Evaluation of the recorded ground motions for the unusual earthquake of 13 August 2006 (M w 5.3) in Michoacán México     

Alejandro Ramírez-Gaytán  Miguel A. Jaimes  William L. Bandy  Victor M. Huerfano  Ricardo A. Salido-Ruiz 《Journal of Seismology》2015,19(4):881-898

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Effect of algae on flocculation of suspended bed sediments in a large shallow lake. Consequences for ecology and sediment transport processes     

Miguel Angel de Lucas Pardo  Dirk Sarpe  Johan Christian Winterwerp 《Ocean Dynamics》2015,65(6):889-903

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Dust attenuation in hydrodynamic simulations of spiral galaxies     

Miguel Rocha  Patrik Jonsson  Joel R. Primack  T. J. Cox 《Monthly notices of the Royal Astronomical Society》2008,383(4):1281-1291

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GGR Biennial Critical Review: Analytical Developments Since 2014          下载免费PDF全文

Kathryn L. Linge  L. Paul Bédard  Roxana Bugoi  Jacinta Enzweiler  Klaus Peter Jochum  Rüdiger Kilian  Jingao Liu  Johanna Marin‐Carbonne  Silke Merchel  Frans Munnik  Luiz F.G. Morales  Claire Rollion‐Bard  A. Kate Souders  Paul J. Sylvester  Ulrike Weis 《Geostandards and Geoanalytical Research》2017,41(4):493-562

This GGR biennial critical review covers developments and innovations in key analytical methods published since January 2014, relevant to the chemical, isotopic and crystallographic characterisation of geological and environmental materials. In nine selected analytical fields, publications considered to be of wide significance are summarised, background information is provided and their importance evaluated. In addition to instrumental technologies, this review also presents a summary of new developments in the preparation and characterisation of rock, microanalytical and isotopic reference materials, including a précis of recent changes and revisions to ISO guidelines for reference material characterisation and reporting. Selected reports are provided of isotope ratio determinations by both solution nebulisation MC‐ICP‐MS and laser ablation‐ICP‐MS, as well as of radioactive isotope geochronology by LA‐ICP‐MS. Most of the analytical techniques elaborated continue to provide new applications for geochemical analysis; however, it is noted that instrumental neutron activation analysis has become less popular in recent years, mostly due to the reduced availability of nuclear reactors to act as a neutron source. Many of the newer applications reported here provide analysis at increasingly finer resolution. Examples include atom probe tomography, a very sensitive method providing atomic scale information, nanoscale SIMS, for isotopic imaging of geological and biological samples, and micro‐XRF, which has a spatial resolution many orders of magnitude smaller than conventional XRF.  相似文献   

A New Appraisal of Sri Lankan BB Zircon as a Reference Material for LA‐ICP‐MS U‐Pb Geochronology and Lu‐Hf Isotope Tracing          下载免费PDF全文

Maristella M. Santos  Cristiano Lana  Ricardo Scholz  Ian Buick  Mark D. Schmitz  Sandra L. Kamo  Axel Gerdes  Fernando Corfu  Simon Tapster  Penelope Lancaster  Craig D. Storey  Miguel A.S. Basei  Eric Tohver  Ana Alkmim  Herminio Nalini  Klaus Krambrock  Cristiano Fantini  Michael Wiedenbeck 《Geostandards and Geoanalytical Research》2017,41(3):335-358

A potential zircon reference material (BB zircon) for laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS) U‐Pb geochronology and Hf isotope geochemistry is described. A batch of twenty zircon megacrysts (0.5–1.5 cm³) from Sri Lanka was studied. Within‐grain rare earth element (REE) compositions are largely homogeneous, albeit with some variation seen between fractured and homogeneous domains. Excluding fractured cathodoluminescence bright domains, the variation in U content for all analysed crystals ranged from 227 to 368 μg g^?1 and the average Th/U ratios were between 0.20 and 0.47. The Hf isotope composition (0.56–0.84 g/100 g Hf) is homogeneous within and between the grains – mean ¹⁷⁶Hf/¹⁷⁷Hf of 0.281674 ± 0.000018 (2s). The calculated alpha dose of 0.59 × 10¹⁸ g^?1 for a number of BB grains falls within the trend of previously studied, untreated zircon samples from Sri Lanka. Aliquots of the same crystal (analysed by ID‐TIMS in four different laboratories) gave consistent U‐Pb ages with excellent measurement reproducibility (0.1–0.4% RSD). Interlaboratory assessment (by LA‐ICP‐MS) from individual crystals returned results that are within uncertainty equivalent to the TIMS ages. Finally, we report on within‐ and between‐grain homogeneity of the oxygen isotope systematic of four BB crystals (13.16‰ VSMOW).  相似文献   

Platiniferous gold–tourmaline aggregates in the gold–palladium belt of Minas Gerais,Brazil: implications for regional boron metasomatism     

Cabral  Alexandre Raphael  Tupinambá  Miguel  Zeh  Armin  Lehmann  Bernd  Wiedenbeck  Michael  Brauns  Michael  Kwitko-Ribeiro  Rogerio 《Mineralogy and Petrology》2017,111(6):807-819

Mineralogy and Petrology - The platiniferous gold–palladium belt of Minas Gerais, Brazil, forms an approximately 240-km-long, roughly north–south-trending domain that includes numerous...  相似文献   

Evaluation of the removal of heavy metals in a natural wetland impacted by mining activities in Mexico     

Juan Miguel Gómez-Bernal  Esther Aurora Ruiz-Huerta  María Aurora Armienta-Hernández  Víctor Manuel Luna-Pabello 《Environmental Earth Sciences》2017,76(23):801

This research is focused on evaluating heavy metals (Cd, Cu, Fe, Mn, Pb, and Zn) uptake and removal by Eleocharis ovata, Cyperus manimae, Typha dominguensis, and Pteridium aquilinum in a natural wetland impacted by mining activities. We analyzed heavy metals content and distribution in native plants, soils, and water of a semipermanent natural wetland in Taxco de Alarcón, Guerrero, and we also determined the physicochemical characteristics of the water. Translocation factor (TF) and bioconcentration factor (BCF) were evaluated. Results showed that physical and chemical conditions are favorable for plants development. Correlation analysis showed a good and positive relation (0.95) between Cu and Pb in soils and plants. In the analyzed matrices: Zn (0.62–2.20 mg/L) exceeded the permissible limits in water, high concentrations of Pb and Zn (26.57–525.67 and 266.67–983.33 mg/kg, respectively) were detected in the studied soils, and Pb exceeded the normal range for E. ovata and P. aquilinum in the analyzed plants. Uptake of heavy metals in the tissues of different species was found in the following order: root > leaf. Data of TF and BCF showed that E. ovata is a tolerant plant with respect to heavy metals exposure since TF value was greater than 1. This study showed that E. ovata could be considered as a bioaccumulator of heavy metals in contaminated soils.  相似文献   

Fire severity and surface rock fragments cause patchy distribution of soil water repellency and infiltration rates after burning   总被引：3，自引：0，他引：3       下载免费PDF全文

Ángel J. Gordillo‐Rivero  Jorge García‐Moreno  Antonio Jordán  Lorena M. Zavala  Fernando M. Granja‐Martins 《水文研究》2014,28(24):5832-5843

Although fire‐induced soil water repellency (SWR) and its effects on soil hydrology and geomorphology have been studied in detail, very few studies have considered the effect of rock fragments resting on the soil surface or partly embedded in soil. In this research, we have studied the effect of rock fragments on the strength and spatial distribution of fire‐induced SWR at different fire severities. A fire‐affected area was selected for this experiment and classified into different zones according to fire severity (unburned, low, moderate and high) and rock fragment cover (low, <20% and high, >60%). During 7 days after fire, SWR and infiltration rates were assessed in the soil surface covered by individual rock fragments and in the midpoint between two adjacent rock fragments (with maximum spacing of 20 cm). SWR increased with fire severity. Rock fragments resting on the soil surface increased the heterogeneity of the spatial distribution of fire‐induced SWR. SWR increased significantly with rock fragment cover in bare areas under moderate and high fire severity, but quantitatively important changes were only observed under high fire severity. In areas with a low rock fragment cover, water repellency from soil surfaces covered by rock fragments increased relative to bare soil surfaces, with increasing SWR. In areas with a high rock fragment cover, SWR increased significantly from non‐covered to covered soil surfaces only after low‐severity burning. Rock fragment cover did not affect infiltration rates, although it decreased significantly in soil surfaces after high‐severity burning in areas under low and high rock fragment cover. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Early contamination of European flounder (Platichthys flesus) by PCDD/Fs and dioxin-like PCBs in European waters     

Margarida Nunes  Filipe Martinho  Anaïs Vernisseau  Philippe Marchand  Bruno Le Bizec  Henk W. van der Veer  Henrique N. Cabral  Fernando Ramos  Miguel A. Pardal 《Marine pollution bulletin》2014

Contamination levels and profiles of 7 polychlorinated-p-dioxins, 10 polychlorinated furans (PCDD/Fs) and 12 dioxin-like polychlorinated biphenyls (dl-PCBs) were investigated in juvenile European flounder (Platichthys flesus) captured in different nursery areas in the northeastern Atlantic coast across its geographical distribution range. The toxic equivalent concentrations (WHO-TEQ_fish) were also determined in order to evaluate which P. flesus population was more exposed to dioxin-like toxicity. Juveniles caught in the Sørfjord (Norway) showed the lowest WHO-TEQ_fish concentration (0.052 pg WHO-TEQ_fish g⁻¹ wet weight) whereas the highest value was observed in fish from the Wadden Sea (The Netherlands; 0.291 pg WHO-TEQ_fish g⁻¹ ww), mainly due to the greater contribution of 2,3,7,8-tetrachlorodibenzo-p-dioxin, the most toxic congener. Nonetheless, when comparing the results with existent tissue residue-based toxicity benchmarks, no adverse effects resulting from PCDD/Fs and dl-PCBs are expected to occur in flounder from the studied systems.  相似文献   

Problems associated with the ‘one-out, all-out’ principle, when using multiple ecosystem components in assessing the ecological status of marine waters     

Ángel Borja  José Germán Rodríguez 《Marine pollution bulletin》2010,60(8):1143-1146

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