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151.
Miguel Tupinambá Monica Heilbron Claudio Valeriano Rubem Porto Júnior Fátima Blanco de Dios Nuno Machado Luiz Guilherme do Eirado Silva Júlio Cesar Horta de Almeida 《Gondwana Research》2012,21(2-3):422-438
The ca. 790–600 Ma Rio Negro Complex (RNC) of the Ribeira belt (Brazil) consists of a plutonic portion of a magmatic arc built by the E-vergent subduction of the ESE border of the São Francisco paleoplate during the amalgamation of Western Gondwana.The plutonic series comprises low- to medium-K granitoids (ca. 790–620 Ma) and high-K granitoids and shoshonite rocks (ca. 610–605). The age span of 185 m.y. is suggestive of a long history of arc-related magmatism, continuously or not in time. The Nd isotopic signatures of the RNC consist of εNd(t) ratios from ? 3 to + 5 for the medium-K series shoshonite series and from ? 14 to ? 3 for the younger high-K group. This time-dependent trend of Nd isotopes is indicative of progressive maturity of the arc over time. The same evolution is indicated by Sr data, as the medium-K rocks have 87Sr/86Sr initial ratios < 0.705 while the high-K rocks yield values between 0.705 and 0.710. The predominance of intermediate rocks over mafic ones suggests an initial intra-oceanic to transitional stage, possibly developed in a distal portion of a passive margin, such as the Japanese arc, evolving to a more developed, differentiated felsic rock associations.The role of transform fault zones, such as the Luanda shear zone, is emphasized in order to explain the consumption of a wide oceanic plate in the inner portion of Western Gondwana. 相似文献
152.
Tássia Mattos Brighenti Nadia Bernardi Bonumá Raghavan Srinivasan Pedro Luiz Borges Chaffe 《水文科学杂志》2013,58(12):1415-1423
ABSTRACTThe Soil and Water Assessment Tool (SWAT) is a watershed-scale hydrologic model that integrates water quantity and quality modules. Despite the large amount of knowledge on the SWAT model, specific understanding of sub-daily applications remains limited. In this review, we identify the shortcomings and possible ways forward in simulating sub-daily processes with the model. A literature review was conducted, along with a participatory method based on a questionnaire. We reviewed 28 scientific articles and categorized them into: (i) model development, (ii) streamflow methods comparison, (iii) water quality, and (iv) other applications. We found that using sub-daily data improves hydrograph peak simulation, while for medium flows use of daily data was better. From all the reviewed studies, a 1-hour time step was the most suitable time scale for the sub-daily model application. The participatory questionnaire confirmed the hypothesis that the main challenge for using the sub-daily routine was the lack of high-resolution data. 相似文献
153.
This study analyzes the impacts of latent and sensible heat exchanges between the atmosphere and the ocean in a non-explosive Shapiro–Keyser type cyclogenesis event that occurred over the southwestern South Atlantic Ocean. The synoptic evolution shows a relatively strong warm front and a cold frontal fracture during the system’s development and a warm seclusion in its mature stage, characterizing a Shapiro–Keyser type cyclone. Numerical experiments with the ARW-WRF Model version 3.3 were used to investigate the influences of sensible and latent fluxes on the track of the surface low, intensity of the fronts and coupling of the lower and upper troposphere. The simulations indicate that in the presence of these fluxes the cyclone underwent greater intensification, had a longer life time and longer trajectory, and presented a typical southeastward movement. In the absence of these fluxes, the cyclone developed a weaker warm front with consequent reduction of diabatic heating due to grid scale precipitation along it. This reduced the negative pressure tendency southeast of the cyclone center and the surface cyclone moved northeastward, showing a decoupling of the lower- and upper-level waves. A consequence of this anomalous tracking is the location of the surface cyclone beneath the upper-level trough axis, where there is no upper-level divergence associated with cyclonic vorticity advection contributing to the further system intensification. Numerical experiments suggest that for this Shapiro–Keyser type cyclone the air–sea interaction processes are crucial to obtain a cyclone with features similar to the observations. 相似文献
154.
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156.
de Jesus Eduardo Marcos da Rocha Rosmeri Porfírio Crespo Natália Machado Reboita Michelle Simões Gozzo Luiz Felippe 《Climate Dynamics》2021,56(1-2):537-557
Climate Dynamics - In this study, multi-model ensembles are used to understand regional features of future climate trends of cyclones and associated winds in eastern South America. For this, we... 相似文献
157.
Ludmila de Freitas Marcílio Vieira Martins Filho José Carlos Casagrande Ivanildo Amorim de Oliveira Luiz Gabriel da Silva 《Environmental Earth Sciences》2018,77(18):642
The evaluation of soil quality is an important tool for degradation monitoring and sustainable management implementation. The objective of this study was to measure physical and chemical soil properties to set soil quality and validate a model of soil quality indicator in latosols (oxisols) under sugarcane cropping and native forest. The study was carried out in the cities of Araras, Santa Ernestina, and Guariba in São Paulo State, Brazil. We collected 24 samples of disturbed and undisturbed soil at 0.0–0.10 m layer from three areas grown with sugarcane and neighboring locations under native woodland. We assessed the following soil properties: (a) chemical—pH in CaCl2, organic matter (OM), phosphorus (P), potassium (K+), calcium (Ca2+), magnesium (Mg2+), potential acidity (H?+?Al), aluminum (Al3+), and sulfur (S); (b) physical—macro- and microporosity, soil bulk density (Ds), aggregate stability, mean weight diameter (MWD), rill (Kr) and interrill (Ki) global erodibility, shear stress (τc), and magnetic susceptibility (MS). Data underwent multivariate statistics to identify the properties that denote soil quality and to set their weights within the functions of soil quality indicator (SQI). This study showed that the multivariate analysis was efficient in determining which physical and chemical properties were most sensitive, of which we can mention total sand, MS, clay, microporosity, Mg, Ca, pH, and OM. We can therefore conclude that the quality indicators of soils grown with sugarcane were lower than those under forest were, showing the need for adoption of conservation management practices. 相似文献
158.
159.
Galina P. Bulanova Michael J. Walter Chris B. Smith Simon C. Kohn Lora S. Armstrong Jon Blundy Luiz Gobbo 《Contributions to Mineralogy and Petrology》2010,160(4):489-510
We report on a suite of diamonds from the Cretaceous Collier 4 kimberlite pipe, Juina, Brazil, that are predominantly nitrogen-free
type II crystals showing complex internal growth structures. Syngenetic mineral inclusions comprise calcium- and titanium-rich
phases with perovskite stoichiometry, Ca-rich majoritic-garnet, clinopyroxene, olivine, TAPP phase, minerals with stoichiometries
of CAS and K-hollandite phases, SiO2, FeO, native iron, low-Ni sulfides, and Ca–Mg-carbonate. We divide the diamonds into three groups on the basis of the carbon
isotope compositions (δ13C) of diamond core zones. Group 1 diamonds have heavy, mantle-like δ13C (−5 to −10‰) with mineral inclusions indicating a transition zone origin from mafic protoliths. Group 2 diamonds have intermediate
δ13C (−12 to −15‰), with inclusion compositions indicating crystallization from near-primary and differentiated carbonated melts
derived from oceanic crust in the deep upper mantle or transition zone. A 206Pb/238U age of 101 ± 7 Ma on a CaTiSi-perovskite inclusion (Group 2) is close to the kimberlite emplacement time (93.1 ± 1.5 Ma).
Group 3 diamonds have extremely light δ13C (−25‰), and host inclusions have compositions akin to high-pressure–temperature phases expected to be stable in pelagic
sediments subducted to transition zone depths. Collectively, the Collier 4 diamonds and their inclusions indicate multi-stage,
polybaric growth histories in dynamically changing chemical environments. The young inclusion age, the ubiquitous chemical
and isotopic characteristics indicative of subducted materials, and the regional tectonic history, suggest a model in which
generation of sublithospheric diamonds and their inclusions, and the proto-kimberlite magmas, are related genetically, temporally
and geographically to the interaction of subducted lithosphere and a Cretaceous plume. 相似文献
160.
Elfany Reis do Nascimento Lopes Carlos de Souza José Paixão de Sousa Jocy Ana Filho José Luiz Albuquerque Lourenço Roberto Wagner 《Water Resources》2021,48(1):29-40
Water Resources - The objective of this study is to develop an anthropic exposure indicator for river basins using quantitative and qualitative aspects of the landscape and morphometric analysis... 相似文献