Probabilistic Estimation of Seismically Thin-Layer Thicknesses with Application to Evaporite Formations     

Teixeira  Leonardo  Maul  Alexandre  Lupinacci  Wagner 《Surveys in Geophysics》2022,43(4):1085-1116

Surveys in Geophysics - The identification of potassium (K) and magnesium (Mg) salts prior to the well drilling is a key factor to avoid washouts, closing pipes, fluid loss damage, and borehole...  相似文献   

U-Pb Saturn: New U-Pb/Pb-Pb Data Reduction Software for LA-ICP-MS     

Joao P.A. Silva  Cristiano Lana  Ariela Mazoz  Ian Buick  Ricardo Scholz 《Geostandards and Geoanalytical Research》2023,47(1):49-66

U-Pb Saturn is new freeware for U-Pb LA-ICP-MS data reduction. It has been developed to provide easy interaction with and visualisation of LA-ICP-MS U-Pb datasets, and allows fast and reliable data reduction of hundreds of data-points. Saturn offers dynamic graphic interfaces to quickly view, evaluate, and plot U-Pb and Pb-Pb isotope data. It operates online (or offline), giving the freedom to change parameters and reprocess data at any stage of data acquisition. The main interface allows the user to: (1) choose the best statistics for drift correction, (2) include/exclude offset factors and (3) apply (or not) Pb_c corrections in different modes. Signal intensities are displayed in a separate graphic interface that allows users to interact with the time-resolved signal of individual spot analyses. All graphic windows are interactive; any modification to data treatment (e.g., inclusion or exclusion of analyses of reference material, or modification of the time-resolved signal windows) is instantaneously updated on the data tables. Saturn is particularly attractive for beginners in LA-ICP-MS U-Pb geochronology as it is non-commercial, easy to install, and very interactive. Coding information and a version of the software can be accessed at http://www.air.ufop.br .  相似文献   

Kimberlites distribution in Angola and prospective areas for new discoveries     

Ustinov  Victor N.  Feijo Bartolomeu  Ana M.  Zagainy  Alexander K.  Felix  Joao T.  Mikoev  Igor I.  Stegnitskiy  Yury B.  Lobkova  Ludmila P.  Kukui  Irina M.  Nikolaeva  Evelina V.  Antonov  Sergei A. 《Mineralogy and Petrology》2018,112(2):383-396

Based on a comprehensive analysis of kimberlite pipes of Angola, including the near surface structural setting, deep lithospheric structure, pipe morphology and emplacement, mineralogical and petrographic features, diamond characteristics and locations of secondary deposits four geographical regions have been outlined within Angola representing four types of diamond bearing potential. These areas include high diamond bearing potential pipes, possible potential, no potential, and unclear potential areas. It was found that the depth of magmatism and diamond potential of kimberlites increases from the Atlantic coast in southwestern Angola into the continent in the north-easterly direction. Areas prospective for the discovery of new primary diamond deposits have been identified.

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Causes of WRF surface energy fluxes biases in a stratocumulus region     

A. Jousse  A. Hall  F. Sun  J. Teixeira 《Climate Dynamics》2016,46(1-2):571-584

In this study, we evaluate the ability of the Weather Research and Forecasting model to simulate surface energy fluxes in the southeast Pacific stratocumulus region. A total of 18 simulations is performed for the period of October to November 2008, with various combinations of boundary layer, microphysics, and cumulus schemes. Simulated surface energy fluxes are compared to those measured during VOCALS-REx. Using a process-based model evaluation, errors in surface fluxes are attributed to errors in cloud properties. Net surface flux errors are mostly traceable to errors in cloud liquid water path (LWP_cld), which produce biases in downward shortwave radiation. Two mechanisms controlling LWP_cld are diagnosed. One involves microphysics schemes, which control LWP_cld through the production of raindrops. The second mechanism involves boundary layer and cumulus schemes, which control moisture available for cloud by regulating boundary layer height. In this study, we demonstrate that when parameterizations are appropriately chosen, the stratocumulus deck and the related surface energy fluxes are reasonably well represented. In the most realistic experiments, the net surface flux is underestimated by about 10 W m^?2. This remaining low bias is due to a systematic overestimation of the total surface cooling due to sensible and latent heat fluxes in our simulations. There does not appear to be a single physical reason for this bias. Finally, our results also suggest that inaccurate representation of boundary layer height is an important factor limiting further gains in model realism.  相似文献   

Instrumental neutron activation analysis,gamma spectrometry and geographic information system techniques in the determination and mapping of rare earth element in phosphogypsum stacks     

Renata Coura Borges  Déborah Inês Teixeira Fávaro  Vanessa Godoy Caldas  Dejanira da Costa Lauria  Alfredo Victor Bellido Bernedo 《Environmental Earth Sciences》2016,75(8):705

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Interpretation case study of the Sahl El Qaa area, southern Sinai Peninsula, Egypt     

Taha Rabeh  Jorge Miguel Miranda  Joao Carvalho  Andrei Bocin 《Geophysical Prospecting》2009,57(3):447-459

The study area is located in the Sinai Peninsula, which is considered one of the most promising regions for oil resources. Three different tectonic forces affect the area in the triple junction structures associated with the opening of the Gulf of Suez and the strike slip movement along the Gulf of Aqaba. The main goal of this work is to model the structure of the basement rocks in the study area using magnetic methods. To achieve this, a high-resolution land magnetic survey was acquired and the results were combined with existing seismic reflection data. The magnetic interpretation was carried out using the analytical signal, horizontal gradient, Euler and Werner deconvolution and 3D magnetic modelling methods. We concluded that most of the deduced structures are trending in N–S, N35°–N45° west and E–W directions. The Aqaba trend (N15°–N25° east) is barely noticeable. The depth to the basement rocks ranges from 1 km to more than 2 km below sea level and these results are in agreement with the available well log data. In addition, interpretation of seismic reflection sections was carried out and compared with overlapping magnetic profiles interpreted using Euler deconvolution. They show that the sedimentary section was affected by the basement tectonics, with faults extending from the basement upwards through the sedimentary cover. These faults constitute good potential structural traps for oil accumulation.  相似文献   

Potential rates and environmental controls of denitrification and nitrous oxide production in a temperate urbanized estuary   总被引：4，自引：0，他引：4  

Catarina Teixeira  Catarina Magalhes  Rui A.R. Boaventura  Adriano A. Bordalo 《Marine environmental research》2010,70(5):336-342

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Effects of a nuclear power plant thermal discharge on habitat complexity and fish community structure in Ilha Grande Bay, Brazil   总被引：1，自引：0，他引：1  

Tatiana Pires Teixeira  Leonardo Mitrano Neves  Francisco Gerson Araújo   《Marine environmental research》2009,68(4):188-195

Fish communities and habitat structures were evaluated by underwater visual censuses a rocky location impacted by thermal discharge (I) and at two control locations, one in a Sargassum bed (C1) and the other in a rocky shore with higher structural complexity (C2). Habitat indicators and fish communities exhibited significant differences between the impacted and control locations, with the impacted one showing a significant decrease in fish species richness and diversity, as well as a decrease in benthic cover. At the I location, only 13 fish species were described, and the average water temperature was 32 ± 0.4 °C, compared with 44 species at C1 (25.9 ± 0.3 °C) and 33 species at C2 (24.6 ± 0.2 °C). Significant differences in fish communities among locations were found by ANOSIM with Eucinostomus argenteus, Mugil sp. and Haemulon steindachneri typical of location I, while Abudefduf saxatilis, Stegastes fuscus and Malacoctenus delalandi were typical of the control locations. Our study shows that thermal pollution alters benthic cover and influences fish assemblages by altering composition and decreasing richness.  相似文献   

The barnacle Balanus amphitrite as a biomonitor for Cd: Radiolabelled experiments     

Eduardo Teixeira da Silva  Michael Ridd  David Klumpp   《Marine environmental research》2009,67(4-5):177-182

Radiolabelled experiments were carried out to measure necessary parameters in the development of a biodynamic ecotoxicological simulation model of Cd accumulation in the barnacle biomonitor Balanus amphitrite. The Cd uptake rate constant from the dissolved phase, the Cd assimilation efficiency (AE) from suspended particulate matter (SPM) and the efflux rate constant were obtained using ¹⁰⁹Cd. A Cd uptake rate constant from the dissolved phase (k_u) of 0.0072 L g⁻¹ h⁻¹ was determined for the barnacle under environmentally realistic dissolved Cd concentrations (maximum of 400 ng L⁻¹). Cd AE from SPM was determined from the barnacle feeding on SPM with low and high chl a concentrations, resulting in AEs of 39.0% and 48.7%, respectively, and an efflux rate of 0.0072 d⁻¹. The difference between the AEs resulted from differences in chl a:SPM ratios suggesting a general tendency of higher AE when SPM is enriched with chl a. These results reinforce that the accuracy of ecotoxicological models for metal accumulation in organisms depends on how representative the selected food items are of the organism’s natural diet.  相似文献   

The effect of oscillations on the flow patterns near a simulated bed     

M.A.V.C. Araújo  J.C.F. Teixeira  S.F.C.F. Teixeira 《Coastal Engineering》2010

This work investigates the effect of oscillations on the flow near a simulated bed and their impact on erosion. Those oscillations were generated by using wavy lids at the top of a small toroidal channel. Particular attention is dedicated to their influence on the velocity field and turbulence near the bed. The experiments were made in a mini circular flume using a 2D LDA system. It was concluded that such oscillations induce non negligible shear stresses in the flow main stream, becoming more important to the dispersion of entrained matter into the flow than to the initiation of the erosion process.  相似文献