing a metasomatic assemblage; (2) low-degree melting of this metasomatized mantle gives rise to Bulai mafic magmas. Such a model is supported by geochemical modelling and is consistent with previous studies concluding that sanukitoids result from interactions between slab melts and the overlying mantle wedge. Before 2.5 Ga, melting of hydrous subducted metabasalts produced large volumes of TTG (Tonalite-Trondhjemite-Granodiorite) forming most of the volume of Archaean continental crust. By constrast, our geochemical study failed in demonstrating any significant role played by melting of

  3. The early Cretaceous orogen-scale Dabieshan metamorphic core complex: implications for extensional collapse of the Triassic HP-UHP orogenic belt in east-central China

    Science.gov (United States)

    Ji, Wenbin; Lin, Wei; Faure, Michel; Shi, Yonghong; Wang, Qingchen

    2017-06-01

    The Dabieshan massif is famous as a portion of the world's largest HP-UHP metamorphic belt in east-central China that was built by the Triassic North-South China collision. The central domain of the Dabieshan massif is occupied by a huge migmatite-cored dome [i.e., the central Dabieshan dome (CDD)]. Origin of this domal structure remains controversial. Synthesizing previous and our new structural and geochronological data, we define the Cretaceous Dabieshan as an orogen-scale metamorphic core complex (MCC) with a multistage history. Onset of lithospheric extension in the Dabieshan area occurred as early as the commencement of crustal anatexis at the earliest Cretaceous (ca. 145 Ma), which was followed by primary (early-stage) detachment during 142-130 Ma. The central Dabieshan complex in the footwall and surrounding detachment faults recorded a consistently top-to-the-NW shearing. It is thus inferred that the primary detachment was initiated from a flat-lying detachment zone at the middle crust level. Removal of the orogenic root by delamination at ca. 130 Ma came into the extensional climax, and subsequently isostatic rebound resulted in rapid doming. Along with exhumation of the footwall, the mid-crustal detachment zone had been warped as shear zones around the CDD. After 120 Ma, the detachment system probably experienced a migration accommodated to the crustal adjustment, which led to secondary (late-stage) detachment with localized ductile shearing at ca. 110 Ma. The migmatite-gneiss with HP/UHP relicts in the CDD (i.e., the central Dabieshan complex) was product of the Cretaceous crustal anatexis that consumed the deep-seated part of the HP-UHP slices and the underlying para-autochthonous basement. Compared with the contemporaneous MCCs widely developed along the eastern margin of the Eurasian continent, we proposed that occurrence of the Dabieshan MCC shares the same tectonic setting as the "destruction of the North China craton". However, geodynamic trigger

  4. Provenance and tectonic setting of siliciclastic rocks associated with the Neoproterozoic Dahongliutan BIF: Implications for the Precambrian crustal evolution of the Western Kunlun orogenic belt, NW China

    Science.gov (United States)

    Hu, Jun; Wang, He; Wang, Min

    2017-10-01

    The Late Neoproterozoic Dahongliutan BIF is associated with siliciclastic rocks in the Tianshuihai terrane of the Western Kunlun orogenic belt (WKO), NW China. The sedimentary rocks have various weathering indices (e.g., CIA = 57-87, PIA = 61-96 and Th/U = 4.85-12.45), indicative of varying degrees of weathering in the source area. The rocks have trace element ratios, such as Th/Sc = 0.60-1.21 and Co/Th = 0.29-1.67, and light rare earth element (LREE) enriched chondrite-normalized REE patterns, suggesting that they were mainly sourced from intermediate and felsic rocks. Available U-Pb ages of detrital zircon from these rocks reveal that the detrital sources may have been igneous and metamorphic rocks from the WKO and the Tarim Block. Our study suggests that the Dahongliutan BIF and hosting siliciclastic rocks may have deposited in a setting transitional from a passive to active continental margin, probably related to the Late Neoproterozoic-Early Cambrian seafloor spreading and subduction of the Proto-Tethys Ocean. U-Pb dating of 163 detrital zircons defines five major age populations at 2561-2329 Ma, 2076-1644 Ma, 1164-899 Ma, 869-722 Ma and 696-593 Ma. These age groups broadly correspond to the major stages of supercontinent assembly and breakup events widely accepted for Columbia, Rodinia and Gondwana. Some zircons have TDM2 model ages of 3.9-1.8 Ga and negative εHf(t) values, suggesting that the Archean to Paleoproterozoic (as old as Eoarchean) crustal materials were episodically reworked and incorporated into the late magmatic process in the WKO. Some Neoproterozoic zircons have TDM2 model ages of 1.47-1.07 Ga and 1.81-1.53 Ga and positive εHf(t) values, indicating juvenile crustal growth during the Mesoproterozoic. Our new results, combined with published data, imply that both the Tianshuihai terrane in the WKO and the Tarim Block share the same Precambrian tectonic evolution history.

  5. High-pressure pelitic granulites from the Jiao-Liao-Ji Belt, North China Craton: A complete P-T path and its tectonic implications

    Science.gov (United States)

    Zou, Yi; Zhai, Mingguo; Santosh, M.; Zhou, Ligang; Zhao, Lei; Lu, Junsheng; Shan, Houxiang

    2017-02-01

    The Paleoproterozoic khondalite series rocks were widely distributed along the Jiao-Liao-Ji Belt (JLJB), North China Craton (NCC). Metamorphic investigations on these rocks can definitely shed light on the tectonic evolution of the JLJB and provide some clues for Paleoproterozoic history of the NCC. Here we present a comprehensive metamorphic study of high-pressure (HP) pelitic granulites from the Jiaobei terrane in the southern part of the JLJB and combine microstructure, mineral chemistry, Raman spectroscopy, thermobarometry, and P-T-X pseudosections in NCKFMASHTO to trace the metamorphic evolution of these rocks. Staurolite inclusion in kyanite was firstly reported using Raman spectroscopy and four successive mineral assemblages (M1-M4) were identified. Integrated method of thermobarometry and pseudosection modeling constrains P-T conditions of 6-8 kbar at below 660 °C, 15-16.6 kbar at 850-860 °C, 8.8-10.5 kbar at 830-870 °C, 5.8-7.8 kbar at 660-700 °C, for M1-M4, respectively. By employing the melt-reintegrated method, a prograde P-T trajectory is evaluated and hence a complete P-T path is defined that involves a prograde trajectory with marked increase both in pressure and temperature to peak metamorphism, followed by isothermal decompression and subsequent near-isobaric cooling. Such a P-T path implies that a subduction process before collision followed by subsequent extension and cooling processes, was involved in the formation the JLJB, consistent with an orogenic event. Available geochronological data suggests that HP granulites-facies metamorphism probably initiated at 1.90-1.95 Ga and that exhumation and cooling of the metamorphic terrane occurred at 1.80-1.85 Ga, indicating a long-lived hot orogeny during Paleoproterozoic. This contribution provides mineralogical evidence for low-pressure prograde metamorphism in HP pelitic granulites and hence gives a complete P-T path, placing a more rigorous metamorphic constraint on evolution of the JLJB.

  6. Geochemistry and zircon U-Pb geochronology of granitoids in the East Kunlun Orogenic Belt, northern Tibetan Plateau: origin and tectonic implications

    Science.gov (United States)

    Zhou, Bo; Dong, Yunpeng; Zhang, Feifei; Yang, Zhao; Sun, Shengsi; He, Dengfeng

    2016-11-01

    The East Kunlun Orogenic Belt (EKOB) in the northern margin of the Tibet Plateau is characterized by widespread granitic plutons, which are keys to understanding the tectonic evolution of the EKOB. The Zhiyu pluton, newly recognized in the central part of the EKOB, mainly consists of monzogranites, biotite granites and quartz diorites. Their LA-ICPMS zircon U-Pb results show formation ages of 447 ± 1.6 Ma, 448 ± 2.5 Ma and 408 ± 1.8 Ma. The monzogranites and biotite granites are characterized by relatively high Sr (208-631 ppm), low Y (4.28-15.82 ppm) and Yb (0.44-1.59 ppm) contents, thus resulting in elevated Sr/Y (30-105) and (La/Yb)N (4-79) ratios, indicating geochemical features of adakitic rocks. These adakitic granites are medium- to high-K, calcic or calc-alkaline in composition, and display a weak peraluminous character. They have low MgO (0.57-1.84 wt.%, average 1.01 wt.%), Mg# (40-53, average 45), as well as low Cr (3.67-17.98 ppm, average 7.19 ppm) and Ni (2.59-9.30 ppm, average 4.71 ppm) contents. These rocks are enriched in LREE, and show negligible or variable positive Eu anomalies (Eu/Eu∗ = 0.61-3.80, average 1.45) and significant negative Nb and Ta anomalies. Majority of the zircon grains from these adakitic granitic rocks have positive εHf(t) values of 0.09-5.21 with two-stage model ages ranging from 1.1 Ga to 1.6 Ga. These features are compatible with those of adakitic rocks derived from a thickened lower crust in the garnet stability field. Their formation is mainly controlled by the process of crust thickening following the closure of the Qimantag Ocean. The younger quartz diorites belong to medium- to high-K, calc-alkalic or alkali-calcic and metaluminous series, and exhibit a relatively high MgO (2.23-5.18 wt.%) and Mg# (40-56, average 50.11), with significant LREE enrichment and negative Eu anomalies, as well as depletion of Nb, Ta. In addition, the quartz diorites have an enriched εHf(t) values ranging from -5.25 to -3.19. Combining

  7. Middle Cretaceous dinosaur assemblages from northern Brazil and northern Africa and their implications for northern Gondwanan composition

    Science.gov (United States)

    Candeiro, Carlos Roberto A.

    2015-08-01

    Dinosaurs are one of the most dominant groups in Cretaceous reptilian faunas. A summary of their record in northern Brazil and northern Africa during the middle of the Cretaceous Period (Aptian-Cenomanian) is presented here. Dinosaurs are represented by 32 species (three ornithischians, six sauropods and 23 theropods) from Brazil, Egypt, Lybia, Morocco, Niger, Sudan and Tunisia. These dinosaur assemblages provide fundamental data about distribution and composition of sauropods and theropods in northern Gondwana during the middle of the Cretaceous Period and confirm these assemblages to be among the most important dinosaur faunas in the north Gondwana areas.

  8. Petrogenesis of the Early Permian volcanic rocks in the Chinese South Tianshan: Implications for crustal growth in the Central Asian Orogenic Belt

    Science.gov (United States)

    Huang, He; Zhang, Zhaochong; Santosh, M.; Zhang, Dongyang; Wang, Tao

    2015-07-01

    The Paleozoic and Early Mesozoic magmatic suites in the Central Asian Orogenic Belt (CAOB) provide important insights on the crustal growth and reworking process associated with the construction of the largest Phanerozoic orogen on the Earth. Among the tectonic blocks of the CAOB, the South Tianshan Terrane (STT) occupies the southwestern margin and is located adjacent to the Tarim Craton. Here we investigate the Early Permian Xiaotikanlike Formation in the central part of the Chinese STT in Xinjiang in Northwest China. The formation is composed of a series of terrestrial volcanic lava flows and volcanic breccia, interbedded with siltstones, sandstones and sandy conglomerates. Zircon U-Pb and Lu-Hf isotopic analysis, whole-rock major oxide, trace element and Sr-Nd isotopic data are presented for the volcanic lava flows of the Xiaotikanlike Formation exposed in the Boziguo'er, Laohutai and Wensu regions. The new zircon ages from our study, together with those reported in previous investigations on the rhyolitic lava flow from the Wensu region, suggest that the volcanic rocks of the Xiaotikanlike Formation simultaneously erupted at ca. 285 Ma. The lavas of the formation show a wide range of SiO2 (49.88 to 78.56 wt.%). The basaltic rocks show SiO2 from 49.88 to 53.78 wt.%, MgO from 3.73 to 7.01 wt.% and Mg# from 41 to 61. They possess slightly enriched Sr-Nd isotope signature [(87Sr/86Sr)t = 0.70495-0.70624 and εNd(t) = - 0.5 to + 0.6], and have trace and rare earth element patterns similar to those of oceanic island basalts (OIBs). Petrographic and whole-rock chemical characteristics indicate that the basaltic lava flows are dominantly tholeiitic, and were likely derived from a spinel-dominated peridotite asthenospheric mantle source. The felsic lavas of the Xiaotikanlike Formation show SiO2 in the range of 60.71 to 78.56 wt.% and display overall similar immobile element pattern characterized by notable troughs at Nb-Ta, P and Ti and gently sloping REEs. Zircon Lu

  9. Geological Fluid Mapping in the Tongling Area: Implications for the Paleozoic Submarine Hydrothermal System in the Middle-Lower Yangtze Metallogenic Belt, East China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The Tongling area is one of the 7 ore-cluster areas in the Middle-Lower Yangtze metallogenic belt, East China, and has tectonically undergone a long-term geologic history from the late Paleozoic continental rifting, through the Middle Triassic continent-continent collision to the Jurassic-Cretaceous intracontinental tectono-magmatic activation. The Carboniferous sedimentary-exhalative processes in the area produced widespread massive sulfides with ages of 303-321 Ma, which partly formed massive pyrite-Cu deposits, but mostly provided significant sulfur and metals to the skarn Cu mineralization associated with the Yanshanian felsic intrusions.To understand the Carboniferous submarine hydrothermal system, an area of about 1046 km2 was chosen to carry out the geological fluid mapping. Associated with massive sulfide formation, footwall sequences 948 m to 1146 m thick, composed of the Lower Silurian-Upper Devonian sandstone, siltstone and thin-layered shale, were widely altered. This hydrothermal alteration is interpreted to reflect largescale hydrothermal fluid flow associated with the late Paleozoic crustal rifting and subsidence. Three hydrothermal alteration types, i.e., deep-level semiconformable silicification (S1), fracture-controlled quartz-sericite-pyrite alteration (S2-3), and upper-level sub-discordant quartz-sericite-chlorite alteration (D3), were developed to form distinct zones in the mapped area. About 50-m thick semiconformable siliclfication zones are located at ~1-km depth below massive sulfides and developed between an impermeable shale caprock (S1) and the underlying Ordovician unaltered limestone.Comparisons with modern geothermal systems suggest that the alteration zones record a sub-seafloor aquifer with the most productive hydrothermal fluid flow. Fracture-controlled quartz-sericite-pyrite alteration formed transgressive zones, which downward crosscut the semiconformable alteration zones,and upwards grade into sub-discordant alteration zones

  10. Late-Pleistocene to precolumbian behind-the-arc mafic volcanism in the eastern Mexican Volcanic Belt; implications for future hazards

    Science.gov (United States)

    Siebert, Lee; Carrasco-Núñez, Gerardo

    2002-06-01

    An area of widespread alkaline-to-subalkaline volcanism lies at the northern end of the Cofre de Perote-Citlaltépetl (Pico de Orizaba) volcanic chain in the eastern Mexican Volcanic Belt (MVB). Two principal areas were active. About a dozen latest-Pleistocene to precolumbian vents form the 11-km-wide, E-W-trending Cofre de Perote vent cluster (CPVC) at 2300-2800 m elevation on the flank of the largely Pleistocene Cofre de Perote shield volcano and produced an extensive lava field that covers >100 km 2. More widely dispersed vents form the Naolinco volcanic field (NVF) in the Sierra de Chiconquiaco north of the city of Jalapa (Xalapa). Three generations of flows are delineated by cone and lava-flow morphology, degree of vegetation and cultivation, and radiocarbon dating. The flows lie in the behind-the-arc portion of the northeastern part of the MVB and show major- and trace-element chemical patterns transitional between intraplate and subduction zone environments. Flows of the oldest group originated from La Joya cinder cone (radiocarbon ages ˜42 000 yr BP) at the eastern end of the CPVC. This cone fed an olivine-basaltic flow field of ˜20 km 2 that extends about 14 km southeast to underlie the heavily populated northern outskirts of Jalapa, the capital city of the state of Veracruz. The Central Cone Group (CCG), of intermediate age, consists of four morphologically youthful cinder cones and associated vents that were the source of a lava field>27 km 2 of late-Pleistocene or Holocene age. The youngest group includes the westernmost flow, from Cerro Colorado, and a lava flow ˜2980 BP from the Rincón de Chapultepec scoria cone of the NVF. The latest eruption, from the compound El Volcancillo scoria cone, occurred about 870 radiocarbon years ago and produced two chemically and rheologically diverse lava flows that are among the youngest precolumbian flows in México and resemble paired aa-pahoehoe flows from Mauna Loa volcano. The El Volcancillo eruption

  11. Reversible denaturation of Brazil nut 2S albumin (Ber e1) and implication of structural destabilization on digestion by pepsin

    NARCIS (Netherlands)

    Koppelman, S.J.; Nieuwenhuizen, W.F.; Gaspari, M.; Knippels, L.M.J.; Penninks, A.H.; Knol, E.F.; Hefle, S.L.; Jongh, H.H.J.de

    2005-01-01

    The high resistance of Brazil nut 2S albumin, previously identified as an allergen, against proteolysis by pepsin was examined in this work. Although the denaturation temperature of this protein exceeds the 110 °C at neutral pH, at low pH a fully reversible thermal denaturation was observed at ∼82 °

  12. The Promise and Peril of the State in Neoliberal Times: Implications for the Critical Environmental Education Movement in Brazil

    Science.gov (United States)

    Stahelin, Nicolas; Accioly, Inny; Sánchez, Celso

    2015-01-01

    Neoliberal ideology has made an impact on environmental education (EE) policies and practices in Brazil. The EE in Family Agriculture Program, of national scope and administered by the Ministry of the Environment, seeks to promote sustainable development in rural areas, specifically through strategies focused on adult education and non-formal…

  13. DESIGN TRENDS IN TIMING BELTS

    OpenAIRE

    Grzegorz DOMEK

    2014-01-01

    Paper presents the state of the art gear with timing belts. Areas of use pose new challenges for designers gear. It has materials and technologies used in the production. Has been developed algorithm of design timing belts to new applications

  14. Analysis of the influence of the Colatina Belt in the Campos and Espirito Santo Basins-Brazil; Analise da influencia da Faixa Colatina nas Bacias de Campos e Espirito Santo

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Gustavo Henrique Teixeira da; Simoes, Luiz Sergio Amarante; Souza, Iata Anderson de [Universidade Estadual Paulista (UNESP), Rio Claro, SP (Brazil). Inst. de Geociencias e Ciencias Exatas

    2008-07-01

    Recent discoveries in the Espirito Santo Basin confirm the importance of it in the national exploratory scenery (oil and gas production). The new fields like Carapo and Camarupim, beyond others, next to already known Golfinho and Canapu, totalize an addition of 560 million barrels. In this way, studies in the area add importance, as the case of the present research, where if it looked to analyze the influence of Colatina Belt in Espirito Santo Basin and secondarily in Campos Basin. The results had been gotten through the integration of diverse data, such as lineaments extracted from images SRTM, potential maps and analyze of seismic lines. It was concluded that the Colatina Belt if projects for the interior of the basins, but that the same one seems to be dislocated in relation to the direct projection of the continental features, being that its influence can be felt with bigger emphasis in the Campos Basin, while in the Espirito Santo it look like to have low importance with regard to the exploration aspects. Also it was verified the presence of numerous halo kinetic structures that affect all the mapped horizons, this element determine great importance in the generation of structural traps. (author)

  15. Radiation belts of jupiter.

    Science.gov (United States)

    Stansberry, K G; White, R S

    1973-12-07

    Predictions of Jupiter's electron and proton radiation belts are based mainly on decimeter observations of 1966 and 1968. Extensive calculations modeling radial diffusion of particles inward from the solar wind and electron synchrotron radiation are used to relate the predictions and observations.

  16. The power of light: socio-economic and environmental implications of a rural electrification program in Brazil

    Science.gov (United States)

    Borges da Silveira Bezerra, Paula; Ludovique Callegari, Camila; Ribas, Aline; Lucena, André F. P.; Portugal-Pereira, Joana; Koberle, Alexandre; Szklo, Alexandre; Schaeffer, Roberto

    2017-09-01

    Universal access to electricity is deemed critical for improving living standards and indispensable for eradicating poverty and achieving sustainable development. In 2003, the ‘Luz para Todos’ (LpT—Light for All) program was launched aiming to universalize access to electricity in Brazil. The program focused on rural and isolated areas, also targeting to bring development to those regions along with electrification. This paper evaluates the results of the LpT program in improving socio-economic development in the poorest regions of Brazil. After an initial qualitative analysis, an empirical quantitative assessment of the influence of increased electrification rates on the components of the Human Development Index (HDI) is performed. The empirical results of this study showed that electrification had a positive influence on all dimensions of the HDI, with the education component having the strongest effect. Although complementary policies were needed to achieve this, results show that electricity access is a major requirement to improve quality of life.

  17. Necrophagous beetles associated with carcasses in a semi-arid environment in northeastern Brazil: implications for forensic entomology.

    Science.gov (United States)

    Mayer, Ana C G; Vasconcelos, Simão D

    2013-03-10

    Data on the ecology and bionomics of necrophagous beetles are scarce in tropical countries despite their relevance in forensic investigations. We performed a survey on the diversity and temporal pattern of colonization of beetles on pig carcasses in a fragment of dry forest in northeastern Brazil. We collected 1550 adults of diverse feeding habits from 12 families, of which 96% had necrophagous and/or copro-necrophagous habits and belonged to four families: Dermestidae, Scarabaeidae, Cleridae and Trogidae. Three species, Dermestes maculatus, Necrobia rufipes and Omorgus suberosus are reported for the first time with an expanded geographical distribution that includes the semi-arid region in Brazil. Adult beetles were collected as early as 24h after death. One endemic species, Deltochilum verruciferum, stood out in terms of numerical dominance and temporal occurrence during different stages of decomposition. Its intimate association with carrion emphasizes their potential role in forensic entomology in the region.

  18. The presence of phenomenology in physical education in Brazil: implications for the study of the body and other problematizations

    Directory of Open Access Journals (Sweden)

    Felipe Quintão de Almeida

    2013-12-01

    Full Text Available This paper discusses the uses of phenomenology in Physical Education in Brazil. In methodological terms, it describes five studies that belong to this theoretical framework in the field, represented by authors such as Silvino Santin, Manuel Sérgio, Wagner Wey Moreira, Elenor Kunz and Terezinha Petrúcia da Nóbrega. It problematizes some aspects of this reception, by highlighting not only its boundaries, but also the challenges for research and reflection within this tradition in physical education

  19. Y-STR haplotype diversity and population data for Central Brazil: implications for environmental forensics and paternity testing.

    Science.gov (United States)

    Vieira, T C; Gigonzac, M A D; Silva, D M; Rodovalho, R G; Santos, G S; da Cruz, A D

    2014-04-30

    The central region of Brazil was colonized by internal migration of individuals of different origins, who contributed to the genetic diversity existing in this population. This study determined the allele frequencies and haplotype diversity of Y-STRs in Goiás State, Central Brazil, and compared the data obtained with a sample of the Brazilian population, consisting of individuals from the five geographical regions of Brazil. A total of 353 males were typed for 12 Y-chromosome short tandem repeat (Y-STR) markers. We selected males who had no degree of relatedness, from the five mesoregions of Goiás State. DNA was extracted from blood samples followed by the amplification of the 12 Y-chromosome loci. The products were analyzed to obtain the allele profiles on an ABI3500 automated sequencer using the Gene Mapper software. Allele frequencies and haplotype diversity were estimated by direct counting, and gene diversity for each locus was computed using the Arlequin software. The results are consistent with the history of miscegenation of the population of Central Brazil, in which we observed 321 different haplotypes. The average gene diversity at the 12 loci was 0.645. DYS385b and DYS389I showed the highest (0.704) and lowest (0.520) genetic diversity values, respectively. The FST value between the Brazilian and Goiás populations was 0.00951, showing no statistical significance. The results of this study allowed the establishment of haplotypes found in the forensic samples of Goiás State serving as a reference in the elucidation of criminal cases and paternity tests, as well as population and evolutionary inferences.

  20. Diversity and distribution of aquatic insects in Southern Brazil wetlands: implications for biodiversity conservation in a Neotropical region

    Directory of Open Access Journals (Sweden)

    Leonardo Maltchik

    2012-03-01

    Full Text Available The selection of priority areas is an enormous challenge for biodiversity conservation. Some biogeographic methods have been used to identify the priority areas to conservation, and panbiogeography is one of them. This study aimed at the utilization of panbiogeographic tools, to identify the distribution patterns of aquatic insect genera, in wetland systems of an extensive area in the Neotropical region (~280 000km², and to compare the distribution of the biogeographic units identified by the aquatic insects, with the conservation units of Southern Brazil. We analyzed the distribution pattern of 82 genera distributed in four orders of aquatic insects (Diptera, Odonata, Ephemeroptera and Trichoptera in Southern Brazil wetlands. Therefore, 32 biogeographic nodes corresponded to the priority areas for conservation of the aquatic insect diversity. Among this total, 13 were located in the Atlantic Rainforest, 16 in the Pampa and three amongst both biomes. The distribution of nodes showed that only 15% of the dispersion centers of insects were inserted in conservation units. The four priority areas pointed by node cluster criterion must be considered in further inclusions of areas for biodiversity conservation in Southern Brazil wetlands, since such areas present species from differrent ancestral biota. The inclusion of such areas into the conservation units would be a strong way to conserve the aquatic biodiversity in this region.

  1. Diversity and distribution of aquatic insects in Southern Brazil wetlands: implications for biodiversity conservation in a Neotropical region.

    Science.gov (United States)

    Maltchik, Leonardo; Dalzochio, Marina Schmidt; Stenert, Cristina; Rolon, Ana Silvia

    2012-03-01

    The selection of priority areas is an enormous challenge for biodiversity conservation. Some biogeographic methods have been used to identify the priority areas to conservation, and panbiogeography is one of them. This study aimed at the utilization of panbiogeographic tools, to identify the distribution patterns of aquatic insect genera, in wetland systems of an extensive area in the Neotropical region (approximately 280 000km2), and to compare the distribution of the biogeographic units identified by the aquatic insects, with the conservation units of Southern Brazil. We analyzed the distribution pattern of 82 genera distributed in four orders of aquatic insects (Diptera, Odonata, Ephemeroptera and Trichoptera) in Southern Brazil wetlands. Therefore, 32 biogeographic nodes corresponded to the priority areas for conservation of the aquatic insect diversity. Among this total, 13 were located in the Atlantic Rainforest, 16 in the Pampa and three amongst both biomes. The distribution of nodes showed that only 15% of the dispersion centers of insects were inserted in conservation units. The four priority areas pointed by node cluster criterion must be considered in further inclusions of areas for biodiversity conservation in Southern Brazil wetlands, since such areas present species from different ancestral biota. The inclusion of such areas into the conservation units would be a strong way to conserve the aquatic biodiversity in this region.

  2. ‘Indicator’ carbonaceous phyllite/graphitic schist in the Archean Kundarkocha gold deposit, Singhbhum orogenic belt, eastern India: Implications for gold mineralization vis-a-vis organic matter

    Indian Academy of Sciences (India)

    P R Sahoo; A S Venkatesh

    2014-10-01

    Carbonaceous rocks in the form of graphitic schist and carbonaceous phyllite are the major host rocks of the gold mineralization in Kundarkocha gold deposit of the Precambrian Singhbhum orogenic belt in eastern India. The detection of organic carbon, essentially in the carbonaceous phyllite and graphitized schist within the Precambrian terrain, is noted from this deposit. A very close relationship exists between gold mineralization and ubiquitous carbonaceous rocks containing organic carbon that seems to play a vital role in the deposition of gold in a Precambrian terrain in India and important metallogenetic implications for such type of deposits elsewhere. However, the role played by organic matter in a Precambrian gold deposit is debatable and the mechanism of precipitation of gold and other metals by organic carbon has been reported elsewhere. Fourier transform infrared spectroscopy (FTIR) results and total organic carbon (TOC) values suggest that at least part of the organic material acted as a possible source for the reduction that played a significant role in the precipitation of gold. Lithological, electron probe analysis (EPMA), fluid inclusions associated with gold mineralization, Total Carbon (TC), TOC and FTIR results suggest that the gold mineralization is spatially and genetically associated with graphitic schist, carbonaceous phyllite/shale that are constituted of immature organic carbon or kerogen. Nano-scale gold inclusions along with free milling gold are associated with sulfide mineral phases present within the carbonaceous host rocks as well as in mineralized quartz-carbonate veins. Deposition of gold could have been facilitated due to the organic redox reactions and the graphitic schist and carbonaceous phyllite zone may be considered as the indicator zone.

  3. The empty primordial asteroid belt.

    Science.gov (United States)

    Raymond, Sean N; Izidoro, Andre

    2017-09-01

    The asteroid belt contains less than a thousandth of Earth's mass and is radially segregated, with S-types dominating the inner belt and C-types the outer belt. It is generally assumed that the belt formed with far more mass and was later strongly depleted. We show that the present-day asteroid belt is consistent with having formed empty, without any planetesimals between Mars and Jupiter's present-day orbits. This is consistent with models in which drifting dust is concentrated into an isolated annulus of terrestrial planetesimals. Gravitational scattering during terrestrial planet formation causes radial spreading, transporting planetesimals from inside 1 to 1.5 astronomical units out to the belt. Several times the total current mass in S-types is implanted, with a preference for the inner main belt. C-types are implanted from the outside, as the giant planets' gas accretion destabilizes nearby planetesimals and injects a fraction into the asteroid belt, preferentially in the outer main belt. These implantation mechanisms are simple by-products of terrestrial and giant planet formation. The asteroid belt may thus represent a repository for planetary leftovers that accreted across the solar system but not in the belt itself.

  4. Kuiper Belt Occultation Predictions

    CERN Document Server

    Fraser, Wesley C; Trujillo, Chad; Stephens, Andrew W; Kavelaars, JJ; Brown, Michael E; Bianco, Federica B; Boyle, Richard P; Brucker, Melissa J; Hetherington, Nathan; Joner, Michael; Keel, William C; Langill, Phil P; Lister, Tim; McMillan, Russet J; Young, Leslie

    2013-01-01

    Here we present observations of 7 large Kuiper Belt Objects. From these observations, we extract a point source catalog with $\\sim0.01"$ precision, and astrometry of our target Kuiper Belt Objects with $0.04-0.08"$ precision within that catalog. We have developed a new technique to predict the future occurrence of stellar occultations by Kuiper Belt Objects. The technique makes use of a maximum likelihood approach which determines the best-fit adjustment to cataloged orbital elements of an object. Using simulations of a theoretical object, we discuss the merits and weaknesses of this technique compared to the commonly adopted ephemeris offset approach. We demonstrate that both methods suffer from separate weaknesses, and thus, together provide a fair assessment of the true uncertainty in a particular prediction. We present occultation predictions made by both methods for the 7 tracked objects, with dates as late as 2015. Finally, we discuss observations of three separate close passages of Quaoar to field star...

  5. Radionuclide concentrations in raw and purified phosphoric acids from Brazil and their processing wastes: implications for radiation exposures.

    Science.gov (United States)

    da Conceição, Fabiano Tomazini; Antunes, Maria Lúcia Pereira; Durrant, Steven F

    2012-02-01

    Radionuclides from the U and Th natural series are present in alkaline rocks, which are used as feedstock in Brazil for the production of raw phosphoric acid, which can be considered as a NORM (naturally occurring radioactive material). As a result of the purification of raw phosphoric acid to food-grade phosphoric acid, two by-products are generated, i.e., solid and liquid wastes. Taking this into account, the main aim of this study was to evaluate the fluxes of natural radionuclide in the production of food-grade phosphoric acids in Brazil, to determine the radiological impact caused by ingestion of food-grade phosphoric acid, and to evaluate the solid waste environmental hazards caused by its application in crop soils. Radiological characterization of raw phosphoric acid, food-grade phosphoric acid, solid waste, and liquid waste was performed by alpha and gamma spectrometry. The (238)U, (234)U, (226)Ra, and (232)Th activity concentrations varied depending on the source of raw phosphoric acid. Decreasing radionuclides activity concentrations in raw phosphoric acids used by the producer of the purified phosphoric acid were observed as follows: Tapira (raw phosphoric acid D) > Catalão (raw phosphoric acids B and C) > Cajati (raw phosphoric acid A). The industrial purification process produces a reduction in radionuclide activity concentrations in food-grade phosphoric acid in relation to raw phosphoric acid produced in plant D and single raw phosphoric acid used in recent years. The most common use of food-grade phosphoric acid is in cola soft drinks, with an average consumption in Brazil of 72 l per person per year. Each liter of cola soft drink contains 0.5 ml of food-grade phosphoric acid, which gives an annual average intake of 36 ml of food-grade phosphoric acid per person. Under these conditions, radionuclide intake through consumption of food-grade phosphoric acid per year per person via cola soft drinks is not hazardous to human health in Brazil

  6. Brazil: Mitigation and Adaptation to Climate Change

    OpenAIRE

    Carlos E. Ludeña; Maria Netto

    2011-01-01

    In order to understand the implications of GHG emissions reduction targets in the Brazilian economy it is important to understand the sector composition of these emissions in Brazil. According to the 2010 Second National Communications of Brazil to the UNFCCC, in 2005, the majority of Brazil's emissions (87.2%) corresponded to carbon dioxide (CO2) emissions.

  7. Late Paleozoic closure of the Ob-Zaisan Ocean along the Irtysh/Chara shear zone and implications for arc amalgamation and oroclinal bending in the western Central Asian Orogenic Belt

    Science.gov (United States)

    Li, Pengfei; Sun, Min; Rosenbaum, Gideon

    2016-04-01

    Carboniferous to Permian. References: Abrajevitch, A., Van der Voo, R., Bazhenov, M.L., Levashova, N.M., McCausland, P.J.A., 2008. The role of the Kazakhstan orocline in the late Paleozoic amalgamation of Eurasia. Tectonophysics 455, 61-76. Levashova, N., Degtyarev, K., Bazhenov, M., 2012. Oroclinal bending of the Middle and Late Paleozoic volcanic belts in Kazakhstan: Paleomagnetic evidence and geological implications. Geotectonics 46, 285-302. Xiao, W., Huang, B., Han, C., Sun, S., Li, J., 2010. A review of the western part of the Altaids: A key to understanding the architecture of accretionary orogens. Gondwana Research 18, 253-273. Acknowledgements: This study was financially supported by the Major Basic Research Project of the Ministry of Science and Technology of China (Grant: 2014CB448000 and 2014CB440801), Hong Kong Research Grant Council (HKU705311P, HKU704712P and HKU17303415), National Science Foundation of China (41273048), HKU seed funding (201111159137) and HKU CRCG grants. This work is a contribution of the Joint Laboratory of Chemical Geodynamics between HKU and CAS (Guangzhou Institute of Geochemistry), IGCP 592 and PROCORE France/Hong Kong Joint Research Scheme.

  8. Freshwater temperature in the state of Rio Grande do Sul, Southern Brazil, and its implication for fish culture

    Directory of Open Access Journals (Sweden)

    Luciano de Oliveira Garcia

    Full Text Available In this study we verified data of water temperatures collected by CORSAN-RS from 1996 to 2004 in several cities of the state of Rio Grande do Sul, southern Brazil, and analyzed the possibility of raising the most cultivated fish species in Brazil. The water temperature from 1996 to 2004 was 16 to 28ºC in summer, 17 to 23ºC in fall, 14 to 17ºC (down to 9ºC in the coldest months in winter and 14 to 21ºC in spring. Native species of this state, such as silver catfish (Rhamdia quelen, traíra (Hoplias malabaricus, dorado (Salminus brasiliensis, pintado (Pimelodus maculatus, as well as carps (family Cyprinidae, are resistant to the low winter temperatures. These species have a lower growth rate in coldest months (winter/spring but a good development in warmer months (summer/fall, reaching a satisfactory performance throughout the year. In the periods of more intense cold, mortality of some introduced species, such as surubim from Amazon Basin (Pseudoplatystoma sp., pirapitinga (Piaractus brachypomus, pirarucu (Arapaimas gigas, pacu (Piaractus mesopotamicus, tambaqui (Colossoma macropomum and Nile tilapia (Oreochromis niloticus may occur. In addition, as most tropical species have a thermal range for growth and reproduction between 20 to 28ºC, some species may have poor development even in fall. Therefore, water temperature in this state should be considered in the choice of fish species to be cultivated.

  9. Insects (Diptera) associated with cadavers at the Institute of Legal Medicine in Pernambuco, Brazil: implications for forensic entomology.

    Science.gov (United States)

    Oliveira, Tatiana Costa; Vasconcelos, Simao Dias

    2010-05-20

    Increasing rates of unsolved homicides in Brazil prompt the need for applied entomological data to be used as a complementary tool by criminal investigators. In that context, we analyzed the occurrence of forensically important insect species (Order Diptera) on 14 cadavers taken into the Institute of Legal Medicine (ILM), in Pernambuco, Brazil, according to the conditions of the body and the pattern of colonisation by insects. Simultaneously, we surveyed the diversity of insects in the surrounding environment using bait traps. Five species were present on cadavers: Chrysomya albiceps, Chrysomya megacephala and Cochliomyia macellaria (Calliphoridae), Oxysarcodexia riograndensis and Ravinia belforti (Sarcophagidae). A total of 4689 adult insects belonging to 24 species of seven dipteran families (Calliphoridae, Sarcophagidae, Muscidae, Fanniidae, Phoridae, Anthomyiidae and Stratiomyidae) was collected at the ILM premises. C. albiceps was the most frequent species on the corpses and the most abundant in the traps. Species referred to as of forensic importance, such as Lucilia eximia, Chrysomya putoria, Oxysarcodexia modesta and Ophyra chalcogaster were collected on traps, but not on cadavers. There seems to be a limited colonisation of cadavers at the scene of the death, despite the ubiquity of necrophagous species in the area. The results contribute to differentiate between species that are involved in decomposition and those found in and around the mortuary installations of the ILM, thus providing potential clues about the locality of death and the post-mortem interval.

  10. Lap belt injuries in children.

    LENUS (Irish Health Repository)

    McGrath, N

    2010-07-01

    The use of adult seat belts without booster seats in young children may lead to severe abdominal, lumbar or cervical spine and head and neck injuries. We describe four characteristic cases of lap belt injuries presenting to a tertiary children\\'s hospital over the past year in addition to a review of the current literature. These four cases of spinal cord injury, resulting in significant long-term morbidity in the two survivors and death in one child, arose as a result of lap belt injury. These complex injuries are caused by rapid deceleration characteristic of high impact crashes, resulting in sudden flexion of the upper body around the fixed lap belt, and consequent compression of the abdominal viscera between the lap belt and spine. This report highlights the dangers of using lap belts only without shoulder straps. Age-appropriate child restraint in cars will prevent these injuries.

  11. Silviculture of eucaliptus plantations in the Paraiba do Sul basin, Brazil, and its potential implication on the basin ecohydrology.

    Science.gov (United States)

    Carriello, Felix; Andres Rodriguez, Daniel; Marques Neves, Otto; Vicens, Raul

    2014-05-01

    Silviculture of eucaliptus plantations is an important driver of the Mata Atlântica biome conversion into another land use in the Paraíba do Sul basin, in the southeastern of Brazil. This region is located in one of the most developed areas in Brazil, between Rio de Janeiro and São Paulo, the most important cities in Brazil, linked by Presidente Dutra highway. Between both cities there are another cities that produce a variety of goods - from meat to planes, cars and mobile phones. This area is, at the same time, one the most important hot spot for the Mata Atlântica biome. Here we have a large Mata Atlântica fragment protected by law and others fragments being conversed to pasture, agriculture, silviculture and urban areas. Paraiba do Sul river drains the region and runs into Rio de Janeiro State. The basin is highly anthropized, with multiple approaches of its waters resources. Its waters also serve Rio de Janeiro metropolitan area. Because land use and land cover changes impact the water yield in a basin, the study of its dynamic its of great importance for water resources management. We study the land use and land cover change in the region between 1986 and 2010, focusing in the development of silviculture of eucaliptus plantations. We used the HAND (Height Above Nearest Drainage) approach that uses the height above the nearest water body, acquired from SRTM Data and transformed into a Terrain Numeric Mode, to classify the landscape into three different ecohydrological environments: floodplain, mountain top and hillslope. This classes were intersected with 1986 and 2010 land use and cover change classification obtained from Landsat imagery. Results show that silviculture has increased in the region from 1986 to 2010. In both years, silviculture areas are mainly located at the hillslope (47%), while floodplain and mountain top share 28 % and 23 % respectively. Available census data from the Brazilian Institute of Geography and Statistics, IBGE, for 1995 and

  12. SLH Timing Belt Powertrain

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Abe

    2014-04-09

    The main goal of this proposal was to develop and test a novel powertrain solution for the SLH hydroEngine, a low-cost, efficient low-head hydropower technology. Nearly two-thirds of U.S. renewable electricity is produced by hydropower (EIA 2010). According to the U.S. Department of Energy; this amount could be increased by 50% with small hydropower plants, often using already-existing dams (Hall 2004). There are more than 80,000 existing dams, and of these, less than 4% generate power (Blankinship 2009). In addition, there are over 800 irrigation districts in the U.S., many with multiple, non-power, low-head drops. These existing, non-power dams and irrigation drops could be retrofitted to produce distributed, baseload, renewable energy with appropriate technology. The problem is that most existing dams are low-head, or less than 30 feet in height (Ragon 2009). Only about 2% of the available low-head hydropower resource in the U.S. has been developed, leaving more than 70 GW of annual mean potential low-head capacity untapped (Hall 2004). Natel Energy, Inc. is developing a low-head hydropower turbine that operates efficiently at heads less than 6 meters and is cost-effective for deployment across multiple low-head structures. Because of the unique racetrack-like path taken by the prime-movers in the SLH, a flexible powertrain is required. Historically, the only viable technological solution was roller chain. Despite the having the ability to easily attach blades, roller chain is characterized by significant drawbacks, including high cost, wear, and vibration from chordal action. Advanced carbon- fiber-reinforced timing belts have been recently developed which, coupled with a novel belt attachment system developed by Natel Energy, result in a large reduction in moving parts, reduced mass and cost, and elimination of chordal action for increased fatigue life. The work done in this project affirmatively addressed each of the following 3 major uncertainties concerning

  13. Lithogeochemistry and geochronology of the subalkaline felsic plutonism that marks the end of the Paleoproterozoic orogeny in the Salvador-Esplanada belt, São Francisco craton (Salvador, state of Bahia, Brazil

    Directory of Open Access Journals (Sweden)

    Jailma Santos de Souza-Oliveira

    Full Text Available Studies conducted over the last decade concerning the rocks that underlie the municipality of Salvador have shown a complex geological history with a great diversity of medium- to high-grade metamorphic lithotypes, deformed in several phases and frequently cut by tabular mafic dykes and irregular granitic bodies. The latter, which were the subject of this study, frequently outcrop along the coastline of Salvador and are classified petrographically as monzo-syenogranites. They are classified as subalkaline and peraluminous according to their geochemical data, and stand out for being enriched in light rare earth elements and having a strong negative Europium (Eu anomaly. These rocks are produced from anatectic melts or through the interaction of mantle-derived magmas with crustal materials. The negative values of εNd(t (-6.08 corroborate with the crustal character and in the diagrams of tectonic ambience, they are plotted in the field of post-tectonic granites. The Sm-Nd model age (TDM around 2.9 Ga indicates a neoarchean source for these lithotypes, whereas their U-Pb zircon age (LA-ICPMS of 2,064 ± 36 Ma is similar to the U-Pb (SHRIMP and Pb-Pb (evaporation ages for late-tectonic granites of the Itabuna-Curaçá-Salvador belt. Considering the results of recent studies in the area of Salvador, the monzo-syenogranites can be interpreted as late-tectonic intrusions, since they are affected by dextral shear zones correlated with the last stage of deformation registered in the granulites of Salvador.

  14. One Laptop per Child and its Implications for the Process of Written Language Learning: A Case Study in Brazil

    Directory of Open Access Journals (Sweden)

    Silvia de Oliveira Kist

    2013-08-01

    Full Text Available This is a case study on the reading and writing practices of six year old children engaged in the daily use of digital technology, conducted in a public school in Porto Alegre (RS/Brazil and made possible by the One Laptop per Child (OLPC project. Its aim was to investigate the practices carried out by students and the possibilities and conditions under which the computer can become a tool that enables them to enter the “literate world”. The students’ practices were examined based on three units of analysis: practices proposed by a teacher, spontaneous practices and representative cases. These practices were categorized into three areas: literacy, fluency of written language and technological fluency. The research began with a theoretical proposal that had to be modified as a result of the study, and emphasizes the importance of pedagogical proposals for children in the initial process of written language learning.

  15. HASTERN BELT OF ZIMBABWE AND THEIR IMPLICATIONS

    African Journals Online (AJOL)

    Productivity of maize (Zea mays) is low in the small-holder sector of ... specific with farmers in more productive Mutasa showing high preference for grain ... optimum plant types, the preferred option for ... efficiency due to upright leaves and a large sink ..... make impact by improving this cultivar. ... due to superior test density.

  16. Coronal radiation belts

    CERN Document Server

    Hudson, H S; Frewen, S F N; DeRosa, M L

    2009-01-01

    The magnetic field of the solar corona has a large-scale dipole character, which maps into the bipolar field in the solar wind. Using standard representations of the coronal field, we show that high-energy ions can be trapped stably in these large-scale closed fields. The drift shells that describe the conservation of the third adiabatic invariant may have complicated geometries. Particles trapped in these zones would resemble the Van Allen Belts and could have detectable consequences. We discuss potential sources of trapped particles.

  17. Consumer Willingness to Pay for Dengue Vaccine (CYD-TDV, Dengvaxia®) in Brazil; Implications for Future Pricing Considerations

    Science.gov (United States)

    Godói, Isabella P.; Santos, André S.; Reis, Edna A.; Lemos, Livia L. P.; Brandão, Cristina M. R.; Alvares, Juliana; Acurcio, Francisco A.; Godman, Brian; Guerra Júnior, Augusto A.

    2017-01-01

    Introduction and Objective: Dengue virus is a serious global health problem with an estimated 3.97 billion people at risk for infection worldwide. In December 2015, the first vaccine (CYD-TDV) for dengue prevention was approved in Brazil, developed by Sanofi Pasteur. However, given that the vaccine will potentially be paid via the public health system, information is need regarding consumers’ willingness to pay for the dengue vaccine in the country as well as discussions related to the possible inclusion of this vaccine into the public health system. This was the objective of this research. Methods: We conducted a cross-sectional study with residents of Greater Belo Horizonte, Minas Gerais, about their willingness to pay for the CYD-TDV vaccine. Results: 507 individuals were interviewed. These were mostly female (62.4%) had completed high school (62.17%), were working (74.4%), had private health insurance (64.5%) and did not have dengue (67.4%). The maximum median value of consumers’ willingness to pay for CYD-TDV vaccine is US$33.61 (120.00BRL) for the complete schedule and US$11.20 (40.00BRL) per dose. At the price determined by the Brazil’s regulatory chamber of pharmaceutical products market for the commercialization of Dengvaxia® for three doses, only 17% of the population expressed willingness to pay for this vaccine. Conclusion: Brazil is currently one of the largest markets for dengue vaccine and the price established is a key issue. We believe the manufacturer should asses the possibility of lower prices to reach a larger audience among the Brazilian population. PMID:28210223

  18. Cryptic signatures of Neoproterozoic accretionary events in northeast Brazil imaged by magnetotellurics: Implications for the assembly of West Gondwana

    Science.gov (United States)

    Padilha, Antonio L.; Vitorello, Icaro; Pádua, Marcelo B.; Fuck, Reinhardt A.

    2017-03-01

    The Borborema Province, in northeast Brazil, is a complex orogenic system severely affected by deformational, metamorphic, and magmatic processes mostly during the Gondwana convergence in late Neoproterozoic-early Phanerozoic Brasiliano/Pan-African Orogeny. New magnetotelluric (MT) data collected along the northwestern part of the province and eastern part of the contiguous Parnaíba Basin are combined with previous MT data to assess the regional deep electrical resistivity structure. Dimensionality analysis shows that a 3D electrical structure predominates in the subsurface and thus 3D inversion was carried out. The final geoelectric model allows delineating the geometry and variation in physical properties of different lithospheric blocks bounded by major electrical discontinuities. These lithospheric blocks constitute a coalesced mosaic made up of four main terrane compartments: a resistive cratonic keel detected along the western part of the study area, currently hidden beneath the Parnaíba Basin (Parnaíba block); two complex domains in the center characterized by several resistive and conductive zones throughout the crust and upper mantle (Ceará Central and Rio Grande do Norte domains); and a conductive block in the east, with the geoelectric response being controlled by possible remains of late Neoproterozoic subduction activity to the south (Central sub-province). The interfaces between these blocks are interpreted as suture zones correlated to their Neoproterozoic collage, one curved conductor concealed by the sediments of the Parnaíba Basin and bordering the eastern margin of the basin, another huge conductor corresponding to the location of the Orós-Jaguaribe subdomain on the surface, and a third interface coinciding with the position of the Patos shear zone. The presence of these proposed sutures could be a conspicuous evidence of a Neoproterozoic accretion system in northeast Brazil and would support tectonic evolution models for the West Gondwana

  19. Dunlop Enerka Belting supplies and installs Europe's longest conveyor belt at British Coal-Mine

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@ Dunlop Enerka Belting of Farington, U.K., has supplied a steel cord conveyor belt to the mine complex at Selby in North Yorkshire operated by RJB Mining plc. The new conveyor belt replaces the belt supplied and installed in 1981 by Dunlop Enerka Belting (then BTR Belting Ltd.).

  20. Experimental models of 'Basement'-controlled salients - application to the proterozoic fold-thrust belt of the quadrilátero ferrífero (Minas Gerais, Southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Caroline J. S. Gomes

    2003-06-01

    Full Text Available Scaled sandbox models are used to simulate the development of ´basement´-controlled, salients. We investigate the controlling factors on the development of closed curvatures in map-view, considering constant both the sand pack thickness and the space between obstacles. These models are compared with the Fundão-Cambotas Fault System in the Proterozoic fold-thrust belt in the Quadrilátero Ferrífero region, along the southeastern margin of the São Francisco craton. In the experiments, a pronounced curvature resulted from the margin-controlled salient process in the presence (i of a basal ductile detachment, or (ii of pre-existing structures. The results suggest that the convex-to-the-foreland, west-vergent Fundão-Cambotas Fault System that borders the Archean basement highs and displaced older Transamazonian structures westward, is partly a consequence of interaction of propagating thrusts with obstacles in the foreland.Em presente trabalho são desenvolvidos experimentos, em escala, em caixas de areia, para a simulação de saliências pelo processo de propagação de sistemas compressivos ao longo de margens irregulares. Estes modelos visam analisar a configuração estrutural do Sistema de Cisalhamento Fundão-Cambotas, no cinturão de dobras e falhas proterozóico, do domínio leste do Quadrilátero Ferrífero, sudeste do Craton São Francisco. Investigaram-se as possíveis causas para a formação de curvaturas, em planta, mantendo-se constantes os parâmetros, espessura do pacote de areia e distância entre obstáculos no antepaís. Os experimentos demonstram que a formação de saliências fortemente curvas ocorre ao longo de margens irregulares, na presença de um descolamento basal dúctil ou pela ação de estruturas pré-existentes. Assim, relaciona-se a geometria convexa do Sistema de Cisalhamento Fundão-Cambotas, ladeado, a norte e a sul, por altos estruturais do embasamento arqueano, vergente para oeste e que desloca

  1. Diversity and distribution of aquatic insects in Southern Brazil wetlands: implications for biodiversity conservation in a Neotropical region

    Directory of Open Access Journals (Sweden)

    Leonardo Maltchik

    2012-03-01

    Full Text Available The selection of priority areas is an enormous challenge for biodiversity conservation. Some biogeographic methods have been used to identify the priority areas to conservation, and panbiogeography is one of them. This study aimed at the utilization of panbiogeographic tools, to identify the distribution patterns of aquatic insect genera, in wetland systems of an extensive area in the Neotropical region (~280 000km², and to compare the distribution of the biogeographic units identified by the aquatic insects, with the conservation units of Southern Brazil. We analyzed the distribution pattern of 82 genera distributed in four orders of aquatic insects (Diptera, Odonata, Ephemeroptera and Trichoptera in Southern Brazil wetlands. Therefore, 32 biogeographic nodes corresponded to the priority areas for conservation of the aquatic insect diversity. Among this total, 13 were located in the Atlantic Rainforest, 16 in the Pampa and three amongst both biomes. The distribution of nodes showed that only 15% of the dispersion centers of insects were inserted in conservation units. The four priority areas pointed by node cluster criterion must be considered in further inclusions of areas for biodiversity conservation in Southern Brazil wetlands, since such areas present species from differrent ancestral biota. The inclusion of such areas into the conservation units would be a strong way to conserve the aquatic biodiversity in this region.La selección de áreas prioritarias es un enorme desafío para la conservación de la biodiversidad. Métodos biogeográficos se han utilizado para identificar áreas prioritarias para la conservación, como la panbiogeografía. Este estudio tuvo como objetivo el empleo de herramientas panbiogeográficas, para identificar los patrones de distribución de los géneros de insectos acuáticos, en los sistemas de humedales de una extensa área de la región Neotropical (~280 000km², y así comparar la distribución de las

  2. DESIGN TRENDS IN TIMING BELTS

    Directory of Open Access Journals (Sweden)

    Grzegorz DOMEK

    2014-03-01

    Full Text Available Paper presents the state of the art gear with timing belts. Areas of use pose new challenges for designers gear. It has materials and technologies used in the production. Has been developed algorithm of design timing belts to new applications

  3. Geography of the asteroid belt

    Science.gov (United States)

    Zellner, B. H.

    1978-01-01

    The CSM classification serves as the starting point on the geography of the asteroid belt. Raw data on asteroid types are corrected for observational biases (against dark objects, for instance) to derive the distribution of types throughout the belt. Recent work on family members indicates that dynamical families have a true physical relationship, presumably indicating common origin in the breakup of a parent asteroid.

  4. Airborne Geophysical Surveys in the North-Central Region of Goias (Brazil): Implications for Radiometric Characterization of Subtropical Soils

    CERN Document Server

    Guimarães, S N P; Justo, J S

    2011-01-01

    In this work we present progress obtained in analysis airborne geophysical survey data for the north-central region of the state of Goias (Brazil). The results obtained indicate that most of the subtropical soil types are characterized by Uranium contents of greater than one parts per million (ppm). Only ultisol and oxisol soils are found to have Uranium contents lower than one ppm. Thorium and Potassium abundances also display trends similar to those of Uranium. The K/U ratios fall in the expected range of values for common soils while the Th/U ratios are higher than normal. This latter observation may indicate a characteristic feature of subtropical soils. Alternatively it may be considered as indicative of disequilibrium conditions in radioactive series and consequent underestimation of Uranium in soil layers of the study area. In this context we point out the possibility of using results of radiometric surveys as a convenient complementary tool in identifying geochemical zoning of soils in subtropical env...

  5. Lead isotope evidence for recent uranium mobility in geological formations of Brazil: implications for radioactive waste disposal

    Energy Technology Data Exchange (ETDEWEB)

    Iyer, S.S. [Department of Physics and Astronomy, University of Calgary, Calgary (Canada); Babinski, M. [Instituto de Geociencias, Universidade de Sao Paulo, Sao Paulo (Brazil); Marinho, M.M. [Companhia Baiana de Pesquisa Mineral (CBPM), Salvador (Brazil); Barbosa, J.S.F. [Instituto de Geociencias, Universidade Federal da Bahia, Salvador (Brazil); Sato, I.M.; Salvador, V.L. [Instituto de Pesquisas Energeticas e Nucleares (CNEN/SP), Sao Paulo (Brazil)

    1999-03-01

    Lead-lead isotope data from whole rock samples are used to investigate the recent (last few million years) mobility of U and Th. The method is based on the comparison of the calculated present day U and Th concentrations required to yield the Pb isotope composition in the samples with the actual present day concentrations of U and Th obtained by direct measurement. The geological formations studied include the Neoproterozoic carbonate sediments of the Bambui Group, Archean/Paleoproterozoic granite-greenstone terrain of the Contendas-Mirante Complex and a Proterozoic ortho-gneisses hosting U deposit in Lagoa Real. All these formations are in the Sao Francisco Craton, Brazil. The data show high U mobility in the carbonate sediments and in the deformed ortho-gneisses set in a ductile shear zone. Infiltration of groundwater through fault zones seems to have facilitated the U mobility. The Pb isotope approach is a useful technique complementing U-series disequilibrium studies and may be included for site characterization studies for radioactive waste disposal. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  6. Presence of Zea luxurians (Durieu and Ascherson) Bird in Southern Brazil: Implications for the Conservation of Wild Relatives of Maize

    Science.gov (United States)

    2015-01-01

    Records of the occurrence of wild relatives of maize in South American lowlands are unprecedented, especially in sympatric coexistence with landraces. This fact is relevant, because regions of occurrence of wild relatives of cultivated plants should be a priority for conservation, even if they do not correspond to the center of origin of the species. The aim of this study was to identify and characterize the wild relatives of maize in the Far West of Santa Catarina, southern Brazil. Therefore, phenotypic characterization was performed for five populations, based on 22 morphological traits deemed as fundamental for classifying the species of the genus Zea, and validated through the characterization of chromosomal knobs of two populations. The occurrence and distribution of teosinte populations were described through semi-structured interviews applied to a sample of 305 farmers. A total of 136 teosinte populations were identified; 75% of them occur spontaneously, 17% are cultivated populations, and 8% occur both ways, for the same farm. Populations that were characterized morphologically had trapezoidal fruits mostly, upright tassel branch (4–18), non-prominent main branch and glabrous glumes, with two protruding outer ribs and 8 inner ribs, on average. Cytogenetic analysis identified 10 pairs of homologous chromosomes (2n = 20) with 26 knobs, located in the terminal region of all chromosomes. The similarity of these results with the information reported in the literature indicates that the five populations of wild relatives of maize in this region of Santa Catarina belong to the botanical species Zea luxurians. PMID:26488577

  7. Ostracods (Crustacea) and their palaeoenvironmental implication for the Solimões Formation (Late Miocene; Western Amazonia/Brazil).

    Science.gov (United States)

    Gross, Martin; Ramos, Maria Ines; Caporaletti, Marco; Piller, Werner E

    2013-03-01

    Western Amazonia's landscape and biota were shaped by an enormous wetland during the Miocene epoch. Among the most discussed topics of this ecosystem range the question on the transitory influx of marine waters. Inter alia the occurrence of typically brackish water associated ostracods is repeatedly consulted to infer elevated salinities or even marine ingressions. The taxonomical investigation of ostracod faunas derived from the upper part of the Solimões Formation (Eirunepé; W-Brazil) documents a moderately diverse assemblage (19 species). A wealth of freshwater ostracods (mainly Cytheridella, Penthesilenula) was found co-occurring with taxa (chiefly Cyprideis) usually related to marginal marine settings today. The observed faunal compositions as well as constantly very light δ(18)O- and δ(13)C-values obtained by measuring both, the freshwater and brackish water ostracod group, refer to entirely freshwater conditions. These results corroborate with previous sedimentological and palaeontological observations, which proposed a fluvial depositional system for this part of western Amazonia during the Late Miocene. We demonstrate that some endemic, "brackish" water ostracods (i.e., Cyprideis) have been effectively adapted to freshwater conditions. Thus, their occurrence is no univocal evidence for the influence of brackish or marine waters in western Amazonia during the Miocene.

  8. ["Get it while you can!" attitude: late industrialization and implications for work, environment, and health in Ceará State, Brazil].

    Science.gov (United States)

    Rigotto, Raquel Maria

    2007-01-01

    The present study focuses on the characteristics of late industrialization in a city in Ceará State (in the semiarid region of Northeast Brazil) and its implications for work, environment, and health in the context of industrial mobility and advanced capitalism. Using direct observation of work processes, interviews (with production managers, company presidents, workers, local authorities, and community leaders), institutional visits and secondary data analysis, eight recently built factories that manufacture chemicals, shoes, electric appliances, clothing, mechanical parts, and packaging were analyzed as to relocation, technology, organization, work relations, worker profile, environmental and occupational risks, and the impact of these factors on health and regulatory mechanisms. The lack of adequate criteria for attracting and accepting new investments, leading to a "get it while you can" attitude, the poor quality of jobs and environmental conditions, and the scale of new changes and risks in the area, like the difficulties of the public sector and society in dealing with these challenges, raise the issue of sustainability in the current development processes.

  9. Evidence of mingling between contrasting magmas in a deep plutonic environment: the example of Várzea Alegre, in the Ribeira Mobile Belt, Espírito Santo, Brazil

    Directory of Open Access Journals (Sweden)

    SILVIA R. MEDEIROS

    2001-03-01

    Full Text Available At the end of the geotectonic cycle that shaped the northern segment of the Ribeira Mobile Belt (Upper Proterozoic to Paleozoic age, a late to post-collisional set of plutonic complexes, consisting of a wide range of lithotypes, intruded all metamorphic units. The Várzea Alegre Intrusive Complex is a post-collisional complex. The younger intrusion consists of an inversely zoned multistage structure envolved by a large early emplaced ring of megaporphyritic charnoenderbitic rocks. The combination of field, petrographic and geochemical data reveals the presence of at least two different series of igneous rocks. The first originated from the partial melting of the mantle. This was previously enriched in incompatible elements, low and intermediate REE and some HFS-elements. A second enrichment in LREE and incompatible elements in this series was due to the mingling with a crustal granitic magma. This mingling process changed the composition of the original tholeiitic magma towards a medium-K calc-alkalic magma to produce a suite of basic to intermediate rock types. The granitic magma from the second high-K, calc-alkalic suite originated from the partial melting of the continental crust, but with strong influence of mantle-derived melts.No final do ciclo tectônico que originou o segmento norte do Cinturão Móvel Ribeira (de idade Proterozóica Superior a Paleozóica, uma série de complexos plutônicos tardi- a pós-colisionais, consistindo de larga gama de litotipos, intrudiu todas as unidades metamórficas. O Complexo Intrusivo de Várzea Alegre é um desses complexos pós-colisionais. A intrusão mais jovem consiste de uma estrutura de multiplos estágios, envolvida por um largo anel de rochas charnoenderbíiticas megaporfirícas de posicionmento anterior. A combinação de dados de campo, petrográficos e geoquímicos revela a presença de pelo menos duas séries distintas de rochas ígneas. A primeira foi originada por fusão parcial do manto

  10. Evolution of the Chilka Lake granulite complex, northern Eastern Ghats Belt, India: First evidence of ~ 780 Ma decompression of the deep crust and its implication on the India-Antarctica correlation

    Science.gov (United States)

    Bose, S.; Das, K.; Torimoto, J.; Arima, M.; Dunkley, D. J.

    2016-10-01

    High-grade para- and orthogneissic rocks near the Chilka Lake granulite complex, northern part of the Eastern Ghats Belt show complex structural and petrological history. Based on field and petrographic characters, five (M1-M5) metamorphic events could be identified. The earliest metamorphic event (M1) produced amphibolite grade mineral assemblage which produced the peak granulite (M2) assemblages at 900-950 °C, 8.5-9.0 kbar. The third metamorphic event caused decompression of the deeper crust up to 700-800 °C, 6.0-6.5 kbar. This was followed by cooling (M4) and subsequent thermal overprinting (M5). Fluid-composition during M3 was dominated by high-density CO2 and changed to low-density mixed CO2-H2O during the M3. Zircon U-Pb SHRIMP data suggest 781 ± 9 Ma age for M3 event. Texturally constrained monazite U-Th-Pb EPMA data, on the other hand, yield a group age of 988 ± 23 Ma from grain interior, which can signifies the age of M2 event. Few spots with younger dates in the range of 550-500 Ma are also noted. This interpretation changes the existing tectonothermal history of northern Eastern Ghats Belt. Our data show that the two adjacent crustal domains of the Eastern Ghats Belt show distinctly contrasting Neoproterozoic histories. While the central Domain 2 evolved through early anticlockwise P-T path culminating in ultrahigh temperature, the northern Domain 3 evolved through a clockwise P-T path. It appears that the Domain 3 was contiguous to East Antarctica and became part of the Eastern Ghats Belt during the assembly of Gondwana. The ca. 780 Ma decompression event in the northern Eastern Ghats Belt opens up new possibilities for interpreting the breakup of Rodinia.

  11. Facial trauma in the largest city in Latin America, São Paulo, 15 years after the enactment of the compulsory seat belt law

    Directory of Open Access Journals (Sweden)

    Tarley Eloy Pessoa de Barros

    2010-01-01

    Full Text Available Traffic accidents are a reality throughout Brazil. The face is one of the anatomic parts most affected by these accidents, especially when a seat belt is not used. These accidents are costly for the public health system and have a significant impact on society and the lives of families involved. The compulsory use of seat belts in Brazil, especially in São Paulo, has decreased the rate of facial trauma. This suggests that the public health policies and measures adopted by the Brazilian authorities have benefited the population 15 years after the enactment of the law of compulsory seat belts in the city of São Paulo

  12. Speleoclimate dynamics in Santana Cave (PETAR, São Paulo State, Brazil: general characterization and implications for tourist management

    Directory of Open Access Journals (Sweden)

    Heros Augusto Santos Lobo

    2015-01-01

    Full Text Available Show caves provide tourists with the opportunity to have close contact with natural underground spaces. However, visitation to these places also creates a need for management measures, mainly the definition of tourist carrying capacity. The present work describes the results of climate monitoring and atmospheric profiling performed in Santana Cave (Alto Ribeira State and Tourist Park – PETAR, Brazil between 2008 and 2011. Based on the results, distinct preliminary zones with different levels of thermal variation were identified, which classify Santana Cave as a warm trap. Two critical points along the tourist route (Cristo and Encontro Halls were identified where the temperature of the locality increased by 1.3 °C when tourists were present. Air flow from the inner cave to the outside occurs during the austral summer, and the opposite flow occurs when the outside environment is colder than the air inside the cave during the austral winter. The temperature was used to establish thresholds to the tourist carrying capacity by computing the recovery time of the atmospheric conditions after the changes caused by the presence of tourists. This method suggests a maximum limit of approximately 350 visits per day to Santana Cave. The conclusion of the study is that Santana Cave has an atmosphere that is highly connected with the outside; daily variations in temperature and, to a lesser extent, in the relative humidity occur throughout the entire studied area of the cave. Therefore, the tourist carrying capacity in Santana Cave can be flexible and can be implemented based on the climate seasonality, the tourism demand and other management strategies.

  13. The redox processes in Hg-contaminated soils from Descoberto (Minas Gerais, Brazil): implications for the mercury cycle.

    Science.gov (United States)

    Windmöller, Cláudia C; Durão Júnior, Walter A; de Oliveira, Aline; do Valle, Cláudia M

    2015-02-01

    Investigations of the redox process and chemical speciation of Hg(II) lead to a better understanding of biogeochemical processes controlling the transformation of Hg(II) into toxic and bioaccumulative monomethyl mercury, mainly in areas contaminated with Hg(0). This study investigates the speciation and redox processes of Hg in soil samples from a small area contaminated with Hg(0) as a result of gold mining activities in the rural municipality of Descoberto (Minas Gerais, Brazil). Soil samples were prepared by adding Hg(0) and HgCl2 separately to dry soil, and the Hg redox process was monitored using thermodesorption coupled to atomic absorption spectrometry. A portion of the Hg(0) added was volatilized (up to 37.4±2.0%) or oxidized (from 36±7% to 88±16%). A correlation with Mn suggests that this oxidation is favored, but many other factors must be evaluated, such as the presence of microorganisms and the types of organic matter present. The interaction of Hg with the matrix is suggested to involve Hg(II)-complexes formed with inorganic and organic sulfur ligands and/or nonspecific adsorption onto oxides of Fe, Al and/or Mn. The kinetics of the oxidation reaction was approximated for two first-order reactions; the faster reaction was attributed to the oxidation of Hg(0)/Hg(I), and the slower reaction corresponded to Hg(I)/Hg(II). The second stage was 43-139 times slower than the first. The samples spiked with Hg(II) showed low volatilization and a shifting of the signal of Hg(II) to lower temperatures. These results show that the extent, rate and type of redox process can be adverse in soils. Descoberto can serve as an example for areas contaminated with Hg(0).

  14. Evaluation of the static belt fit provided by belt-positioning booster seats.

    Science.gov (United States)

    Reed, Matthew P; Ebert, Sheila M; Sherwood, Christopher P; Klinich, Kathleen D; Manary, Miriam A

    2009-05-01

    Belt-positioning booster seats are recommended for children who use vehicle seat belts as primary restraints but who are too small to obtain good belt fit. Previous research has shown that belt-positioning boosters reduce injury risk, but the belt fit produced by the wide range of boosters in the US market has not previously been assessed. The present study describes the development of a method for quantifying static belt fit with a Hybrid-III 6-year-old test dummy. The measurement method was applied in a laboratory seat mockup to 31 boosters (10 in both backless and highback modes) across a range of belt geometries obtained from in-vehicle measurements. Belt fit varied widely across boosters. Backless boosters generally produced better lap belt fit than highback boosters, largely because adding the back component moved the dummy forward with respect to the lap belt routing guides. However, highback boosters produced more consistent shoulder belt fit because of the presence of belt routing guides near the shoulder. Some boosters performed well on both lap belt and shoulder belt fit. Lap belt fit in dedicated boosters was generally better than in combination restraints that also can be used with an integrated harness. Results demonstrate that certain booster design features produce better belt fit across a wide range of belt geometries. Lap belt guides that hold the belt down, rather than up, and shoulder belt guides integrated into the booster backrest provided better belt fit.

  15. U-Pb Zircon Ages,Geochemical and Sr-Nd-Hf Isotopic Compositions of Granitoids in Western Songpan-Garze Fold Belt: Petrogenesis and Implication for Tectonic Evolution

    Institute of Scientific and Technical Information of China (English)

    Cai Hongming; Zhang Hongfei; Xu Wangchun

    2009-01-01

    Granitoids are widespread in the Songpan-Garze (松潘-甘孜) fold belt,western China.These granitoids provide insight into regional tectono-magmatic events,basement nature and tectonic evolution.However,previous studies mainly focused on the eastern Songpan-Garze fold belt In this article,five granitoid intrusions from the western Songpan-Garze fold belt have been studied.These intrusions are composed of quartz-diorite and granodiorite.Using LA-ICP-MS zircon dating method,the obtained magma crystallization ages are 219±2 Ma for the quartz-diorite and 216±5 Ma for the granodiorite.The ages,combined with regional geological analyses,show that they formed in a post-collisional tectonic setting.The quartz-diorite and granodiorite display co-linear variation in their chemical compositions.REE compositions for both the quartz-diorite and granodiorite show strongly fractionated patterns with (La/Yb)N=5.02-18.34 and Eu/Eu*=0.44-0.89.The quartz-diorites have initial 87Sr/86Sr ratios (7Sr) of 0.709 29-0.711 97 and εNd(t) values of -8.6 to -6.1 and the granodiorites have Isr values of 0.705 49-0.709 97 and εNd(t) values of -8.3 to -4.3.Zircon Hf isotopic data show εHr(t) values of -3.8 to +1.6 for the quartz-diorites and -1.2 to +3.0 for the granodiorites.Geochemical and Sr-Nd-Hf isotopic compositions indicate that the quartz-diorites and granodiorites have similar petrogenesis.We suggest that the magmas for the quartz-diorites and granodiorites were derived from partial melting of lower crustal mafic source,resulting from amphibole dehydration melting reaction.The probing of the magma source reveals that the western Songpan-Garze fold belt contains an unexposed continental basement,which is similar to the eastern Songpan-Garze fold belt.Geodynamically,it is proposed that a lithospheric delamination model can account for the magma generation for the quartz-diorites and granodiorites in the western Songpan-Garze fold belt.

  16. AUTOMATION OF CONVEYOR BELT TRANSPORT

    Directory of Open Access Journals (Sweden)

    Nenad Marinović

    1990-12-01

    Full Text Available Belt conveyor transport, although one of the most economical mining transport system, introduce many problems to mantain the continuity of the operation. Every stop causes economical loses. Optimal operation require correct tension of the belt, correct belt position and velocity and faultless rolls, which are together input conditions for automation. Detection and position selection of the faults are essential for safety to eliminate fire hazard and for efficient maintenance. Detection and location of idler roll faults are still open problem and up to now not solved successfully (the paper is published in Croatian.

  17. Neoproterozic Re-Os age of a sulfide inclusion in a superdeep diamond: Implications for mantle convection beneath Juina, Brazil

    Science.gov (United States)

    Shirey, S. B.; Smit, K.; Nestola, F.; Steele, A.; Bulanova, G.; Smith, C. B.

    2015-12-01

    Diamonds from the Juina area Brazil have long been known for their sublithospheric or superdeep (e.g. from depths of 300-800 km) origins. These diamonds have yielded new information about high pressure mantle mineralogy, deep crustal recycling, diamond source fluids, and mantle transition zone water content. A type II (low N) diamond (sample J1) from the 93.1±1.5 myr old (Heaman 7IKC 1998 ) Collier 4 kimberlite was studied previously (Walter et al. Nature 2008; Bulanova et al. CMP 2010) as part of a larger suite of eclogitic-composition, inclusion-bearing type II Collier 4 diamonds with complex internal growth structure. Major and trace element analyses of mineral inclusions in these diamonds include Ca-Ti-Si perovskite, Ca-rich majoritic-garnet, clinopyroxene, olivine, jeffbenite, minerals with stoichiometries of CAS and K-hollandite phases, SiO2, FeO, native iron, low-Ni sulfides, and Ca-Mg-carbonate. The C isotopic compositions of the diamond hosts range from a δ13C of -25 to -5‰ ( J1 being -15‰). Collier 4 diamonds have been interpreted to crystallize from carbonatitic melts derived from the recycling of oceanic lithosphere at TransitionZone depths (Walter et al. Nature 2008; Bulanova et al. CMP 2010). A rare Fe-sulfide inclusion in the core of diamond J1 has been dated with the Re-Os system in order to provide age and compositional constraints on the proposed oceanic slab recycling. The rim of J1 contained inclusions of Ca-Ti-Si perovskite that yielded U-Pb age of 101±7 Ma and eclogitic (low Cr, high Ca) majorite that yielded formation pressures (Si - Al+Cr geobarometry) >8 GPa (Bulanova et al. CMP 2010). The Fe-sulfide analyzed was low Ni pyrrhotite determined to be Fe10S11 of a rare 11T polytype by single-crystal X-ray diffraction. The 27 ug interior pyrrhotite had a high Re/Os (187Re/188Os = 854) typical of MORB (Re/Os ~100) and radiogenic Os isotopic composition (187Os/188Os = 8.50±1.38) that yields a 602±16 Ma model age relative to normal mantle

  18. Two million years of river and cave aggradation in NE Brazil: Implications for speleogenesis and landscape evolution

    Science.gov (United States)

    Laureano, Fernando V.; Karmann, Ivo; Granger, Darryl E.; Auler, Augusto S.; Almeida, Renato P.; Cruz, Franciso W.; Strícks, Nicolás M.; Novello, Valdir F.

    2016-11-01

    This study characterizes and provides ages for an extensive sedimentary record occurring in Lapa Doce and Torrinha caves, NE Brazil. With > 40 km of surveyed passages, these caves integrate a distributary cave system fed by allogenic recharge from the surrounding sandstone plateaus. Sediment petrography together with descriptions of depositional facies and architectural elements shows four depositional units related to fluvial and standing water environments. These include, from bottom to top: (1) a channel unit including lateral bars deposited during an ordinary flood regime; (2) a sandy flood unit including minor channel and scour fills derived from bank-full equivalent flood events; (3) mud caps deposited in standing water that often reach the ceiling; and (4) intraclast breccias associated with collapse of the mud caps under saturated conditions. The deposits were dated using a combination of cosmogenic nuclide burial dating and U-series dating of flowstone. Cosmogenic nuclide data point to fluvial aggradation being active since 1.91 + 0.12 My and extending until 0.36 ± 0.08 My, with intensive cave and valley aggradation events between 0.78 ± 0.10 My and 0.44 ± 0.12 My. Long term alluviation of the cave system seems to be important in forming passages, determining their configuration, and setting up a general distributary pattern evident in passage morphology and sedimentary sequences. Mud caps overlapping the fluvial deposits are interpreted as the products of successive rising and lowering of the water table (static level). Radiometric ages of interstratified flowstones and speleothems show that these oscillations were active at least since 115 ky ago and finally ceased around 12 ky ago, indicated by the recurrent age obtained from uneroded capping flowstones. These long-term water table oscillations may drive paragenetic expansion of the whole cave system. Valleys, caves and other landforms in our study area are part of an ancient landscape with multiple

  19. Jovian Early Bombardment: planetesimal erosion in the inner asteroid belt

    CERN Document Server

    Turrini, Diego; Magni, Gianfranco

    2012-01-01

    The asteroid belt is an open window on the history of the Solar System, as it preserves records of both its formation process and its secular evolution. The progenitors of the present-day asteroids formed in the Solar Nebula almost contemporary to the giant planets. The actual process producing the first generation of asteroids is uncertain, strongly depending on the physical characteristics of the Solar Nebula, and the different scenarios produce very diverse initial size-frequency distributions. In this work we investigate the implications of the formation of Jupiter, plausibly the first giant planet to form, on the evolution of the primordial asteroid belt. The formation of Jupiter triggered a short but intense period of primordial bombardment, previously unaccounted for, which caused an early phase of enhanced collisional evolution in the asteroid belt. Our results indicate that this Jovian Early Bombardment caused the erosion or the disruption of bodies smaller than a threshold size, which strongly depen...

  20. Redefinition of the Role of the State in Brazil: implications of the management model for administration policies for basic education

    Directory of Open Access Journals (Sweden)

    Regina Tereza Cestari de Oliveira

    2009-06-01

    Full Text Available This article presents the main elements of the Brazilian State reform project, expressed in the document known as the Guiding Plan for the Reform of the State Apparatus (1995, in which reference is mainly to the alterations in the public administration bureaucracy for public management administration. This reform institutes new regulation relationships between public and private and transfers to civil society, particularly to the third sector, characterized as the non-state public, the execution of a double role: provide social and scientific services and exercise social control. In this way, civil society is called on to act, in fact, as a space for the transference of state responsibilities. Thus, here the attempt is made to discuss the implications of these changes for the management policies of basic education, emphasizing that teaching systems, especially the municiple system, sought to align themselves with the administration model, which has as a basis the principle of efficiency, with emphasis on results.

  1. Seat Belt Use and Stress in Adolescents.

    Science.gov (United States)

    Schichor, Aric; And Others

    1990-01-01

    Explored adolescent seat belt use and psychosocial risk factors in urban minority population (n=541). Found seat belt use reported by 49 percent of respondents. Those reporting no or intermittent seat belt use were significantly more likely than seat belt users to feel down, have decreased home support, have problems with school and the law, and…

  2. 49 CFR 393.93 - Seats, seat belt assemblies, and seat belt assembly anchorages.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Seats, seat belt assemblies, and seat belt... § 393.93 Seats, seat belt assemblies, and seat belt assembly anchorages. (a) Buses—(1) Buses... the driver's seat and seat belt assembly anchorages that conform to the location and...

  3. Chaos on the conveyor belt

    CERN Document Server

    Sándor, Bulcsú; Tél, Tamás; Néda, Zoltán

    2013-01-01

    The dynamics of a spring-block train placed on a moving conveyor belt is investigated both by simple experiments and computer simulations. The first block is connected by spring to an external static point, and due to the dragging effect of the belt the blocks undergo complex stick-slip dynamics. A qualitative agreement with the experimental results can only be achieved by taking into account the spatial inhomogeneity of the friction force on the belt's surface, modeled as noise. As a function of the velocity of the conveyor belt and the noise strength, the system exhibits complex, self-organized critical, sometimes chaotic dynamics and phase transition-like behavior. Noise induced chaos and intermittency is also observed. Simulations suggest that the maximum complexity of the dynamical states is achieved for a relatively small number of blocks, around five.

  4. The Siderian-Orosirian magmatism in the Gavião Paleoplate, Brazil: U-Pb geochronology, geochemistry and tectonic implications

    Science.gov (United States)

    Pereira Cruz, Simone Cerqueira; Figueiredo Barbosa, Johildo Salomão; Pinto, Marilda Santos; Peucat, Jean-Jacques; Paquette, Jean Louis; Santos de Souza, Jailma; de Souza Martins, Violeta; Júnior, Farid Chemale; Carneiro, Mauricio Antonio

    2016-08-01

    continental crust in the formation of these rocks. The Humaitá granitoid probably presents the lowest contribution from the continental crust in its genesis. The rocks from Group 1 were generated as the product of an active continental margin arc situated eastwards from the southern portion of the Gavião Paleoplate. The spatial distribution between the granitoids of groups 1 and 2a suggests westwards subduction and led to a cordilleran model for the Western Bahia Magmatic Arc. Continental collision between the Gavião and Jequié paleoplates occurred around 2.09 Ga and was followed by the setting of late-collision granitoids of groups 2a to 2d. The comparison between the tectonic model presented in this study and other existing models that explain the Siderian-Rhyacian-Orosirian granitogenesis of the Mineiro Belt and Mantiqueira Complex suggests a continuation of the Western Bahia Magmatic Arc and of the collisional orogen that followed, towards the south. The Western Bahia Magmatic Arc emplacement occurred before the Paleoproterozoic granitogenesis of the Serrinha (Bahia-Brazil) and Congo (Africa) paleoplates.

  5. Molybdenite Re/Os dating, zircon U-Pb age and geochemistry of granitoids in the Yangchuling porphyry W-Mo deposit (Jiangnan tungsten ore belt), China: Implications for petrogenesis, mineralization and geodynamic setting

    Science.gov (United States)

    Mao, Jingwen; Xiong, Bikang; Liu, Jun; Pirajno, Franco; Cheng, Yanbo; Ye, Huishou; Song, Shiwei; Dai, Pan

    2017-08-01

    The Yangchuling W-Mo deposit, located in the Jiangnan porphyry-skarn (JNB) tungsten ore belt, is the first recognized typical porphyry W-Mo deposit in China in the 1980's. Stockworks and disseminated W-Mo mineralization occur in the roof pendant of a 0.3 km2 monzogranitic porphyry stock that intruded into a granodiorite stock, hosted by Neoproterozoic phyllite and slate. LA-ICPMS zircon U-Pb analyses suggest that of the monzogranitic porphyry and granodiorite were formed at 143.8 ± 0.5 Ma and 149.8 ± 0.6 Ma, respectively. Six molybdenite samples yielded a Re-Os weighted mean age of 146.4 ± 1.0 Ma. Geochemical data show that both granodiorite and monzogranitic porphyry are characterized by enrichment of large ion lithophile elements (LILE) relative to high field strength elements (HFSE), indicating a peraluminous nature (A/CNK = 1.01-1.08). Two granitoids are characterized by a negative slope with significant light REE/heavy REE fractionation [(La/Yb)N = 8.38-23.20] and negative Eu anomalies (Eu/Eu* = 0.69-0.76). The P2O5 contents of the Yangchuling granitoids range from 0.12% to 0.17% and exhibit a negative correlation with SiO2, reflecting that they are highly fractionated I-type. They have high initial 87Sr/86Sr ratios (0.7104-0.7116), low negative εNd(t) (- 5.05 to - 5.67), and homogeneous εHf(t) between - 1.39 and - 2.17, indicating similar sources. Additionally, two-stage Nd model ages (TDM2) of 1.3-1.4 Ga and two-stage Hf model ages (TDM2) of 1.2-1.3 Ga are consistent, indicating that Neoproterozoic crustal rocks of the Shuangqiaoshan Group could have contributed to form the Yangchuling magmas. Considering the two groups of parallel Late Mesozoic ore belts, namely the Jiangnan porphyry-skarn tungsten belt (JNB) in the south and the Middle-Lower Yangtze River porphyry-skarn Cu-Au-Mo-Fe ore belt (YRB) in the north, the Nanling granite-related W-Sn ore belt (NLB) in the south, the neighboring Qin-Hang porphyry-skarn Cu-Mo-hydrothermal Pb-Zn-Ag ore belt (QHB

  6. Northern Belt of Jupiter

    Science.gov (United States)

    2000-01-01

    [figure removed for brevity, see original site] A four-panel frame shows a section of Jupiter's north equatorial belt viewed by NASA's Cassini spacecraft at four different wavelengths, and a separate reference frame shows the location of the belt on the planet.A fascinating aspect of the images in the four-panel frame is the small bright spot in the center of each. The images come from different layers of the atmosphere, so the spot appears to be a storm penetrating upward through several layers. This may in fact be a 'monster' thunderstorm, penetrating all the way into the stratosphere, as do some summer thunderstorms in the midwestern United States. These images were taken on Nov. 27, 2000, at a resolution of 192 kilometers (119 miles) per pixel. They have been contrast-enhanced to highlight features in the atmosphere.The top panel of the four-panel frame is an image taken in a near-infrared wavelength at which the gases in Jupiter's atmosphere are relatively non-absorbing. Sunlight can penetrate deeply into the atmosphere at this wavelength and be reflected back out, providing a view of an underlying region of the atmosphere, the lower troposphere.The second panel was taken in the blue portion of wavelengths detected by the human eye. At these wavelengths, gases in the atmosphere scatter a modest amount of sunlight, so the clouds we see tend to be at somewhat higher altitudes than in the top panel.The third panel shows near-infrared reflected sunlight at a wavelength where the gas methane, an important constituent of Jupiter's atmosphere, absorbs strongly. Dark places are regions without high-level clouds and consequently large amounts of methane accessible to sunlight. Bright regions are locations with high clouds in the upper troposphere shielding the methane below.The bottom panel was taken in the ultraviolet. At these very short wavelengths, the clear atmosphere scatters sunlight, and hazes in the stratosphere, above the troposphere, absorb sunlight. That

  7. 一带一路与长江经济带战略构想内涵与战略意义--兼论重庆在两大战略中的定位%The Implication of the Belt and Road Initiative and Yangtze Economic Belt Initiative and the Reconsideration on the Positioning of Chongqing in These Two Strategies

    Institute of Scientific and Technical Information of China (English)

    陈文玲

    2016-01-01

    一带一路战略是随着我国成为世界第一大贸易体,成为世界制造业产值第一的国家,成为世界金融大国和创新大国应运而生的。一带一路战略在陆上主要是依托国际大通道,以沿线中心城市为支撑,以重点经贸产业园区为合作平台,建设跨国界的经济通道;在海上主要是以重点港口为节点,共同建设畅通、安全、高效的运输大通道,也即经济走廊,主要连接东南亚、南亚。一带一路战略作为一个需要持续多年推动的大战略,具有非常重大的现实意义和深远的历史意义。一带一路战略倡导建设命运共同体,我国将与一带一路沿线国家追求合作共赢的乘数效应。长江经济带战略实施的重点和目标在于,提高长江经济带沿线经济的竞争力、带动力、支撑力、辐射力、回旋力。一带一路与长江经济带战略充分体现了创新发展、协调发展、开放发展、绿色发展、共享发展的理念。在一带一路战略和长江经济带战略中,重庆作为一个充满动感和活力的城市以及历史文化名城,需要充分利用自身独特的政策集成优势、对外开发开放优势、经济发展空间优势,实现一体化安排和一体化战略设计,打造高度发达的综合立体交通枢纽,成为内陆开放的高地、两大战略的交汇点和连接点以及创新发展的新引擎。%While China has become the world’s first largest trading entity,ranked the top in terms of manufacturing output, and become the large country in terms of financial trading and innovation,the Belt and Road Initiative emerges as the times require. The overland support of the Belt and Road Initiative is the international channels;and we should build the cross-border economic channels taking the central cities long the Belt and Road as the support and the important economic and trade industrial parks as the cooperation platform. The

  8. Seat belt utilisation and awareness in UAE.

    Science.gov (United States)

    Bendak, S; Al-Saleh, K

    2013-01-01

    Seat belts (SBs) are effective devices for reducing injury risk due to traffic accidents. Seat belt wearing was made compulsory in the United Arab Emirates (UAE) in January 1999 for drivers and front seat passengers (FSPs). No comprehensive study has ever assessed SB wearing rates across the country. Also, little is known on drivers' awareness of the importance of wearing seatbelts and how human factors affect wearing habits. This study aims to determine SB wearing rates for drivers and FSPs in UAE through an observational field study. It also aims to investigate perceptions and behaviour of drivers on this issue as well as human factors that affect wearing rate through a randomly distributed questionnaire. The results of the field study show that the overall SB wearing rate across the country was 61% for drivers and 43.4% for FSPs and that there were significant differences between the seven emirates that constitute the country. The questionnaire results show that age, education level, gender, marital status and nationality of drivers affect wearing habits and perceptions. Future implications in terms of improving traffic safety awareness are discussed.

  9. Tectonic and thermal history of the western Serrania del Interior foreland fold and thrust belt and Guarico Basin, north central Venezuela: Implications of new apatite fission track analysis and seismic interpretation

    Science.gov (United States)

    Perez de Armas, Jaime Gonzalo

    Structural analysis, interpretation of seismic reflection lines, and apatite fission-track analysis in the Western Serrania del Interior fold and thrust belt and in the Guarico basin of north-central Venezuela indicate that the area underwent Mesozoic and Tertiary-to-Recent deformation. Mesozoic deformation, related to the breakup of Pangea, resulted in the formation of the Espino graben in the southernmost portion of the Guarico basin and in the formation of the Proto-Caribbean lithosphere between the diverging North and South American plates. The northern margin of Venezuela became a northward facing passive margin. Minor normal faults formed in the Guarico basin. The most intense deformation took place in the Neogene when the Leeward Antilles volcanic island arc collided obliquely with South America. The inception of the basal foredeep unconformity in the Late Eocene-Early Oligocene marks the formation of a perisutural basin on top of a buried graben system. It is coeval with minor extension and possible reactivation of Cretaceous normal faults in the Guarico basin. It marks the deepening of the foredeep. Cooling ages derived from apatite fission-tracks suggest that the obduction of the fold and thrust belt in the study area occurred in the Late Oligocene through the Middle Miocene. Field data and seismic interpretations suggest also that contractional deformation began during the Neogene, and specifically during the Miocene. The most surprising results of the detrital apatite fission-track study are the ages acquired in the sedimentary rocks of the easternmost part of the study area in the foreland fold and thrust belt. They indicate an Eocene thermal event. This event may be related to the Eocene NW-SE convergence of the North and South American plates that must have caused the Proto-Caribbean lithosphere to be shortened. This event is not related to the collision of the arc with South America, as the arc was far to the west during the Eocene.

  10. Effects of vehicle seat and belt geometry on belt fit for children with and without belt positioning booster seats.

    Science.gov (United States)

    Reed, Matthew P; Ebert-Hamilton, Sheila M; Klinich, Kathleen D; Manary, Miriam A; Rupp, Jonathan D

    2013-01-01

    A laboratory study was conducted to quantify the effects of belt-positioning boosters on lap and shoulder belt fit. Postures and belt fit were measured for forty-four boys and girls ages 5-12 in four highback boosters, one backless booster, and on a vehicle seat without a booster. Belt anchorage locations were varied over a wide range. Seat cushion angle, seat back angle, and seat cushion length were varied in the no-booster conditions. All boosters produced better mean lap belt fit than was observed in the no-booster condition, but the differences among boosters were relatively large. With one midrange belt configuration, the lap belt was not fully below the anterior-superior iliac spine (ASIS) landmark on the front of the pelvis for 89% of children in one booster, and 75% of children failed to achieve that level of belt fit in another. In contrast, the lap belt was fully below the ASIS for all but two children in the best-performing booster. Child body size had a statistically significant but relatively small effect on lap belt fit. The largest children sitting without a booster had approximately the same lap belt fit as the smallest children experienced in the worst-performing booster. Increasing lap belt angle relative to horizontal produced significantly better lap belt fit in the no-booster condition, but the boosters isolated the children from the effects of lap belt angles. Reducing seat cushion length in the no-booster condition improved lap belt fit but changing cushion angle did not. Belt upper anchorage (D-ring) location had a strong effect on shoulder belt fit in conditions without shoulder belt routing from the booster. Unexpectedly, the worst average shoulder belt fit was observed in one highback booster with a poorly positioned shoulder belt routing clip. The shoulder belt was routed more outboard, on average, with a backless booster than without a booster, but raising the child also amplified the effect of D-ring location, such that children were

  11. Perspectives on Global and Regional Security and Implications of Nuclear and Space Technologies: U.S.-Brazil Strategic Dialogue, Phase 2 Report

    Science.gov (United States)

    2014-10-01

    enhanced leverage in South- South and BRICs groupings. 6 Under President Lula da Silva’s leadership, Brazil sought to actively enhance and promote its...State,” 25, 35-36; Joe Leahy and James Lamont, “ BRICs to Debate Creation of Common Bank,” Financial Times, March 20, 2012.   4   Challenges in the...conflict. As previously, mentioned, UNASUR is viewed as a proto-security community. The BRICS (Brazil-Russia-India-China-South Africa) grouping

  12. Kuiper Belts Around Nearby Stars

    CERN Document Server

    Nilsson, R; Brandeker, A; Olofsson, G; Pilbratt, G L; Risacher, C; Rodmann, J; Augereau, J -C; Bergman, P; Eiroa, C; Fridlund, M; Thébault, P; White, G J

    2010-01-01

    In order to detect and characterise cold extended circumstellar dust originating from collisions of planetesimal bodies in disks, belts, or rings at Kuiper-Belt distances (30--50\\,AU or beyond) sensitive submillimetre observations are essential. Measurements of the flux densities at these wavelengths will extend existing IR photometry and permit more detailed modelling of the Rayleigh-Jeans tail of the disks spectral energy distribution (SED), effectively constraining dust properties and disk extensions. By observing stars spanning from a few up to several hundred Myr, the evolution of debris disks during crucial phases of planet formation can be studied. // We have performed 870\\,$\\mu$m observations of 22 exo-Kuiper-Belt candidates, as part of a Large Programme with the LABOCA bolometer at the APEX telescope. Dust masses (or upper limits) were calculated from integrated 870\\,$\\mu$m fluxes, and fits to the SED of detected sources revealed the fractional dust luminosities $f_{\\mathrm{dust}}$, dust temperatures...

  13. Religion, spirituality and cardiovascular disease: research, clinical implications, and opportunities in Brazil Religião, espiritualidade e doença cardiovascular: pesquisa, implicações clínicas e oportunidades no Brasil

    Directory of Open Access Journals (Sweden)

    Fernando A. Lucchese

    2013-03-01

    Full Text Available In this paper we comprehensively review published quantitative research on the relationship between religion, spirituality (R/S, and cardiovascular (CV disease, discuss mechanisms that help explain the associations reported, examine the clinical implications of those findings, and explore future research needed in Brazil on this topic. First, we define the terms religion, spirituality, and secular humanism. Next, we review research examining the relationships between R/S and CV risk factors (smoking, alcohol/drug use, physical inactivity, poor diet, cholesterol, obesity, diabetes, blood pressure, and psychosocial stress. We then review research on R/S, cardiovascular functions (CV reactivity, heart rate variability, etc., and inflammatory markers (IL-6, IFN-γ, CRP, fibrinogen, IL-4, IL-10. Next we examine research on R/S and coronary artery disease, hypertension, stroke, dementia, cardiac surgery outcomes, and mortality (CV mortality in particular. We then discuss mechanisms that help explain these relationships (focusing on psychological, social, and behavioral pathways and present a theoretical causal model based on a Western religious perspective. Next we discuss the clinical applications of the research, and make practical suggestions on how cardiologists and cardiac surgeons can sensitively and sensibly address spiritual issues in clinical practice. Finally, we explore opportunities for future research. No research on R/S and cardiovascular disease has yet been published from Brazil, despite the tremendous interest and involvement of the population in R/S, making this an area of almost unlimited possibilities for researchers in Brazil.

  14. Two stages of zircon crystallization in the Jingshan monzogranite, Bengbu Uplift: Implications for the syn-collisional granites of the Dabie-Sulu UHP orogenic belt and the climax of movement on the Tan-Lu fault

    Science.gov (United States)

    Wang, X.; Chen, J.; Griffin, W. L.; O'Reilly, S. Y.; Huang, P. Y.; Li, X.

    2011-03-01

    The detailed study of zircon can provide vital clues about the petrogenetic environment of granitoid rocks. Morphological and chemical studies of zircon grains from the Jingshan monzogranite in the Bengbu Uplift (Anhui province, eastern China) identify three phases of growth. Zircon I is brown, translucent, ovoid, and occurs as inherited cores. It shows two groups of 206Pb/ 238U ages, corresponding to the country rock of the Jingshan monzogranite and the basement of the Bengbu Uplift. Zircon II is colorless, transparent and idiomorphic-hypidiomorphic with Ipr = 0.34-0.52, Ipy = 0.03-0.24 and Iel = 0.26-0.34. It shows a very bright CL due to high contents of trace elements (e.g., Y, U and Th), and the oscillatory zoning associated with sector zoning. It contains 1.40-1.66 wt.% HfO 2 with a mean ɛ Hf (t) of - 17.88. These features indicate the igneous crystallization of Zircon II from a peraluminous granite of mainly crustal origin. Based on the field geology, petrography, geochemical analysis, and especially a weighted mean age of 222 Ma for Zircon II, we argue that the Jingshan monzogranite is a syn-collisional granite of the Dabie UHP orogenic belt. This provides new evidence for the northward subduction of the South China Block beneath the North China Block just before 222 Ma, and allows quantitative estimates of the rate of post-UHP exhumation in the Dabie orogenic belt. Zircon III is also colorless and transparent, but is totally idiomorphic with Ipr = 0.41-1.00, Ipy = 0.88-1.00 and Iel = 0.39-0.83. It occurs only as overgrowths on Zircon II, and shows weak CL due to its depletion in trace elements. Zircon III has widely variable contents of HfO 2 (1.12 to 3.01 wt.%) and Hf-isotope compositions very similar to those of Zircon II. These features suggest crystallization of Zircon III from small volumes of leucosome, probably in the beginning stages of migmatisation. Zircon III has a weighted mean age of 156 Ma, interpreted as representing the climax of movement

  15. Provenance, volcanic record, and tectonic setting of the Paleozoic Ventania Fold Belt and the Claromecó Foreland Basin: Implications on sedimentation and volcanism along the southwestern Gondwana margin

    Science.gov (United States)

    Alessandretti, Luciano; Philipp, Ruy Paulo; Chemale, Farid; Brückmann, Matheus Philipe; Zvirtes, Gustavo; Matté, Vinícius; Ramos, Victor A.

    2013-11-01

    This study focuses on the provenance, volcanic record, and tectonic setting of the Paleozoic Ventania System, a geologic province which comprises the Cambro-Devonian Ventania Fold Belt and the adjoining Permo-Carboniferous Claromecó Foreland Basin, located inboard the deformation front. The Ventania Fold Belt is formed of the Curamalal and Ventana groups, which are composed mainly of mature quartzites that were unconformably deposited on igneous and metamorphic basement. The Pillahuincó Group is exposed as part of the Claromecó Basin and it has lithological and structural features totally distinct from the lowermost groups. This group is composed of immature arkoses and subarkoses with intercalated tuff horizons, unconformably overlaying the quartzites and associated with glacial-marine deposits of the lower Late Carboniferous to Early Permian section. The petrography, as well as major and trace elements (including rare earth elements) support that the Ventania quartzites were derived from cratonic sources and deposited in a passive margin environment. For the Pillahuincó Group, we suggest a transition between rocks derived from and deposited in a passive margin environment to those with geochemical and petrographical signatures indicative of an active continental margin provenance. LA-MC-ICP-MS analysis performed on euhedral and prismatic zircon grains of the tuffs revealed an age of 284 ± 15 Ma. The geochemical fingerprints and geochronological data of the tuffs found in the Claromecó Basin support the presence of an active and widespread Lower Permian pyroclastic activity in southwestern Gondwana, which is interpreted as part of the Choiyoi Volcanic Province in Argentina and Chile.

  16. Usbnd Pb zircon geochronology constraints on the ages of the Tananao Schist Belt and timing of orogenic events in Taiwan: Implications for a new tectonic evolution of the South China Block during the Mesozoic

    Science.gov (United States)

    Chen, Wen-Shan; Huang, Yi-Chang; Liu, Chang-Hao; Feng, Han-Ting; Chung, Sun-Lin; Lee, Yuan-Hsi

    2016-08-01

    The Tananao Schist Belt is a low-pressure metamorphic complex comprised of three lithological units of marble, schist formation, and granite, in ascending order of proportion. Previous studies have found that the schist formation was formed during the Mesozoic. However, there is a lack of geochronological data to corroborate the schist protolith and metamorphic ages. In this study, we have used Usbnd Pb zircon geochronology to provide a time frame for the creation of the schist formation and metamorphism, as well as a new tectonic model. Twenty-three schist and eleven meta-magmatic samples were used for Usbnd Pb dating by LA-ICP-MS. Results from the youngest peak age of detrital zircon indicate that the schist formed in a new depositional age of 120-110 Ma and, therefore, is different from the previously estimated age of the Paleozoic-Mesozoic. Additionally, the block-in-matrix schist indicates an age that ranges from 270 to 80 Ma and was inferred from the chaotic deposits to be a metamorphic mélange. The Tananao Schist Belt appears to represent an arc-trench system that formed during the Cretaceous in the South China Block margin. Moreover, the youngest Usbnd Pb age of 80 Ma from the leucogranite dike and schist, constrains the upper age limit for a metamorphism that is younger than the previously accepted age of 100-90 Ma. The contact layer between Permian-Triassic marble and the overlying early Cretaceous schists remains a chloritoid bed that is, therefore, considered to be a paleosol at the unconformity, which formed over an extended duration of 60 ± 30 Ma. The stratigraphic contact indicates a long period of erosion during the Jurassic and suggests that a tectonic event occurred. However, we propose that two important metamorphic events took place prior to, and following, the schist formation during the Jurassic and late Cretaceous orogenic events.

  17. Geochemistry and zircon U-Pb-Hf isotopes of Early Paleozoic arc-related volcanic rocks in Sonid Zuoqi, Inner Mongolia: Implications for the tectonic evolution of the southeastern Central Asian Orogenic Belt

    Science.gov (United States)

    Chen, Yan; Zhang, Zhicheng; Li, Ke; Yu, Haifei; Wu, Tairan

    2016-11-01

    An Early Paleozoic acid volcanic sequence has been recently detected southeast of Sonid Zuoqi in central Inner Mongolia to constrain the tectonic evolution of the Central Asian Orogenic Belt in this area. First, the volcanic rocks have zircon U-Pb ages of 439-445 Ma. They are characterized by (a) a high silica content, moderate alkali content and low iron content; (b) enrichment in light rare earth elements, depletion of heavy rare earth elements, and negative Eu anomalies; and (c) negative Nb, Ta, and Ti anomalies. Finally, the volcanic samples yield εHf(t) values of - 4.7 to + 9.2 with TDM2 ages of 835-1724 Ma. For petrogenesis, they were possibly arc derived, from predominant juvenile materials with subordinate ancient continental crust. Combined with previous studies, the Early Paleozoic Sonid Zuoqi arc magmatism can be divided into three stages: a primitive arc stage represented by 464-490 Ma low-K, calcic granitoids; a normal continental arc stage represented by 439-445 Ma medium-K, calcic to calcic-alkalic plutons and volcanic rocks and a syn-collisional stage represented by 423-424 Ma high-K granites. Furthermore, the timing and tectonic settings of the above magmatic rocks show similarities to those in Xilinhot and other areas of the northern Early to Mid-Paleozoic orogenic belt (NOB), although the rock assemblies and their proportions vary more or less in different areas. Accordingly, the NOB that formed on this arc was probably attributed to the northward subduction of the Paleo-Asian Ocean beginning at 500 Ma, which experienced this type of arc development and was terminated by a soft collision before the Late Devonian.

  18. Appendiceal transection associated with seat belt restraint.

    Science.gov (United States)

    Go, Seung Je; Sul, Young Hoon; Ye, Jin Bong; Kim, Joong Suck

    2016-08-01

    The seat belt is designed for safety in a motor vehicle and should be worn to prevent severe injuries. But, the seat belt itself can be an injury factor in combination with deceleration forces applied to fixation points of mobile viscera. Here, we present a 23-year-man with traumatic transection of the appendix, highly mobile viscera, following seat belt injury.

  19. French experience in seat belt use.

    NARCIS (Netherlands)

    Lassarre, S. & Page, Y.

    1992-01-01

    This paper concerns the French experience in seat belt use. As well as the seat belt regulations, the strategies employed to reinforce the wearing of seat belts by using information and encouragement campaigns and checks by the police and gendarmerie are described here along with their timetables an

  20. Kuiper belts around nearby stars

    NARCIS (Netherlands)

    Nilsson, R.; Liseau, R.; Brandeker, A.; Olofsson, G.; Pilbratt, G. L.; Risacher, C.; Rodmann, J.; Augereau, J-C.; Bergman, P.; Eiroa, C.; Fridlund, M.; Thebault, P.; White, G. J.

    2010-01-01

    Context. The existence of dusty debris disks around a large fraction of solar type main-sequence stars, inferred from excess far-IR and submillimetre emission compared to that expected from stellar photospheres, suggests that leftover planetesimal belts analogous to the asteroid-and comet reservoirs

  1. Seat belt sign and its significance.

    Science.gov (United States)

    Agrawal, Amit; Inamadar, Praveenkumar Ishwarappa; Subrahmanyam, Bhattara Vishweswar

    2013-07-01

    Safety belts are the most important safety system in motor vehicles and when worn intend to prevent serious injuries. However, in unusual circumstances (high velocity motor vehicle collisions) these safety measures (seat belts) can be the source and cause of serious injuries. The seat belt syndrome was first described as early by Garrett and Braunste in but the term "seat belt sign" was discussed by Doersch and Dozier. Medical personnel's involved in emergency care of trauma patients should be aware of seat belt sign and there should a higher index of suspicion to rule out underlying organ injuries.

  2. U-Pb, Re-Os, and 40Ar/39Ar geochronology of the Nambija Au-skarn and Pangui porphyry Cu deposits, Ecuador: implications for the Jurassic metallogenic belt of the Northern Andes

    Science.gov (United States)

    Chiaradia, Massimo; Vallance, Jean; Fontboté, Lluis; Stein, Holly; Schaltegger, Urs; Coder, Joshua; Richards, Jeremy; Villeneuve, Mike; Gendall, Ian

    2009-05-01

    New U-Pb, Re-Os, and 40Ar/39Ar dates are presented for magmatic and hydrothermal mineral phases in skarn- and porphyry-related ores from the Nambija and Pangui districts of the Subandean zone, southeastern Ecuador. Nambija has been one of the main gold-producing centers of Ecuador since the 1980s due to exceptionally high-grade ores (average 15 g/t, but frequently up to 300 g/t Au). Pangui is a recently discovered porphyry Cu-Mo district. The geology of the Subandean zone in southeastern Ecuador is dominated by the I-type, subduction-related, Jurassic Zamora batholith, which intrudes Triassic volcanosedimentary rocks. The Zamora batholith is in turn cut by porphyritic stocks, which are commonly associated with skarn formation and/or porphyry-style mineralization. High precision U-Pb and Re-Os ages for porphyritic stocks (U-Pb, zircon), associated prograde skarn (U-Pb, hydrothermal titanite), and retrograde stage skarn (Re-Os, molybdenite from veins postdating gold deposition) of the Nambija district are all indistinguishable from each other within error (145 Ma) and indicate a Late Jurassic age for the gold mineralization. Previously, gold mineralization at Nambija was considered to be Early Tertiary based on K-Ar ages obtained on various hydrothermal minerals. The new Jurassic age for the Nambija district is slightly younger than the 40Ar/39Ar and Re-Os ages for magmatic-hydrothermal minerals from the Pangui district, which range between 157 and 152 Ma. Mineralization at Nambija and Pangui is associated with porphyritic stocks that represent the last known episodes of a long-lived Jurassic arc magmatism (˜190 to 145 Ma). A Jurassic age for mineralization at Nambija and Pangui suggests that the Northern Andean Jurassic metallogenic belt, which starts in Colombia at 3° N, extends down to 5° S in Ecuador. It also adds a new mineralization style (Au-skarn) to the metal endowment of this belt.

  3. Tectonic repetitions of the Early Cretaceous Agrio Formation in the Chos Malal fold-and-thrust belt, Neuquén Basin, Argentina: Geometry, kinematics and structural implications for Andean building

    Science.gov (United States)

    Turienzo, M.; Sánchez, N.; Dimieri, L.; Lebinson, F.; Araujo, V.

    2014-08-01

    The Neuquén Basin, developed in a retroarc setting in the central-west of Argentina, contains more than 6000 m of Mesozoic marine and continental sedimentary rocks. These rocks were deformed during the Andean orogeny leading to several thick and thin-skinned fold-and-thrust belts. The Early Cretaceous Agrio Formation is composed by a thick marine succession predominantly of black shales in which highlights a thin fluvial-aeolian sandy interval named Avilé Member. The Avilé Member, one of the most important hydrocarbon reservoirs of the Neuquén Basin, constitutes an excellent structural marker. At the Chos Malal fold-and-thrust belt, the strong mechanical anisotropy given by the contrasting lithology of the Avilé Member within the Agrio Formation favored the location of detachments along the shales and ramps affecting the sandstones during the Andean compression. Detailed field mapping at the Chacay Melehue area allowed us to recognize tectonic repetitions of the Avilé Member, which form imbrications in the simplest case whereas in other places constitute a more complex combination of imbrications, including fault-bend folding that duplicates stratigraphic sequences and fault-propagation folding that deforms more intensely the duplicated units. Along three structural cross-sections we illustrate the geometry of these tectonic repetitions of the Agrio Formation, which in the northern area have an eastward-vergence and in the central and southern regions show a clear westward-vergence. A tear fault along the arroyo Chacay Melehue could explain this vergence change. Forward modeling of the structures at the central cross-section, where a backthrust system produced imbrication, duplication and folding of the Agrio Formation, allows us to propose a balanced kinematic reconstruction of this complex structure and to compare the features produced at different stages of the deformation sequence with field observations. Our kinematic interpretation shows that the

  4. The Rise of the Big Emerging Markets of Brazil, Russia, India, and China: Implications for International Business Teaching in the Next Decade

    Science.gov (United States)

    Scott-Kennel, Joanna; Salmi, Asta

    2008-01-01

    The rise of Brazil, Russia, India, and China will shape global resource use, the location of market demand and international institutions and interdependencies in the decade to come. In this paper we argue that an understanding of the historical and institutional context of the BRICs, and the potential shift towards a multi-polar world is…

  5. The Rise of the Big Emerging Markets of Brazil, Russia, India, and China: Implications for International Business Teaching in the Next Decade

    Science.gov (United States)

    Scott-Kennel, Joanna; Salmi, Asta

    2008-01-01

    The rise of Brazil, Russia, India, and China will shape global resource use, the location of market demand and international institutions and interdependencies in the decade to come. In this paper we argue that an understanding of the historical and institutional context of the BRICs, and the potential shift towards a multi-polar world is…

  6. A Chaos Conveyor Belt

    Science.gov (United States)

    Schmidt, Britney E.

    2013-10-01

    A critical question for the habitability of Europa remains: how does the ice shell work? The detection of shallow subsurface lenses below Europa’s chaos implies that the ice shell is recycled rapidly and that Europa may be currently active. While this is not the first time liquid water has been implicated for Europa, the location of these features combined with new perspective on their dynamics frames the question in a new way. Melt lenses are intriguing potential habitats. Moreover, their formation requires the existence of impurities within the upper ice shell that may be sources of energy for microorganisms. Geomorphic evidence also exists for hydraulic redistribution of fluids both vertically and horizontally through pores and fractures. This process, observed in terrestrial ice shelves, may preserve liquid water within the ice matrix over many kilometers from the source. Horizontal transport of material may produce interconnectivity between distinct regions of Europa, thus preserving habitable conditions within the ice over a longer duration. At a surface age of 40-90 Myr, with 25-50% covered by chaos terrain, Europa's resurfacing rate is very high and water likely plays a significant role. Because of the vigor of overturn implied by this new work, it is likely that surface and subsurface materials are well-mixed within the largest and deepest lenses, providing a mechanism for bringing oxidants and other surface contaminants to the deeper ice shell where it can reach the ocean by convective or compositional effects. The timescales over which large lenses refreeze are large compared to the timescales for vertical transport, while the timescales for smaller lenses are comparable to or shorter than convective timescales. Moreover, marine ice accretion at the bottom of the ice shell may be contributing to a compositional buoyancy engine that would change the makeup of the ice shell. From this point of view, we evaluate the habitability of Europa’s ice and

  7. Ring current and radiation belts

    Science.gov (United States)

    Williams, D. J.

    1987-01-01

    Studies performed during 1983-1986 on the ring current, the injection boundary model, and the radiation belts are discussed. The results of these studies yielded the first observations on the composition and charge state of the ring current throughout the ring-current energy range, and strong observational support for an injection-boundary model accounting for the origins of radiation-belt particles, the ring current, and substorm particles observed at R less than about 7 earth radii. In addition, the results have demonstrated that the detection of energetic neutral atoms generated by charge-exchange interactions between the ring current and the hydrogen geocorona can provide global images of the earth's ring current and its spatial and temporal evolution.

  8. Geochemistry and geochronology of late Mesozoic volcanic rocks in the northern part of the Eastern Pontide Orogenic Belt (NE Turkey): Implications for the closure of the Neo-Tethys Ocean

    Science.gov (United States)

    Özdamar, Şenel

    2016-04-01

    This paper presents 40Ar/39Ar and U-Pb age data, Sr-Nd isotopes, whole-rock and mineral compositions of Upper Cretaceous volcanic rocks from the Ordu area of the Eastern Pontide Orogenic Belt (EPOB) in northeastern Turkey. The volcanic rocks exhibit a wide compositional range: basalt, basaltic-andesites, andesites and a rhyodacite suite; they are characterized by subparallel light rare earth element (LREE)-enrichment, relatively flat heavy rare earth element (HREE) patterns with Eu anomalies and moderate fractionation [average (La/Yb)N = 8.55]. The geochemical results show that the volcanic rocks have calc-alkaline affinity consistent with arc volcanic rocks erupted in an active continental margin. Initial 87Sr/86Sr values vary between 0.70569 and 0.70606, while initial 143Nd/144Nd values lie between 0.51244 and 0.51249. Crustal contamination affected the mantle-originated primary magma, as indicated by increased 87Sr/86Sr and decreased 143Nd/144Nd ratios with increasing SiO2. New precise laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS) 206Pb-238U age analyses of zircon and 40Ar/39Ar age data of plagioclase from the volcanics enable a more precise reconstruction of the EBOP. The ages provide insight into the timing of arc formation in this region, constrain the volcanic activity between 86 My (Coniacian) and 75 My (Campanian) and constrain the timing of closure of the Neo-Tethys.

  9. Sm-Nd data for mafic-ultramafic intrusions in the Svecofennian (1.88 Ga Kotalahti Nickel Belt, Finland – implications for crustal contamination at the Archaean/Proterozoic boundary

    Directory of Open Access Journals (Sweden)

    Hannu V. Makkonen

    2007-01-01

    Full Text Available Sm-Nd data were determined for eight mafic-ultramafic intrusions from the Svecofennian (1.88 Ga Kotalahti Nickel Belt, Finland. The intrusions represent both mineralized and barren types and are located at varying distances from the Archaean/Proterozoic boundary.The samples for the 23 Sm-Nd isotope analyses were taken mostly from the ultramafic differentiates. Results show a range in initial εNd values at 1880 Ma from -2.4 to +2.0. No relationship can be found between the degree of Ni mineralization and initial εNd values, whilea correlation with the geological domain and country rocks is evident. The Majasaari and Törmälä intrusions, which have positive εNd values, were emplaced within the Svecofennian domain in proximity to 1.92 Ga tonalitic gneisses, which have previously yielded initialεNd values of ca. +3. In contrast, the Luusniemi intrusion, which has an εNd value of -2.4 is situated close to exposed Archaean crust. Excluding two analyses from the Rytky intrusion, all data from the Koirus N, Koirus S, Kotalahti, Rytky and Kylmälahti intrusions, withinerror limits, fall in the range -0.7 ± 0.3. The results support the concept of contamination by Archaean material in proximity to the currently exposed craton margin. The composition of the proposed parental magma for the intrusions is close to EMORB, with initialεNd values near +4.

  10. Saturation of Van Allen's belts

    CERN Document Server

    Le Bel, E

    2002-01-01

    The maximum number of electrons that can be trapped in van Allen's belts has been evaluated at CEA-DAM more precisely than that commonly used in the space community. The modelization that we have developed allows to understand the disagreement (factor 50) observed between the measured and predicted electrons flux by US satellites and theory. This saturation level allows sizing-up of the protection on a satellite in case of energetic events. (authors)

  11. Spotlight: Brazil.

    Science.gov (United States)

    Carter, M

    1996-08-01

    Brazil is South America's largest country and home to nearly half of the continent's people. Despite solid economic growth, Brazil has one of the world's widest income disparities. In the early 1990s, nearly 40% of urban and 66% of rural Brazilians lived in poverty. The streets of Brazil's cities are home to a large population of street children. Although it is difficult to estimate, 10 million children and youths may be either homeless or making a meager living off of the streets. Street children may be linked to prostitution and drugs and be the targets or perpetrators of violence. Child labor is an issue in Brazil. Today an estimated 30% of rural children and 9% of urban children ages 10-13 work in the formal economy. In some rural areas, 60% of workers are ages 5-17. Child labor also contributes to Brazil's relatively low educational attainment levels. UNICEF estimates that around 1990 only 1/3 of all Brazilian children continued on to secondary school, compared to 74% and 47%, respectively, for the Latin America and Caribbean regions. Immunization rates among Brazil's children are rising but still lag slightly behind regional averages. The mortality rate for children under age 5 decreased dramatically from 181 deaths for every 1000 live births in 1960 to 61/1000 in 1994. During the same time period, the average number of children born to a woman during her lifetime dropped from 6.2 to 2.8. This fertility decline is related in part to increased access to and acceptance of family planning. Contraceptive prevalence, including traditional and modern methods, is around 66%, with female sterilization and the pill being the most popular methods. Brazil's abortion rates are high, despite laws limiting access to abortion services. One estimate suggests that about 30% of all pregnancies are terminated through abortion each year.

  12. Intelligent seat belt reminders-do they change driver seat belt use in Europe?

    Science.gov (United States)

    Lie, Anders; Krafft, Maria; Kullgren, Anders; Tingvall, Claes

    2008-10-01

    Many modern cars have seat belt reminders (SBRs) using loud and clear sound and light signals. These systems have developed over the last few years. This study investigates how these modern systems influence the seat belt use in real-life traffic in built-up areas in some European cities. The data were collected by field observations in major cities in six European countries and in five cities around Sweden. A selection of car models having seat belt reminders (SBR) were compared to a fleet of similar car models without such reminders. A significant difference in seat belt wearing rate was found in the cars with seat belt reminders. For all observations, the total seat belt wearing rate was 97.5% +/- 0.5% in cars with SBR, while it was 85.8% +/- 0.8% in cars without. There were differences in seat belt use in the different observation locations. The lowest seat belt use was found in Brussels/Belgium with a use rate of 92.6 +/- 2.2% in cars with seat belt reminders and 69.6 +/- 3.1% in cars not fitted with reminders. The highest seat belt use was found in Paris/France where 99.8 +/- 0.4% of the drivers used the seat belt in cars with reminders and 96.9 +/-1.1% were belted in cars without reminders. Seat belt reminders fulfilling Euro NCAP's seat belt reminder protocol are increasing the seat belt use in daily traffic significantly. Around 80% (82.2% +/- 8.6%) of the drivers not putting the belt on without a seat belt reminder do so in cars equipped with an SBR that has a light signal and an associated loud and clear sound signal.

  13. Implications of a 3.472-3.333 Gyr-old subaerial microbial mat from the Barberton greenstone belt, South Africa for the UV environmental conditions on the early Earth.

    Science.gov (United States)

    Westall, Frances; de Ronde, Cornel E J; Southam, Gordon; Grassineau, Nathalie; Colas, Maggy; Cockell, Charles; Lammer, Helmut

    2006-10-29

    Modelling suggests that the UV radiation environment of the early Earth, with DNA weighted irradiances of about three orders of magnitude greater than those at present, was hostile to life forms at the surface, unless they lived in specific protected habitats. However, we present empirical evidence that challenges this commonly held view. We describe a well-developed microbial mat that formed on the surface of volcanic littoral sediments in an evaporitic environment in a 3.5-3.3Ga-old formation from the Barberton greenstone belt. Using a multiscale, multidisciplinary approach designed to strongly test the biogenicity of potential microbial structures, we show that the mat was constructed under flowing water by 0.25 microm filaments that produced copious quantities of extracellular polymeric substances, representing probably anoxygenic photosynthesizers. Associated with the mat is a small colony of rods-vibroids that probably represent sulphur-reducing bacteria. An embedded suite of evaporite minerals and desiccation cracks in the surface of the mat demonstrates that it was periodically exposed to the air in an evaporitic environment. We conclude that DNA-damaging UV radiation fluxes at the surface of the Earth at this period must either have been low (absorbed by CO2, H2O, a thin organic haze from photo-dissociated CH4, or SO2 from volcanic outgassing; scattered by volcanic, and periodically, meteorite dust, as well as by the upper layers of the microbial mat) and/or that the micro-organisms exhibited efficient gene repair/survival strategies.

  14. Paired Magmatic-Metallogenic Belts in Myanmar - an Andean Analogue?

    Science.gov (United States)

    Gardiner, Nicholas; Robb, Laurence; Searle, Michael; Morley, Christopher

    2015-04-01

    contrasting minerals endowment. The Mogok-Mandalay-Mergui (MMM) Belt hosts crustal-melt S-type granites with significant tin-tungsten mineralization, and contains the historically major tungsten deposit of Mawchi. The Wuntho-Popa Arc comprises I-type granites and granodiorites with porphyry-type copper-gold and epithermal gold mineralization, and includes the world-class Monywa copper mine. Recent U-Pb radiometric age dating has shown the potential for the two belts to be both active from the Late Cretaceous to Eocene. The spatial juxtaposition of these two sub-parallel belts, the implication of contemporary magmatism, and their distinct but consistent metallogenic endowment bears strong similarities to the metallogenic belts of the South American Cordillera. Here we investigate whether they together represent the magmatic and metallogenic expression of an Andean-type setting in Myanmar during the subduction of Neo-Tethys. In this analogue the Wuntho-Popa Arc represents a proximal I-type magmatic belt sited immediately above the eastwards-verging Neo-Tethys subduction zone. Exhibiting porphyry-type copper-gold and epithermal gold mineralization, this would therefore be the Myanmar equivalent of the Andean coastal copper belts. Conversely, the parallel MMM Belt, comprised of more distal crustal-melt S-type tin granites, would have an analogue in the Bolivian tin belt.

  15. Synchronous and Cogged Fan Belt Performance Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Cutler, D.; Dean, J.; Acosta, J.

    2014-02-01

    The GSA Regional GPG Team commissioned the National Renewable Energy Laboratory (NREL) to perform monitoring of cogged V-belts and synchronous belts on both a constant volume and a variable air volume fan at the Byron G. Rodgers Federal Building and U.S. Courthouse in Denver, Colorado. These motor/fan combinations were tested with their original, standard V-belts (appropriately tensioned by an operation and maintenance professional) to obtain a baseline for standard operation. They were then switched to the cogged V-belts, and finally to synchronous belts. The power consumption by the motor was normalized for both fan speed and air density changes. This was necessary to ensure that the power readings were not influenced by a change in rotational fan speed or by the power required to push denser air. Finally, energy savings and operation and maintenance savings were compiled into an economic life-cycle cost analysis of the different belt options.

  16. 1962 Satellite High Altitude Radiation Belt Database

    Science.gov (United States)

    2014-03-01

    TR-14-18 1962 Satellite High Altitude Radiation Belt Database Approved for public release; distribution is unlimited. March...the Status of the High Altitude Nuclear Explosion (HANE) Trapped Radiation Belt Database”, AFRL-VS-PS-TR- 2006-1079, Air Force Research Laboratory...Roth, B., “Blue Ribbon Panel and Support Work Assessing the Status of the High Altitude Nuclear Explosion (HANE) Trapped Radiation Belt Database

  17. Neotectonics and structure of the Himalayan deformation front in the Kashmir Himalaya, India: Implication in defining what controls a blind thrust front in an active fold-thrust belt

    Science.gov (United States)

    Gavillot, Y. G.; Meigs, A.; Yule, J. D.; Rittenour, T. M.; Malik, M. O. A.

    2014-12-01

    Active tectonics of a deformation front constrains the kinematic evolution and structural interaction between the fold-thrust belt and most-recently accreted foreland basin. In Kashmir, the Himalayan Frontal thrust (HFT) is blind, characterized by a broad fold, the Suruin-Mastargh anticline (SMA), and displays no emergent faults cutting either limb. A lack of knowledge of the rate of shortening and structural framework of the SMA hampers quantifying the earthquake potential for the deformation front. Our study utilized the geomorphic expression of dated deformed terraces on the Ujh River in Kashmir. Six terraces are recognized, and three yield OSL ages of 53 ka, 33 ka, and 0.4 ka. Vector fold restoration of long terrace profiles indicates a deformation pattern characterized by regional uplift across the anticlinal axis and back-limb, and by fold limb rotation on the forelimb. Differential uplift across the fold trace suggests localized deformation. Dip data and stratigraphic thicknesses suggest that a duplex structure is emplaced at depth along the basal décollement, folding the overlying roof thrust and Siwalik-Muree strata into a detachment-like fold. Localized faulting at the fold axis explains the asymmetrical fold geometry. Folding of the oldest dated terrace, suggest that rock uplift rates across the SMA range between 2.0-1.8 mm/yr. Assuming a 25° dipping ramp for the blind structure on the basis of dip data constraints, the shortening rate across the SMA ranges between 4.4-3.8 mm/yr since ~53 ka. Of that rate, ~1 mm/yr is likely absorbed by minor faulting in the near field of the fold axis. Given that Himalaya-India convergence is ~18.8-11 mm/yr, internal faults north of the deformation front, such as the Riasi thrust absorbs more of the Himalayan shortening than does the HFT in Kashmir. We attribute a non-emergent thrust at the deformation front to reflect deformation controlled by pre-existing basin architecture in Kashmir, in which the thick succession

  18. Geochronology and geochemistry of Permian bimodal volcanic rocks from central Inner Mongolia, China: Implications for the late Palaeozoic tectonic evolution of the south-eastern Central Asian Orogenic Belt

    Science.gov (United States)

    Zhang, Zhicheng; Chen, Yan; Li, Ke; Li, Jianfeng; Yang, Jinfu; Qian, Xiaoyan

    2017-03-01

    Zircon U-Pb ages, geochemical data and Sr-Nd isotopic data are presented for volcanic rocks from the lower Permian Dashizhai Formation. These rocks are widely distributed in the south-eastern Central Asian Orogenic Belt in central Inner Mongolia, China. The volcanic rocks mainly consist of basaltic andesite and rhyolite, subordinate dacite and local andesite, and exhibit bimodal geochemical features. The results of zircon U-Pb dating indicate that the volcanic rocks formed during the early Permian (292-279 Ma). The mafic volcanic rocks belong to low-K tholeiitic to medium-K calc-alkaline series. These mafic volcanic rocks are also characterised by moderately enriched light rare earth element (LREE) patterns; high abundances of Th, U, Zr and Hf; negative Nb, Ta and Ti anomalies; initial 87Sr/86Sr ratios of 0.70514-0.70623; and positive εNd(t) values (+1.9 to +3.8). These features indicate that the mafic volcanic rocks were likely derived from the high-percentage partial melting of subduction-related metasomatised asthenospheric mantle. The felsic rocks show an A-type affinity, with enrichments in alkalis, Th, U and LREEs. The felsic rocks are depleted in Ba, Sr, Nb, Ta and Ti and exhibit moderately LREE-enriched patterns (LaN/YbN = 2.09-6.45) and strongly negative Eu anomalies (Eu/Eu∗ = 0.04-0.25). These features, along with the positive εNd(t) values (+2.6 to +7.7) and young TDM2 ages (TDM2 = 435-916 Ma), indicate that the felsic rocks were likely derived from a juvenile crustal source that mainly consisted of juvenile mid-ocean ridge basalt-related rocks. The volcanic association in this study and in previously published work widely distributed in central Inner Mongolia. The observations in this study suggest that the lower Permian volcanic rocks formed in an identical tectonic environment. The regional geological data indicate that the bimodal volcanic rocks from the lower Permian Dashizhai Formation in the study area formed in an extensional setting that was

  19. Geochronology and geochemistry of early Paleozoic igneous rocks of the Lesser Xing'an Range, NE China: Implications for the tectonic evolution of the eastern Central Asian Orogenic Belt

    Science.gov (United States)

    Wang, Zhi-wei; Xu, Wen-liang; Pei, Fu-ping; Wang, Feng; Guo, Peng

    2016-09-01

    This paper presents new zircon U-Pb, Hf isotope, and whole-rock major and trace element data for early Paleozoic igneous rocks of the Lesser Xing'an Range, NE China, in order to constrain the early Paleozoic tectonic evolution of the eastern Central Asian Orogenic Belt (CAOB). Zircon U-Pb dating indicates that early Paleozoic magmatic events within the northern Songnen-Zhangguangcai Range Massif (SZM) can be subdivided into four stages: Middle Cambrian (~ 505 Ma), Late Cambrian (~ 490 Ma), Early-Middle Ordovician (~ 470 Ma), and Late Ordovician (460-450 Ma). The Middle Cambrian monzogranites are K-rich, weakly to strongly peraluminous, and characterized by pronounced heavy rare earth element (HREE) depletions, high Sr/Y ratios, low Y concentrations, low primary zircon εHf(t) values (- 6.79 to - 1.09), and ancient two-stage model (TDM2) ages (1901-1534 Ma). These results indicate derivation from partial melting of thickened ancient crustal materials that formed during the amalgamation of the northern SZM and the northern Jiamusi Massif (JM). The Late Cambrian monzonite, quartz monzonite, and monzogranite units are chemically similar to A-type granites, and contain zircons with εHf(t) values of - 2.59 to + 1.78 and TDM2 ages of 1625-1348 Ma. We infer that these rocks formed from primary magmas generated by partial melting of Mesoproterozoic accreted lower crustal materials in a post-collisional extensional environment. The Early-Middle Ordovician quartz monzodiorite, quartz monzonite, monzogranite, and rhyolite units are calc-alkaline, relatively enriched in light REEs (LREEs) and large ion lithophile elements (LILEs; e.g., Rb, Th, and U), depleted in HREEs and high field strength elements (HFSEs; e.g., Nb, Ta, and Ti), and contain zircons with εHf(t) values of - 7.33 to + 4.98, indicative of formation in an active continental margin setting. The Late Ordovician alkali-feldspar granite and rhyolite units have A-type granite affinities that suggest they formed in

  20. Geochemical characteristics of the Shujiadian Cu deposit related intrusion in Tongling: Petrogenesis and implications for the formation of porphyry Cu systems in the Middle-Lower Yangtze River Valley metallogenic belt, eastern China

    Science.gov (United States)

    Wang, Shiwei; Zhou, Taofa; Yuan, Feng; Fan, Yu; Cooke, David R.; Zhang, Lejun; Fu, Bin; White, Noel C.

    2016-05-01

    Porphyry Cu deposits can form in intracontinental or post-collision settings; however, both the genesis of fertile magmas and the mechanism of metal enrichment remain controversial. The Shujiadian porphyry Cu deposit is located in the Tongling area of the Middle-Lower Yangtze River Valley metallogenic belt. It is hosted by the Shujiadian complex, which mainly consists of quartz diorite porphyry (143.7 ± 1.7 Ma) and pyroxene diorite (139.8 ± 1.6 Ma). They both belong to the calc-alkaline series, with enrichment in large-ion lithophile elements (LILE) and light rare earth elements (LREE), depletion in high field-strength elements (HFSE) and heavy rare earth elements (HREE), and slightly negative Eu anomalies. Both quartz diorite porphyry and pyroxene diorite have geochemical affinities with adakite, and their low MgO (1.5-3.7 wt%), and Ni (3.7-6.9 ppm), Cr (2.0-44 ppm), and Th/Ce contents (0.06-0.11) indicate that the intrusive rocks have some characteristics of adakite-like rocks derived from thickened lower crust and melts from metabasaltic rocks and eclogites. Plagioclases from the quartz diorite porphyry are andesine (An value = 31.8-40.5) and from the pyroxene diorite are felsic albite and oligoclase with large-scale zones and variable An value (An value = 8.9-18.3), Fe and Sr contents, which indicate that mixing of mafic and felsic magma may have occurred in the shallow magma chamber. Compared to the barren quartz diorite porphyry, relatively lower SiO2 contents (49.5-55.2 wt.%), higher εNd(t) values (- 7.4 to - 6.9), εHf(t) values (- 11.0 to - 9.1) compositions, Ti-in-zircon temperatures (714-785 °C), and variations of HREE contents of the mineralization-related pyroxene diorite suggest mixing with high-temperature mafic magma. Calculated Ce4 +/Ce3 + values of pyroxene diorite plot between the Ni-NiO buffer (NNO) and magnetite-hematite buffer (MH), and barren quartz diorite porphyry samples plot below the Ni-NiO buffer (NNO). Geochemical features of

  1. Geochronology and geochemistry of Late Cretaceous-Paleocene granitoids in the Sikhote-Alin Orogenic Belt: Petrogenesis and implications for the oblique subduction of the paleo-Pacific plate

    Science.gov (United States)

    Tang, Jie; Xu, Wenliang; Niu, Yaoling; Wang, Feng; Ge, Wenchun; Sorokin, A. A.; Chekryzhov, I. Y.

    2016-12-01

    We present zircon U-Pb ages, major and trace element analyses, and zircon Hf isotope data on the Late Cretaceous-Paleocene granitoids at the southern end of the Sikhote-Alin Orogenic Belt of the Russian Far East. These data are used to discuss the petrogenesis of the granitoids in the context of the paleo-Pacific subduction beneath the eastern Eurasia. Zircons from four granitoid samples give emplacement ages of 56, 83, 91, and 92 Ma. These granitoids with high SiO2 (73.43-76.76 wt%) are metaluminous to weakly peraluminous (A/CNK = 0.97-1.03) and belong to the high-K calc-alkaline series (K2O = 3.75-4.95 wt%). They are all enriched in light rare earth elements (LREEs) and large ion lithophile elements (LILEs), and relatively depleted in high field strength elements (HFSEs) with striking depletion also in Ba, Sr, P and Eu. They are petrographically and geochemically consistent with being of I-type granitoids. The zircons have εHf (t) values (- 0.8 to + 7.6) higher than whole-rock εHf (t) values predicted from whole-rock εNd (t) (- 4.1 to + 0.5) in the literature. All these observations suggest that primary magmas parental to these granitoids were likely to have derived from partial melting of a juvenile lower crust accompanied by assimilation with ancient mature crust during magma ascent and evolution. A recent study illustrates that the collision of an exotic terrane carried by the paleo-Pacific plate with the continental China at 100 Ma accreted the basement of the Chinese continental shelf (beneath East and South China Seas), and resulted in a new plate boundary of transform nature between the NNW moving paleo-Pacific plate and the eastern margin of the shelf. Our new data and analysis of existing data support this hypothesis, but we hypothesize that this transform becomes transpressional in its northern segment with oblique subduction of the paleo-Pacific plate beneath northeastern Asia as manifested by the Late Cretaceous-Paleocene granitoids in the Russian

  2. Formation of Kuiper Belt Binaries

    CERN Document Server

    Goldreich, P; Sari, R; Goldreich, Peter; Lithwick, Yoram; Sari, Re'em

    2002-01-01

    It appears that at least several percent of large Kuiper belt objects are members of wide binaries. Physical collisions are too infrequent to account for their formation. Collisionless gravitational interactions are more promising. These provide two channels for binary formation. In each, the initial step is the formation of a transient binary when two large bodies penetrate each other's Hill spheres. Stabilization of a transient binary requires that it lose energy. Either dynamical friction due to small bodies or the scattering of a third large body can be responsible. Our estimates favor the former, albeit by a small margin. We predict that most objects of size comparable to those currently observed in the Kuiper belt are members of multiple systems. More specifically, we derive the probability that a large body is a member of a binary with semi-major axis of order a. The probability depends upon sigma, the total surface density, Sigma, the surface density of large bodies having radius R, and theta=10^-4, t...

  3. Jupiter's radiation belts and atmosphere

    Science.gov (United States)

    De Pater, I.; Dames, H. A. C.

    1979-01-01

    Maps and stripscans of the radio emission from Jupiter were made during the Pioneer 10 flyby in December 1973 at wavelengths of 6 cm, 21 cm, and 50 cm using the Westerbork telescope in the Netherlands. With this instrument the disk of the planet was resolved at 6 and 21 cm. The pictures are averaged over 15 deg of Jovian longitude. At 21 cm the stripscans clearly show the existence of a 'hot region' in the radiation belts at a System III longitude (1965.0) of 255 + or - 10 deg. Its flux is about 9% of the total nonthermal flux, and it has a volume emissivity enhanced by a factor of about 1.6 with respect to the general radiation belts. The temperature of the thermal disk at 21 cm appears to be 290 + or - 20 K. This is likely due to a high ammonia mixing ratio in the atmosphere, a factor of 4-5 larger than the expected solar value of 0.00015.

  4. Beyond the Kuiper Belt Edge

    Science.gov (United States)

    Sheppard, Scott

    2013-01-01

    Of the thousands of known objects beyond Neptune, only one has a perihelion significantly beyond 50 AU, Sedna at 75 AU. Most Kuiper Belt surveys to date either did not go faint enough, did not have the required long cadence to detect very slow moving objects or covered too small of an area of sky to efficiently detect objects beyond 50 AU. The dynamical and physical properties of objects in this region offer key constraints on the formation and evolution of our solar system. In order to probe the Sedna like population of objects with moderate radii (100 km) we are conducting a deep wide-field outer solar system survey. This survey will allow us to determine if the objects beyond 50 AU are fainter than expected, if there is truly a dearth of objects, or if the Kuiper Belt continues again after some sizable gap possibly caused by a planet sized object. We will be able to examine the origin of Sedna and determine if it is unique (as once believed for Pluto) or one of a new class of object. We request one night in 2013B to recover a very interesting object that we discovered at Subaru in July 2012 and complete the sky coverage needed to constrain the Sedna-like population. This one night was awarded to us in 2012B but lost because of instrument problems.

  5. Cofilin activation during podosome belt formation in osteoclasts.

    Directory of Open Access Journals (Sweden)

    Anne Blangy

    Full Text Available Podosomes are dynamic actin-based structures found constitutively in cells of monocytic origin such as macrophages, dendritic cells and osteoclasts. They have been involved in osteoclast cell adhesion, motility and matrix degradation, and all these functions rely on the ability of podosomes to form supra-molecular structures called podosome belts or sealing zones on mineralized substrates. Podosomes contain two distinct domains, an actin-rich core enriched in actin polymerization regulators, surrounded by a ring of signaling and plaque molecules. The organization of podosome arrays into belts is linked to actin dynamics. Cofilin is an actin-severing protein that is known to regulate cytoskeleton architecture and cell migration. Cofilin is present in lamellipodia and invadopodia where it regulates actin polymerization. In this report, we show that cofilin is a novel component of the podosome belt, the mature osteoclast adhesion structure. Time-course analysis demonstrated that cofilin is activated during primary osteoclast differentiation, at the time of podosome belt assembly. Immunofluorescence studies reveal a localization of active cofilin in the podosome core structure, whereas phosphorylated, inactive cofilin is concentrated in the podosome cloud. Pharmacological studies unraveled the role of a specific cofilin phosphatase to achieve cofilin activation during osteoclast differentiation. We ruled out the implication of PP1/PP2A and PTEN in this process, and rather provided evidence for the involvement of SSH1. In summary, our data involve cofilin as a regulator of podosome organization that is activated during osteoclast differentiation by a RANKL-mediated signaling pathway targeting the SSH1 phosphatase.

  6. High-K calc-alkaline magmatism at the Archaean-Proterozoic boundary: implications for mantle metasomatism and continental crust petrogenesis. Example of the Bulai pluton (Central Limpopo Belt, South Africa)

    Science.gov (United States)

    Laurent, Oscar; Martin, Hervé; Doucelance, Régis; Moyen, Jean-François; Paquette, Jean-Louis

    2010-05-01

    The Neoarchaean Bulai pluton, intrusive within the supracrustal granulites of the Central Limpopo Belt (Limpopo Province, South Africa) is made up of large volumes of porphyritic granodiorites with subordinate enclaves and dykes which have monzodioritic and charno-enderbitic compositions. New U-Pb LA-ICP-MS dating on separated zircons yielded pluton emplacement ages ranging between 2.60 and 2.63 Ga, which are slightly older than previous proposed ages (~ 2.57-2.61 Ga). The whole-rock major- and trace-element composition of the Bulai pluton evidences unequivocal affinities with "high-Ti" late-Archaean sanukitoids. It belongs to a high-K calc-alkaline differentiation suite, with metaluminous affinities (0.7 affinities, such as eNd ranging between -0.5 and 0.5, and in addition, are very rich in all incompatible trace elements, which is particularly obvious in monzodioritic enclaves and enderbites where primitive mantle-normalized LILE and LREE contents are up to 300. These characteristics point to an enriched mantle source for the Bulai batholith. Chondrite normalized, REE patterns are strongly fractionated ([La/Yb]N ~ 25-80), mainly due to high LREE contents (LaN ~ 250-630), and chiefly high HFSE contents (Nb ~ 15-45 ppm ; up to 770 ppm Zr) indicate that the metasomatic agent is a silicic melt rather than a hydrous fluid. Moreover, based on high Nb/Ta, Th/Rb, La/Rb and low Sr/Nd and Ba/La, we suggest that the metasomatic agent is a granitic melt generated by melting of terrigenous sediments. Interactions of this melt with mantle peridotites implies that sediments are located under a mantle slice; geometry which is easily achieved in subduction zone settings. This conclusion is supported by the fact that Bulai trace element patterns are very similar to those of sub-actual potassic magmas generated in magmatic arc environments by interactions between mantle and terrigenous sediments (e.g. Sunda arc). Geochemical modeling indicates that the mafic facies of the Bulai

  7. Geochronological, geochemical and mineralogical constraints of emplacement depth of TTG suite from the Sinassi Batholith in the Central African Fold Belt (CAFB) of northern Cameroon: Implications for tectonomagmatic evolution

    Science.gov (United States)

    Houketchang Bouyo, M.; Penaye, J.; Njel, U. O.; Moussango, A. P. I.; Sep, J. P. N.; Nyama, B. A.; Wassouo, W. J.; Abaté, J. M. E.; Yaya, F.; Mahamat, A.; Ye, Hao; Wu, Fei

    2016-04-01

    The Sinassi Batholith in the Central African Fold Belt (CAFB) of northern Cameroon represents the largest volume of plutonic rocks or granitoids massif of the Western Cameroonian Domain. It is made up dominantly of tonalite-trondhjemite-granodiorite (TTG) suite and lesser granite which are locally more or less deformed, and composed of varying proportions of quartz, plagioclase, K-feldspar, biotite, hornblende, sphene, magnetite, apatite and zircon. Major and trace element compositions of fifteen rock samples of granitoids (Djourdé granodiorite, Sinassi quartz diorite and orthogneisses groups) indicate that investigated rocks from the Sinassi Batholith are characterized by medium- to high-K calc-alkaline affinity and metaluminous I-type signature. In addition, their chondrite- and primitive mantle-normalized trace element patterns are strongly fractionated ((La/Yb)N = 2.96-61.40) and show respectively enrichment in LREE relative to HREE and enrichment in LILE compared to HFSE with moderate to slight negative Nb-Ta, Ti and Eu anomalies consistent with a continental magmatic arc setting related to a subduction zone. Geothermobarometric calculations using hornblende-plagioclase thermometry and aluminum-in-hornblende barometry on eleven rock samples indicate that plutons from Sinassi Batholith were emplaced at average temperatures and pressures ranging between 698 and 720 °C and 4.06-5.82 kbar (Djourdé granitoids), 698-728 °C and 4.04-5.34 kbar (Sinassi granitoids) and 667-670 and 4.23-4.76 kbar (orthogneisses group) respectively. The average emplacement depths estimates for the investigated granitoids is constrained at ca 16-18 km, indicating that at least 16 km of crustal rocks of the Sinassi Batholith must have been eroded or uplifted at approximately exhumation rates of 0.08-0.10 mm/year. Regardless of their Th/U ratios, geochronological results highlight three main events characterizing the Neoproterozoic tectonomagmatic evolution within the Sinassi Batholith

  8. Parameters affecting seat belt use in Greece.

    Science.gov (United States)

    Yannis, G; Laiou, A; Vardaki, S; Papadimitriou, E; Dragomanovits, A; Kanellaidis, G

    2011-09-01

    The objective of this research is the exploration of seat belt use in Greece and particularly the identification of the parameters affecting seat belt use in Greece. A national field survey was conducted for the analytical recording of seat belt use. A binary logistic regression model was developed, and the impact of each parameter on seat belt use in Greece was quantified. Parameters included in the model concern characteristics of car occupants (gender, age and position in the car), the type of the car and the type of the road network. The data collection revealed that in Greece, the non-use of seat belt on the urban road network was higher than on the national and rural road network and young and older men use seat belts the least. The developed model showed that travelling on a national road is negative for not wearing the seat belt. Finally, the variable with the highest impact on not wearing a seat belt is being a passenger on the back seats.

  9. Intelligent Belt Conveyor Monitoring and Control

    NARCIS (Netherlands)

    Pang, Y.

    2010-01-01

    Belt conveyors have been used worldwide in continuous material transport for about 250 years. Traditional inspection and monitoring of large-scale belt conveyors focus on individual critical components and response to catastrophic system failures. To prevent operational problems caused by the lack

  10. The Administrator's "Handy Dandy" Tool Belt

    Science.gov (United States)

    Anderson, Terry

    2012-01-01

    Every good leader needs a tool belt. Throughout the author's years of building early childhood programs, she has acquired a number of tools for her personal belt. These tools have helped her sharpen her skills in supporting teachers and staff, connecting with families, and educating children. This article focuses on those leadership skills that…

  11. Intelligent Belt Conveyor Monitoring and Control

    NARCIS (Netherlands)

    Pang, Y.

    2010-01-01

    Belt conveyors have been used worldwide in continuous material transport for about 250 years. Traditional inspection and monitoring of large-scale belt conveyors focus on individual critical components and response to catastrophic system failures. To prevent operational problems caused by the lack o

  12. Biomechanics of seat belt restraint system.

    Science.gov (United States)

    Sances, Anthony; Kumaresan, Srirangam; Herbst, Brian; Meyer, Steve; Hock, Davis

    2004-01-01

    Seat belt system restrains and protects occupants in motor vehicle crashes and any slack in seat belt system induces additional loading on occupant. Signs of belt loading are more obvious in high-speed frontal collisions with heavy occupants. However subtle changes may occur at low speeds or with low forces from occupants during rollovers. In certain cases, the seat belt webbing is twisted and loaded by the occupant. The loading of webbing induces an observable fold/crimp on the seat belt. The purpose of the study is to biomechanically evaluate the force required to produce such marks using an anthropometric physical test dummy. Two tests were conducted to determine the amount of force required to put an observable fold/crimp in a shoulder belt. A head form designed by Voight Hodgson was used to represent the neck which interacted with the belt. The force was applied with a pneumatic pull ram (central hydraulic 89182 N) and the force was measured with a 44,000 N transducer load cell (DSM-10K). Results indicate that the force of over 1,000 N produced a fold or crimp in the belt.

  13. Seat Belts on School Buses: Some Considerations.

    Science.gov (United States)

    Soule, David

    1982-01-01

    A representative of the National Highway Traffic Safety Administration weighs advantages and discusses issues associated with installing seat belts in school buses. Federal regulations and research findings are considered. A list of guideline questions for school districts planning to install seat belts is included. (PP)

  14. Implicações de custo financeiro e recursos humanos em assistência odontológica no Brasil segundo o modelo escandinavo Implications in terms of costs and manpower of using the Scandinavian dental care model in Brazil

    Directory of Open Access Journals (Sweden)

    Jefferson L. Traebert

    1996-12-01

    Full Text Available Objetivou-se detectar e analisar as implicações em custos e recursos humanos em odontologia de uma hipotética aplicação dos conceitos escandinavos de atenção odontológica no Brasil. Duas sociedades foram escolhidas para serem estudadas: Suécia, país da Escandinávia, e Santa Catarina, Estado da região Sul do Brasil. A análise teórica dessas implicações foi realizada a partir da determinação das necessidades de recursos humanos em odontologia, considerando-se os altos índices de doenças bucais no Estado brasileiro. Utilizou-se o programa de software "Health Through Oral Health" da Organização Mundial da Saúde-Federação Dentária Internacional (1989. Os resultados mostraram alto custo financeiro e a necessidade de se aumentar em até 85% o recurso humano disponível para atuar em saúde bucal no Estado de Santa Catarina. Concluiu-se que os princípios de alta provisão de recursos humanos e financeiros, característicos do modelo escandinavo, não serviriam para serem adotados por Santa Catarina e, extensivamente, pelo Brasil.The implications in terms of dental manpower and costs of applying the Scandinavian system of dental care in Brazil are specified and analysed. Two societies were chosen for study: those of Sweden, in Scandinavia and Santa Catarina, State in southern Brazil. The theoretical analysis of the implications was undertaken on the basis of an estimate of dental and auxiliary manpower required to deal with the high levels of oral disease and needs (caries, teeth needing extraction, periodontal diseases and the need for full dentures in Santa Catarina. This estimate was undertaken by means of the World Health Organization-Fédération Dentaire Internationale (WHO-FDI Model "Health Through Oral Health" (1989. The implications in costs, taking the total Swedish expenditure per dentist as a basis, were calculated and applied to the manpower calles for by the WHO-FDI model. The high costs resulting showed that the

  15. Seat belt use in cars with air bags.

    Science.gov (United States)

    Williams, A F; Wells, J K; Lund, A K

    1990-12-01

    Seat belt use was observed in 1,628 cars with air bags and manual belts and 34,223 cars with manual seat belts only. Sixty-six percent of drivers in cars with air bags wore seat belts compared to 63 percent of drivers in cars with manual belts only. The study found no evidence for the speculation that drivers with air bags will reduce their seat belt use because they believe an air bag alone provides sufficient protection.

  16. Implications and Challenges for the Energy Sector in Brazil and Mexico to Meet the Carbon Emission Reductions Committed in Their INDC during the COP 21-CMP11

    Directory of Open Access Journals (Sweden)

    Janaina Camile Pasqual

    2016-05-01

    Full Text Available Despite contributing only 1% to global emissions each, two of the largest economies in Latin America, Brazil and Mexico, are strongly committed to reducing their carbon dioxide (CO2 emissions by 43% and 40% respectively by the year 2030. Achieving these goals, however, will not only necessitate the implementation of technical innovations, cleaner energy sources and active participation of all sectors, but will also require significant changes in the energy policies of both countries. This article will identify the goals stated by Brazil and Mexico in their Intended Nationally Determined Contributions (INDCs, and examine the actual and prospective primary energy mixes and consequent CO2 emissions. In addition, strategies related to technical, economic and social efforts needed to achieve these purposes are explored. Finally, the opportunities for achieving COP21-CMP11 commitments through the implementation of renewable energy in different sectors will be discussed; while showing their potential for also providing energy sovereignty and potential economic benefits for both nations.

  17. The occurrence of fluor-wagnerite in UHT granulites and its implications towards understanding fluid regimes in the evolution of deep crust: a case study from the Eastern Ghats Belt, India

    Science.gov (United States)

    Das, Kaushik; Tomioka, Naotaka; Bose, Sankar; Ando, Jun-ichi; Ohnishi, Ichiro

    2016-09-01

    We report the occurrence of a rare phosphate mineral, fluor-wagnerite (Mg1.91-1.94Fe0.06-0.07Cafluor-wagnerite can act as an indicator for the presence of F-bearing fluids for rocks with high X Mg and/or fO2. The occurrence of F-rich minerals as monitors for fluid compositions has important implications for the onset of biotite dehydration melting and hence melt production in the deep crust. We propose that fluor-wagnerite can occur as an accessory mineral associated with F-rich fluids in lower-mid crustal rocks, and F in coexisting minerals should be taken into consideration when reconciling the petrogenetic grid of biotite-dehydration melting.

  18. Radiation belt dynamics during solar minimum

    Energy Technology Data Exchange (ETDEWEB)

    Gussenhoven, M.S.; Mullen, E.G. (Geophysics Lab., Air Force Systems Command, Hanscom AFB, MA (US)); Holeman, E. (Physics Dept., Boston College, Chestnut Hill, MA (US))

    1989-12-01

    Two types of temporal variation in the radiation belts are studied using low altitude data taken onboard the DMSP F7 satellite: those associated with the solar cycle and those associated with large magnetic storm effects. Over a three-year period from 1984 to 1987 and encompassing solar minimum, the protons in the heart of the inner belt increased at a rate of approximately 6% per year. Over the same period, outer zone electron enhancements declined both in number and peak intensity. During the large magnetic storm of February 1986, following the period of peak ring current intensity, a second proton belt with energies up to 50 MeV was found at magnetic latitudes between 45{degrees} and 55{degrees}. The belt lasted for more than 100 days. The slot region between the inner and outer electron belts collapsed by the merging of the two populations and did not reform for 40 days.

  19. The petrochemistry of the auriferous, volcanosedimentary Riacho dos Machados Group, Central-eastern Brazil: geotectonic implications for shear-hosted gold mineralization

    Science.gov (United States)

    da Fonseca, E.; Lobato, L. M.; Baars, F. J.

    1997-12-01

    The Ouro Fino Gold Deposit at the Riacho dos Machados Mine is located in the Araçuaí Fold Belt at the eastern margin of the São Francisco Craton. The gold is shear zone-hosted and associated principally with a sulphide-bearing, quartzmuscovite schist, derived from the hydrothermal alteration of pelitic and quartzofeldspathic schists of the Riacho dos Machados Group (RMG). Along the shear zones, mineral associations typical of the amphibolite facies are progressively altered to assemblages typical of the greenschist facies. It has become evident from the studies that the process of segregation and concentration of chemical elements and minerals is the very process of mineralization, involving the concentration of Au. The RMG comprises ultramafic, mafic and acid metavolcanic rocks intercalated in a sequence of metapelites. The metapelites have textures and geochemistry compatible with greywackes. The dacitic and mafic/ultramafic rocks are of calc-alkaline and tholeiitic subalkaline association, respectively. The RMG probably formed within a continental volcanic arc. The thrust faults that establish the regional architecture, and which host the Riacho dos Machados gold mineralization, are related to a continental collision of unknown age between the precursor to the São Francisco Craton and the Guanambi-Correntina Block.

  20. The occurrence of fluor-wagnerite in UHT granulites and its implications towards understanding fluid regimes in the evolution of deep crust: a case study from the Eastern Ghats Belt, India

    Science.gov (United States)

    Das, Kaushik; Tomioka, Naotaka; Bose, Sankar; Ando, Jun-ichi; Ohnishi, Ichiro

    2017-06-01

    We report the occurrence of a rare phosphate mineral, fluor-wagnerite (Mg1.91-1.94Fe0.06-0.07Cahistories. Based on mineral chemical data and micro-Raman analyses, we document an unusual high Mg-F-rich chemistry of the F-wagnerite, which occur both in peak metamorphic porphyroblastic assemblages as well as in the retrograde matrix assemblage. Therefore, in absence of other common phosphates like apatite, fluor-wagnerite can act as an indicator for the presence of F-bearing fluids for rocks with high X Mg and/or fO2. The occurrence of F-rich minerals as monitors for fluid compositions has important implications for the onset of biotite dehydration melting and hence melt production in the deep crust. We propose that fluor-wagnerite can occur as an accessory mineral associated with F-rich fluids in lower-mid crustal rocks, and F in coexisting minerals should be taken into consideration when reconciling the petrogenetic grid of biotite-dehydration melting.

  1. New data on the stem and leaf anatomy of two conifers from the Lower Cretaceous of the Araripe Basin, northeastern Brazil, and their taxonomic and paleoecological implications

    Science.gov (United States)

    Batista, Maria Edenilce Peixoto; Silva, Delmira da Costa; Sales, Marcos A. F.; Sá, Artur A.; Saraiva, Antônio A. F.; Loiola, Maria Iracema Bezerra

    2017-01-01

    Pseudofrenelopsis and Brachyphyllum are two conifers that were part of the Lower Cretaceous (Aptian) taphoflora of the Crato Formation, Araripe Basin, northeastern Brazil. The former genus includes, so far, P. capillata and indeterminate species, whilst the latter is mainly represented by B. obesum, the most common plant megafossil recovered from that stratigraphic unit. Here, the stem and leaf anatomy of Pseudofrenelopsis sp. and B. obesum specimens is revisited, including the first report of some epidermal and vascular traits for both taxa from the Crato Formation. Along with its paleoecological significance, the new data suggest the presence of more than one Pseudofrenelopsis species in the Aptian taphoflora of the Araripe Basin and further support the taxonomic placement of B. obesum within Araucariaceae. PMID:28257466

  2. Local Knowledge of Pond Fish-Farming Ecosystem Services: Management Implications of Stakeholders’ Perceptions in Three Different Contexts (Brazil, France and Indonesia

    Directory of Open Access Journals (Sweden)

    Syndhia Mathé

    2015-06-01

    Full Text Available This article addresses ecosystem service perceptions in the case of pond fish-farming systems in Brazil, France and Indonesia. The Millennium Ecosystem Assessment vision suggests a more integrated reflection on environmental policies with greater adaptability to local knowledge and the development of social learning processes, which tend to promote more sustainable changes in behavior and practice than do sanctions. This study considers a part of the identification of ecosystem services. It shows that perceptions differ with the context, and found few differences depending on the type of stakeholders (fish farmers and other stakeholders. From a methodological viewpoint, this paper opens up new prospects for valuing ecosystem services through a perception study.

  3. Seat belt use law in developing countries

    Institute of Scientific and Technical Information of China (English)

    SangWanLee

    1999-01-01

    Objective:To highlight the way to successful implementation of mandantory seat belt use law in developing countries particulary where have significant increase in number or cars and subsequent increase in car occupant casualties.Methods:Literatures concerning seat belt use were reviewed and experiences of the world.Satisfactory or not,investigated.It summed up general aspects of seat belt use as well as benefits,attitude toward legislation and measures to enhance the usage.Results:Seat belt use has been proven and stood time tested as the most effective means to protect car occupants from road crash injuries.It appears to be arduous to achieve the golal of seat belt use law in developing countries. but possible via strategies appropriately leading to legislation and promotion of the belt usage.Conclusions:It is prime necessity for the government authorities to recognize the importance of seat belt use.There needs an organizational structure composed of relevant professional from both private and government sectors which is able to carry out every steps toward successful legislation and implementation:education,publicity,enforcement,evaluation and dissemination of the law's benefits.

  4. Drive Alive: Teen Seat Belt Survey Program

    Directory of Open Access Journals (Sweden)

    Loftin, Laurel

    2010-08-01

    Full Text Available Objective: To increase teen seat belt use among drivers at a rural high school by implementing the Drive Alive Pilot Program (DAPP, a theory-driven intervention built on highway safety best practices.Methods: The first component of the program was 20 observational teen seat belt surveys conducted by volunteer students in a high school parking lot over a 38-month period before and after the month-long intervention. The survey results were published in the newspaper. The second component was the use of incentives, such as gift cards, to promote teen seat belt use. The third component involved disincentives, such as increased police patrol and school policies. The fourth component was a programmatic intervention that focused on education and media coverage of the DAPP program.Results: Eleven pre-intervention surveys and nine post-intervention surveys were conducted before and after the intervention. The pre- and post-intervention seat belt usage showed significant differences (p<0.0001. The average pre-intervention seat belt usage rate was 51.2%, while the average post-intervention rate was 74.5%. This represents a percentage point increase of 23.3 in seat belt use after the DAPP intervention.Conclusion: Based on seat belt observational surveys, the DAPP was effective in increasing seat belt use among rural high school teenagers. Utilizing a theory-based program that builds on existing best practices can increase the observed seat belt usage among rural high school students. [West J Emerg Med. 2010; 11(3: 280-283.

  5. U-Pb zircon geochronology of ''brasiliano'' granitoids from the Serido orogenic belt (Borborema Province, NE Brazil). Ages U-Pb sur zircon de granitoides ''brasilianos'' de la ceinture du Serido (Province Borborema, NE Bresil)

    Energy Technology Data Exchange (ETDEWEB)

    Leterrier, J.; Bertrand, J.M. (Centre National de la Recherche Scientifique (CNRS), 54 - Nancy (France). Centre de Recherches Petrographiques et Geochimiques); Pin, C. (Clermont-Ferrand-2 Univ., 63 - Aubiere (France)); Jardim de Sa, E.

    1994-06-01

    Diorites previously attributed to an early stage of the 'brasiliano' plutonic evolution of the Serido belt yielded U-Pb zircon age of 579 [+-]7 Ma. The age of associated granites is slightly younger although a synchronous emplacement of granites and diorites is suggested by field relationships. Such an age difference may result from difficulties to distinguish 'crystallization age' from 'emplacement age', which is still to be determined precisely. (authors). 16 refs., 3 figs., 1 tab.

  6. Computer-aided design of conveyor belts

    Energy Technology Data Exchange (ETDEWEB)

    Karolewski, B.; Pytel, J.

    1984-01-01

    Possibilities are discussed for using mathematical models of belt conveyors for development of computer-aided design of conveyors for coal mining. Examples of optimization tasks and methods for their solution using computerized simulation are analyzed. The analysis is illustrated by an algorithm used to design a starter for the drive system of a belt conveyor. Electromagnetic moment and starting current are used as optimization criteria. A simplified model of a belt conveyor is used. The model consists of an equation of motion with variable braking moment and variable moment of inertia. 3 references.

  7. Collisional evolution of the early asteroid belt

    Science.gov (United States)

    Gil-Hutton, Ricardo; Brunini, Adrián

    1999-04-01

    We present numerical results obtained by a simulation of the collisional process between asteroids and scattered comets from the Uranus-Neptune zone. This mechanism allows the use of single exponent incremental size distributions for the initial belt reaching a final distribution that matches the observed population very well. Since the cometary bombardment was extremely efficient removing mass from the primordial asteroid belt in a very short time, we always obtained belts with total masses less than 0.001 M ⊕ after ≈ 2×10 7 yrs. This result allows processes with an important initial mass preserving Vestas basaltic crust.

  8. Slim belt induced morphea-Price paid for a slimmer look

    Directory of Open Access Journals (Sweden)

    Tasleem Arif

    2015-07-01

    Full Text Available Morphea, also known as localized scleroderma, encompasses a group of distinct conditions characterized by sclerosis of the skin and the underlying tissues. Many triggering factors have been implicated in the development of morphea like trauma, immobilization, bacille Calmette–Guérin (BCG vaccination, injections of vitamin K, mechanical compression from clothing, etc. but slim belt as a cause of morphea has not been previously reported to the best of our knowledge. We report a 28 year old married obese woman who developed a shiny brownish indurated plaque over the abdomen after three months of use of a slim belt for her obesity. Skin biopsy was consistent with the diagnosis of morphea. She was prescribed topical tacrolimus 0.1% ointment and improved with course of time. The present case illustrates the first description of morphea as a result of use of slim belt which has not been previously reported in the literature.

  9. 30 CFR 56.14131 - Seat belts for haulage trucks.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Seat belts for haulage trucks. 56.14131 Section... Equipment Safety Devices and Maintenance Requirements § 56.14131 Seat belts for haulage trucks. (a) Seat belts shall be provided and worn in haulage trucks. (b) Seat belts shall be maintained in...

  10. Differences in thoracic injury causation patterns between seat belt restrained children and adults.

    Science.gov (United States)

    Arbogast, Kristy B; Locey, Caitlin M; Zonfrillo, Mark R

    2012-01-01

    The objective of this research was to delineate age-based differences in specific thoracic injury diagnoses for seat belt restrained rear seat occupants and describe the associated injury causation in order to provide insight into how the load of the seat belt is transferred to occupants of various sizes. Using data from the Crash Investigation Research and Engineering Network (CIREN), 20 cases of rear seated, lap and shoulder belt restrained occupants with AIS2+ thoracic injuries in frontal crashes were reviewed. Seven were children and adolescents age 8-15 years, 5 were 16-24 years, 3 were 25-54 years, and 5 were 55+ years. Six of the seven 8-15 year olds sustained injuries to the lung in the form of pulmonary contusion or pneumothorax. Only three of the seven sustained a skeletal (sternum or rib) fracture; only one of these three involved multiple ribs bilaterally. In contrast, four of the five 16-24 year olds sustained at least one rib fracture - often multiple and bilateral. The adult cohort (25+ years) was involved in predominantly more minor crashes; however they all sustained complex rib fractures - seven of the eight involved multiple ribs, four of the eight were also bilateral. Belt compression - either from the shoulder belt or the lap belt - was identified as the primary cause of the thoracic injuries. Often, there was clear evidence of the location of belt loading from AIS 1 chest contusions or abrasions. These findings have implications for age-based thoracic injury criteria suggesting that that different metrics may be needed for different age groups.

  11. Simulation of engine auxiliary drive V-belt slip motion. Part 1. Development of belt slip model; Engine hoki V belt slip kyodo no simulation. 1. Belt slip model no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Kurisu, T. [Mazda Motor Corp., Hiroshima (Japan)

    1997-10-01

    V-belts are widely used for driving auxiliary components of an engine. Inadequet design of such belt system sometimes results in troubles such as belt squeak, side rubber separation and/or bottom rubber crack. However, there has been no design tools which can predict belt slip quantitatively. The author developed a motion simulation program of Auxiliary Drive V-Belt System considering belt slip. The program showed good prediction accuracy for belt slip motion. This paper describes the simulation model. 1 ref., 12 figs.

  12. Seat Belt Usage on School Buses.

    Science.gov (United States)

    Farmer, Ernest

    1985-01-01

    Studies on seat belt usage conducted under contract with governmental organizations or prepared by professional societies, state and local organizations, and transportation specialists have made significant contributions, but none has successfully resolved the issue. (MLF)

  13. Handbook Timing Belts Principles, Calculations, Applications

    CERN Document Server

    Perneder, Raimund

    2012-01-01

    Timing belts offer a broad range of innovative drivetrain solutions; they allow low-backlash operation in robot systems, they are widely used in automated processes and industrial handling involving highly dynamic start-up loads, they are low-maintenance solutions for continuous operation applications, and they can guarantee exact positioning at high operating speeds. Based on his years of professional experience, the author has developed concise guidelines for the dimensioning of timing belt drives and presents proven examples from the fields of power transmission, transport and linear transfer technology. He offers definitive support for dealing with and compensating for adverse operating conditions and belt damage, as well as advice on drive optimization and guidelines for the design of drivetrain details and supporting systems. All market-standard timing belts are listed as brand neutral. Readers will discover an extensive bibliography with information on the various manufacturers and their websites. This...

  14. Radiation Belt Storm Probe (RBSP) Mission

    Science.gov (United States)

    Sibeck, D. G.; Fox, N.; Grebowsky, J. M.; Mauk, B. H.

    2009-01-01

    Scheduled to launch in May 2012, NASA's dual spacecraft Living With a Star Radiation Belt Storm Probe mission carries the field and particle instrumentation needed to determine the processes that produce enhancements in radiation belt ion and electron fluxes, the dominant mechanisms that cause the loss of relativistic electrons, and the manner by which the ring current and other geomagnetic phenomena affect radiation belt behavior. The two spacecraft will operate in low-inclination elliptical lapping orbits around the Earth, within and immediately exterior to the Van Allen radiation belts. During course of their two year primary mission, they will cover the full range of local times, measuring both AC and DC electric and magnetic fields to 10kHz, as well as ions from 50 eV to 1 GeV and electrons with energies ranging from 50 eV to 10 MeV.

  15. Radiation Belt and Plasma Model Requirements

    Science.gov (United States)

    Barth, Janet L.

    2005-01-01

    Contents include the following: Radiation belt and plasma model environment. Environment hazards for systems and humans. Need for new models. How models are used. Model requirements. How can space weather community help?

  16. The Compositional Structure of the Asteroid Belt

    CERN Document Server

    DeMeo, Francesca E; Walsh, Kevin J; Chapman, Clark R; Binzel, Richard P

    2015-01-01

    The past decade has brought major improvements in large-scale asteroid discovery and characterization with over half a million known asteroids and over 100,000 with some measurement of physical characterization. This explosion of data has allowed us to create a new global picture of the Main Asteroid Belt. Put in context with meteorite measurements and dynamical models, a new and more complete picture of Solar System evolution has emerged. The question has changed from "What was the original compositional gradient of the Asteroid Belt?" to "What was the original compositional gradient of small bodies across the entire Solar System?" No longer is the leading theory that two belts of planetesimals are primordial, but instead those belts were formed and sculpted through evolutionary processes after Solar System formation. This article reviews the advancements on the fronts of asteroid compositional characterization, meteorite measurements, and dynamical theories in the context of the heliocentric distribution of...

  17. Eccentricity distribution in the main asteroid belt

    CERN Document Server

    Malhotra, Renu

    2016-01-01

    The observationally complete sample of the main belt asteroids now spans more than two orders of magnitude in size and numbers more than 64,000 (excluding collisional family members). We undertook an analysis of asteroids' eccentricities and their interpretation with simple physical models. We find that Plummer's (1916) conclusion that the asteroids' eccentricities follow a Rayleigh distribution holds for the osculating eccentricities of large asteroids, but the proper eccentricities deviate from a Rayleigh distribution: there is a deficit of eccentricities smaller than $\\sim0.1$ and an excess of larger eccentricities. We further find that the proper eccentricities do not depend significantly on asteroid size but have strong dependence on heliocentric distance: the outer asteroid belt follows a Rayleigh distribution, but the inner belt is strikingly different. Eccentricities in the inner belt can be modeled as a vector sum of a primordial eccentricity vector of random orientation and magnitude drawn from a Ra...

  18. 巴西代理银行制度实践及启示%Correspondent Banking in Brazil and Its Implication for China

    Institute of Scientific and Technical Information of China (English)

    帅旭

    2011-01-01

    This article analyzes the development of Brazilian correspondent banking system and its role in poverty alleviation.As a model of branchless banking service,correspondent banking can broaden the financial coverage and enhance the credit availability in rural area in a economical way.The correspondent banking model in Brazil is conducive to the reform of China's rural finance.%本文在对巴西代理银行发展现状、监管立法以及发挥的作用进行研究,研究表明,作为一种不通过分支机构提供银行服务的运营模式,代理银行制度具有低成本拓展金融覆盖率和提高农村资金可得性的优势。巴西代理银行制度为我国弥补农村金融服务空白提供了借鉴和启示。

  19. 'Protective' silence surrounding AIDS: Reasons and implications of non-disclosure among pregnant women living with HIV in Rio de Janeiro (Brazil).

    Science.gov (United States)

    Monteiro, Simone; Villela, Wilza; Soares, Priscilla; Pinho, Adriana; Fraga, Livia

    2016-07-25

    The persistence of stigma surrounding AIDS remains a challenge in the epidemic's fourth decade. Based on qualitative research, this study analyses how pregnant women living with HIV/AIDS (PWLHA) experience and cope with AIDS stigma. A total of 29 semi-structured interviews were conducted with PWLHA focusing on socioeconomic profiles, the contexts in which they discovered HIV infection, experiences with health-care sites and ways of dealing with AIDS-related stigma. We recruited PWLHA at two prevention of mother-to-child transmission sites in Rio de Janeiro, Brazil. The PWLHA's testimony indicates that access to care and treatment has a profound effect on the deconstruction of their understanding of AIDS as a fatal disease. However, fear of AIDS stigma is still predominant. The law guarantees HIV non-disclosure, and women see it as a way to protect themselves from discrimination. We argue, however, that the silence surrounding HIV diagnosis perpetuates the psychosocial and structural mechanisms that reproduce stigma. We conclude that diverse sectors of society, including health-care facilities, must be involved in confronting stigma by demystifying AIDS, improving patients' knowledge of their rights, and increasing their access to material and symbolic goods.

  20. Genetic and morphological diversity of Moenkhausia oligolepis (Characiformes: Characidae) populations in the tributaries of the Araguaia River, Brazil: implications for taxonomy and conservation.

    Science.gov (United States)

    Domingos, T J; Moraes, L N; Moresco, R M; Margarido, V P; Venere, P C

    2014-09-29

    Molecular genetic assessments that consider ecological information, in addition to endogamy levels, genetic diversity, and the genetic differentiation among species and populations, are particularly important for the conservation of biological diversity. Prime candidates for conservation genetic review are those subject to human use, including harvests for the ornamental fish trade. Colorful South American tetra, such as Moenkhausia oligolepis and M. forestii, are good examples of fish species that are widely collected and exported worldwide. This study aimed to evaluate the population-specific characteristics of M. oligolepis and M. forestii by comparing morphometric and molecular analyses based on ISSR markers, to provide information that would facilitate the sustainable management of these 2 species. Seventy-two specimens were collected from the Araguaia-Tocantins and Paraguay River Basins in Brazil. All specimens were measured and analyzed using ISSR markers. Population-exclusive bands were found among the 86 detected bands, while morphometric clusters reflected the geographical distribution of individuals. Correlated genetic and morphological variation supported the presence of 3 distinct groups from tributaries of the Araguaia and Mortes Rivers. Using the same techniques, all M. oligolepis populations were isolated from M. forestii. This study on Moenkhausia presents an interesting example that could be used to construct a framework of South American ichthyodiversity, and reinforces the necessity of habitat conservation to prevent the loss of biological diversity.

  1. A new turtle from the Upper Cretaceous Bauru Group of Brazil, updated phylogeny and implications for age of the Santo Anastácio Formation

    Science.gov (United States)

    Menegazzo, Mirian Costa; Bertini, Reinaldo José; Manzini, Flávio Fernando

    2015-03-01

    A new Podocnemidinura specimen from the Upper Cretaceous Bauru Group (Paraná Basin) of southeastern Brazil was described. The Bauru Group provided an important portrait of the Brazilian Mesozoic terrestrial biota, which boasts a vertebrate fauna formed from fishes, frogs, lacertilians, crocodyliforms, dinosaurs and mammals; records of palynomorphs; and invertebrate fauna consisted of gastropods, bivalves, ostracods and conchostracans. Nevertheless, the age of these continental deposits is not precisely estimated, which prevents global correlations, and its fauna is argued to be endemic. The new specimen described is the first turtle from the Santo Anastácio Formation, and its morphological comparison with other South American forms provided a significant advancement in the understanding of the age of this unit (Late Cretaceous). This study permitted a revision of the turtle taxa of the Bauru Group. As a result, some taxa were considered synonym, including the new Santo Anastácio form. The specimen is still unnamed due to the absence of skull characters that preclude its accurate positioning within the Bauru Group skull-based taxa. In addition, the phylogenetic affinities of this taxon were analyzed into Podocnemidinura clade.

  2. Bio-Optical Properties of the Inner Continental Shelf off Santos Estuarine System, Southeastern Brazil, and their Implications for Ocean Color Algorithm Performance

    Directory of Open Access Journals (Sweden)

    Melissa Carvalho

    2014-07-01

    Full Text Available Optical characterizations of coastal water masses are important tools for a better understanding of physical and biochemical processes and aid the optimization of ocean color algorithms. In this study we present three optical classes of water observed during October/2005 and March/2006 on the inner continental shelf adjacent to Santos Bay (Brazil, based on remote sensing reflectance. ANOVA indicated a crescent estuarine influence in classes 1 to 3. Class 3 presented the highest chlorophyll-a and nutrient concentration and highest light absorption coefficients. Colored dissolved organic matter (CDOM dominated the light absorption in all classes and was strongly correlated to salinity in October/2005 due to the influence of the La Plata plume. The results indicated that CDOM dynamics in the Santos inner shelf are very complex. The performance of global chlorophyll algorithms was significantly smaller for October/2005 than for March/2006. As inconsistent changes in light absorption spectra by phytoplankton were detected between samplings, the results show that future bio-optical algorithms for this region must be optimized preferentially considering CDOM optical parameters.

  3. Gamma spectrometric and magnetic interpretation of Cabaçal copper deposit in Mato Grosso (Brazil): Implications for hydrothermal fluids remobilization

    Science.gov (United States)

    Ribeiro, Vanessa Biondo; Mantovani, Marta Silvia Maria

    2016-12-01

    The Cabaçal Au-Zn-Cu Deposit, Mato Grosso, Brazil, was explored between 1987 and 1991, when 869,279 tons of ore rich in Au and Cu have been extracted. The hydrothermal alteration in the Cabaçal mine suggests a volcanogenic genetic model in which hydrothermal centers generated sericitization, chloritization and silicification alterations at different stages. The hydrothermal alteration affects the radioelements in different ways, generating a characteristic gamma spectrometric signature for the affected area. The eTh/K ratio map evidenced that the hydrothermalized area extends beyond south limits of the Cabaçal gabbro dykes formation, which host Cabaçal and Santa Helena mines. Magnetic data over the region show the same behavior for this formation, indicating that the magnetic source extends in subsurface. This behavior was recovered by the 3D model inverted for the region, which recovered a positive apparent magnetic contrast associated with this body, with an increasing deepness to south. It is possible that the south subsurface portion of the magnetic source may contain economic concentrations of Au remobilized by hydrothermal fluids. However, to confirm this hypothesis it is necessary to develop geochemical and borehole analysis of the area.

  4. TSUBASA (MDS-1) observations of energetic electrons and magnetic field variations in outer radiation belt

    Science.gov (United States)

    Nakamura, M.; Matsuoka, H.; Liu, H.; Koshiishi, H.; Koga, K.; Matsumoto, H.; Goka, T.

    2002-12-01

    We have investigated variations of energetic electrons (> 0.4 MeV) and magnetic field in the radiation belt obtained from the Standard DOse Monitor (SDOM) and the MAgnetoMeter (MAM) of the Space Environment Data Acquisition equipment (SEDA) onboard TSUBASA (the Mission Demonstration Test Satellite (MDS)-1) launched on February 4, 2002. Since TSUBASA is operated in the geostationary transfer orbit, it has provided rare opportunities of directly observing near-equatorial radiation belt plasma particles and magnetic field, having already included several large magnetic storms. The energetic electrons in the outer radiation belt are contributors to the total radiation dose deposited in lightly shielded spacecraft electronics for high altitude orbits and are known to have a drastic variability associated with geomagnetic storm and high speed solar wind streams. The abrupt energetic electron flux decreases in the outside of outer radiation belt show characteristic variations of in situ magnetic field. These observations have implications for the possible mechanisms of the depletion and the following recovery and/or buildup of energetic electrons in the outer radiation belt.

  5. Drive Alive: Teen Seat Belt Survey Program

    OpenAIRE

    Burkett, Katie M.; Davidson, Steve; Cotton, Carol; Barlament, James; Loftin, Laurel; Stephens, James; Dunbar, Martin; Butterfield, Ryan

    2010-01-01

    Objective: To increase teen seat belt use among drivers at a rural high school by implementing the Drive Alive Pilot Program (DAPP), a theory-driven intervention built on highway safety best practices. Methods: The first component of the program was 20 observational teen seat belt surveys conducted by volunteer students in a high school parking lot over a 38-month period before and after the month-long intervention. The survey results were published in the newspaper. The second compo...

  6. Jupiter's Radiation Belts: Can Pioneer 10 Survive?

    Science.gov (United States)

    Hess, W N; Birmingham, T J; Mead, G D

    1973-12-07

    Model calculations of Jupiter's electron and proton radiation belts indicate that the Galilean satellites can reduce particle fluxes in certain regions of the inner magnetosphere by as much as six orders of magnitude. Average fluxes should be reduced by a factor of 100 or more along the Pioneer 10 trajectory through the heart of Jupiter's radiation belts in early December. This may be enough to prevent serious radiation damage to the spacecraft.

  7. Seat-belt message and the law?

    Science.gov (United States)

    Sengupta, S K; Patil, N G; Law, G

    1989-09-01

    This paper attempts to draw together available information on the use of seat belts, one of the most important safety devices for a person in a car. Considering the high rate of mortality and morbidity due to road traffic accidents in Papua New Guinea the authors strongly feel that seat-belt usage should be made compulsory. When one looks at the history of the implementation of such a successful countermeasure in other countries it seems that legislation is the only answer.

  8. The private security in Brazil: Some aspects related to the motivations, regulation and social implications of the sector/La seguridad privada en Brasil: Algunos aspectos relacionados con las motivaciones, reglamento y las implicaciones sociales del sector

    Directory of Open Access Journals (Sweden)

    André Zanetic (Brasil

    2009-01-01

    Full Text Available The growth of private security verified in many countries in the middle of twentieth century displays important questions about state responsibility in relation to the security. In Brazil, where the growth is very significant mainly in the last two decades, not much is possible to know about the real dimension of the sector and about the conditions that carried out this appearance and expansion. Taking into consideration approaches observed in the international literature and the data relative to this sector, this work analyze the Brazilian regulatory framework, showing the implications about some more problematic features. El crecimiento de la seguridad privada ha crecido en muchos países en pleno siglo XX, donde muestra importantes cuestiones sobre la responsabilidad del Estado en relación con la seguridad. En Brasil, donde el crecimiento es muy importante principalmente en las últimas dos décadas, no es posible conocer sobre la dimensión real del sector y sobre las condiciones que llevan a cabo este aspecto y expansión. Teniendo en consideración criterios observados en la literatura internacional y los datos en relación con este sector, este trabajo analiza el marco regulador brasileño, mostrando las implicaciones acerca de algunas de las características más problemáticas.

  9. Jupiter's magnetosphere and radiation belts

    Science.gov (United States)

    Kennel, C. F.; Coroniti, F. V.

    1979-01-01

    Radioastronomy and Pioneer data reveal the Jovian magnetosphere as a rotating magnetized source of relativistic particles and radio emission, comparable to astrophysical cosmic ray and radio sources, such as pulsars. According to Pioneer data, the magnetic field in the outer magnetosphere is radially extended into a highly time variable disk-shaped configuration which differs fundamentally from the earth's magnetosphere. The outer disk region, and the energetic particles confined in it, are modulated by Jupiter's 10 hr rotation period. The entire outer magnetosphere appears to change drastically on time scales of a few days to a week. In addition to its known modulation of the Jovian decametric radio bursts, Io was found to absorb some radiation belt particles and to accelerate others, and most importantly, to be a source of neutral atoms, and by inference, a heavy ion plasma which may significantly affect the hydrodynamic flow in the magnetosphere. Another important Pioneer finding is that the Jovian outer magnetosphere generates, or permits to escape, fluxes of relativistic electrons of such intensities that Jupiter may be regarded as the dominant source of 1 to 30 MeV cosmic ray electrons in the heliosphere.

  10. THE GOULD'S BELT DISTANCE SURVEY

    Directory of Open Access Journals (Sweden)

    L. Loinard

    2011-01-01

    Full Text Available Observaciones que utilizan la interferometría de muy larga línea de base (VLBI por sus siglas en ingl´es pueden proveer la posición de radiofuentes compactas con una precisión del orden de 50 micro-segundos de arco. Esto es suficiente para medir la paralaje trigonométrica y los movimientos propios de cualquier objeto localizado hasta 500 pc del Sol con una precisión mejor que unos porcientos. Por ser magnéticamente activas, las estrellas jóvenes a menudo emiten emisión radio compacta detectable usando técnicas VLBI. Aquí, mostraremos cómo observaciones VLBI ya han restringido la distancia a las regiones de formación estelar cercanas más frecuentemente estudiadas (Tauro, Ofiuco, Orión, etc. y han empezado a revelar su estructura y su cinemática interna. Luego, describiremos un gran proyecto (llamado The Gould's Belt Distance Survey diseñado para proveer una vista detallada de la formación estelar en la vecindad Solar, usando observaciones VLBI.

  11. Heparin pharmacovigilance in Brazil.

    Science.gov (United States)

    Junqueira, Daniela Rezende Garcia; Viana, Thércia Guedes; Peixoto, Eliane R de M; Barros, Fabiana C R de; Carvalho, Maria das Graças; Perini, Edson

    2011-01-01

    To investigate the biological origin of injectable unfractioned heparin available in Brazilian market by discussing the impact of the profile of commercial products and the changes in heparin monograph on the drug safety. The Anvisa data base for the Registered Products of Pharmaceutical Companies and the Dictionary of Pharmaceutical Specialties (DEF 2008/2009) were searched. A survey with industries having an active permission for marketing the drug in Brazil was conducted. Five companies were granted a permission to market unfractioned heparin in Brazil. Three of them are porcine in origin and two of them are bovine in origin, with only one explicitly showing this information in the package insert. The effectiveness and safety of heparin studied in non-Brazilian populations may not represent the Brazilian reality, since most countries no longer produce bovine heparin. The currently marketed heparin has approximately 10% less anticoagulant activity than that previously produced and this change may have clinical implications. Evidence about the lack of dose interchangeability between bovine and porcine heparins and the unique safety profile of these drugs indicates the need to follow the treatment and the patients' response. Events threatening the patient's safety must be reported to the pharmacovigilance system in each particular country.

  12. Decay rate of the second radiation belt.

    Science.gov (United States)

    Badhwar, G D; Robbins, D E

    1996-01-01

    Variations in the Earth's trapped (Van Allen) belts produced by solar flare particle events are not well understood. Few observations of increases in particle populations have been reported. This is particularly true for effects in low Earth orbit, where manned spaceflights are conducted. This paper reports the existence of a second proton belt and it's subsequent decay as measured by a tissue-equivalent proportional counter and a particle spectrometer on five Space Shuttle flights covering an eighteen-month period. The creation of this second belt is attributed to the injection of particles from a solar particle event which occurred at 2246 UT, March 22, 1991. Comparisons with observations onboard the Russian Mir space station and other unmanned satellites are made. Shuttle measurements and data from other spacecraft are used to determine that the e-folding time of the peak of the second proton belt. It was ten months. Proton populations in the second belt returned to values of quiescent times within eighteen months. The increase in absorbed dose attributed to protons in the second belt was approximately 20%. Passive dosimeter measurements were in good agreement with this value.

  13. Scientific Collaboration Along the Trinational Frontier of Brazil-Bolivia-Peru: Implications for Regional Land-Use in the MAP Region of Southwestern Amazonia

    Science.gov (United States)

    Brown, I.

    2002-12-01

    High-speed road systems are connecting southwestern Amazonia (~1.5 million km2) to Pacific and Atlantic ports as well as providing greater access to Brazilian, Bolivian and Peruvian urban markets. Coupled with this increased accessibility are ambitious governmental plans to expand production of timber, non-timber forest products, and beef, all of which are likely to modify human migrations in the region. The heart of southwestern Amazonia lies in the trinational frontier region of Madre de Dios Department/Peru, eastern Acre State/Brazil and Pando Department/Bolivia (MAP region: ~200,000 km2, ~500,000 inhabitants). The MAP region composes a global hot spot of terrestrial biodiversity and has become an axis of integration for the three countries. Faced with rapid change in socioeconomic trends, regional environmental scientists and professionals have promoted collaborative projects to analyze land use trends and their forcing functions and to supply these results to local and regional societies. In addition, they have begun to develop a regional scientific community that bridges different nationalities and specialties. The projects are both international - as they involve three countries - and local/regional as they involve institutions that are within a radius of 300 km of the border. In the past two years, LBA-sponsored activities have helped bring over 100 professionals together in the region in five MAP-oriented workshops. The research results are now influencing public policy and are being incorporated into the regional school systems with the objective of maximizing the benefits and minimizing the adverse impacts of the changing socio-economic trends on land-use and development in the MAP region.

  14. Implicações e perspectivas da pesquisa educacional no Brasil cotemporâneo Implications of and perspectives on educational research in contemporary Brazil

    Directory of Open Access Journals (Sweden)

    Bernadete A. Gatti

    2001-07-01

    Full Text Available Este artigo busca recuperar no tempo aspectos do desenvolvimento das pesquisas educacionais no Brasil, associando-os a conjunturas histórico-sociais. Trabalham-se algumas questões de teorias e métodos, hegemonias de grupos de investigação e questões institucionais. Ressalta-se o papel da década de 80, na qual vigorosos debates são travados, a partir dos quais vêm à luz problemas intrínsecos a procedimentos de pesquisa e sua validade. Discute-se em que condições se pode falar de impacto social das pesquisas educacionais, analisando-se a possível porosidade dos conhecimentos advindos de pesquisas em educação nas ações de educadores e em políticas educacionais, perguntando-se também se a consistência metodológica desempenha, nessa porosidade, algum papel.This article studies the development of educational research in Brazil over time, relating it to the social and historical context, working on such issues as theory and method, hegemony of the research groups and institutional questions. The 1980s stand out as a time when vigorous debates were engaged based on which problems intrinsic to research procedures and their validity came to light. The article discusses under what conditions we can speak of the social impact of educational studies on educational action and policy, analyzing the possible fallibility of knowledge derived from such research and also asking whether methodological consistency plays some role in this fallibility.

  15. The 1.90-1.88 Ga magmatism in the southernmost Guyana Shield, Amazonas, Brazil: Geology, geochemistry, zircon geochronology, and tectonic implications

    Science.gov (United States)

    Valério, Cristóvão da Silva; Souza, Valmir da Silva; Macambira, Moacir José Buenano

    The southernmost Guyana Shield-Uatumã subdomain, northeastern Amazonas State, Brazil is dominantly formed by granitoid and volcanic rocks from the Água Branca Suite (ABS), undivided Granite Stocks (GS) and São Gabriel volcano-plutonic system (SGS). The ABS is characterized by a granite series that exhibits comparatively low Fe/(Fe + Mg) ratio, low (Nb/Zr) N, high Sr values and high Rb/Zr ratio. Its rocks display metaluminous to weakly peraluminous (A/CNK 0.94-1.06), high-K calc-alkaline, I normal-type character and have moderately to strongly fractionated rare earth elements (REE) pattern. The SG granites and SGS effusive-ignimbrite-granite association is metaluminous to weakly peraluminous (A/CNK 0.84-1.18), high-K calc-alkaline, has moderately to weakly fractionated REE trend, higher Fe/(Fe + Mg) ratio, lower Sr content and lower Rb/Zr ratio. The ABS geochemical signature is consistent with formation from volcanic arc rocks and small participation of collisional setting rocks, whereas the SG and SGS have post-collisional tectonic rocks-related geochemical signature. This model is in harmony with a post-collisional extensional regime, started with the 1.90-1.89 Ga Água Branca magmatism, and culminated with the 1.89-1.88 Ga São Gabriel system at an early stage of intracratonic reactivation, which included intrusion of mafic dikes. The Uatumã subdomain was related to mantle underplating with continental uplift and its origin involved contributions of 2.3-2.44 Ga Archean-contaminated Trans-Amazonian, 2.13-2.21 Ga Trans-Amazonian, 1.93-1.94/2.0 Ga Tapajós-Parima. Foliation styles point out that part of the Água Branca granitoids recorded later deformational effects, likely related to the Rio Negro Province formation.

  16. Ore mineralogy of the Serra Pelada Au-Pd-Pt deposit, Carajás, Brazil and implications for ore-forming processes

    Science.gov (United States)

    Berni, Gabriel V.; Heinrich, Christoph A.; Lobato, Lydia M.; Wall, Vic

    2016-08-01

    Serra Pelada is a world-class hydrothermal Au-Pd-Pt deposit located at the eastern border of the Amazon craton, northern Brazil. The rocks at Serra Pelada have experienced intense tropical weathering for about 70 Ma, but drill core samples preserve the primary mineralogy and hydrothermal alteration features, with extreme grades of Au, Pd and Pt individually reaching hundreds of parts per million (ppm) by weight. Mineralization at Serra Pelada occurs in hydrothermally altered metasiltstones and dolomitic metasandstones at the hinge zone of a recumbent syncline, comprising zones of hematite, chlorite-carbon, argillic, and siliceous alteration. The main hydrothermal gangue minerals are quartz, kaolinite, sericite, amesite, hematite, monazite, florencite and variable amounts of highly reflective carbonaceous matter. Hydrothermal carbon input is evident from precipitated carbon occurring along crenulation planes and veinlets associated with the precious metals. Ore and accessory minerals include a variety of sulphide, selenide, arsenide, sulphate and oxide minerals, including gold with variable metal contents, palladian gold, fischesserite, sudovikovite, sperrylite, selenian braggite, isomertieite, mertieite-II and secondary Au-Pt-Pd alloys. The composition of fischesserite varies from the ideal formula (Ag3AuSe2) towards a more Ag-rich composition, indicating a disordered solid solution form that is stable only above 260 °C, consistent with the high thermal maturity of associated carbonaceous matter approaching graphite. Primary ore and gangue minerals at Serra Pelada comprise a suite of elements that are best transported in oxidising conditions and precipitated upon reduction. This suggests that fluid mixing between a highly oxidised (metal carrier) and a reduced fluid was a key process for high-grade noble metal precipitation at Serra Pelada.

  17. Coal petrology of coal seams from the Leao-Butia Coalfield, Lower Permian of the Parana Basin, Brazil - Implications for coal facies interpretations

    Energy Technology Data Exchange (ETDEWEB)

    Silva, M.B. [Laboratorio de Oceanografia Geologica, Departamento de Geociencias, Fundacao Universidade Federal do Rio Grande, FURG, Av. Italia km 08, Campus Carreiros, 96201-900, Rio Grande, RS (Brazil); Kalkreuth, W.; Holz, M. [Instituto de Geociencias, UFRGS, Av. Bento Goncalves, 9500 91501-970 Porto Alegre, RS (Brazil)

    2008-02-01

    In the Leao-Butia Coalfield, Rio Grande do Sul the coal seams occur in the Rio Bonito Formation, Guata Group, Tubarao Supergroup of the Parana Basin, Brazil and are of Permian (Artinskian-Kungurian) age. This study is the first detailed investigation on the coal petrographic characterization of the coal-bearing sequence in relation to the depositional settings of the precursor mires, both in terms of whole seam characterization and in-seam variations. The study is based on the analyses of nine coal seams (I2, CI, L4, L3, L2, L1, S3, S2, S1), which were selected from core of borehole D-193, Leao-Butia and represent the entire coal-bearing sequence. The interpretation of coal facies and depositional environment is based on lithotype, maceral and microlithotype analyses using different facies-critical petrographic indices, which were displayed in coal facies diagrams. The seams are characterized by the predominance of dull lithotypes (dull, banded dull). The dullness of the coal is attributed to relatively high mineral matter, inertinite and liptinite contents. The petrographic composition is dominated by vitrinite (28-70 vol.% mmf) and inertinite (> 30 vol.% mmf) groups. Liptinite contents range from 7 to 30 vol.% (mmf) and mineral matter from 4-30 vol.%. Microlithotypes associations are dominated by vitrite, duroclarite, carbominerite and inertite. It is suggested that the observed vertical variations in petrographic characteristics (lithotypes, microlithotypes, macerals, vitrinite reflectance) were controlled by groundwater level fluctuations in the ancient mires due to different accommodation/peat accumulation rates. Correlation of the borehole strata with the general sequence-stratigraphical setting suggests that the alluvial fan system and the coal-bearing mudstone succession are linked to a late transgressive systems tract of sequence 2. Based on average compositional values obtained from coal facies diagrams, a deposition in a limno-telmatic to limnic coal

  18. Spatial distribution of Culicidae (Diptera larvae, and its implications for Public Health, in five areas of the Atlantic Forest biome, State of São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Rafael Piovezan

    Full Text Available ABSTRACT In view of the adaptive ability of mosquitoes and their role in the transport of infective agents, entomological surveys undertaken in transitional environments are very important for the determination of the risk they represent for Public Health. Among the principal vectors of the infectious agents involved in the occurrence of important arboviruses, such as dengue, for example, are the Culicidae-insects capable of installing themselves in the urban nuclei, which exist within areas containing vestigial forests. This present study conducted a survey of mosquito species by means of traps to catch their larvae installed in five rural areas within the Atlantic Forest domain and containing its vestigial vegetation in the municipality of Santa Bárbara D'Oeste, São Paulo, Brazil. A total of 13,241 larvae belonging to six mosquito species were collected on 920 occasions (32.52% of positive collections. Aedes albopictus (64.23% and Aedes aegypti (32.75% were the most frequent, followed by Culex quinquefasciatus (1.32%, Aedes fluviatilis (1.04%, Culex Complex Coronator (0.40% and Toxorhynchites theobaldi (0.22%. Three areas were analyzed by means of Simpson's diversity index and the spatial analysis showed that the sites with the greatest abundance of Ae. aegypti presented lower diversity values and were associated with more highly consolidated urban nuclei. The vector of dengue, chikungunya and zika has great infesting ability in urban areas, which means that the early implementation of entomological surveillance and control activities in specific areas - such as transitional ones - is highly important.

  19. Survival and Development of Spodoptera frugiperda and Chrysodeixis includens (Lepidoptera: Noctuidae) on Bt Cotton and Implications for Resistance Management Strategies in Brazil.

    Science.gov (United States)

    Sorgatto, Rodrigo J; Bernardi, Oderlei; Omoto, Celso

    2015-02-01

    In Brazil, Spodoptera frugiperda (J. E. Smith) and Chrysodeixis includens (Walker) are important cotton pests and target of control of Bollgard II (Cry1Ac/Cry2Ab2) and WideStrike (Cry1Ac/Cry1F) cotton technologies. To subsidize an insect resistance management program, we conducted laboratory studies to evaluate the toxicity of these Bt cotton plants throughout larval development of S. frugiperda and C. includens. In bioassays with leaf disc, the efficacy of both Bt cotton plants against neonates was >80% for S. frugiperda and 100% for C. includens. However, S. frugiperda larvae that survived on Bt cotton had >76% of growth inhibition and stunting. In bioassays with S. frugiperda and C. includens larvae fed on non-Bt near-isoline during different time period (from 3 to 18 d) and then transferred to Bollgard II or WideStrike leaves showed that larval susceptibility decreased as larval age increased. For Bollgard II cotton, in all S. frugiperda instars, there were larvae that reached the pupal and adult stages. In contrast, on WideStrike cotton, a few larvae in fifth and sixth instar completed the biological cycle. For C. includens, some larvae in sixth instar originated adults in both Bt cotton plants. In conclusion, Bollgard II and WideStrike cotton technologies showed high efficacy against neonates of S. frugiperda and C. includens. However, the mortality of these species decreases as larval age increase, allowing insect survival in a possible seed mixture environment and favoring the resistance evolution.

  20. Geochemistry of upland lacustrine sediments from Serra dos Carajás, Southeastern Amazon, Brazil: Implications for catchment weathering, provenance, and sedimentary processes

    Science.gov (United States)

    Sahoo, Prafulla Kumar; Felix Guimarães, José Tasso; Martins Souza-Filho, Pedro Walfir; Sousa da Silva, Marcio; Maurity, Clovis Wagner; Powell, Mike A.; Rodrigues, Tarcísio Magevski; Fonseca da Silva, Delmo; Mardegan, Sílvia Fernanda; Furtini Neto, Antonio Eduardo; Dall'Agnol, Roberto

    2016-12-01

    A multi-proxy geochemical study of surficial sediments of an upland lake (Amendoim Lake), located in the Serra dos Carajás region, Brazil, was carried out to understand catchment weathering and provenance of sediments in the basin, as well as sedimentary processes. The carbon and nitrogen isotopic compositions of organic matter in the sediment were quite homogeneous, and suggest that the organic sources for this lake are mainly composed of palms and submerged macrophytes. The R-mode factor analysis indicates that most of the trace elements, including rare earth elements (REEs), are clustered with Al (Group 1), Si is grouped with Zr and Hf (Group 4), total organic carbon (TOC) with TS and Hg (Group 2), and Fe with Mn and As (Group 3). The elements of the Group 1 show strong positive correlations with Al, suggesting that these elements are hosted in detrital minerals during laterization in the catchment basin and not significantly affected by diagenesis. The high CIA values (96-99) of sediments together with their position in A-CN-K and log (Fe2O3/K2O) vs log (SiO2/Al2O3) plots indicate intense chemical weathering in source area. However, similar geochemical signatures between lake sediments and catchment lateritic crust indicates that mechanical erosion was the dominant sediment formation process. REE patterns normalized to chondrite along with geochemical indices (Al/K, Al/Ti, La/Th, La/Al, Ti/Zr, Zr/Hf, Th/Sc, Co/Th, Ba/Sr, and Eu/Eu*) also indicate that the sediments are mainly derived from laterite crust. This study provides reliable background information to reconstruct weathering processes and lake evolution in the Serra dos Carajás area.

  1. Water-soluble ions species of size-resolved aerosols: Implications for the atmospheric acidity in São Paulo megacity, Brazil

    Science.gov (United States)

    Vieira-Filho, Marcelo; Pedrotti, Jairo J.; Fornaro, Adalgiza

    2016-11-01

    Over the last decade, an increase of ammonium salts in atmospheric deposition has been reported worldwide, especially in megacities. The present study aims to give a better comprehension analysis about particulate matter acidity in São Paulo megacity (MASP), Brazil. Size-resolved aerosols were sampled in MASP, during 2012 winter, showing a bimodal mass concentration distribution, with sulfate concentration exceeding 3.40 μg m- 3, which accounted for over 25% of PM0.56 mass. Regarding the relative distribution of ionic species, 90% of NH4+ levels, were restricted to smaller than 1 μm diameter range. The average neutralization index for PM < 1 μm was 0.62, which indicated an ammonia-limiting atmosphere due to partial neutralization of atmospheric acids. Particles of the accumulation mode presented more acid behavior than other aerosol fractions, with pH value as low as 4.15 in PM0.56. The total neutralization index registered the lowest value for PM0.56, but it did not respond promptly to aerosol variations as the E-AIM model predictions. The highest discrepancies between the acidity proxies occurred in the smaller fractions of particulate matter, especially in the after-filter (AF) stage (diameter < 0.020 μm). In addition, AF stage had the highest contribution to PM total mass, about 14% for all the stages analyzed. Such contribution indicates that acidity in ultrafine particles are still mixed for the MASP and need further investigation.

  2. Triggering Sublimation-driven Activity of Main Belt Comets

    Science.gov (United States)

    Haghighipour, N.; Maindl, T. I.; Schäfer, C.; Speith, R.; Dvorak, R.

    2016-10-01

    It has been suggested that the comet-like activity of main belt comets (MBCs) is due to the sublimation of sub-surface water–ice that has been exposed as a result of their surfaces being impacted by meter-sized bodies. We have examined the viability of this scenario by simulating impacts between meter-sized and kilometer-sized objects using a smooth particle hydrodynamics approach. Simulations have been carried out for different values of the impact velocity and impact angle, as well as different target material and water-mass fractions. Results indicate that for the range of impact velocities corresponding to those in the asteroid belt, the depth of an impact crater is slightly larger than 10 m, suggesting that if the activation of MBCs is due to the sublimation of sub-surface water–ice, this ice has to exist no deeper than a few meters from the surface. Results also show that ice exposure occurs in the bottom and on the interior surface of impact craters, as well as on the surface of the target where some of the ejected icy inclusions are re-accreted. While our results demonstrate that the impact scenario is indeed a viable mechanism to expose ice and trigger the activity of MBCs, they also indicate that the activity of the current MBCs is likely due to ice sublimation from multiple impact sites and/or the water contents of these objects (and other asteroids in the outer asteroid belt) is larger than the 5% that is traditionally considered in models of terrestrial planet formation, providing more ice for sublimation. We present the details of our simulations and discuss their results and implications.

  3. Seat belts, airbags and child protection devices. [previously: Seat belts and child restraint seats.

    NARCIS (Netherlands)

    2010-01-01

    In the Netherlands, the use of seat belts results in a yearly reduction of hundreds of fatalities. Seat belts reduce the risk of fatal injury by 37 to 48%, depending on the position in the car. At 50%, the effect of child protection devices is even slightly higher. When last measured (in 2010), 97%

  4. Brazil's new national policy on solid waste

    DEFF Research Database (Denmark)

    Jabbour, A.B.L.d.S.; Jabbour, C.J.C.; Sarkis, J.

    2014-01-01

    Brazil, one of the world's largest developing countries, has recently introduced a new solid waste management regulatory policy. This new regulatory policy will have implications for a wide variety of stakeholders and sets the stage for opportunities and lessons to be learned. These issues...

  5. Hydrothermal alteration features in the Vargeão basaltic impact structure (South Brazil): Implications about the presence of liquid water in Mars

    Science.gov (United States)

    Yokoyama, E.; Nédélec, A.; Baratoux, D.; Berger, G.; Trindade, R. I.

    2013-05-01

    This study presents new petrological data about the hydrothermal fluid percolation in impact craters. Impact cratering process is of primary importance in the evolution of solid bodies of the Solar System. However, impact craters on basaltic rocks, which are the best analog for the surface of other planets and satellites, are rare on Earth. Recently, one medium-size complex crater was identified on volcanic rocks of the Paraná basin (south Brazil), providing an additional analog for the craters of most rocky planets and satellites. The 12 km wide Vargeão is a complex impact structure formed on volcanics rocks of the Serra Geral Formation (about 133-131 Ma), which are locally intertrapped by aeolian-sandstones of Botucatu Formation. Vargeão is morphologically characterized by a well-preserved rim and a smoothed central uplift. The rim region is characterized by concentric gravitational faults that affect tholeiitic basalt flows hundreds of meters thick and rhyodacites few tens of meters thick. Associated with these faults occur the formation of local networks of small red breccia veins. The central uplift has fractured basaltic rocks that contain a lot of red oxidized breccias veins cutted by some white veins. This study is focused on the petrogenesis of these centimeter breccia veins that are found in all lithologies. We conducted a detailed petrological study (petrography, microprobe, SEM, Raman spectroscopy, Magnetic data, Spectroscopy of reflectance and XRD) on these veins and their host-rocks. Our results show that the veins were strongly affected by the post-impact hydrothermal fluids. The hydrothermal alteration varies geographically in the structure. On the rim area this alteration consists of total or partial substitution of the melt matrix by quartz, calcite, iron oxides, zeolites and clay minerals. At the central area, the alteration mineral assembly is composed of quartz, iron oxides, zeolites, clay minerals and rarely calcite. Usually, the alteration

  6. Taphonomy of a Baurusuchus (Crocodyliformes, Baurusuchidae) from the Adamantina Formation (Upper Cretaceous, Bauru Basin), Brazil: Implications for preservational modes, time resolution and paleoecology

    Science.gov (United States)

    Araújo Júnior, Hermínio Ismael de; Silva Marinho, Thiago da

    2013-11-01

    Upper Cretaceous vertebrate accumulations from the Adamantina Formation are known due to their high taxonomic diversity. On the other hand, taphonomic analyses still are rare, limiting the understanding of processes related to the biostratinomic and fossildiagenetic histories of this lithostratigraphic unit. In 2005, fossils were collected from an outcrop located at Jales municipality, state of São Paulo, southeastern Brazil. From this outcrop, a well-preserved Baurusuchus was recovered, which displays a peculiar set of taphonomic signatures. This paper identifies and interprets taphonomic features of a specimen of Baurusuchus (Crocodyliformes, Baurusuchidae; UFRJ DG 418-R) from the Adamantina Formation (Upper Cretaceous of the Bauru Basin), in Jales municipality, state of São Paulo. Brief taphonomic comparisons with other specimens previously studied (crocodiles and dinosaurs) and a lithofaciological analysis of the outcrop were undertaken in order to enhance the knowledge of the stratigraphy and paleoenvironment and improve the time resolution for the Adamantina Formation in the region of Jales. Furthermore, paleoecological data were interpreted based on the taphonomic analysis. The fossil is composed of an articulated segment of vertebral column, ribs, part of the pelvic girdle and gastralia. There is no hydraulic equivalence between both the specimen of Baurusuchus and the size of quartz grain predominant in the fossiliferous layer, suggesting death in situ or short transport as a “water carcass”. Teeth marks identified on the pubes were assigned to a small/juvenile baurusuchid crocodyliform or a theropod dinosaur. The repositioning of some elements (ribs and dorsal osteoderms) is suggestive of mummification. Desiccation marks were observed and attributed to the stage 1 of weathering. These features suggest subaerial exposure of the carcass prior to burial, however, probably after the mummification. On the other hand, the subaerial exposure was short

  7. Capture techniques' use of Caranguejo-uçá crabs (Ucides cordatus in Paraíba state (northeastern Brazil and its socio-environmental implications

    Directory of Open Access Journals (Sweden)

    Douglas M. Nascimento

    2012-12-01

    Full Text Available The present study was undertaken in two traditional communities that are located on the margins of the estuary and mangrove complex of the Mamanguape River, Paraíba state (PB, Brazil. This work describes the crabs capture techniques tapamento and redinha, and identifies the negative socio-environmental impacts of redinha, using qualitative methods (open and semi-structured interviews, guided tours, direct observation and the administration of questionnaires. Results indicate that currently only two principle techniques are used to capture Ucides cordatus: redinha and tapamento. Tapamento has a low impact in relation to redinha. Redinha was pointed out by interviewees as a system that has social impact (social conflicts, breaking of traditions, substitution and extinction of techniques and environmental impact (less selective captures and high productivity, mangrove pollution, death of crabs caught in traps, cutting of the roots of Rhizophora mangle, micro-habitat loss resulting from galleries destroyed and polluted. Knowledge of crab harvesting carried out using these two techniques and the possible social and environmental impacts caused by redinha, can lead to more effective planning and actions towards the conservation of the species.O estudo foi realizado em duas comunidades tradicionais localizadas às margens do complexo estuário-manguezal do rio Mamanguape, Paraíba (PB, Brasil. Foram descritas as técnicas de captura (tapamento e redinha, identificando os impactos socioambientais negativos provocados pela redinha na captura de caranguejos, utilizando métodos qualitativos (entrevistas abertas e semiestruturadas, turnês guiadas, observação direta e questionários. Os resultados indicaram que atualmente apenas estas técnicas são usadas na captura de Ucides cordatus. O tapamento apresenta baixo impacto em relação à redinha, que é apontada pelos entrevistados como causadora de impactos sociais (conflitos sociais, rompimento de

  8. Potential Jupiter-Family comet contamination of the main asteroid belt

    Science.gov (United States)

    Hsieh, Henry H.; Haghighipour, Nader

    2016-10-01

    We present the results of "snapshot" numerical integrations of test particles representing comet-like and asteroid-like objects in the inner Solar System aimed at investigating the short-term dynamical evolution of objects close to the dynamical boundary between asteroids and comets as defined by the Tisserand parameter with respect to Jupiter, TJ (i.e., TJ = 3). As expected, we find that TJ for individual test particles is not always a reliable indicator of initial orbit types. Furthermore, we find that a few percent of test particles with comet-like starting elements (i.e., similar to those of Jupiter-family comets) reach main-belt-like orbits (at least temporarily) during our 2 Myr integrations, even without the inclusion of non-gravitational forces, apparently via a combination of gravitational interactions with the terrestrial planets and temporary trapping by mean-motion resonances with Jupiter. We estimate that the fraction of real Jupiter-family comets occasionally reaching main-belt-like orbits on Myr timescales could be on the order of ∼ 0.1-1%, although the fraction that remain on such orbits for appreciable lengths of time is certainly far lower. For this reason, the number of JFC-like interlopers in the main-belt population at any given time is likely to be small, but still non-zero, a finding with significant implications for efforts to use apparently icy yet dynamically asteroidal main-belt comets as tracers of the primordial distribution of volatile material in the inner Solar System. The test particles with comet-like starting orbital elements that transition onto main-belt-like orbits in our integrations appear to be largely prevented from reaching low eccentricity, low inclination orbits, suggesting that the real-world population of main-belt objects with both low eccentricities and inclinations may be largely free of this potential occasional Jupiter-family comet contamination. We therefore find that low-eccentricity, low-inclination main-belt

  9. Flat belt continuously variable high speed drive

    Energy Technology Data Exchange (ETDEWEB)

    Kumm, E.L.

    1992-02-01

    A study was undertaken at Kumm Industries funded by DOE in the NBS/DOE Energy-Related Inventions Program starting in August 1990 to design, construct and test a novel very high speed flat belt drive. The test arrangement as shown in Figure 1 consists of a multiple belt-pulley configuration that transmits power from a low speed (2000--4000 RPM) input to a small pulley turbine'' (27,000 to 55,000 RPM) and then to the low speed output variable radius pulley (2000--5000 RPM) via a special self-active tensioner. Transmitting 25 HP to and from the turbine'' corresponds to obtaining 50 HP in one direction only in a possible turbo compounded engine application. The high speed of the turbine'' belts, i.e. 100 meters/sec. at 55,000 RPM, while transferring substantial power is a new much higher operating regime for belts. The study showed that the available belts gave overall test rig efficiencies somewhat above 80% for the higher speeds (50,000 RPM) and higher powers (corresponding to above 90% in the turbocompound application) and a significantly better efficiencies at slightly lower speeds. The tests revealed a number of improved approaches in the design of such high speed drives. It appears that there is considerable possibility for further improvement and application of such equipment.

  10. Absence of Martian Radiation Belts and Implications Thereof.

    Science.gov (United States)

    Van Allen, J A; Frank, L A; Krimigis, S M; Hills, H K

    1965-09-10

    A system of sensitive particle detectors on Mariner IV showed the presence of electrons of energy (E(e)) less than 40 kiloelectron volts out to a radial distance of 165,000 kilometers in the morning fringe of the earth's magnetosphere but failed to detect any such electrons during the close encounter with Mars on 14-15 July 1965, at the time when the minimum areocentric radial distance was 13,200 kilometers. This result can mean that the ratio of the magnetic dipole moment of Mars to that of the earth (M(M)/M(E)) is surely less than 0.001 and probably is less than 0.0005. The corresponding upper limits on the equatorial magnetic field at the surface of Mars are 200 and 100 gammas, respectively. It appears possible that the solar wind interacts directly with the Martian atmosphere.

  11. The effects of Maine's change to primary seat belt law on seat belt use and public perception and awareness.

    Science.gov (United States)

    Chaudhary, Neil K; Tison, Julie; Casanova, Tara

    2010-04-01

    Maine upgraded its seat belt law to primary enforcement on September 20, 2007. Belt observations during the day and night were conducted along with awareness surveys in state licensing offices. Both daytime and nighttime observed belt use increased in the months following implementation of the law (daytime 77-84%; night 69-81%). Although daytime belt use was generally higher, nighttime belt use showed a greater increase than daytime belt use. Awareness surveys indicated that Maine motorists were clearly aware of the law change and its consequences. Survey respondents also indicated having heard both messages about enforcement and messages encouraging belt use. Primary seat belt laws may have a stronger effect on belt use at night--when risk is higher--than during the day.

  12. New information on Riograndia guaibensis Bonaparte, Ferigolo & Ribeiro, 2001 (Eucynodontia, Tritheledontidae from the Late Triassic of southern Brazil: anatomical and biostratigraphic implications

    Directory of Open Access Journals (Sweden)

    Marina B. Soares

    2011-03-01

    Full Text Available The tritheledontid Riograndia guaibensis was the first cynodont described for the "Caturrita Formation" fauna from the Late Triassic of southern Brazil (Santa Maria 2 Sequence. The type materials did not preserve anatomical information regarding braincase, occiput, basicranium, zygomatic arch, postdentary bones and craniomandibular joint. Here new materials are described and supply the missing information. Riograndia shows a suite of important anatomical features quite derived among the non-mammaliaform eucynodonts, such as the partial closure of the medial orbital wall and braincase, extensive secondary osseous palate, wide primary palate, basicranium with jugular foramen separated from the periphery of fenestra rotunda, narrow zygomatic arch and much reduced postdentary bones. Many of these features constitute synapomorphies shared only with the other members of mammaliamorpha. Thus, the almost complete cranial, mandibular and dental information from the new fossils of Riograndia can bring a significant improve in the understanding of the anatomy and phylogenetic relationships of the tritheledontids and help to elucidate the transformational steps involved in the cynodont-mammal transition. Additionally, Riograndia is a key taxon in refining the "Caturrita Formation" biostratigraphy, enabling the connection of several fossiliferous outcrops that have a rich tetrapod fauna that can be correlated with other Triassic faunas from Gondwana and Laurasia.O triteledontídeo Riograndia guiabensis foi o primeiro cinodonte descrito para a fauna da "Formação Caturrita" do Triássico Superior do sul do Brasil (Sequência Santa Maria 2. Os materiais da série-tipo não forneceram informações anatômicas relativas à caixa craniana, ociput, basicrânio, arco zigomático, ossos pós-dentários e articulação crânio-mandibular. Neste artigo são descritos novos materiais que suprem as informações anatômicas não contempladas anteriormente. Riograndia

  13. Micro-structural and compositional variations of hydrothermal epidote-group minerals from a peralkaline granite, Corupá Pluton, Graciosa Province, South Brazil, and their petrological implications

    Directory of Open Access Journals (Sweden)

    Silvio R.F. Vlach

    2012-06-01

    Full Text Available Epidote-group minerals, together with albite, quartz, fluorite, Al-poor and Fe-rich phyllosilicates, zircon, and minor oxides and sulphides, are typical hydrothermal phases in peralkaline alkali-feldspar granites from the Corupá Pluton, Graciosa Province, South Brazil. The epidote-group minerals occur as single crystals and as aggregates filling in rock interstices and miarolitic cavities. They display complex recurrent zoning patterns with an internal zone of ferriallanite-(Ce, followed by allanite-(Ce, then epidote-ferriepidote, and an external zone with allanite-(Ce, with sharp limits, as shown in BSE and X-ray images. REE patterns show decreasing fractionation degrees of LREE over HREE from ferriallanite to epidote. The most external allanite is enriched in MREE. LA-ICP-MS data indicate that ferriallanite is enriched (>10-fold in Ti, Sr and Ga, and depleted in Mg, Rb, Th and Zr relative to the host granite. Allanite has lower Ga and Mn and higher Zr, Nb and U contents as compared to ferriallanite, while epidote is enriched in Sr, U and depleted in Pb, Zr, Hf, Ti and Ga. The formation of these minerals is related to the variable concentrations of HFSE, Ca, Al, Fe and F in fluids remaining from magmatic crystallization, in an oxidizing environment, close to the HM buffer. L-MREE were in part released by the alteration of chevkinite, their main primary repository in the host rocks.Minerais do grupo do epidoto, com albita, quartzo, fluorita, filossilicatos pobres em Al e ricos em Fe, zircão e quantidades menores de óxidos e sulfetos são fases hidrotermais típicas em álcali-feldpato granitos peralcalinos do Pluton Corupá, Província Graciosa, Sul do Brasil. Os minerais do grupo do epidoto ocorrem como cristais individuais ou agregados que preenchem interstícios e cavidades miarolíticas na rocha. Mostram zonamento complexo, recorrente, descrito por uma zona interna de ferriallanita-(Ce, seguida por allanita-(Ce, epidoto-ferriepidoto e uma

  14. Friction and Wear in Timing Belt Drives

    Directory of Open Access Journals (Sweden)

    B. Stojanovic

    2010-09-01

    Full Text Available Timing belt tooth goes into contact with a drive pulley, stretched to the maximum, because of the previous tension. When the contact begins the peak of the belt tooth makes the contact with the outer surface of the pulley teeth. The process of the teeth entering into the contact zone is accompanied with the relative sliding of their side surfaces and appropriate friction force. The normal force value is changing with the parabolic function, which also leads to the changes of the friction force. The biggest value of the normal force and of the friction force is at the tooth root. Hollow between teeth and the tip of the pulley teeth are also in contact. Occasionally, the face surface of the belt and the flange are also in contact. The friction occurs in those tribomechanical systems, also. Values of these friction forces are lower compared with the friction force, which occurs at the teeth root.

  15. Ionospheric heating for radiation-belt control

    Energy Technology Data Exchange (ETDEWEB)

    Burke, W.J.; Villalon, E.

    1990-10-01

    Pitch-angle scattering interactions of electromagnetic waves in the ELF/VLF bands with trapped electrons, as formulated by Kennel and Petschek 1, describe the dynamics of the freshly filled radiation belts flux tubes. The natural existence of a slot region with electron fluxes below the Kennel-Petschek limit requires non-local wave sources. We describe a set of planned, active experiments in which VLF radiation will be injected from ground and space based transmitters in conjunction with the CRRES satellite in the radiation belts. These experiments will measure the intensity of waves driving pitch-angle diffusion and the electron energies in gyroresonance with the waves. An ability to reduce the flux of energetic particles trapped in the radiation belts by artificial means could improve the reliability of microelectronic components on earth-observing satellites in middle-altitude orbits.

  16. Drive Alive: Teen Seat Belt Survey Program

    OpenAIRE

    Loftin, Laurel; Barlament, James; Cotton, Carol; Davidson, Steve M; Burkett, Katie M.; Stephens, James

    2010-01-01

    Objective: To increase teen seat belt use among drivers at a rural high school by implementing the Drive Alive Pilot Program (DAPP), a theory-driven intervention built on highway safety best practices.Methods: The first component of the program was 20 observational teen seat belt surveys conducted by volunteer students in a high school parking lot over a 38-month period before and after the month-long intervention. The survey results were published in the newspaper. The second component was t...

  17. Development of belt conveyor driving system

    Institute of Scientific and Technical Information of China (English)

    FU Jun-qing(付峻青); WANG Cong(王聪); HUO Wei(霍伟)

    2004-01-01

    A short review for the existing various driving methods for belt conveyor was given, which include the analysis and comparison about the advantages, disadvantages and suitable application range of these methods. Based on this the variable-frequency-control(VFC) method for belt conveyor drive was fully discussed with focus on its application in medium-high voltage range. The principle of Neutral Point Clamped (NPC) Three-Level Inverter using high-voltage IGBTs together with the control strategy of rotor field-oriented vector control for induction motor drive were illustrated.

  18. The radiation belt of the Sun

    CERN Document Server

    Gruzinov, Andrei

    2013-01-01

    For a given solar magnetic field, the near-Sun (phase-space) density of cosmic ray electrons and positrons of energy above about 10GeV can be calculated from first principles, without any assumptions about the cosmic ray diffusion. This is because the sunlight Compton drag must be more important than diffusion. If the solar magnetic field has an appreciable dipole component, the electron/positron density should have a belt-like dent, perhaps extending to several solar radii. The belt structure appears because the quasi-bound orbits are depopulated by the sunlight Compton drag.

  19. Composite Microdiscs with a Magnetic Belt

    DEFF Research Database (Denmark)

    Knaapila, Matti; Høyer, Henrik; Helgesen, Geir

    2015-01-01

    We describe an emulsion-based preparation of patchy composite particles (diameter of 100-500 mu m) consisting of a disclike epoxy core and a belt of porous polystyrene particles (diameter of 30 mu m) with magnetite within the pores. Compared to the magnetically uniform polystyrene particles......, the spontaneous aggregation of composite particles is suppressed when dispersed into liquid, which is attributed to the increased particle size, reduced magnetic susceptibility, and the shape of the magnetic domain distribution within the particles (spherical versus a belt). When the composite particles...

  20. Ionospheric heating for radiation belt control

    Science.gov (United States)

    Burke, William J.; Villalon, Elena

    1990-10-01

    Pitch-angle scattering interactions of electromagnetic waves in the ELF/VLF bands with trapped electrons describe the dynamics of the freshly filled radiation belts flux tubes. The natural existence of a 'slot' region with electron fluxes below the Kennel-Petschek limit requires non-local wave sources. A set of planned, active experiments is described in which VLF radiation is injected from ground and space band transmitters in conjunction with the Combined Release and Radiation Effects Satellite in the radiation belts. These experiments can measure the intensity if waves driving pitch-angle diffusion and the electron energies in gyroresonance with the waves.

  1. CALCULATION OF TENSION FORCE OF BELT CONVEYOR

    Directory of Open Access Journals (Sweden)

    Ismet Ibishi

    2012-12-01

    Full Text Available In this paper is done the explanation on tension fashion of the belt conveyor which is employed in Kosovo Energy Corporation – KEK, for coal transportation to provide electric power plant. The aim of the paper enables to recognize tension forces not to pass with deformation of belt so that this problem will damage the workingprocess. Work principle is based on initial tension and tension during working process. The fact is known that the tension starts from the carriage on the way to tension mechanization, so forces on the rope passing through pulley there has to dominate the friction coefficient. All this process is related to economy of transportationmechanism.

  2. Limnological evaluation of water in the Rio Grande and Taquacetuba branches of the Billings Complex (São Paulo, Brazil and management implications

    Directory of Open Access Journals (Sweden)

    Marcelo Pompêo

    2010-12-01

    Full Text Available The large population contingent and the precarious urban planning in the metropolitan region of São Paulo have resulted in uncontrolled growth in areas where springs exist, generating strong pressures on the reservoirs. Concomitantly, a lack of articulation between public and private policy has led to various socio-environmental conflicts in the Billings watershed. This spring, which is responsible for the direct and indirect supply of water to millions of people, represents an enormous challenge for water resource management. In this context, this study aimed to analyze the seasonal limnological conditions of the Billings Complex, in particular the Rio Grande and Taquacetuba branches, and discuss the implications for the management procedure applied in the branches. Physical (water temperature, pH, electrical conductivity, suspended material, organic and inorganic suspended material chemical (dissolved oxygen, total phosphorus and nitrogen, nitrate, nitrite, ammonium and inorganic phosphorus and biological (chlorophyll-a variables of the water were analyzed and the Trophic State Index was calculated. The results indicate a hypertrophic state in the Taquacetuba branch. The Rio Grande branch presented a mesotrophic state which is, however, artificially maintained due to copper sulfate and hydrogen peroxide treatments. The results are also discussed in light of CONAMA Resolution 357/2005. Levels of chlorophyll-a and total phosphorous in the Taquacetuba branch do not conform to the proposed class of use, class I. In this branch, monitoring must be intensified and measures adopted to reduce the level of nutrients in the main body of the Billings complex.

  3. Crystallization conditions of porphyritic high-K calc-alkaline granitoids in the extreme northeastern Borborema Province, NE Brazil, and geodynamic implications

    Science.gov (United States)

    Campos, Benedita Cleide Souza; Vilalva, Frederico Castro Jobim; Nascimento, Marcos Antônio Leite do; Galindo, Antônio Carlos

    2016-10-01

    An integrated textural and chemical study on amphibole, biotite, plagioclase, titanite, epidote, and magnetite was conducted in order to estimate crystallization conditions, along with possible geodynamic implications, for six Ediacaran porphyritic high-K calc-alkaline granite plutons (Monte das Gameleiras, Barcelona, Acari, Caraúbas, Tourão, and Catolé do Rocha) intrusive into Archean to Paleoproterozoic rocks of the São José do Campestre (SJCD) and Rio Piranhas-Seridó (RPSD) domains, northern Borborema Province. The studied rocks include mainly porphyritic leucocratic monzogranites, as well as quartz-monzonites and granodiorites. Textures are marked by K-feldspar megacrysts (5-15 cm long) in a fine-to medium-grained matrix composed of quartz, plagioclase, amphibole, biotite, as well as titanite, epidote, Fesbnd Ti oxides, allanite, apatite, and zircon as accessory minerals. Amphibole, biotite and titanite share similar compositional variations defined by increasing Al and Fe, and decreasing Mg contents from the plutons emplaced into the SJCP (Monte das Gameleiras and Barcelona) towards those in the RPSD (Acari, Caraúbas, Tourão, and Catolé do Rocha). Estimated intensive crystallization parameters reveal a weak westward range of increasing depth of emplacement, pressure and temperature in the study area. The SJCD plutons (to the east) crystallized at shallower crustal depths (14-21 km), under slightly lower pressure (3.8-5.5 kbar) and temperature (701-718 °C) intervals, and high to moderate oxygen fugacity conditions (+0.8 plutons (to the west) were emplaced at slightly deeper depths (18-23 km), under higher, yet variable pressures (4.8-6.2 kbar), temperatures (723-776 °C), and moderate to low oxygen fugacity conditions (-1.0 < ΔFQM < +1.8). These results reinforce the contrasts between the tectono-strutuctural domains of São José do Campestre and Rio Piranhas-Seridó in the northern Borborema Province.

  4. Biochemical Education in Brazil.

    Science.gov (United States)

    Vella, F.

    1988-01-01

    Described are discussions held concerning the problems of biochemical education in Brazil at a meeting of the Sociedade Brazileira de Bioquimica in April 1988. Also discussed are other visits that were made to universities in Brazil. Three major recommendations to improve the state of biochemistry education in Brazil are presented. (CW)

  5. Biochemical Education in Brazil.

    Science.gov (United States)

    Vella, F.

    1988-01-01

    Described are discussions held concerning the problems of biochemical education in Brazil at a meeting of the Sociedade Brazileira de Bioquimica in April 1988. Also discussed are other visits that were made to universities in Brazil. Three major recommendations to improve the state of biochemistry education in Brazil are presented. (CW)

  6. 30 CFR 56.15020 - Life jackets and belts.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Life jackets and belts. 56.15020 Section 56.15020 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... § 56.15020 Life jackets and belts. Life jackets or belts shall be worn where there is danger from...

  7. 30 CFR 57.15020 - Life jackets and belts.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Life jackets and belts. 57.15020 Section 57.15020 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... Protection Surface Only § 57.15020 Life jackets and belts. Life jackets or belts shall be worn where there is...

  8. 14 CFR 125.211 - Seat and safety belts.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Seat and safety belts. 125.211 Section 125... Requirements § 125.211 Seat and safety belts. (a) No person may operate an airplane unless there are available... share one approved safety belt and two persons occupying a multiple lounge or divan seat may share...

  9. 49 CFR 392.16 - Use of seat belts.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Use of seat belts. 392.16 Section 392.16... VEHICLES Driving of Commercial Motor Vehicles § 392.16 Use of seat belts. A commercial motor vehicle which has a seat belt assembly installed at the driver's seat shall not be driven unless the driver...

  10. Observed seat belt use in Kumasi Metropolis, Ghana.

    Science.gov (United States)

    Afukaar, Francis K; Damsere-Derry, James; Ackaah, Williams

    2010-01-01

    We conducted an observational survey of seat belt use to determine the use rate of drivers and front-right passengers of vehicles in Kumasi, Ghana. Unobtrusive observations of seat belt use were made at 41 locations composed of signalized intersections and roundabouts where vehicles come to a halt or slow down considerably. The overall driver seat belt use rate was 17.6% compared to 4.9% for front-right passengers. Driver belt use was 33.2% for private cars, 9.0% for taxis, 8.3% for minibus (trotro), 13.1% for large buses and 9.7% for trucks. Overall seat belt use was higher for female drivers than for male drivers (44.8% versus 16.4%, p seat belt use rate increased with age. Passengers belted more often if drivers were belted, but about three-quarters of male passengers and 70-80% of female passengers were unbelted even when drivers were belted. In conclusion, the seat belt use rate was generally low in Kumasi, Ghana, and it is a function of occupant seating position, gender, vehicle type and usage, age group, and location setting. The results provide important preliminary data about seat belt use, particularly among male drivers and commercial vehicle occupant population. The study also suggests the need to develop effective strategies and programs that address low seat belt use in Ghana.

  11. School Buses & Seat Belts: A Discussion.

    Science.gov (United States)

    Alaska State Dept. of Education, Juneau.

    Safety belts are not installed in school buses for several reasons. School buses are constructed differently from automobiles in terms of (1) the locations of doors and instrument panels relative to passengers, (2) outer construction, (3) seat design and padding, and (4) visibility on the road. Under current regulations, bus seats are constructed…

  12. Design aspects of multiple driven belt conveyors

    NARCIS (Netherlands)

    Nuttall, A.J.G.

    2007-01-01

    Worldwide belt conveyors are used to transport a great variety of bulk solid materials. The desire to carry higher tonnages over longer distances and more diverse routes, while keeping exploitation costs as low as possible, has fuelled many technological advances. An interesting development in the r

  13. Design aspects of multiple driven belt conveyors

    NARCIS (Netherlands)

    Nuttall, A.J.G.

    2007-01-01

    Worldwide belt conveyors are used to transport a great variety of bulk solid materials. The desire to carry higher tonnages over longer distances and more diverse routes, while keeping exploitation costs as low as possible, has fuelled many technological advances. An interesting development in the

  14. Is the Cameron River greenstone belt allochthonous?

    Science.gov (United States)

    Kusky, T. M.

    1986-01-01

    Many tectonic models for the Slave Province, N.W.T., Canada, and for Archean granite - greenstone terranes in general, are implicitly dependent on the assumption that greenstone belt lithologies rest unconformably upon older gneissic basement. Other models require originally large separations between gneissic terranes and greenstone belts. A key question relating to the tectonics of greenstone belts is therefore the original spatial relationship between the volcanic assemblages and presumed-basement gneisses, and how this relationship has been modified by subsequent deformation. What remains unclear in these examples is the significance of the so-called later faulting of the greenstone - gneiss contacts. Where unconformities between gneisses and overlying sediments are indisputable, such as at Point Lake, the significance of faults which occur below the base of the volcanic succession also needs to be evaluated. As part of an on-going investigation aimed at answering these and other questions, the extremely well-exposed Cameron River Greenstone Belt and the Sleepy Dragon Metamorphic Complex in the vicinity of Webb Lake and Sleepy Dragon Lake was mapped.

  15. Pregnancy: Should I Use a Seat Belt?

    Science.gov (United States)

    ... always wear your seat belt even if your car has air bags.Where should I sit if I’m a ... editorial staff Categories: Family Health, Pregnancy and ChildbirthTags: air bag, auto accident, automobile safety, car accident, car safety, fetal injury, patient ...

  16. The thrust belts of Western North America

    Energy Technology Data Exchange (ETDEWEB)

    Moulton, F.C.

    1993-08-01

    Most of the Basin and Range physiographic province of western North America is now believed to be part of the overthrust. The more obvious overthrust belt along the eastern edge of the Basin and Range Province is named the Sevier orogenic belt, where older rocks are observed thrust onto younger rocks. More detailed surface geological mapping, plus deep multiple-fold geophysical work and many oil and gas wildcat wells, have confirmed an east-vergent shortened and stacked sequence is present in many places in the Basin and Range. This western compressive deformed area in east central Nevada is now named the Elko orogenic belt by the U.S. Geological Survey. This older compressed Elko orogenic belt started forming approximately 250 m.y. ago when the North American plate started to move west as the Pangaea supercontinent started to fragment. The North American plate moved west under the sediments of the Miogeocline that were also moving west. Surface-formed highlands and oceanic island arcs on the west edge of the North American plate restricted the westward movement of the sediments in the Miogeocline, causing east-vergent ramp thrusts to form above the westward-moving North American plate. The flat, eastward-up-cutting thrust assemblages moved on the detachment surfaces.

  17. Belts and Chains. FOS: Fundamentals of Service.

    Science.gov (United States)

    John Deere Co., Moline, IL.

    This manual on belts and chain drives is one of a series of power mechanics texts and visual aids on theory, of operation, diagnosis, and repair of automotive and off-the-road agricultural and construction equipment. Materials provide basic information and illustrations for use by vocational students and teachers as well as shop servicemen and…

  18. Belts and Chains. FOS: Fundamentals of Service.

    Science.gov (United States)

    John Deere Co., Moline, IL.

    This manual on belts and chain drives is one of a series of power mechanics texts and visual aids on theory, of operation, diagnosis, and repair of automotive and off-the-road agricultural and construction equipment. Materials provide basic information and illustrations for use by vocational students and teachers as well as shop servicemen and…

  19. Economic Valuation of Green Belt: Focusing on the Conservation Value of Green Belt in Greater Seoul

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Joon Koo [Seoul National University, Seoul (Korea); Shin, Young Cheol [Daejin University, Pochon (Korea)

    2000-09-01

    The purpose of this paper is to measure the benefits of conservation of the green belt in the Greater Seoul area by CVM using dichotomous choice with a follow-up elicitation method. According to the government's plan, part of the green belt in the Greater Seoul area is to be freed from green belt designation. The mean willingness-to-pay(WTP) to conserve the green belt in the current state turns out to be about 7,430 won(95% confidence interval 6,220{approx}8,640 won) per household, which amounts to 308 billion won per year for entire population of Seoul. This WTP figure is found to be significantly influenced by level of education, sex, and the variables related to the perception and attitudes of respondents. (author). 26 refs., 3 tabs.

  20. Belt fires and mine escape problems

    Energy Technology Data Exchange (ETDEWEB)

    Kovac, J.G.; Lazzara, C.P. [Bureau of Mines, Pittsburgh, PA (United States); Kravitz, J.H.

    1996-12-31

    A conveyor belt fire in an underground coal mine is a serious threat to life and property. About 30% of the reportable underground coal mine fires from 1988 through 1992 occurred in belt entries. In one instance, a fire started in the drive area of a belt line, spread rapidly, and resulted in seating of the entire mine. Large-scale studies conducted by the U.S. Bureau of Mines in an aboveground fire gallery at Lake Lynn Laboratory clearly show the hazards of conveyor belt fires. Mine conveyor belt formulations which passed the current Federal acceptance test for fire-resistant betting were completely consumed by propagating fires or propagated flame, with flame spread rates ranging from 0.3 to 9 m/min. High downstream temperatures and large quantities of smoke and toxic gases, such as carbon monoxide, were generated as the belting burned. The smoke and gases can be spread by the mine`s ventilation system and can create significant problems for miners in the process of evacuation, such as reduction in visibility and incapacitation. In the aftermath of a belt fire, the atmosphere inside of the mine can become smoke filled or unbreathable, forcing miners to evacuate while wearing Self-Contained Self-Rescuers (SCSR`s), Sometimes there is confusion about how to regard the rated duration of an MSHA/NIOSH-approved 60-min. SCSR, especially when an SCSR is used in a way which takes it outside of the test conditions under which it was approved. As examples, for a mine escape that takes a miner from the deepest point of penetration in the mine to the surface: How long will a 60-min. SCSR actually last? and How many SCSR`s will a miner need? To answer these kinds of questions, in-mine data being gathered on escape times, distance and heart rates using miners escaping on foot and under oxygen. A model will be developed and validated which predicts how much oxygen is actually needed for a mine escape, and compares oxygen consumption bare faced versus wearing an SCSR.

  1. Imaging Jupiter Radiation Belts At Low Frequencies

    Science.gov (United States)

    Girard, J. N.; de Pater, I.; Zarka, P.; Santos-Costa, D.; Sault, R.; Hess, S.; Cecconi, B.; Fender, R.; Pewg, Lofar

    2014-04-01

    The ultra-relativistic electrons, trapped in the inner radiation belts of Jupiter, generates a strong synchrotron radio emission (historically known as the jovian decimeter radiation (DIM)) which is beamed, polarized (~20% linear, ~1% circular) and broadband. It has been extensively observed by radio telescopes/ probes and imaged by radio interferometers over a wide frequency spectrum (from >300 MHz up to 22 GHz). This extended emission presents two main emission peaks constantly located on both sides of the planet close to the magnetic plane. High latitude emissions were also regularly observed at particular frequencies, times and in particular observational configurations. This region of the magnetosphere is "frozen" due to the strong magnetic field (~4.2 G as the equator) and therefore is forced to rotate at the planetary period (T≈9h55m). Due to the tilt (~ 10o) between the spin axis of the planet and the magnetic axis (which can be seen as dipolar in first approximation), the belts and the associated radio emission wobble around the planet center. The analysis of the flux at different frequencies highlighted spatial, temporal and spectral variabilities which origins are now partly understood. The emission varies at different time scales (short-time variations of hours to long-term variation over decades) due to the combination of visibility effect (wobbling, beaming, position of the observer in the magnetic rotating reference frame) [1], [2] and intrinsic local variations (interaction between relativistic electrons and satellites/dust, delayed effect of the solar wind ram pressure, impacts events) [3], [4], [5]. A complete framework is necessary to fully understand the source, loss and transport processes of the electrons originating from outside the belt, migrating by inward diffusion and populating the inner region of the magnetosphere. Only a few and unresolved measurements were made below 300 MHz and the nonsystematic observation of this radio emission

  2. International survey of seat belt use exemptions.

    Science.gov (United States)

    Weiss, H; Sirin, H; Levine, J A; Sauber, E

    2006-08-01

    Substantial evidence of seatbelt efficacy has been shown by several studies, and it is widely recommended that motor vehicle occupants use properly fitted seat belts. However, some (but a heretofore unknown number of) countries with national seat belt laws permit various exemptions which may lower use rates. The aim of this study was to survey the variety of exemptions to national seat belt laws. This investigation relied on identifying respondents from national traffic safety agencies, other governmental and non-governmental organizations, Internet searches, personal contacts, and other sources. Questionnaires were deployed through a web based survey supplemented by email and postal versions. Responses were received from 30 countries of which 28 (93.7%) had a national seat belt law. About two thirds (63.7%) of the 28 national laws applied to both front and back seat passengers. The leading exemption types included vehicles made before a certain year (n = 13), antique vehicles (n = 12), military vehicles (n = 11), buses (n = 9), and emergency vehicles (n = 8). Most responding countries reported one or more specific categories of individuals as exempt including those with medical exemptions (n = 20), taxi drivers (n = 11), police (n = 9), emergency medical personnel (n = 8), physically disabled people (n = 6), and pregnant women (n = 6). Out of 26 responses to the question regarding current level of enforcement, 42.3% felt enforcement was "very good or good" and 57.7% characterized it as "fair or poor". This study represents one of the largest international traffic law surveys reported. Most national seatbelt laws offer perilous exemptions to a broad array of vehicle types and road user groups. These findings, coupled with concern over the level of enforcement in the majority of countries surveyed, suggest that international road safety efforts have a long way to go to improve coverage and enforcement of national seat belt laws.

  3. China belting up or down? Seat belt wearing trends in Nanjing and Zhoushan.

    Science.gov (United States)

    Routley, Virginia; Ozanne-Smith, Joan; Li, Dan; Yu, Min; Wang, Jianyue; Zhang, Junhe; Tong, Zhendong; Wu, Ming; Wang, Peihua; Qin, Yu

    2008-11-01

    National seat belt wearing legislation became effective in China May 2004 and associated provincial and city regulations followed. Despite rapid motorisation seat belt studies in China have been scarce. Patterns and trends in urban seat belt wearing were observed for all driver, front and rear seating positions over the years 2005-2007 in two eastern cities Nanjing (Jiangsu Province) and Zhoushan (Zhejiang Province). There were 35,256 vehicles observed in Nanjing, 20,939 in Zhoushan and 95,933 occupants overall. Males dominated all seating positions, especially drivers. Seat belt wearing overall was significantly higher for drivers (49.9% Nanjing, 47.4% Zhoushan) than for front seat passengers (9.1% Nanjing, 1.0% Zhoushan) and virtually nonexistent for rear passengers (0.5% Nanjing, 0.2% Zhoushan). Generally levels declined significantly from year to year (drivers Nanjing 66.7%, 47.7%, 38.6%; Zhoushan 57.4%, 57.9%, 30.6%; front passengers Nanjing 19.2%, 6.6%, 3.2%). Zhoushan wearing did not initially decline, 2006 observations coinciding with anticipation of provincial regulations (July 2006). Observations revealed an absence of child restraints. Pretend wearing/belt tampering was observed almost exclusively in taxi drivers (14.2% of Nanjing taxi drivers, 11.3% of Zhoushan's). Awareness of and attitudes to urban seat belt laws should be investigated, appropriate countermeasures developed and enforcement reassessed.

  4. The Gould Belt, the de Vaucouleurs-Dolidze Belt, and the Orion Arm

    CERN Document Server

    Bobylev, V V

    2014-01-01

    Based on masers with measured trigonometric parallaxes, we have redetermined the spatial orientation parameters of the Local (Orion) arm. Using 23 sources (the Gould Belt objects were excluded), we have found that their spatial distribution can be approximated by a very narrow ellipsoid elongated in the direction L_1=77.1+/-2.9^o whose symmetry plane is inclined to the Galactic plane at an angle of 5.6+/-0.2^o. The longitude of the ascending node of the symmetry plane is l_\\Omega=70+/-3^o. A new estimate for the pitch angle of the Local spiral arm has been obtained by an independent method: i=12.9+/-2.9^o. Previously, a belt of young B stars, the de Vaucouleurs.Dolidze belt, was pointed out on the celestial sphere with parameters close to such an orientation. We have refined the spatial orientation parameters of this belt based on a homogeneous sample of protostars. The de Vaucouleurs.Dolidze belt can be identified with the Local arm, with the belt proper as a continuous band on the celestial sphere like the ...

  5. Aqueous alteration on main-belt asteroids

    Science.gov (United States)

    Fornasier, S.; Lantz, C.; Barucci, M.; Lazzarin, M.

    2014-07-01

    The study of aqueous alteration is particularly important for unraveling the processes occurring during the earliest times in Solar System history, as it can give information both on the thermal processes and on the localization of water sources in the asteroid belt, and for the associated astrobiological implications. The aqueous alteration process produces the low temperature (< 320 K) chemical alteration of materials by liquid water which acts as a solvent and produces materials like phyllosilicates, sulphates, oxides, carbonates, and hydroxides. This means that liquid water was present in the primordial asteroids, produced by the melting of water ice by heating sources, very probably by ^{26}Al decay. Hydrated minerals have been found mainly on Mars surface, on primitive main-belt asteroids (C, G, B, F, and P-type, following the classification scheme by Tholen, 1984) and possibly also on few transneptunian objects. Reflectance spectroscopy of aqueous altered asteroids shows absorption features in the 0.6-0.9 and 2.5-3.5-micron regions, which are diagnostic of, or associated with, hydrated minerals. In this work, we investigate the aqueous alteration process on a large sample of 600 visible spectra of C-complex asteroids available in the literature. We analyzed all these spectra in a similar way to characterize the absorption-band parameters (band center, depth, and width) and spectral slope, and to look for possible correlations between the aqueous alteration process and the asteroids taxonomic classes, orbital elements, heliocentric distances, albedo, and sizes. We find that 4.6 % of P, 7.7 % of F, 9.8 % of B, 50.5 % of C, and 100 % of the G-type asteroids have absorption bands in the visible region due to hydrated silicates. Our analysis shows that the aqueous alteration sequence starts from the P-type objects, practically unaltered, and increases through the P → F → B → C → G asteroids, these last being widely aqueously altered, strengthening thus

  6. Seat Belt Use Among Adult Workers - 21 States, 2013.

    Science.gov (United States)

    Boal, Winifred L; Li, Jia; Rodriguez-Acosta, Rosa L

    2016-06-17

    Roadway incidents involving motorized vehicles accounted for 24% of fatal occupational injuries in the United States during 2013 and were the leading cause of fatal injuries among workers.* In 2013, workers' compensation costs for serious, nonfatal injuries among work-related roadway incidents involving motorized land vehicles were estimated at $2.96 billion.(†) Seat belt use is a proven method to reduce injuries to motor vehicle occupants (1). Use of lap/shoulder seat belts reduces the risk for fatal injuries to front seat occupants of cars by 45% and the risk to light truck occupants by 60%.(§) To characterize seat belt use among adult workers by occupational group, CDC analyzed data from the 2013 Behavioral Risk Factor Surveillance System (BRFSS) and found that not always using a seat belt was significantly associated with occupational group after controlling for factors known to influence seat belt use. Occupational groups with the highest prevalences of not always using a seat belt included construction and extraction; farming, fishing, and forestry; and installation, maintenance, and repair. To increase seat belt use among persons currently employed, states can enact and enforce primary seat belt laws, employers can set and enforce safety policies requiring seat belt use by all vehicle occupants, and seat belt safety advocates can target interventions to workers in occupational groups with lower reported seat belt use.

  7. LOAD DISTRIBUTION ON DRUMS OF DOUBLE DRIVE BELT CONVEYOR

    Institute of Scientific and Technical Information of China (English)

    薛河; 苏清祖; 马胜利

    1999-01-01

    The double drum drive is widely used on the mine belt conveyor, which are divided the rigid connected double drums and separately driving double drums according to connected method of two drums. Because of the change of real work condition, the load distribution is changed on the two drive drums, which may produce a slippage between a drum and belt. Slippage may intensify the wear of the drum, and sometimes causing the fire of the belt. This restricts the development toward narrow belt, high velocity and large power of belt conveyor. In this paper, the factors affecting the load distribution of two drums of double drum belt conveyor are'systematically analyzed and some computing formulas derived, by these formulas, the actual load distribution onthe two drums of rigid connected or separately driving belt conveyor can be separately calculated. These formulas also can be as the theory base for adjusting the driving force of two drums.

  8. New molecular identifiers for Simulium limbatum and Simulium incrustatum s.l. and the detection of genetic substructure with potential implications for onchocerciasis epidemiology in the Amazonia focus of Brazil.

    Science.gov (United States)

    Conceição, Priscila A; Crainey, James L; Almeida, Tatiana P; Shelley, Anthony J; Luz, Sergio L B

    2013-08-01

    The Amazonia onchocerciasis focus of southern Venezuela and northern Brazil is the larger of the two remaining Latin American onchocerciasis foci where disease transmission still occurs and is often regarded as the most challenging of all the Latin American foci to eliminate onchocerciasis. The site is home to a population of over 20,000 semi-nomadic, hunter-gatherer Yanomami people and is made-up of a mosaic of rainforest and savannah ecologies, which are influenced by the area's undulating terrain and rich geological diversity. At least six blackfly vectors have been implicated in onchocerciasis transmission in this focus; however, because of the difficulty in their routine identification the relative importance of each has been obscured. Simulium limbatum and Simulium incrustatum s.l. have both been recorded as vectors in the Amazonia focus, but they are difficult to discriminate morphologically and thus the ecological range of these species, and indeed the presence of S. limbatum in the Amazonia focus at all, have remained controversial. In the work described here, we report 15 S. incrustatum s.l. CO1 sequences and 27 S. limbatum sequences obtained from field-caught adult female blackflies collected from forest and savannah localities, inside and just outside the Amazonia focus. Phylogenetic analysis with the sequences generated in this study, showed that both the S. limbatum and the S. incrustatum s.l. CO1 sequences obtained (even from specimens living in sympatry) all fell into discrete species-specific bootstrap-supported monophyletic groups and thus confirmed the utility of the CO1 gene for identifying both these species inside the Amazonia focus. As the S. limbatum-exclusive cluster included CO1 sequences obtained from forest-caught and morphologically identified specimens these results provide the clearest evidence yet of the presence of S. limbatum inside the Amazonia focus. The question, however, of whether S. limbatum is actually a vector in the focus

  9. Triggering Comet-Like Activity of Main Belt Comets

    Science.gov (United States)

    Haghighipour, Nader; Maindl, Thomas I.; Schaefer, Christoph; Speith, Roland; Dvorak, Rudolf

    2016-10-01

    Main-belt comets (MBCs) have attracted a great deal of interest since their identification as activated asteroids by Hsieh and Jewitt in 2006. It has been suggested that the comet-like activity of these objects are due to the sublimation of sub-surface water-ice that has been exposed as a result of their surfaces being impacted by small (e.g, m-sized) bodies. We have examined the viability of this scenario by simulating impacts between m-sized impactors and km-sized targets using a smooth particle hydrodynamics (SPH) approach. We have carried out simulations for a range of impact velocities and angles, material type and strength, and water content of the target allowing m-sized impactors to erode enough of an MBC's surface to trigger its activation. Results indicate that for the range of impact velocities corresponding to those in the asteroid belt, the depth of an impact crater is slightly larger than 10 m suggesting that if the activation of MBCs is due to the sublimation of sub-surface water-ice, this ice has to exist no deeper than a few meters from the surface. Our simulations point to a clearly notable spread in the aggregated crater depths due to different impact energy, impact angles, and MBC's water contents showing deeper craters due to less overall material strength. Results also show that ice-exposure occurs in the bottom and on the interior surface of impact craters as well as the surface of the target where some of the ejected icy inclusions are re-accreted. Our results, in addition to demonstrating that the impact scenario is indeed a viable mechanism to expose ice and trigger the activity of MBCs, indicate that the activity of the current MBCs is likely due to ice sublimation from multiple impact sites and/or the water contents of these objects (and other asteroids in the outer asteroid belt) is larger than the 5% that is traditionally considered in models of terrestrial planet formation. We present details of our simulations and discuss their

  10. Asteroid Belts in Debris Disk Twins: Vega and Fomalhaut

    Science.gov (United States)

    Su, Kate Y. L.; Rieke, George H.; Malhortra, Renu; Stapelfeldt, Karl R.; Hughes, A. Meredith; Bonsor, Amy; Wilner, David J.; Balog, Zoltan; Watson, Dan M.; Werner, Michael W.; Misselt, Karl A.

    2013-01-01

    Vega and Fomalhaut are similar in terms of mass, ages, and global debris disk properties; therefore, they are often referred to as debris disk twins. We present Spitzer 10-35 micrometers spectroscopic data centered at both stars and identify warm, unresolved excess emission in the close vicinity of Vega for the first time. The properties of the warm excess in Vega are further characterized with ancillary photometry in the mid-infrared and resolved images in the far-infrared and submillimeter wavelengths. The Vega warm excess shares many similar properties with the one found around Fomalhaut. The emission shortward of approximately 30 micrometers from both warm components is well described as a blackbody emission of approximately 170 K. Interestingly, two other systems, Eri and HR 8799, also show such an unresolved warm dust using the same approach. These warm components may be analogous to the solar system s zodiacal dust cloud, but of far greater mass (fractional luminosity of approximately 10(exp-5) to 10(exp-6) compared to 10(exp-8) to 10(exp-7). The dust temperature and tentative detections in the submillimeter suggest that the warm excess arises from dust associated with a planetesimal ring located near the water-frost line and presumably created by processes occurring at similar locations in other debris systems as well. We also review the properties of the 2 micrometers hot excess around Vega and Fomalhaut, showing that the dust responsible for the hot excess is not spatially associated with the dust we detected in the warm belt.We suggest it may arise from hot nano grains trapped in the magnetic field of the star. Finally, the separation between the warm and cold belt is rather large with an orbital ratio greater than or approximately 10 in all four systems. In light of the current upper limits on the masses of planetary objects and the large gap, we discuss the possible implications for their underlying planetary architecture and suggest that multiple, low

  11. Assessing the Main-Belt Comet Population with Comet Hunters

    Science.gov (United States)

    Schwamb, Megan E.; Hsieh, Henry H.; Zhang, Zhi-Wei; Chen, Ying-Tung; Lintott, Chris; Wang, Shiang-Yu; Mishra, Ishan

    2017-01-01

    Cometary activity in the asteroid belt is a recent discovery. Evidence suggests recent collisions play a role excavating subsurface water ice in these Main Belt Comets (MBCs). MBCs may be an alternative source of Earth’s water. The properties and origins of the MBCs remain elusive. To date ~15 MBCs are known, but only with many tens to 100s of MBCs can we fully explore this new reservoir and its implications for the early Earth.Automated routines identify cometary objects by comparing the point spread functions (PSFs) of moving objects to background stars. This approach may miss cometary activity with low-level dust comae or trails that are too weak or extended to affect an object's near-nucleus PSF profile. Direct visual inspection of moving objects by survey team members can often catch such unusual objects, but such an approach is impractical for the largest surveys to date, and will only become more intractable with the next generation wide-field surveys.With the Internet, tens of thousands of people can be engaged in the scientific process. With this citizen science approach, the combined assessment of many non-experts often equals or rivals that of a trained expert and in many cases outperforms automated algorithms. The Comet Hunters (http://www.comethunters.org) project enlists the public to search for MBCs in data from the Hyper Suprime-Cam (HSC) wide survey. HSC is to date the largest field-of-view camera (covering a 1.5 degree diameter circle on sky) on a 8-10-m class telescope. The HSC wide survey provides the sensitivity to detect cometary activity at lower levels than have been possible for previous surveys.We will give an overview of the Comet Hunters project. We will present the results from the first ~10,000 HSC asteroids searched and provide an estimate on the frequency of cometary activity in the Main Asteroid beltAcknowledgements: This work uses data generated via the Zooniverse.org platform, development of which was supported by a Global

  12. Persistence of Salmonella on egg conveyor belts is dependent on the belt type but not on the rdar morphotype.

    Science.gov (United States)

    Stocki, S L; Annett, C B; Sibley, C D; McLaws, M; Checkley, S L; Singh, N; Surette, M G; White, A P

    2007-11-01

    Commercial caged layer flocks in Alberta, Canada, are commonly monitored for Salmonella enterica serovar Enteritidis (SE) and S. enterica serovar Typhimurium (ST) by environmental sampling. In one recent case, a SE strain isolated from the egg conveyor belt was a source of persistent infection for the flock. This study was undertaken to examine Salmonella colonization on egg conveyor belts and to determine whether the rdar morphotype, a conserved physiology associated with aggregation and long-term survival, contributed to persistence. Four woven belts constructed of natural or nonnatural fibers and a 1-piece belt made of vinyl were tested with rdar-positive ST and SE strains and a rdar-negative ST DeltaagfD reference strain. The type of egg belt was the most important factor influencing Salmonella colonization and persistence. The vinyl belt, with the least surface area available for colonization, had the fewest Salmonella remaining after washing and disinfection, whereas the hemp-plastic belt, with the greatest surface area, had the most Salmonella remaining. Real-time gene expression indicated that the rdar morphotype was involved in colonizing the egg belt pieces; however, it was not essential for persistence. In addition, rdar-positive and rdar-negative strains were equally similarly to disinfection on the egg belt pieces. The results indicate that Salmonella can persist on a variety of egg belts by mechanisms other than the rdar morphotype, and that using egg conveyer belts with reduced surface area for bacterial colonization can lessen contamination problems.

  13. Ionic composition of the earth's radiation belts

    Science.gov (United States)

    Spjeldvik, W. N.

    1983-01-01

    Several different ion species have been positively identified in the earth's radiation belts. Besides protons, there are substantial fluxes of helium, carbon and oxygen ions, and there are measurable quantities of even heavier ions. European, American and Soviet space experimenters have reported ion composition measurements over wide ranges of energies: at tens of keV (ring-current energies) and below, and at hundreds of keV and above. There is still a gap in the energy coverage from several tens to several hundreds of keV where little observational data are available. In this review emphasis is placed on the radiation belt ionic structure above 100 keV. Both quiet time conditions and geomagnetic storm periods are considered, and comparison of the available space observations is made with theoretical analysis of geomagnetically trapped ion spatial, energy and charge state distributions.

  14. HP metamorphic belt of the western Alps

    Institute of Scientific and Technical Information of China (English)

    RobertoCompagnoni

    2003-01-01

    The understanding of the subduction-related processes benefited by the studies of the high-pressure (HP) meta-morphic rocks from the western Alps. The most stimu-lating information was obtained from the inner part of the western Alpine belt, where most tectonic units show an early Alpine eclogite-facies recrystallisation. This is especially true for the Austroalpine Sesia Zone and the Penninic Dora-Maira massif. From the Sesia zone,which consists of a wide spectrum of continental crust lithologies recrystallised to quartz-eclogite-facies min-eral assemblages, the first finding of a jadeite-bearingmeta-granitoid has been described, supporting evidencethat even continental crust may subduct into the mantle.From the Dora-Maira massif the first occurrence of regional metamorphic coesite has been reported, open-ing the new fertile field of the ultrahigh-pressure meta-morphism (UHPM), which is now becoming the rule in the collisional orogenic belts.

  15. Alien Asteroid Belt Compared to our Own

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1: Band of Light Comparison This artist's concept illustrates what the night sky might look like from a hypothetical alien planet in a star system with an asteroid belt 25 times as massive as the one in our own solar system (alien system above, ours below; see Figure 1). NASA's Spitzer Space Telescope found evidence for such a belt around the nearby star called HD 69830, when its infrared eyes spotted dust, presumably from asteroids banging together. The telescope did not find any evidence for a planet in the system, but astronomers speculate one or more may be present. The movie begins at dusk on the imaginary world, when HD 69830, like our Sun, has begun to set over the horizon. Time is sped up to show the onset of night and the appearance of a brilliant band of light. This light comes from dust in a massive asteroid belt, which scatters sunlight. In our solar system, anybody observing the skies on a moonless night far from city lights can see the sunlight that is scattered by dust in our asteroid belt. Called zodiacal light and sometimes the 'false dawn,' this light appears as a dim band stretching up from the horizon when the Sun is about to rise or set. The light is faint enough that the disk of our Milky Way galaxy remains the most prominent feature in the sky. (The Milky Way disk is shown perpendicular to the zodiacal light in both pictures.) In contrast, the zodiacal light in the HD 69830 system would be 1,000 times brighter than our own, outshining even the Milky Way.

  16. Kanfenggou UHP Metamorphic Fragment in Eastern Qinling Orogen and Its Relationship to Dabie-Sulu UHP and HP Metamorphic Belts, Central China

    Institute of Scientific and Technical Information of China (English)

    Suo Shutian; Zhong Zengqiu; Zhou Hanwen; You Zhendong

    2003-01-01

    In the Central Orogenic Belt, China, two UHP metamorphic belts are discriminated mainly based on a detailed structural analysis of the Kanfenggou UHP metamorphic fragment exposed in the eastern Qinling orogen, and together with previous regional structural, petrological and geochronological data at the scale of the orogenic domain. The first one corresponds to the South Altun-North QaidamNorth Qinling UHP metamorphic belt. The other is the Dabie-Sulu UHP and HP metamorphic belts. The two UHP metamorphic belts are separated by a series of tectonic slices composed by the Qinling rock group, Danfeng rock group and Liuling or Foziling rock group etc. respectively, and are different in age of the peak UHP metamorphism and geodynamic implications for continental deep subduction and collision. Regional field and petrological relationships suggest that the Kanfenggou UHP metamorphic fragment that contains a large volume of the coesite- and microdiamond-bearing eclogite lenses is compatible with the structures recognized in the South Altun and North Qaidam UHP metamorphic fragments exposed in the western part of China, thereby forming a large UHP metamorphic belt up to 1 000 km long along the orogen strike. This UHP metamorphic belt represents an intercontinental deep subduction and collision belt between the Yangtze and Sino-Korean cratons, occurred during the Paleozoic. On the other hand, the well-constrained Dabie-Sulu UHP and HP metamorphic belts occurred mainly during Triassic time (250-220 Ma), and were produced by the intrucontinental deep subduction and collision within the Yangtze craton. The Kanfenggou UHP metamorphic fragment does not appear to link with the Dabie-Sulu UHP and HP metamorphic belts along the orogen. There is no reason to assume the two UHP metamorphic belts us a single giant deep subduction and collision zone in the Central Orogenic Belt situated between the Yangtze and Sino-Korean cratons. Therefore, any dynamic model for the orogen must account

  17. Seat belt use during pregnancy in Iran: attitudes and practices

    Institute of Scientific and Technical Information of China (English)

    Mojgan Karbakhsh; Zahra Ershadi; Ali Khaji; Fatemeh Rahimi-Sharbaf

    2010-01-01

    Objective: Seat belt use during pregnancy reduces injury to the mother and her fetus. During recent years, the use of seat belts has been mandated by law in Iran. The purpose of this study was to determine the attitudes and practices of pregnant women regarding seat belt use.Methods: In this cross-sectional study, we asked 335 pregnant women at a hospital-based prenatal care clinic on the use of safety belt before and during pregnancy. SPSS version 13.0 was used for data analysis.Results: The mean age of study subjects was 27.3 years±5.3 years with the median of 27 years. Compared with the seat belt use before pregnancy, no change was detected in 48.7% of the women; seat belt use had increased in 17.5 %of them and decreased in 33.8 %. Eighty-one percent of women knew the correct placing of both lap belt and shoulder belt. Only 4% of women had received education on proper restraint use during pregnancy.Conclusions: The prevalence of seat belt use during pregnancy is lower than reports which are mostly from developed nations. The fact that about one-third of women have decreased their seat belt usage during pregnancy highlights the importance of education of mothers on this topic.

  18. Taxi driver seat belt wearing in Nanjing, China.

    Science.gov (United States)

    Routley, Virginia; Ozanne-Smith, Joan; Qin, Yu; Wu, Ming

    2009-01-01

    To determine and validate patterns of seat belt use and attitudes of taxi drivers on wearing a seat belt following national and provincial seat belt legislation in 2004-2005. Roadside daylight seat belt observation and interview survey methods were used, as well as observations from inside taxis during routine trips and a taxi driver focus group. The setting was Nanjing, Jiangsu Province, PR China in April of 2006 and 2007. Prevalence of seat belt use and attitudes to wearing a seat belt were determined, as were vehicle and driver characteristics, and comparisons with other motor-vehicle driver's seat belt use and attitudes. Taxi drivers interviewed were predominantly male and aged 30-39 years. They spent more hours per week in their vehicles and had more driving experience than other drivers. Over half (56.2%) of taxi drivers interviewed reported that they always wore seat belts, while observation of taxi drivers showed lower wearing rates (i.e., roadside observation was 43.8%, and observation from inside taxis was 36.2%). Belt tampering was a practice of 12-15% of taxi drivers. "Fine avoidance, safety, high speed and long trips" were given as important reasons for wearing and "feeling trapped and uncomfortable" for not wearing. Seat belt reminder signs in taxis were common (82.6% of taxis), but did not appear to impact on driver seat belt use. The four research methods found taxi drivers to have consistently low "correct wearing" rates. As in several other countries, taxi drivers are particularly resistant to seat belt use. Innovative strategies, including occupational health and safety approaches, may be required to achieve increased levels of seat belt use.

  19. Aortic ruptures in seat belt wearers.

    Science.gov (United States)

    Arajärvi, E; Santavirta, S; Tolonen, J

    1989-09-01

    Several investigations have indicated that rupture of the thoracic aorta is one of the leading causes of immediate death in victims of road traffic accidents. In Finland in 1983, 92% of front-seat passengers were seat belt wearers on highways and 82% in build-up areas. The mechanisms of rupture of the aorta have been intensively investigated, but the relationship between seat belt wearing and injury mechanisms leading to aortic rupture is still largely unknown. This study comprises 4169 fatally injured victims investigated by the Boards of Traffic Accident Investigation of Insurance Companies during the period 1972 to 1985. Chest injuries were recorded as the main cause of death in 1121 (26.9%) victims, 207 (5.0%) of those victims having worn a seat belt. Aortic ruptures were found at autopsy in 98 victims and the exact information of the location of the aortic tears was available in 68. For a control group, we analyzed 72 randomly chosen unbelted victims who had a fatal aortic rupture in similar accidents. The location of the aortic rupture in unbelted victims was more often in the ascending aorta, especially in drivers, whereas in seat belt wearers the distal descending aorta was statistically more often ruptured, especially in right-front passengers (p less than 0.05). The steering wheel predominated statistically as the part of the car estimated to have caused the injury in unbelted victims (37/72), and some interior part of the car was the most common cause of fatal thoracic impacts in seat belt wearers (48/68) (p less than 0.001). The mechanism of rupture of the aorta in the classic site just distal to the subclavian artery seems to be rapid deceleration, although complex body movements are also responsible in side impact collisions. The main mechanism leading to rupture of the ascending aorta seems to be severe blow to the bony thorax. This also often causes associated thoracic injuries, such as heart rupture and sternal fracture. Injuries in the ascending

  20. Media Monopoly in Brazil.

    Science.gov (United States)

    Amaral, Roberto; Guimaraes, Cesar

    1994-01-01

    Documents the process of broadcasting media development in Brazil, the failure of new technologies to produce democratization, and the barriers to democratization erected by monopolization and "metastasis." (SR)

  1. Denudation History and Paleogeographic Reconstruction of the Phanerozoic of southern Mantiqueira Province, Brazil

    Science.gov (United States)

    Jelinek, A. R.; Chemale, F., Jr.

    2012-12-01

    In this work we deal with the Phanerozoic history of the Southern Mantiqueira Province and adjacent areas after the orogen-collapse of the Brasiliano orogenic mountains in southern Brazil and Uruguay, based on thermocronological data (fission track and U-Th/He on apatite) and thermal history modelling. During the Paleozoic intraplate sedimentary basins formed mainly bordering the orogenic systems, and thus, these regions have not been overprinted by younger orogenic processes. In the Mesocenozoic this region was affected by later fragmentation and dispersal due to the separation of South America and Africa. Denudation history of both margins quantified on the basis of thermal history modeling of apatite fission track thermocronology indicates that the margin of southeastern Brazil and Uruguay presented a minimum 3.5 to 4.5 Km of denudation, which included the main exposure area of the Brasiliano orogenic belts and adjacent areas. The Phanerozoic evolution of the West Gondawana is thus recorded first by the orogenetic collapses of the Brasiliano and Pan-African belts, at that time formed a single mountain system in the Cambrian-Ordovician period. Subsequentlly, formed the intraplate basins as Paraná, in southeastern Brazil, and Congo and some records of the Table Mountains Group and upper section of Karoo units, in Southwestern Africa. In Permotriassic period, the collision of the Cape Fold Belt and Sierra de la Ventana Belt at the margins of the West Gondwana supercontinent resulted an elastic deformation in the cratonic areas, where the intraplate depositional basin occurred, and also subsidence and uplift of the already established Pan-African-Brasiliano Belts. Younger denudation events, due to continental margin uplift and basin subsidence, occurred during the rifting and dispersal of the South America and Africa plates, which can be very well defined by the integration of the passive-margin sedimentation of the Pelotas and Santos basins and apatite fission

  2. Modal analysis of coupled vibration of belt drive systems

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-jun; CHEN Li-qun

    2008-01-01

    The modal method is applied to analyze coupled vibration of belt drive systems. A belt drive system is a hybrid system consisting of continuous belts modeled as strings as well as discrete pulleys and a tensioner arm. The characteristic equation of the system is derived from the governing equation. Numerical results demenstrate the effects of the transport speed and the initial tension on natural frequencies.

  3. Past and current mangrove dynamics on the Bragança Peninsula, Northern Brazil

    OpenAIRE

    2003-01-01

    A wide mangrove belt of about 350 km occurs along the coast between the Amazon estuary and the Gurupi River (North Brazil). The main objective of this work was to identify and analyze the present effect of inundation frequency on system structure and of past changes in relative sea-level and climate, using tools such as palynology, radiocarbon dating, remote sensing and the Geographic Information Systems (GIS).The combination of topography and tidal regime data allowed, together with GIS tool...

  4. Period Determination of Six Main Belt Asteroids

    Science.gov (United States)

    Ferrero, Andrea

    2014-07-01

    Observations of six main-belt asteroids (MBA) produced lightcurve parameters of: 487 Venetia, P = 13.34 ± 0.01 h, A = 0.20 mag; 684 Hildburg, P = 15.89 ± 0.01 h, A = 0.22 mag; 772 Tanete, P = 8.629 ± 0.001 h, A = 0.18 mag.; 1181 Lilith, P = 15.04 ± 0.01 h, A = 0.11 mag.; 1246 Chaka, P = 25.44 ± 0.01 h, A = 0.25 mag.; and 2834 Christy Carol, P = 12.79 ± 0.01 h, A = 0.39 mag.

  5. Water activities in the Kerala Khondalite Belt

    Science.gov (United States)

    Chacko, Thomas; Kumar, G. R. Ravindra; Peterson, J. W.

    1988-01-01

    The author and colleagues presented their determinations of water activities in various granulite-facies rocks of the Kerala Khondalite Belt. Using mineral equilibria, thermodynamic data, and assumed geopressure-geotemperature conditions of 5.5 kbar and 750 C, they calculated uniformly low a(H2O) values of about 0.27 over a large geographic region. They suggested that these conditions were produced by the presence of abundant CO2-rich fluids, derived either from deeper levels or from metamorphic reactions involving graphite.

  6. Linear Motor for Drive of Belt Conveyor

    Directory of Open Access Journals (Sweden)

    Milan Krasl

    2006-01-01

    Full Text Available This paper introduces a novel approach on the design of a linear motor for drive of belt conveyor (LMBC. The motor is a simple combination of asynchronous motor in plane. The electromagnetic forces is one of the most important parameters of electrical machines. This parameter is necessary for the checking of the design. This paper describes several variants: linear motor with slots in platens, slots in one half of platens and optimization of slots. The electromagnetic force can be found with the help of a Finite Elements Method – based program. For solution was used QuickField program.

  7. Solar Neutrons and the Earth's Radiation Belts.

    Science.gov (United States)

    Lingenfelter, R E; Flamm, E J

    1964-04-17

    The intensity and spectrum of solar neutrons in the vicinity of the earth are calculated on the assumption that the low-energy protons recently detected in balloon and satellite flights are products of solar neutron decay. The solar-neutron flux thus obtained exceeds the global average cosmic-ray neutron leakage above 10 Mev, indicating that it may be an important source of both the inner and outer radiation belts. Neutron measurements in the atmosphere are reviewed and several features of the data are found to be consistent with the estimated solar neutron spectrum.

  8. Parametric resonances of convection belt system

    Institute of Scientific and Technical Information of China (English)

    Zhi-an YANG; Gao-feng LI

    2009-01-01

    Based on the Coriolis acceleration and the Lagrangian strain formula,a generalized equation for the transverse vibration system of convection belts is derived using Newton's second law.The method of multiple scales is directly applied to the governing equations,and an approximate solution of the primary parameter resonance of the system is obtained.The detuning parameter,cross-section area,elastic and viscoelastic parameters,and axial moving speed have a significant influences on the amplitudes of steady-state response and their existence boundaries.Some new dynamical phenomena are revealed.

  9. Orion revisited. III. The Orion Belt population

    Science.gov (United States)

    Kubiak, K.; Alves, J.; Bouy, H.; Sarro, L. M.; Ascenso, J.; Burkert, A.; Forbrich, J.; Großschedl, J.; Hacar, A.; Hasenberger, B.; Lombardi, M.; Meingast, S.; Köhler, R.; Teixeira, P. S.

    2017-02-01

    Aims: This paper continues our study of the foreground population to the Orion molecular clouds. The goal is to characterize the foreground population north of NGC 1981 and to investigate the star formation history in the large Orion star-forming region. We focus on a region covering about 25 square degrees, centered on the ɛ Orionis supergiant (HD 37128, B0 Ia) and covering the Orion Belt asterism. Methods: We used a combination of optical (SDSS) and near-infrared (2MASS) data, informed by X-ray (XMM-Newton) and mid-infrared (WISE) data, to construct a suite of color-color and color-magnitude diagrams for all available sources. We then applied a new statistical multiband technique to isolate a previously unknown stellar population in this region. Results: We identify a rich and well-defined stellar population in the surveyed region that has about 2000 objects that are mostly M stars. We infer the age for this new population to be at least 5 Myr and likely 10 Myr and estimate a total of about 2500 members, assuming a normal IMF. This new population, which we call the Orion Belt population, is essentially extinction-free, disk-free, and its spatial distribution is roughly centered near ɛ Ori, although substructure is clearly present. Conclusions: The Orion Belt population is likely the low-mass counterpart to the Ori OB Ib subgroup. Although our results do not rule out Blaauw's sequential star formation scenario for Orion, we argue that the recently proposed blue streams scenario provides a better framework on which one can explain the Orion star formation region as a whole. We speculate that the Orion Belt population could represent the evolved counterpart of an Orion nebula-like cluster. The catalog (Full Table A.1) is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/598/A124

  10. CHAOTIC BELT PHENOMENA IN NONLINEAR ELASTIC BEAM

    Institute of Scientific and Technical Information of China (English)

    张年梅; 杨桂通

    2003-01-01

    The chaotic motions of axial compressed nonlinear elastic beam subjected totransverse load were studied. The damping force in the system is nonlinear. Consideringmaterial and geometric nonlinearity, nonlinear governing equation of the system wasderived. By use of nonlinear Galerkin method, differential dynamic system was set up.Melnikov method was used to analyze the characters of the system. The results showed thatchaos may occur in the system when the load parameters P0 and f satisfy some conditions.The zone of chaotic motion was belted. The route from subharmonic bifurcation to chaoswas analyzed. The critical conditions that chaos occurs were determined.

  11. The Radiation Belt Storm Probes Mission: Advancing Our Understanding of the Earth's Radiation Belts

    Science.gov (United States)

    Sibeck, David; Kanekal, Shrikanth; Kessel, Ramona; Fox, Nicola; Mauk, Barry

    2012-01-01

    We describe NASA's Radiation Belt Storm Probe (RBSP) mission, whose primary science objective is to understand, ideally to the point of predictability, the dynamics of relativistic electrons and penetrating ions in the Earth's radiation belts resulting from variable solar activity. The overarching scientific questions addressed include: 1. the physical processes that produce radiation belt enhancement events, 2. the dominant mechanisms for relativistic electron loss, and 3. how the ring current and other geomagnetic processes affect radiation belt behavior. The RBSP mission comprises two spacecraft which will be launched during Fall 2012 into low inclination lapping equatorial orbits. The orbit periods are about 9 hours, with perigee altitudes and apogee radial distances of 600 km and 5.8 RE respectively. During the two-year primary mission, the spacecraft orbits precess once around the Earth and lap each other twice in each local time quadrant. The spacecraft are each equipped with identical comprehensive instrumentation packages to measure, electrons, ions and wave electric and magnetic fields. We provide an overview of the RBSP mission, onboard instrumentation and science prospects and invite scientific collaboration.

  12. Origins and Asteroid Main-Belt Stratigraphy for H-, L-, LL-Chondrite Meteorites

    Science.gov (United States)

    Binzel, Richard; DeMeo, Francesca; Burbine, Thomas; Polishook, David; Birlan, Mirel

    2016-10-01

    We trace the origins of ordinary chondrite meteorites to their main-belt sources using their (presumably) larger counterparts observable as near-Earth asteroids (NEAs). We find the ordinary chondrite stratigraphy in the main belt to be LL, H, L (increasing distance from the Sun). We derive this result using spectral information from more than 1000 near-Earth asteroids [1]. Our methodology is to correlate each NEA's main-belt source region [2] with its modeled mineralogy [3]. We find LL chondrites predominantly originate from the inner edge of the asteroid belt (nu6 region at 2.1 AU), H chondrites from the 3:1 resonance region (2.5 AU), and the L chondrites from the outer belt 5:2 resonance region (2.8 AU). Each of these source regions has been cited by previous researchers [e.g. 4, 5, 6], but this work uses an independent methodology that simultaneously solves for the LL, H, L stratigraphy. We seek feedback from the planetary origins and meteoritical communities on the viability or implications of this stratrigraphy.Methodology: Spectroscopic and taxonomic data are from the NASA IRTF MIT-Hawaii Near-Earth Object Spectroscopic Survey (MITHNEOS) [1]. For each near-Earth asteroid, we use the Bottke source model [2] to assign a probability that the object is derived from five different main-belt source regions. For each spectrum, we apply the Shkuratov model [3] for radiative transfer within compositional mixing to derive estimates for the ol / (ol+px) ratio (and its uncertainty). The Bottke source region model [2] and the Shkuratov mineralogic model [3] each deliver a probability distribution. For each NEA, we convolve its source region probability distribution with its meteorite class distribution to yield a likelihood for where that class originates. Acknowledgements: This work supported by the National Science Foundation Grant 0907766 and NASA Grant NNX10AG27G.References: [1] Binzel et al. (2005), LPSC XXXVI, 36.1817. [2] Bottke et al. (2002). Icarus 156, 399. [3

  13. Effects of driver characteristics on seat belt fit.

    Science.gov (United States)

    Reed, Matthew P; Ebert, Sheila M; Hallman, Jason J

    2013-11-01

    A laboratory study of posture and belt fit was conducted with 46 men and 51 women, 61% of whom were age 60 years or older and 32% age 70 years or older. In addition, 28% of the 97 participants were obese, defined as body mass index ≥ 30 kg/m^2. A mockup of a passenger vehicle driver's station was created and five belt anchorage configurations were produced by moving the buckle, outboard-upper (D-ring), and outboard-lower anchorages. An investigator recorded the three-dimensional locations of landmarks on the belt and the participant's body using a coordinate measurement machine. The location of the belt with respect to the underlying skeletal structures was analyzed, along with the length of belt webbing. Using linear regression models, an increase in age from 20 to 80 years resulted in the lap belt positioned 18 mm further forward relative to the pelvis, 26 mm greater lap belt webbing length, and 19 mm greater shoulder belt length. An increase in stature of 350 mm (approximately the range from 5th-percentile female to 95th-percentile male in the U.S. population) was associated with the lap belt 14 mm further forward relative to the pelvis, the shoulder belt 37 mm more outboard relative to the body centerline, and 38 mm less shoulder belt webbing length. Among the driver factors considered, body mass index had the greatest effects. An increase of BMI in 20 kg/m^2, which spans approximately the central 90% of U.S. adults, was associated with the lap belt being placed 102 mm further forward and 94 mm higher, relative to the pelvis, and increases in lap and shoulder belt webbing length of 276 and 258 mm, respectively. Gender did not have important effects on the analyzed belt fit measures after taking into account stature and body mass index. These results offer important considerations for future crash safety assessments and suggest that further research is needed to consider belt fit for older and obese occupants.

  14. 东南极普里兹带多期变质作用及其对罗迪尼亚和冈瓦纳超大陆重建的启示%Polymetamorphism of the Prydz Belt, East Antarctica: Implications for the reconstruction of the Rodinia and Gondwana supercontinents

    Institute of Scientific and Technical Information of China (English)

    刘晓春

    2009-01-01

    The Prydz Belt in East Antarctica is a typical polymetmorphic belt that experienced Grenvillian and Pan-African high-grade metamorphism. The tectonic evolution of the belt is closely related to the formation of the supercontinents Rodinia and Gondwana. New petrological and geochronological data suggest that the Grenvillian metamorphism involving two episodes at>970Ma and 930~900Ma spreads over the main part of the Prydz Belt. Metamorphic peak during this peroid reaches relatively high temperature and high pressure granulite facies conditions. The Grenvillian orogenesis underwent long-term magmatic accretion along an active continental margin or arc and the final collision of Indian, Kalahari craton and the western portion of East Antarctica, which forms an important part of the Rodinia supercontinent. The Pan-African metamorphism in the Prydz Belt reaches high-pressure granulite facies conditions, accompaning a near isothermal decompressional P-T path, rather than low-to medium-pressure granulite facies conditions as previously thought. The widespread Grenvillian metamorphism in the Prydz Belt indicates that the Pan-African tectonothermal event may have developed on the eastern margin of the Indo-Antarctica continental block, and the real suture should be located southeastwards of the present Prydz Belt. Further to the Antarctic inland, it might pass through the Gamburtsev Subglacial Mountains. The precise dating for different rock types reveals that the Pan-African orogenesis of the Prydz Belt commenced at 570Ma and lasted to 490Ma, which is roughly contemporaneous with the late collisional stage in the East African Orogen. Therefore, the final assembly of Gondwana may have been completed by the collision of West Gondwana, Indo-Antarctica and Australo-Antarctica continental blocks during the same time.%东南极普里兹带是一条经受格林维尔期和泛非期高级构造热事件影响的多相变质带,其构造演化过程与罗迪尼亚和冈瓦纳超

  15. SEAT BELT USE INTENTION AMONG BRAZILIAN UNDERGRADUATE STUDENTS/ INTENCIÓN DE USO DEL CINTURÓN DE SEGURIDAD EN ESTUDIANTES UNIVERSITARIOS BRASILEÑOS/ INTENÇÃO DE USO DO CINTO DE SEGURANÇA EM ESTUDANTES UNIVERSITÁRIOS BRASILEIROS

    Directory of Open Access Journals (Sweden)

    Alessandra Bianchi

    2012-12-01

    Full Text Available The objectives of this study were to explore selfreported seat belt use and group differences in different scenarios in a Brazilian sample and research the variables related to it. 120 college students answered a questionnaire with variables from the theory of planned behavior in order to evaluate the intention of seat belt use among car occupants. Results indicated that attitude and intention were the variables that most contributed to explaining seat belt use. Intention was highly correlated with seat belt use, and attitude was correlated with intention. Seat belt use was more frequent among drivers and taxi passengers, but not among front and rear seat passengers. The article discusses the implications of the findings for possible interventions to encourage the use of seat belts among drivers and passengers.

  16. Maximum covariance analysis to identify intraseasonal oscillations over tropical Brazil

    Science.gov (United States)

    Barreto, Naurinete J. C.; Mesquita, Michel d. S.; Mendes, David; Spyrides, Maria H. C.; Pedra, George U.; Lucio, Paulo S.

    2017-09-01

    A reliable prognosis of extreme precipitation events in the tropics is arguably challenging to obtain due to the interaction of meteorological systems at various time scales. A pivotal component of the global climate variability is the so-called intraseasonal oscillations, phenomena that occur between 20 and 100 days. The Madden-Julian Oscillation (MJO), which is directly related to the modulation of convective precipitation in the equatorial belt, is considered the primary oscillation in the tropical region. The aim of this study is to diagnose the connection between the MJO signal and the regional intraseasonal rainfall variability over tropical Brazil. This is achieved through the development of an index called Multivariate Intraseasonal Index for Tropical Brazil (MITB). This index is based on Maximum Covariance Analysis (MCA) applied to the filtered daily anomalies of rainfall data over tropical Brazil against a group of covariates consisting of: outgoing longwave radiation and the zonal component u of the wind at 850 and 200 hPa. The first two MCA modes, which were used to create the { MITB}_1 and { MITB}_2 indices, represent 65 and 16 % of the explained variance, respectively. The combined multivariate index was able to satisfactorily represent the pattern of intraseasonal variability over tropical Brazil, showing that there are periods of activation and inhibition of precipitation connected with the pattern of MJO propagation. The MITB index could potentially be used as a diagnostic tool for intraseasonal forecasting.

  17. Fading of Jupiter's South Equatorial Belt

    Science.gov (United States)

    Sola, Michael A.; Orton, Glenn; Baines, Kevin; Yanamandra-Fisher, Padma

    2011-01-01

    One of Jupiter's most dominant features, the South Equatorial Belt, has historically gone through a "fading" cycle. The usual dark, brownish clouds turn white, and after a period of time, the region returns to its normal color. Understanding this phenomenon, the latest occurring in 2010, will increase our knowledge of planetary atmospheres. Using the near infrared camera, NSFCAM2, at NASA's Infrared Telescope Facility in Hawaii, images were taken of Jupiter accompanied by data describing the circumstances of each observation. These images are then processed and reduced through an IDL program. By scanning the central meridian of the planet, graphs were produced plotting the average values across the central meridian, which are used to find variations in the region of interest. Calculations using Albert4, a FORTRAN program that calculates the upwelling reflected sunlight from a designated cloud model, can be used to determine the effects of a model atmosphere due to various absorption, scattering, and emission processes. Spectra that were produced show ammonia bands in the South Equatorial Belt. So far, we can deduce from this information that an upwelling of ammonia particles caused a cloud layer to cover up the region. Further investigations using Albert4 and other models will help us to constrain better the chemical make up of the cloud and its location in the atmosphere.

  18. Distribution of dust from Kuiper belt objects

    CERN Document Server

    Gorkavyi, N N; Taidakova, T; Mather, J C; Gorkavyi, Nick N.; Ozernoy, Leonid M.; Taidakova, Tanya; Mather, John C.

    2000-01-01

    (Abridged) Using an efficient computational approach, we have reconstructed the structure of the dust cloud in the Solar system between 0.5 and 100 AU produced by the Kuiper belt objects. Our simulations offer a 3-D physical model of the `kuiperoidal' dust cloud based on the distribution of 280 dust particle trajectories produced by 100 known Kuiper belt objects ; the resulting 3-D grid consists of $1.9\\times 10^6$ cells containing $1.2\\times 10^{11}$ particle positions. The following processes that influence the dust particle dynamics are taken into account: 1) gravitational scattering on the eight planets (neglecting Pluto); 2) planetary resonances; 3) radiation pressure; and 4) the Poynting-Robertson (P-R) and solar wind drags. We find the dust distribution highly non-uniform: there is a minimum in the kuiperoidal dust between Mars and Jupiter, after which both the column and number densities of kuiperoidal dust sharply increase with heliocentric distance between 5 and 10 AU, and then form a plateau betwee...

  19. Chaotic Diffusion of Resonant Kuiper Belt Objects

    CERN Document Server

    Tiscareno, Matthew S

    2008-01-01

    We carried out extensive numerical orbit integrations to probe the long-term chaotic dynamics of the two strongest mean motion resonances of Neptune in the Kuiper belt, the 3:2 (Plutinos) and 2:1 (Twotinos). Our primary results include a computation of the relative volumes of phase space characterized by large- and small-resonance libration amplitudes, and maps of resonance stability measured by mean chaotic diffusion rate. We find that Neptune's 2:1 resonance has weaker overall long-term stability than the 3:2 -- only 15% of Twotinos are projected to survive for 4 Gyr, compared to 28% of Plutinos. We find that Pluto has only a modest effect, causing a ~4% decrease in the Plutino population that survives to 4 Gyr. Given current observational estimates, we conclude that the primordial populations of Plutinos and Twotinos formerly made up more than half the population of the classical and resonant Kuiper Belt. We also conclude that Twotinos were originally nearly as numerous as Plutinos, consistent with models ...

  20. The Dynamical Evolution of the Asteroid Belt

    CERN Document Server

    Morbidelli, Alessandro; O'Brien, David P; Minton, David A; Bottke, William F

    2015-01-01

    The asteroid belt is the leftover of the original planetesimal population in the inner solar system. However, currently the asteroids have orbits with all possible values of eccentricities and inclinations compatible with long-term dynamical stability, whereas the initial planetesimal orbits should have been quasi-circular and almost co-planar. The total mass in the asteroid population is a small fraction of that existing primordially. Also, asteroids with different chemical/mineralogical properties are not ranked in an orderly manner with mean heliocentric distance as one could expect from the existence of a radial gradient of the temperature in the proto-planetary disk, but they are partially mixed. These properties show that the asteroid belt has been severely sculpted by one or a series of processes during its lifetime. This paper reviews the processes that have been proposed so far, discussing the properties that they explain and the problems that they are confronted with. Emphasis is paid to the interpl...

  1. Young Stellar Objects in the Gould Belt

    CERN Document Server

    Dunham, Michael M; Evans, Neal J; Broekhoven-Fiene, Hannah; Cieza, Lucas; Di Francesco, James; Gutermuth, Robert A; Harvey, Paul M; Hatchell, Jennifer; Heiderman, Amanda; Huard, Tracy; Johnstone, Doug; Kirk, Jason M; Matthews, Brenda C; Miller, Jennifer F; Peterson, Dawn E; Young, Kaisa E

    2015-01-01

    We present the full catalog of Young Stellar Objects (YSOs) identified in the 18 molecular clouds surveyed by the Spitzer Space Telescope "cores to disks" (c2d) and "Gould Belt" (GB) Legacy surveys. Using standard techniques developed by the c2d project, we identify 3239 candidate YSOs in the 18 clouds, 2966 of which survive visual inspection and form our final catalog of YSOs in the Gould Belt. We compile extinction corrected SEDs for all 2966 YSOs and calculate and tabulate the infrared spectral index, bolometric luminosity, and bolometric temperature for each object. We find that 326 (11%), 210 (7%), 1248 (42%), and 1182 (40%) are classified as Class 0+I, Flat-spectrum, Class II, and Class III, respectively, and show that the Class III sample suffers from an overall contamination rate by background AGB stars between 25% and 90%. Adopting standard assumptions, we derive durations of 0.40-0.78 Myr for Class 0+I YSOs and 0.26-0.50 Myr for Flat-spectrum YSOs, where the ranges encompass uncertainties in the ado...

  2. Modulation of forelimb and hindlimb muscle activity during quadrupedal tied-belt and split-belt locomotion in intact cats.

    Science.gov (United States)

    Frigon, A; Thibaudier, Y; Hurteau, M-F

    2015-04-02

    The modulation of the neural output to forelimb and hindlimb muscles when the left and right sides step at different speeds from one another in quadrupeds was assessed by obtaining electromyography (EMG) in seven intact adult cats during split-belt locomotion. To determine if changes in EMG during split-belt locomotion were modulated according to the speed of the belt the limb was stepping on, values were compared to those obtained during tied-belt locomotion (equal left-right speeds) at matched speeds. Cats were chronically implanted for EMG, which was obtained from six muscles: biceps brachii, triceps brachii, flexor carpi ulnaris, sartorius, vastus lateralis and medial gastrocnemius. During tied-belt locomotion, cats stepped from 0.4 to 1.0m/s in 0.1m/s increments whereas during split-belt locomotion, cats stepped with left-right speed differences of 0.1 to 0.4m/s in 0.1m/s increments. During tied-belt locomotion, EMG burst durations and mean EMG amplitudes of all muscles respectively decreased and increased with increasing speed. During split-belt locomotion, there was a clear differential modulation of the EMG patterns between flexors and extensors and between the slow and fast sides. Changes in the EMG pattern of some muscles could be explained by the speed of the belt the limb was stepping on, while in other muscles there were clear dissociations from tied-belt values at matched speeds. Therefore, results show that EMG patterns during split-belt locomotion are modulated to meet task requirements partly via signals related to the stepping speed of the homonymous limb and from the other limbs.

  3. Ambient Response Analysis of the Great Belt Bridge

    DEFF Research Database (Denmark)

    Brincker, Rune; Frandsen, J. B.; Andersen, P.

    2000-01-01

    In this paper an ambient response analysis of the Great Belt Bridge is presented. The Great Belt Bridge is one of the largest suspension bridges in the world, and the analysis was carried out in order to investigate the possibilities of estimating reliable damping values from the ambient response...

  4. Increasing of horizontal velocity of particles leaving a belt conveyor

    Directory of Open Access Journals (Sweden)

    Tavares Abraão

    2017-01-01

    Full Text Available We investigate the transport of granular materials by a conveyor belt via numerical simulations. We report an unusual increasing of particles horizontal velocity when they leave the belt and initiate free-fall. Using Discrete Elements Method, the mechanism underlying this phenomenon were investigated, and a study on how particle and system properties influences this effect were conducted.

  5. Teaching Taekwondo in Physical Education: Incorporating the Color Belt System

    Science.gov (United States)

    Oh, Hyun-Ju; Hannon, James C.; Banks, Aaron

    2006-01-01

    Taekwondo is an excellent lifetime physical activity that provides both physical and mental benefits to its participants. The color belt system may be creatively used in physical education to encourage improvement in all learning domains. This article provides information on incorporating the color belt system into physical education, and provides…

  6. Respiratory Belt Transducer Constructed Using a Singing Greeting Card Beeper

    Science.gov (United States)

    Bhaskar, Anand; Subramani, Selvam; Ojha, Rajdeep

    2013-01-01

    An article by Belusic and Zupancic described the construction of a finger pulse sensor using a singing greeting card beeper. These authors felt that this beeper made of piezoelectric material could be easily modified to function as a respiratory belt transducer to monitor respiratory movements. Commercially available respiratory belt transducers,…

  7. Teaching Taekwondo in Physical Education: Incorporating the Color Belt System

    Science.gov (United States)

    Oh, Hyun-Ju; Hannon, James C.; Banks, Aaron

    2006-01-01

    Taekwondo is an excellent lifetime physical activity that provides both physical and mental benefits to its participants. The color belt system may be creatively used in physical education to encourage improvement in all learning domains. This article provides information on incorporating the color belt system into physical education, and provides…

  8. Respiratory Belt Transducer Constructed Using a Singing Greeting Card Beeper

    Science.gov (United States)

    Bhaskar, Anand; Subramani, Selvam; Ojha, Rajdeep

    2013-01-01

    An article by Belusic and Zupancic described the construction of a finger pulse sensor using a singing greeting card beeper. These authors felt that this beeper made of piezoelectric material could be easily modified to function as a respiratory belt transducer to monitor respiratory movements. Commercially available respiratory belt transducers,…

  9. Safety belt usage in Finland and in other Nordic countries.

    NARCIS (Netherlands)

    Valtonen, J.

    1992-01-01

    Legislation has played a significant role in increasing safety belt usage in Finland and in the other Nordic countries. Publicity and enforcement have, however, been required to support the legislation. The development of safety belt regulations has been nearly similar in all these countries, both i

  10. Canadian seat belt wearing rates, promotion programs, and future directions.

    NARCIS (Netherlands)

    Grant, B.A.

    1992-01-01

    On the basis of a national driver seat belt survey conducted in Canada each year, the most important results are presented. A number of programmes for increasing seat belt use has been evaluated in Canada. Finally, a description is given of some of the current and planned activities within Canada wh

  11. HUMAN NEURONAL INTERLIMB COORDINATION DURING SPLIT-BELT LOCOMOTION

    NARCIS (Netherlands)

    DIETZ, [No Value; ZIJLSTRA, W; DUYSENS, J

    1994-01-01

    Human interlimb coordination and the adaptations in leg muscle activity were studied during walking on a treadmill with split belts. Four different belt speeds (0.5, 1.0, 1.5, 2.0 m/s) were offered in all possible combinations for the left and right leg. Subjects adapted automatically to a differenc

  12. Human neuronal interlimb coordination during split-belt locomotion

    NARCIS (Netherlands)

    Dietz, V.; Zijlstra, W.G.; Duysens, J.E.J.

    1994-01-01

    Human interlimb coordination and the adaptations in leg muscle activity were studied during walking on a treadmill with split belts. Four different belt speeds (0.5, 1.0, 1.5, 2.0 m/s) were offered in all possible combinations for the left and right leg. Subjects adapted automatically to a differenc

  13. Biomechanical considerations for abdominal loading by seat belt pretensioners.

    Science.gov (United States)

    Rouhana, Stephen W; El-Jawahri, Raed E; Laituri, Tony R

    2010-11-01

    While seat belts are the most effective safety technology in vehicles today, there are continual efforts in the industry to improve their ability to reduce the risk of injury. In this paper, seat belt pretensioners and current trends towards more powerful systems were reviewed and analyzed. These more powerful systems may be, among other things, systems that develop higher belt forces, systems that remove slack from belt webbing at higher retraction speeds, or both. The analysis started with validation of the Ford Human Body Finite Element Model for use in evaluation of abdominal belt loading by pretensioners. The model was then used to show that those studies, done with lap-only belts, can be used to establish injury metrics for tests done with lap-shoulder belts. Then, previously-performed PMHS studies were used to develop AIS 2+ and AIS 3+ injury risk curves for abdominal interaction with seat belts via logistic regression and reliability analysis with interval censoring. Finally, some considerations were developed for a possible laboratory test to evaluate higher-powered pretensioners.

  14. An Evaluation of the Seat Belt Education Campaign.

    Science.gov (United States)

    Rochon, James

    A seat belt education campaign conducted in Canada to dispel myths surrounding seat belts and promote a better understanding of their functions was evaluated. Two telephone surveys, each comprised of 4,000 respondents, were conducted. The first was done immediately before the campaign and the second immediately succeeding the campaign. Also, a…

  15. Compliance with Seat Belt Use in Makurdi, Nigeria: An ...

    African Journals Online (AJOL)

    2011-03-23

    Mar 23, 2011 ... has been estimated that using seat belts can reduce the risk ... 24‑h direct observational study of seat belt usage among vehicle occupants in Makurdi, Benue. State ... In Nigeria, the Federal Road Safety Corps (FRSC) was.

  16. Brazil : Eradicating Child Labor in Brazil

    OpenAIRE

    World Bank

    2001-01-01

    The report reviews evidence of child labor in Brazil, and the Government's efforts to eradicate its worst forms, by examining background assessments of ongoing programs for its prevention. It seeks to identify promising strategies, addressing the needs of highly vulnerable children in urban areas, engaged in activities such as drug commerce, prostitution, or other dangerous activities. One...

  17. Aedes albopictus em área rural do Brasil e implicações na transmissão de febre amarela silvestre Aedes albopictus in rural zone of Brazil and its implication in the sylvatic yellow fever transmission

    Directory of Open Access Journals (Sweden)

    Almério de Castro Gomes

    1999-02-01

    Full Text Available Durante estudos ecológicos sobre mosquitos anofelíneos no município de Bataguassu, Estado de Mato Grosso do Sul, foram encontradas larvas e adultos de Aedes albopictus. Pela primeira vez sua introdução ocorre numa área enzoótica do vírus selvático da febre amarela no Brasil. Isto sugere risco potencial para transferência desse vírus para área urbana infestada com Aedes aegypti.Larvae and adult forms of Aedes albopictus were found during ecological study of anopheline mosquitos in the rural zone of the state of Mato Grosso do Sul in Brazil. This occurrence was registered, for the first time in Brazil, in an enzoootic area if sylvatic yellow fever virus. This implies a potential risk of the transfer of this virus to an urban area infested with Aedes aegypti.

  18. Experimental Measurements of Belt Gears in Newly Developed Device

    Directory of Open Access Journals (Sweden)

    Jozef Mascenik

    2016-05-01

    Full Text Available The paper deals with the alternative of determination of state of the belt gear. To realize themeasurements a newly developed device was designed for measurement and diagnostics of the belt gears. The main task is to detect the V-belt slip expressed by the coefficient of elastic creep and of specific slip with a measuring device. The measurements regarding can be performed if input revolutions of the electric motor and torque of the belt gear are constant whereas the tensioning force of the belt gear changes. It is also possible to perform the measurement if the input revolutions of the electric motor and the tensioning forces are constant and the torque changes.

  19. Nonoperative management of pediatric aortic injury with seat belt syndrome.

    Science.gov (United States)

    Parrish, Dan W; Barnhorst, Amanda; Trebska-McGowan, Katarzyna; Amendola, Michael; Haynes, Jeffrey H

    2015-08-01

    "Seat belt syndrome" was first described by Garret and Braunstein in 1962. The syndrome involves skin and abdominal wall ecchymosis (seat belt sign) intra-abdominal solid organ and visceral injuries, as well as Chance fractures (compression and/or wedging deformity of the anterior portion of the vertebral body with disruption or fracture of the posterior elements, generally at L1-L3). We present a case of a 12-year-old male involved in a high-speed motor vehicle collision wearing only a lap belt resulting in seat belt syndrome, with disruption of the abdominal wall, mesenteric avulsion with multiple intestinal perforations, abdominal aortic dissection, and an L2 Chance fracture with cord transection. Intraoperative decision making is outlined with this scenario of complex injuries, and the literature of seat belt syndrome associated with blunt aortic injuries and its management is reviewed.

  20. Survey of current situation in radiation belt modeling

    Science.gov (United States)

    Fung, Shing F.

    2004-01-01

    The study of Earth's radiation belts is one of the oldest subjects in space physics. Despite the tremendous progress made in the last four decades, we still lack a complete understanding of the radiation belts in terms of their configurations, dynamics, and detailed physical accounts of their sources and sinks. The static nature of early empirical trapped radiation models, for examples, the NASA AP-8 and AE-8 models, renders those models inappropriate for predicting short-term radiation belt behaviors associated with geomagnetic storms and substorms. Due to incomplete data coverage, these models are also inaccurate at low altitudes (e.g., radiation data from modern space missions and advancement in physical modeling and data management techniques have now allowed the development of new empirical and physical radiation belt models. In this paper, we will review the status of modern radiation belt modeling. Published by Elsevier Ltd on behalf of COSPAR.

  1. Landscape distribution characteristics of northern foothill belts of Tianshan Mountains

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The foothill belts of Tianshan Mountains are about 280 km long and 60 km wide, and the study area extends from Kuitun city to Fukang city. They are transitional belts between mountains and plains, appearing in three rows of folds with different morphologies and their age becoming younger from south to north. Based on GIS and RS methods, and materials of the previous researchers, this paper deals with the genetics of the foothill belts and their landscape features resulting from folding by neotectonic movements, and also describes their length, width and slope by remote sensing image interpretation. The characteristics of the foothill belts are found to be very important for the surrounding environment by preventing groundwater from flowing into plains, changing groundwater, increasing flow of surface runoff, in addition to their roles in protecting the surrounding environment. The purpose of this paper is to provide an in-depth understanding of the foothill belts and influence on its surrounding environment.

  2. Detecting extrasolar asteroid belts through their microlensing signatures

    Science.gov (United States)

    Lake, Ethan; Zheng, Zheng; Dong, Subo

    2017-02-01

    We propose that extrasolar asteroid belts can be detected through their gravitational microlensing signatures. Asteroid belt + star lens systems create so-called 'pseudo-caustics', regions in the source plane where the magnification exhibits a finite but discontinuous jump. These features allow such systems to generate distinctive signatures in the microlensing light curves for a wide range of belt configurations, with source trajectories as far as tenths of the Einstein ring radius from the centre of the lens. Sample light curves for a range of asteroid belt parameters are presented. In the near future, space-based microlensing surveys like WFIRST, which will have the power of detecting per cent-level changes in microlensing light curves even with subminute exposure times, may be able to discover extrasolar asteroid belts with masses of the order of an earth mass.

  3. Heads for shifting new generation of belt conveyors

    Energy Technology Data Exchange (ETDEWEB)

    Dembinski, M.

    1980-03-01

    New design of belt conveyors characterized by rigid section joints and conveyor to pontoon joints significantly influences loading of machines shifting belt conveyors to new locations. A new belt conveyor shifting machine head design, called SGP12 (selflocking head for vertical loads up to 120 kN) is described. Design is shown in 4 diagrams. It is stressed that in the SGP-12 the force clamping rollers on rails is automatically controlled depending on the height to which the rails are lifted. Clamping force is proportional to the height. This means of controlling the clamping force excludes damage to the head and reduces wear of the rollers. The SGP12 is, therefore, superior to the GP-12 shifting head of similar capacity. It is suggested that the SGP-12 is characterized by simple design, easier operation, higher reliability and greater safety. The SGP-12 can be used to shift belt conveyors with belts 2250 mm to 3000 mm wide.

  4. Radiation-belt dynamics during solar minimum. Technical report

    Energy Technology Data Exchange (ETDEWEB)

    Gussenhoven, M.S.; Mullen, E.G.; Holeman, E.

    1989-12-01

    Two types of temporal variation in the radiation belts are studied using low altitude data taken onboard the DMSP F7 satellite: those associated with the solar cycle and those associated with large magnetic storm effects. Over a three-year period from 1984 to 1987 and encompassing solar minimum, the protons in the heart of the inner belt increased at a rate of approximately 6% per year. Over the same period, outer zone electron enhancements declined both in number and peak intensity. During the large magnetic storm of February 1986, following the period of peak ring current intensity, a second proton belt with energies up to 50 MeV was found at magnetic latitudes between 45 deg. and 55 deg. The belt lasted for more than 100 days. The slot region between the inner and outer electron belts collapsed by the merging of the two populations and did not reform for 40 days.

  5. A Study on the Vibration of the Charging Belt in an Electrostatic Accelerator

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The vibration of the charging belt in an electrostatic accelerator has intense influences on the accelerator operation. A calculating model was set up in this paper to study the belt vibration. The results show that the belt tension, belt velocity and belt current all contribute to the belt vibration. There is an optimal relationship among the three factors by which the belt would run most smoothly. There exists a minimum value of optimal tension for various belt velocities. The vibrating frequency of the is generally around several Hz.

  6. Equilibria and Free Vibration of a Two-Pulley Belt-Driven System with Belt Bending Stiffness

    Directory of Open Access Journals (Sweden)

    Jieyu Ding

    2014-01-01

    Full Text Available Nonlinear equilibrium curvatures and free vibration characteristics of a two-pulley belt-driven system with belt bending stiffness and a one-way clutch are investigated. With nonlinear dynamical tension, the transverse vibrations of the translating belt spans and the rotation motions of the pulleys and the accessory shaft are coupled. Therefore, nonlinear piecewise discrete-continuous governing equations are established. Considering the bending stiffness of the translating belt spans, the belt spans are modeled as axially moving beams. The pattern of equilibria is a nontrivial solution. Furthermore, the nontrivial equilibriums of the dynamical system are numerically determined by using two different approaches. The governing equations of the vibration near the equilibrium solutions are derived by introducing a coordinate transform. The natural frequencies of the dynamical systems are studied by using the Galerkin method with various truncations and the differential and integral quadrature methods. Moreover, the convergence of the Galerkin truncation is investigated. Numerical results reveal that the study needs 16 terms after truncation in order to determine the free vibration characteristics of the pulley-belt system with the belt bending stiffness. Furthermore, the first five natural frequencies are very sensitive to the bending stiffness of the translating belt.

  7. Main-belt comets: sublimation-driven activity in the asteroid belt

    CERN Document Server

    Hsieh, Henry H

    2015-01-01

    Our knowledge of main-belt comets (MBCs), which exhibit comet-like activity likely due to the sublimation of volatile ices, yet orbit in the main asteroid belt, has increased greatly since the discovery of the first known MBC, 133P/Elst-Pizarro, in 1996, and their recognition as a new class of solar system objects after the discovery of two more MBCs in 2005. I review work that has been done over the last 10 years to improve our understanding of these enigmatic objects, including the development of systematic discovery methods and diagnostics for distinguishing MBCs from disrupted asteroids (which exhibit comet-like activity due to physical disruptions such as impacts or rotational destabilization). I also discuss efforts to understand the dynamical and thermal properties of these objects.

  8. The JCMT Gould Belt Survey: Understanding the influence of molecular outflows on Gould Belt clouds

    CERN Document Server

    Drabek-Maunder, E; Buckle, J V; Di Francesco, J; Richer, J

    2015-01-01

    Using JCMT Gould Belt Survey data from CO J=3-2 isotopologues, we present a meta-analysis of the outflows and energetics of star-forming regions in several Gould Belt clouds. The majority of the regions are strongly gravitationally bound. There is evidence that molecular outflows transport large quantities of momentum and energy. Outflow energies are at least 20 per cent of the total turbulent kinetic energies in all of the regions studied and greater than the turbulent energy in half of the regions. However, we find no evidence that outflows increase levels of turbulence, and there is no correlation between the outflow and turbulent energies. Even though outflows in some regions contribute significantly to maintaining turbulence levels against dissipation, this relies on outflows efficiently coupling to bulk motions. Other mechanisms (e.g. supernovae) must be the main drivers of turbulence in most if not all of these regions.

  9. Audiology in Brazil.

    Science.gov (United States)

    Bevilacqua, Maria Cecilia; Novaes, Beatriz Caiuby; Morata, Thais C

    2008-02-01

    The profession of audiology took root in Brazil nearly a half a century ago and has since blossomed into a flourishing, well-developed field. Currently, audiologists in Brazil work at private institutions, including private medical practices and dedicated speech and hearing clinics. They are also employed in a wide array of public institutions, including community clinics, elementary schools, colleges, and universities. In both the private sector and health clinics, audiologists perform diagnostic evaluations of auditory and vestibular disorders, select and fit hearing aids, and provide aural rehabilitation. At the public level, they assist with workers' health programs, dispense hearing aids, and aural rehabilitation. There is always room to grow, however, and the future of audiology in Brazil holds both challenges and opportunity. The following article will sketch the development of audiology training and practice in Brazil, provide a picture of how the field stands today, and summarize the unique challenges which the profession faces in this large and diverse nation.

  10. Ambient tremors in a collisional orogenic belt

    Science.gov (United States)

    Chuang, Lindsay Yuling; Chen, Kate Huihsuan; Wech, Aaron G.; Byrne, Timothy; Peng, Wei

    2014-01-01

    Deep-seated tectonic tremors have been regarded as an observation tied to interconnected fluids at depth, which have been well documented in worldwide subduction zones and transform faults but not in a collisional mountain belt. In this study we explore the general features of collisional tremors in Taiwan and discuss the possible generation mechanism. In the 4 year data, we find 231 ambient tremor episodes with durations ranging from 5 to 30 min. In addition to a coseismic slip-induced stress change from nearby major earthquake, increased tremor rate is also highly correlated with the active, normal faulting earthquake swarms at the shallower depth. Both the tremor and earthquake swarm activities are confined in a small, area where the high attenuation, high thermal anomaly, the boundary between high and low resistivity, and localized veins on the surfaces distributed, suggesting the involvement of fluids from metamorphic dehydration within the orogen.

  11. NASA's Radiation Belt Storm Probe Mission

    Science.gov (United States)

    Sibeck, David G.

    2011-01-01

    NASA's Radiation Belt Storm Probe (RBSP) mission, comprising two identically-instrumented spacecraft, is scheduled for launch in May 2012. In addition to identifying and quantifying the processes responsible for energizing, transporting, and removing energetic particles from the Earth's Van Allen radiation, the mission will determine the characteristics of the ring current and its effect upon the magnetosphere as a whole. The distances separating the two RBSP spacecraft will vary as they move along their 1000 km altitude x 5.8 RE geocentric orbits in order to enable the spacecraft to separate spatial from temporal effects, measure gradients that help identify particle sources, and determine the spatial extent of a wide array of phenomena. This talk explores the scientific objectives of the mission and the manner by which the mission has been tailored to achieve them.

  12. East Central Uplift Belt of Junggar Basin

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    @@ Mosuowandong ( Z3 ) and Dongdaohaizi (Z4) are two bidding blocks located in the east part of central uplift Belt, the hinterland of Junggar Basin. Xinjiang Uygur Autonomous Region. It totally covers an area of 8 100km2. Topographically, the two blocks are quite gentle with elevation of 380-400 m on average. The north part is desert and the south area is good for farming. There are three ephemeral streams flowing across the desert from south to north. The ground water is buried at the depth ranging from 6 to 8 m. It belongs to continental climate with the annually averaged precipitation of 80 mm. The traffic is rather convenient in the south part of both blocks. There are several sand-paved roads and two asphalt roads connected with the highway from Karamay to Urumqi City.

  13. Subsurface Meridional Circulation in the Active Belts

    CERN Document Server

    Hernandez, I Gonzalez; Hill, F; Howe, R; Komm, R

    2008-01-01

    Temporal variations of the subsurface meridional flow with the solar cycle have been reported by several authors. The measurements are typically averaged over periods of time during which surface magnetic activity existed in the regions were the velocities are calculated. The present work examines the possible contamination of these measurements due to the extra velocity fields associated with active regions plus the uncertainties in the data obtained where strong magnetic fields are present. We perform a systematic analysis of more than five years of GONG data and compare meridional flows obtained by ring-diagram analysis before and after removing the areas of strong magnetic field. The overall trend of increased amplitude of the meridional flow towards solar minimum remains after removal of large areas associated with surface activity. We also find residual circulation toward the active belts that persist even after the removal of the surface magnetic activity, suggesting the existence of a global pattern o...

  14. Oscillations control of a transmission belt by Excitation Clipping using Clutch Clamping Control (E4C)

    Science.gov (United States)

    Temporelli, Robin; Micheau, Philippe

    2017-04-01

    A transmission belt deals with non-linear phenomena such as parametric excitations that can bring the belt in an instability region resulting in large transverse oscillations. These oscillations can cause belt life deflection, noise and unexpected vibration on its environment. The present study proposes a new strategy to control oscillations of a transmission belt subject to periodic tension fluctuations. Indeed, for a transmission belt, periodic torque fluctuations cause periodic belt tension fluctuations which can be a source of excitation for the belt and resulting in belt oscillations under certain conditions. The presence of a clutch between the belt end-point and the source of torque fluctuations offers a means to clip torque fluctuations and thus to clip belt excitation. In keeping with this notion, belt oscillations can be controlled by an Excitation Clipping using Clutch Clamping Control (E4C) strategy. Through an example of a transmission belt subject to periodic tension fluctuations, the E4C strategy is presented and a new analytical model of belt behavior with its E4C strategy is constructed. Free belt oscillations (E4C is not activated) and controlled belt oscillations (E4C is activated) are observed through an experimental setup and predicted owing to the new analytical model. Finally, the E4C strategy leads to frequency unlocking that successfully removes belt oscillations. This new analytical model furthermore provides an accurate prediction of belt behavior with its E4C strategy.

  15. Geometry, kinematics and evolution of the Tongbai orogenic belt

    Institute of Scientific and Technical Information of China (English)

    HUANG Shaoying; XU Bei; WANG Changqiu; ZHAN Sheng; DENG Rongjing

    2006-01-01

    The Tongbai orogenic belt (TOB) is composed of six tectonic units. From south to north these units are: Tongbai gneiss rise (TGR); Hongyihe-Luozhuang eclogite belt (HLE); Maopo-Hujiazhai igneous rock belt (MHI); Zhoujiawan flysch belt (ZFB); Yangzhuang greenschist belt (YGB); and Dongjiazhuang marble belt (DMB).The geometry and kinematic images of the TOB include: the antiformal structures caused by a later uplift process, the top-to-north ductile shear structure that related to a process that the ultrahigh pressure rocks are brought to surface, the top-to-south ductile shear thrust and the sinistrial shear structures related to a south-north direction compression, and the east-west direction fold structures in the upper crust. In the view of the multistage subduction-collision orogenic belt, according to the characters of petrology and its distribution, geometry, kinematics and structural chronology in these tectonic units, tectonic evolution of the TOB can be divided into four stages: oceanic crust subduction during 400-300 Ma, continental collision during 270-250 Ma, continental deep subduction and uplift during 250-205 Ma and doming deformation during 200-185 Ma.

  16. North Florida is part of the stroke belt.

    OpenAIRE

    Siegel, P. Z.; Wolfe, L E; Wilcox, D.; Deeb, L C

    1992-01-01

    Florida is the only State in the southeastern United States that is not part of the "stroke belt." The National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health, defines the stroke belt as those States with an age-adjusted stroke mortality rate for the years 1979 to 1981 that is more than 10 percent above the national annual rate of 40.3 per 100,000 population. By reproducing at the county level the methods that were used at the State level to describe the stroke belt, ...

  17. Radiation Belt Storm Probes: Resolving Fundamental Physics with Practical Consequences

    Science.gov (United States)

    Ukhorskiy, Aleksandr Y.; Mauk, Barry H.; Fox, Nicola J.; Sibeck, David G.; Grebowsky, Joseph M.

    2011-01-01

    The fundamental processes that energize, transport, and cause the loss of charged particles operate throughout the universe at locations as diverse as magnetized planets, the solar wind, our Sun, and other stars. The same processes operate within our immediate environment, the Earth's radiation belts. The Radiation Belt Storm Probes (RBSP) mission will provide coordinated two-spacecraft observations to obtain understanding of these fundamental processes controlling the dynamic variability of the near-Earth radiation environment. In this paper we discuss some of the profound mysteries of the radiation belt physics that will be addressed by RBSP and briefly describe the mission and its goals.

  18. Human neuronal interlimb coordination during split-belt locomotion

    OpenAIRE

    Dietz, V; Zijlstra, W G; Duysens, J.E.J.

    1994-01-01

    Human interlimb coordination and the adaptations in leg muscle activity were studied during walking on a treadmill with split belts. Four different belt speeds (0.5, 1.0, 1.5, 2.0 m/s) were offered in all possible combinations for the left and right leg. Subjects adapted automatically to a difference in belt speed within 10–20 stride cycles.This adaptation was achieved by a reorganization of the stride cycle with a relative shortening of the duration of the support and lengthening of the swin...

  19. Resistance and other parameters of belt conveyor shifting

    Energy Technology Data Exchange (ETDEWEB)

    Dembinski, M.

    1988-07-01

    Discusses a method developed by Poltegor for calculating energy consumption of belt conveyor shifting in brown coal surface mines in Poland. A program for simulating effects of all significant factors that represent the environment, physical and mechanical properties of soil, effects of weather and atmospheric precipitations, design of belt conveyors, effects of soil or coal buildup and conveyor wear is used. Indices that describe effects of major groups of factors are used for calculating resistance to belt conveyor shifting considering local conditions. Investigations carried out in the Belchatow brown coal mine show the method to be accurate and reliable.

  20. Power Transmission Through Timing Belt In Two Wheeler Motors

    Directory of Open Access Journals (Sweden)

    Gurumurthy Veerapathiran

    2015-03-01

    Full Text Available This paper studies the effect of noise and friction on performance of the chain drive system for motor bikes. Experiment shows that chain transmission in chain drive system leads to poor overall performance, due to its noise and chain gets loose due to aging and sprockets wear due to chain friction etc., the proposed system consists of drive and driven pulley with timing belt transmission. Compared to conventional method, proposed method give improved tension in pulleys and belt by the additional arrangement called belt tensioner. This gives good overall performance of the system, and reduces noise, vibration and gives high transmission speed.

  1. Discovery of Cu-Zn, Cu-Sn intermetallic minerals and its significance for genesis of the Mianning-Dechang REE Metallogenic Belt, Sichuan Province, China

    Institute of Scientific and Technical Information of China (English)

    XIE Yuling; HOU Zengqian; XU Jiuhua; YUAN Zhongxin; BAI Ge; LI Xiaoyu

    2006-01-01

    Mianning-Dechang Himalayan REE Metallogenetic Belt in Sichuan Province lies along the western margin of the Yangtze Craton. We have conducted detailed mineralogical studies on ore minerals collected from Maoniuping and Dalucao, the two largest deposits in the belt. With optical microscope, SEM/EDS, and EPMA, three rare intermetallic minerals, i.e., zinccopperite (Cu2Zn), Sn- bearing native copper, and Cu-bearing jupiter were found to occur in the main ore along with barite, fluorite, apatite, sulfide and bastnaesite. Since the conditions under which zinccopperite and Sn- bearing native copper formed are quite unique, finding of these minerals, for the first time in domestic REE deposits, has significant implications for the genesis of the ore deposits in which they occur. In comparison with Cu-Zn intermetallic minerals in other occurrences, we propose that the formation of this REE metallogenetic belt is associated with fast upwelling of the Himalayan magma from deep source.

  2. Effect of one-way clutch on the nonlinear vibration of belt-drive systems with a continuous belt model

    Science.gov (United States)

    Ding, Hu; Zu, Jean W.

    2013-11-01

    This study focuses on the nonlinear steady-state response of a belt-drive system with a one-way clutch. A dynamic model is established to describe the rotations of the driving pulley, the driven pulley, and the accessory shaft. Moreover, the model considers the transverse vibration of the translating belt spans for the first time in belt-drive systems coupled with a one-way clutch. The excitation of the belt-drive system is derived from periodic fluctuation of the driving pulley. In automotive systems, this kind of fluctuation is induced by the engine firing harmonic pulsations. The derived coupled discrete-continuous nonlinear equations consist of integro-partial-differential equations and piece-wise ordinary differential equations. Using the Galerkin truncation, a set of nonlinear ordinary differential equations is obtained from the integro-partial-differential equations. Applying the Runge-Kutta time discretization, the time histories of the dynamic response are numerically solved for the driven pulley and the accessory shaft and the translating belt spans. The resonance areas of the coupled belt-drive system are determined using the frequency sweep. The effects of the one-way clutch on the belt-drive system are studied by comparing the frequency-response curves of the translating belt with and without one-way clutch device. Furthermore, the results of 2-term and 4-term Galerkin truncation are compared to determine the numerical convergence. Moreover, parametric studies are conducted to understand the effects of the system parameters on the nonlinear steady-state response. It is concluded that one-way clutch not only decreases the resonance amplitude of the driven pulley and shaft's rotational vibration, but also reduces the resonance region of the belt's transverse vibration.

  3. Trio of Neptunes and their Belt

    Science.gov (United States)

    2006-05-01

    Using the ultra-precise HARPS spectrograph on ESO's 3.6-m telescope at La Silla (Chile), a team of European astronomers have discovered that a nearby star is host to three Neptune-mass planets. The innermost planet is most probably rocky, while the outermost is the first known Neptune-mass planet to reside in the habitable zone. This unique system is likely further enriched by an asteroid belt. ESO PR Photo 18a/06 ESO PR Photo 18a/06 Planetary System Around HD 69830 (Artist's Impression) "For the first time, we have discovered a planetary system composed of several Neptune-mass planets", said Christophe Lovis, from the Geneva Observatory and lead-author of the paper presenting the results [1]. During more than two years, the astronomers carefully studied HD 69830, a rather inconspicuous nearby star slightly less massive than the Sun. Located 41 light-years away towards the constellation of Puppis (the Stern), it is, with a visual magnitude of 5.95, just visible with the unaided eye. The astronomers' precise radial-velocity measurements [2] allowed them to discover the presence of three tiny companions orbiting their parent star in 8.67, 31.6 and 197 days. "Only ESO's HARPS instrument installed at the La Silla Observatory, Chile, made it possible to uncover these planets", said Michel Mayor, also from Geneva Observatory, and HARPS Principal Investigator. "Without any doubt, it is presently the world's most precise planet-hunting machine" [3]. ESO PR Photo 18d/06 ESO PR Photo 18d/06 Phase Folded Measurements of HD 69830 The detected velocity variations are between 2 and 3 metres per second, corresponding to about 9 km/h! That's the speed of a person walking briskly. Such tiny signals could not have been distinguished from 'simple noise' by most of today's available spectrographs. The newly found planets have minimum masses between 10 and 18 times the mass of the Earth. Extensive theoretical simulations favour an essentially rocky composition for the inner planet, and

  4. 30 CFR 57.14131 - Seat belts for surface haulage trucks.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Seat belts for surface haulage trucks. 57.14131... and Equipment Safety Devices and Maintenance Requirements § 57.14131 Seat belts for surface haulage trucks. (a) Seat belts shall be provided and worn in haulage trucks. (b) Seat belts shall be...

  5. Practical and medical aspects of the use of car seat belts.

    NARCIS (Netherlands)

    Edelman, A. & Kampen, L.T.B. van

    1974-01-01

    An analysis is made of the influence of use and non-use of seat belts on type and severity of injuries to drivers and of the influence of seat belt type on type and severity of injuries to drivers. Users of lap belts and users of 3-point belts enjoy a comparable and considerable reduction of injury

  6. MACRO MODEL OF SEAT BELT USE BY CAR DRIVERS AND PASSENGERS

    Directory of Open Access Journals (Sweden)

    Kazimierz JAMROZ

    2013-12-01

    Full Text Available The article presents some problems of seat belt use by car drivers and passengers. It looks in particular at seat belt use and effectiveness in selected countries. Next, factors of seat belt use are presented and methodology of model development. A macro model of seat belt use is presented based on data from around fifty countries from different continents.

  7. Feasibility of electro-osmotic belt filter dewatering technology at pilot scale

    CSIR Research Space (South Africa)

    Snyman, HG

    2000-01-01

    Full Text Available -effective dewatering technologies, electro-osmotic belt filtering was developed by Smollen and Kafaar in 1995. The mechanical equipment resembles a belt filter press but the belts are stainless steel, woven belts, which act as the electrodes. In this study...

  8. Zika: Why Brazil, Why Now

    Science.gov (United States)

    ... medlineplus.gov/news/fullstory_160251.html Zika: Why Brazil, Why Now Several factors -- including economics, climate and ... 5, 2016 THURSDAY, Aug. 4, 2016 (HealthDay News) -- Brazil, by a wide margin, has been the country ...

  9. Origin of the Main-Belt Comets: Formed In-Situ or Interlopers from the Outer Solar System?

    Science.gov (United States)

    Hsieh, Henry H.; Haghighipour, Nader

    2014-11-01

    Since the discovery of the first main-belt comet (MBC), 133P/Elst-Pizarro, the dynamical origin of cometary objects in the asteroid belt has been the subject of great interest. The comet-like activity of MBCs appears to be driven by the sublimation of water ice, which is intriguing given studies showing that icy objects from the asteroid belt region could have been a significant primordial source of terrestrial water. However, while dynamical modeling of the first three known MBCs (Haghighipour, 2009, M&PS, 44, 1863-1869) favored in-situ formation as the most probable scenario for the origin of these objects, the possibility that MBCs could be interlopers from the outer solar system has never been definitively ruled out. The Tisserand parameter with respect to Jupiter, T_J, is commonly used to characterize the dynamical origin of a small solar system object. Asteroids believed to have formed in situ in the asteroid belt generally have T_J>3 and comets which are presumed to have formed in the outer solar system generally have T_J3, suggesting that they formed in situ, but we are interested in investigating whether objects with T_Jfact evolve onto stable main-belt orbits with T_J>3. We have studied this issue by integrating the orbits of a large number of test particles with T_J values close to 3 (2.8 3 that are dynamically unstable over typical cometary dynamical lifetimes. Intriguingly, we also find that a small fraction of particles with T_J fact evolve onto orbits similar to those of certain known MBCs, specifically those with large eccentricities or inclinations. This suggests that an outer solar system origin for those MBCs cannot be excluded. We will discuss the implications of these results for our understanding of the origin of the MBCs, as well as their utility as tracers of ice in the inner solar system.

  10. The importance of energetic particle injections and cross-energy and -species interactions to the acceleration and loss of relativistic electrons in Earth's outer radiation belt (invited talk)

    Science.gov (United States)

    Turner, Drew; Gkioulidou, Matina; Ukhorskiy, Aleksandr; Gabrielse, Christine; Runov, Andrei; Angelopoulos, Vassilis

    2014-05-01

    Earth's radiation belts provide a natural laboratory to study a variety of physical mechanisms important for understanding the nature of energetic particles throughout the Universe. The outer electron belt is a particularly variable population, with drastic changes in relativistic electron intensities occurring on a variety of timescales ranging from seconds to decades. Outer belt variability ultimately results from the complex interplay between different source, loss, and transport processes, and all of these processes are related to the dynamics of the inner magnetosphere. Currently, an unprecedented number of spacecraft are providing in situ observations of the inner magnetospheric environment, including missions such as NASA's THEMIS and Van Allen Probes and ESA's Cluster and operational monitors such as NOAA's GOES and POES constellations. From a sampling of case studies using multi-point observations, we present examples showcasing the significant importance of two processes to outer belt dynamics: energetic particle injections and wave-particle interactions. Energetic particle injections are transient events that tie the inner magnetosphere to the near-Earth magnetotail; they involve the rapid inward transport of plasmasheet particles into the trapping zone in the inner magnetosphere. We briefly review key concepts and present new evidence from Van Allen Probes, GOES, and THEMIS of how these injections provide: 1. the seed population of electrons that are subsequently accelerated locally to relativistic energies in the outer belt and 2. the source populations of ions and electrons that produce a variety of ULF and VLF waves, which are also important for driving outer belt dynamics via wave-particle interactions. Cases of electron acceleration by chorus waves, losses by plasmaspheric hiss and EMIC waves, and radial transport driven by ULF waves will also be presented. Finally, we discuss the implications of this developing picture of the system, namely how

  11. FORMATION AND EVOLUTION OF THE CENOZOIC THRUST FOLD BELT IN JINPING, SICHUAN

    Institute of Scientific and Technical Information of China (English)

    LIAO Zhongli; DENG Yongfu; LIAO Guangyu

    2003-01-01

    The Jinping orogenic belt in Sichuan, China consists mainly of the Jinpingshan intracontinental thrust-nappe belt, foreland thrust-nappe belt and foreland uplift belt. Based on analyses about the characteristics of the structural units in this area, the authors propose in this paper that Chapuzi-Bazhe revival fault belt is the regional boundary fault, and points out that after the formation of the Pre-Sinian basement, the western edge of the Yangtze paraplatform was turned into the passive continental margin in Sinian to Triassic, then into the Mesozoic collision orogenic belt, and finally into the Cenozoic orogenic belt through intracontinental orogeny.

  12. "Abomination"--life as a Bible belt gay.

    Science.gov (United States)

    Barton, Bernadette

    2010-01-01

    Drawing on observation, autoethnography, and audio-taped interviews, this article explores the religious backgrounds and experiences of Bible Belt gays. In the Bible Belt, Christianity is not confined to Sunday worship. Christian crosses, messages, paraphernalia, music, news, and attitudes permeate everyday settings. Consequently, Christian fundamentalist dogma about homosexuality-that homosexuals are bad, diseased, perverse, sinful, other, and inferior-is cumulatively bolstered within a variety of other social institutions and environments in the Bible Belt. Of the 46 lesbians and gay men interviewed for this study (age 18-74 years), most describe living through spirit-crushing experiences of isolation, abuse, and self-loathing. This article argues that the geographic region of the Bible Belt intersects with religious-based homophobia. Informants explained that negative social attitudes about homosexuality caused a range of harmful consequences in their lives including the fear of going to hell, depression, low self-esteem, and feelings of worthlessness.

  13. Back belts in occupational setting: what are the evidences?

    Directory of Open Access Journals (Sweden)

    João Marcos Bernardes

    2012-01-01

    Full Text Available Although, widely used the mechanisms of action and the effectiveness of back belts in the prevention of occupational low back disorders remains uncertain, generating controversy about its use. Therefore, the purpose of this study was to do a critical literature review about back belts use in the prevention of occupational low back pain in the occupational setting. In order to do that, a bibliographic research in the following data basis: Medline, SciELO and LILACS was conducted. There is evidence that back belts use reduces spine range of motion, however the studies about intra-abdominal pressure and muscle activity presented contradictory results, as the epidemiologic studies, not allowing the recommendation of its use in the prevention of occupational low back pain. Based on this literature review it is suggested therefore, the implementation of new studies, to confirm or not the effectiveness of back belts as personal protective equipment, in the prevention of occupational low back disorders.

  14. Jupiter's radiation belt ions - A comparison of theory and observation

    Science.gov (United States)

    Summers, Danny; Thorne, Richard M.; Mei, YI

    1989-01-01

    Radial profiles are constructed for the Jovian radiation belt flux-tube content Y-asterisk from the reported phase-space density of energetic particles obtained from Voyager 1 data over the range L = 6 to L = 9. These experimental profiles are compared with theoretical solutions for Y-asterisk from an interchange-diffusion model of the coupled radiation belt and Iogenic ion populations. Subject to certain limitations of the Voyager 1 data, the model solutions are found to be consistent with the data for a variety of input parameters. Model solutions are also found corresponding to radiation belt ions that are expected to be mainly responsible for the auroral energy input. Comparison of the present theoretical profiles with the data implies that the energetic radiation belt ions should have a peak loss rate within a factor of three of that for strong diffusion scattering.

  15. CRED REA Fish Team Belt Transect Survey at Laysan 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 3 sites at Laysan in the Northwest...

  16. Periumbilical allergic contact dermatitis: blue jeans or belt buckles?

    Science.gov (United States)

    Byer, Tara T; Morrell, Dean S

    2004-01-01

    Nickel is the most ubiquitous contact allergen among children and adolescents. Metal blue jeans buttons and belts have been noted to cause nickel dermatitis around the umbilicus. For these children, traditional teaching is strict avoidance of all pants with metal snaps/buttons, particularly blue jeans. In this study we tested 90 pairs of blue jeans and 47 belts for nickel using the dimethylglyoxime spot test. Only 10% of blue jeans tested positive, while 53% of belts tested positive. Furthermore, 10 pairs of nickel-negative blue jeans remained negative after 10 washings. Overall we found no resistance to testing in clothing stores. From these results, we recommend that patients with allergic contact dermatitis secondary to nickel need not strictly avoid blue jeans and metal belt buckles. Rather, families should be encouraged to use the dimethylglyoxime spot test to test these items for nickel prior to purchase.

  17. 5m Main Belt Asteroid Population Estimation Using Vesta Imagery

    Science.gov (United States)

    Rynders, Michael; Trilling, David E.

    2016-10-01

    The Main Belt is the largest source of Near-Earth asteroids, but objects 2 pixels in diameter that were counted in a 33km 2 region to give a crater density. By knowing the crater density and making some reasonable assumptions about the orbital distribution of asteroids and the age of Vesta's surface, an estimate of the population of small asteroids in the inner main belt was made. It was found that the inner region of the main asteroid belt contains approximately 20 billion asteroids larger than 5 m. These results agree well with the measured inner Main Belt Size distribution derived by the Wide-field Infrared Survey Explorer, WISE (Masiero et al. 2011).

  18. Cenozoic intracontinental deformation of the Kopeh Dagh Belt, Northeastern Iran

    Science.gov (United States)

    Chu, Yang; Wan, Bo; Chen, Ling; Talebian, Morteza

    2016-04-01

    Compressional intracontinental orogens represent large tectonic zones far from plate boundaries. Since intracontinental mountain belts cannot be framed in the conventional plate tectonics theory, several hypotheses have been proposed to account for the formations of these mountain belts. The far-field effect of collision/subduction at plate margins is now well accepted for the origin and evolution of the intracontinental crust thickening, as exemplified by the Miocene tectonics of central Asia. In northern Iran, the Binalud-Alborz mountain belt witnessed the Triassic tectonothermal events (Cimmerian orogeny), which are interpreted as the result of the Paleotethys Ocean closure between the Eurasia and Central Iran blocks. The Kopeh Dagh Belt, located to the north of the Binalud-Alborz Belt, has experienced two significant tectonic phases: (1) Jurassic to Eocene rifting with more than 7 km of sediments; and (2) Late Eocene-Early Oligocene to Quaternary continuous compression. Due to the high seismicity, deformation associated with earthquakes has received more and more attention; however, the deformation pattern and architecture of this range remain poorly understood. Detailed field observations on the Cenozoic deformation indicate that the Kopeh Dagh Belt can be divided into a western zone and an eastern zone, separated by a series of dextral strike-slip faults, i.e. the Bakharden-Quchan Fault System. The eastern zone characterized by km-scale box-fold structures, associated with southwest-dipping reverse faults and top-to-the NE kinematics. In contrast, the western zone shows top-to-the SW kinematics, and the deformation intensifies from NE to SW. In the northern part of this zone, large-scale asymmetrical anticlines exhibit SW-directed vergence with subordinate thrusts and folds, whereas symmetrical anticlines are observed in the southern part. In regard to its tectonic feature, the Kopeh Dagh Belt is a typical Cenozoic intracontinental belt without ophiolites or

  19. Corporate Governance Country Assessment : Brazil

    OpenAIRE

    World Bank

    2005-01-01

    This report assesses Brazil's corporate governance policy framework. It highlights recent improvements in corporate governance regulation, makes policy recommendations, and provides investors with a benchmark against which to measure corporate governance in Brazil. It is an update of the 2005 corporate governance Report on the Observance of Standards and Codes (ROSC). Brazil's experience o...

  20. Design of MGA trajectories for main belt asteroid

    Institute of Scientific and Technical Information of China (English)

    崔祜涛; 乔栋; 崔平远; 栾恩杰

    2003-01-01

    Asteroid exploration is one of the most sophisticated missions currently being investigated. Gravityassist trajectories have proven valuable in interplanetary missions such as the Pioneer, Voyager and Galileo. In this paper, we design interplanetary trajectory for main belt asteroid exploration mission with the Mars gravityassist (MGA) using "pork chop" plots and patched-conic theory and give some initial valuable trajectory parameters on main belt asteroid exploration mission with MGA.

  1. The Role of Plasma in Radiation Belt Loss.

    Science.gov (United States)

    Jahn, J. M.; Bonnell, J. W.; Kurth, W. S.; Millan, R. M.; Goldstein, J.; Jaynes, A. N.; Blake, J. B.; Denton, R. E.

    2015-12-01

    The radiation belts are zones of relativistic electrons encircling the Earth. Their radial structure is controlled by the competition between source and loss processes. Most commonly, a two-belt structure prevails, though a more complicated three-belt structure - an inner belt plus two outer electron belts - have repeatedly been observed. The plasma conditions that enable and enhance loss-facilitating wave activity in the inner magnetosphere are still under discussion. Relativistic electrons have been thought to more easily resonate with electromagnetic ion-cyclotron waves (EMIC) when the total plasma density is large (i.e., in the plasmasphere and plume). However, there is evidence that this interaction may be not as strong as thought, and that instead the field-aligned motion of lower energy ring current ions (up to a few 10's keV) may play a key role. Similarly, the exact influence of large heavy ion (O+) concentrations remains unsettled. We use 2.5+ years of Van Allen Probes observations to study the region of plasmasphere-outer belt overlap (and its vicinity). By now, the Van Allen Probes provide a complete and very dense coverage of the complete magnetosphere inside geosynchronous orbit We focus our interest on understanding the plasma conditions that can favor EMIC wave growth. We investigate the temperature anisotropy A (modified by plasma β) of the warm/hot plasma, and contrast it with the location specifics of the plasmasphere (i.e., very high total density) and the occurrence of high O+ concentrations in the overlap regions with the radiation belt(s). We present both average conditions for all parameters during a variety of geomagnetic conditions, and highlight specific loss and overlap events in an effort to establish favorable plasma conditions for relativistic electron loss during those times.

  2. Trapped radiation belts of saturn: first look.

    Science.gov (United States)

    Fillius, W; Ip, W H; McIlwain, C E

    1980-01-25

    Pioneer 11 has made the first exploration of the magnetosphere and trapped radiation belts of Saturn. Saturn's magnetosphere is intermediate in size between Earth's and Jupiter's, with trapped particle intensities comparable to Earth's. The outer region of Saturn's magnetosphere contains lower energy radiation and is variable with time; the inner region contains higher energy particles. The pitch angle distributions show a remarkable variety of field-aligned and locally mirroring configurations. The moons and especially the rings of Saturn are effective absorbers of trapped particles; underneath the rings, the trapped radiation is completely absorbed. We confirm the discovery of a new ring, called the F ring, a new division, the Pioneer division, and a moon, called 1979 S 2. The latter has probably been seen from Earth. There may be evidence for more bodies like 1979 S 2, but at this stage the interpretation of the data is ambiguous. Using particle diffusion rates, we estimate that the cross-sectional area of the F ring is > 7 x 10(13) square centimeters and that the opacity is > 10(-5). Cosmic-ray albedo neutron decay should be looked into as a source of energetic particles in the inner magnetosphere of Saturn.

  3. Radiation Belt Electron Dynamics: Modeling Atmospheric Losses

    Science.gov (United States)

    Selesnick, R. S.

    2003-01-01

    The first year of work on this project has been completed. This report provides a summary of the progress made and the plan for the coming year. Also included with this report is a preprint of an article that was accepted for publication in Journal of Geophysical Research and describes in detail most of the results from the first year of effort. The goal for the