Assessment of the acid drainage neutralization capacity and the toxic metals lixiviation of tailing from Guanajuato mining district,Mexico   总被引：1，自引：0，他引：1  

María Elena García-Arreola  Luisa María Flores-Vélez  Marcos Loredo-Tovías  Alfredo Aguillón-Robles  Rubén Alfonso López-Doncel  Irene Cano-Rodríguez  Sonia Hortensia Soriano-Pérez 《Environmental Earth Sciences》2018,77(9):355

In Mexico, many environmental problems are generated by large mining activities taking place in several mining districts. These mining activities produce great quantities of residues; large majorities of these have high sulfur content, which could generate acid drainage due to their interaction with the oxygen in the environment. The study area was located in the Mining District of Guanajuato, Mexico with abandoned tailings generated mainly by the gold and silver production. Two areas, called as Monte de San Nicolás (SN) and Peregrina (P) were selected for this study. The results study shows that there was no risk of production of acid drainage, since these tailings contained high amount of carbonates, which neutralized the generation of acidity and consequently decreased the possibility of leaching of some elements. However, not all elements leach in acid pH, as arsenic bound to oxyhydroxides, which is in a basic environment and its increased release by increasing the pH.  相似文献   

Characterization of fluid inclusions from mineralized pegmatites of the Damara Belt,Namibia: insight into late-stage fluid evolution and implications for mineralization     

Ashworth  Luisa  Kinnaird  Judith Ann  Nex  Paul Andrew Martin  Erasmus  Rudolph Marthinus  Przybyłowicz  Wojciech Józef 《Mineralogy and Petrology》2018,112(6):753-765

Mineralogy and Petrology - Mineralized NYF and LCT pegmatites occur throughout the northeast-trending Neoproterozoic Damara Belt, Namibia. Mineralization in the pegmatites varies geographically,...  相似文献   

Analysis of stratigraphical sequences at Cocina Cave (Spain) using rare earth elements geochemistry     

Gianni Gallello  Mirco Ramacciotti  Oreto García-Puchol  Simon Chenery  Alfredo Cortell-Nicolau  MARíA Luisa Cervera  Agustin Diez-Castillo  Agustín Pastor  Sarah B. McClure 《Boreas: An International Journal of Quaternary Research》2021,50(4):1190-1208

This study investigates the stratigraphical sequence of Cocina Cave (Spain) employing and testing for the first time the capability of rare earth elements as markers of human activities in caves. Located in Dos Aguas (Valencian Community, Spain), Cocina Cave is characterized by the presence of several Holocene archaeological deposits from the final Mesolithic to the present day and is a pivotal site for understanding the socio-ecological dynamics of the last hunter-gatherer inhabitants of the Iberian Peninsula and the transition to pastoral and agricultural economies in the Western Mediterranean. However, the identification of strata from particular time-periods in the cave is often difficult due to the homogeneity of layers, the poor archaeological record in some strata and the presence of severe disturbance phenomena. The methodological approach of this study consisted of cross-referencing rare earth elements and other chemical markers with the archaeological stratigraphical interpretation, in an attempt to not only support the identification of the anthropic contribution to the formation of Cocina Cave strata, but also to characterize and confirm different natural and occupational episodes, particularly those associated with hunter-gatherer, early agriculturalist, and shepherd activities. Sediments were collected from different excavation areas and analysed for major elements, trace elements, rare earth elements (REE), soil organic matter (SOM) amounts and pH. Multivariate statistics were employed to group samples according to their elemental profile, and these were then compared to the archaeological temporal interpretation. The obtained results showed that REE amount and fractionation geochemical processes were regulated by carbonates, phosphates and pH. The use of REE as markers was particularly useful as their concentrations and their calculated ratios and anomaly distributions were demonstrated to be highly consistent with the archaeological stratigraphical interpretation.  相似文献   

Distribution of dissolved labile and particulate iron and copper in Terra Nova Bay polynya (Ross Sea,Antarctica) surface waters in relation to nutrients and phytoplankton growth     

Paola Rivaro  Carmela Ianni  Serena Massolo  M. Luisa Abelmoschi  Cinzia De Vittor  Roberto Frache 《Continental Shelf Research》2011,31(7-8):879-889

The distribution of the dissolved labile and of the particulate Fe and Cu together with dissolved oxygen, nutrients, chlorophyll a and total particulate matter was investigated in the surface waters of Terra Nova Bay polynya in mid-January 2003. The measurements were conducted within the framework of the Italian Climatic Long-term Interactions of the Mass balance in Antarctica (CLIMA) Project activities. The labile dissolved fraction was operationally defined by employing the chelating resin Chelex-100, which retains free and loosely bound trace metal species. The dissolved labile Fe ranges from below the detection limit (0.15 nM) to 3.71 nM, while the dissolved labile Cu from below the detection limit (0.10 nM) to 0.90 nM. The lowest concentrations for both metals were observed at 20 m depth (the shallowest depth for which metals were measured). The concentration of the particulate Fe was about 5 times higher than the dissolved Fe concentration, ranging from 0.56 to 24.83 nM with an average of 6.45 nM. The concentration of the particulate Cu ranged from 0.01 to 0.71 nM with an average of 0.17 nM. The values are in agreement with the previous data collected in the same area. We evaluated the role of the Fe and Cu as biolimiting metals. The N:dissolved labile Fe ratios (18,900–130,666) would or would not allow a complete nitrate removal, on the basis of the N:Fe requirement ratios that we calculated considering the N:P and the C:P ratios estimated for diatoms. This finding partially agrees with the Si:N ratio that we found (2.29). Moreover we considered a possible influence of the dissolved labile Cu on the Fe uptake process.  相似文献   

Performance of the Italian strong motion network during the 2009, L��Aquila seismic sequence (central Italy)     

Elisa Zambonelli  Rita de Nardis  Luisa Filippi  Mario Nicoletti  Mauro Dolce 《Bulletin of Earthquake Engineering》2011,9(1):39-65

On April 6, 2009, the town of L’Aquila in the Abruzzo region (central Italy) was struck by a seismic event at 01:32 (UTC), of magnitude M_W = 6.3. The mainshock was followed by a long period of intense seismic activity and within seven days after the mainshock there were seven events of magnitude M_W ≥ 5 that occurred from April 6 to April 13. This long seismic sequence was characterized by a complex rupture mechanism that involved two major normal faults of the central Apennines: the Paganica and the Gorzano faults. The strong-motions of the mainshock were recorded by 64 stations of the Italian Strong-motion Network (RAN) operated by the National Civil Protection Department (DPC). Six stations of a local strong-motion array were working in NW L’Aquila suburb area. One of them, located at about 6 km from the Paganica fault surface tip-line, set up in trigger mode, recorded continuously for more than 20 min the mainshock and the aftershocks. Besides the mainshock, the RAN stations recorded in total 78 foreshocks and aftershocks of M_L ≥ 3.5, during the period from January to December 2009. The corresponding waveforms provide the most extensive digital strong ground motion data set ever recorded in Italy. Moreover, the 48 three-component observations of events of magnitude M_W ≥ 5, recorded at a distance less than 15 km from each of the major involved faults, provide a significant increasing of near-field records available for the Italian territory. Six days after the mainshock, the strong-motion dataset, referred to preliminary locations of the events with M_L ≥ 4.0, was made available on the DPC web site () and at the same time it was delivered to the ITACA database (). This dataset has been used by many authors in scientific papers and by engineers, geophysicists and geologists for professional technical works. In this paper, the present-day available strong-motion signals from the L’Aquila sequence and the performance of the Italian strong-motion network in terms of the number and quality of recorded data, the geometry and data transmission system are described. In addition the role of the temporary network that represents an extension of the permanent Italian strong-motion network, supporting the emergency response by civil protection authorities and improving the network coverage has been evaluated.  相似文献   

Shell‐shape and morphometric variability in Mytilus galloprovincialis from micro‐tidal environments: responses to different hydrodynamic drivers          下载免费PDF全文

Vanessa Moschino  Monica Bressan  Luigi Cavaleri  Luisa Da Ros 《Marine Ecology》2015,36(4):1440-1453

Tidal conditions differently influence inter‐tidal organisms in terms of general physiological and metabolic responses. In this study we investigated the morphological response in shells of Mytilus galloprovincialis native to different micro‐tidal coastal environments in the Northern Adriatic Sea. Our purpose was to highlight the ecophenotypic variability across tidal levels and to elucidate how tidal currents and waves produced by anthropogenic activities may play a part in modulating shell morphology. Three sampling sites were selected: an open‐sea area 15 km off‐shore and two sites within the lagoon of Venice, the first near one of its three inlets, and the other one in the proximity of Venice city centre. At each sampling site, organisms were seasonally collected at different depths within their vertical zonation, either in the inter‐tidal zone – i.e. at both the highest and lowest tide zonation limits, and subtidally. The mussel shells were analysed by investigation of their morphometric relationships (height/length and width/length ratios) and by elliptic Fourier analysis of the shell contours. Shell thickness and condition index were also evaluated for a better comprehension of energy allocation/partitioning. Estimates based on long‐term measurements, visual observation, wind statistics and wave growth laws allowed an evaluation of the forces acting on shells. At the open‐sea site, the observed phenotypic variability of both shell shape and thickness was clearly related to the tidal vertical zonation. At the two lagoon sites, the currents generated by tidal flow through the inlet and the waves caused by the frequent passage of boats influenced both shell shape and thickness. A trade‐off between protection and growth was apparent along the tide gradient, as emphasized by the differences in the partitioning and allocation of energy between shell and flesh production.  相似文献   

Sequence stratigraphic framework of a mixed turbidite-contourite depositional system along the NW slope of the South China Sea   总被引：1，自引：0，他引：1  

Luisa Palamenghi  Hanno Keil  Volkhard Spiess 《Geo-Marine Letters》2015,35(1):1-21

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Seismostratigraphic analysis with centennial to decadal time resolution of the sediment sink in the Ganges-Brahmaputra subaqueous delta     

Luisa Palamenghi  Tilmann SchwenkVolkhard Spiess  Hermann R. Kudrass 《Continental Shelf Research》2011,31(6):712-730

The deltas of large rivers have become the focus of many research studies due to their vulnerability in times of expected sea level rise. One major delta in peril is the Ganges-Brahmaputra Delta (Bangladesh) due to its low elevation and high subsidence rate. In this study, high-resolution seismic and sediment echosounder data of the subaqueous part of the delta are analyzed by an integrated seismo-acoustic stratigraphic approach.Transparent Units (TUs) are the most prominent, continuously traceable architectural elements within the sigmoidal clinoform. TUs consist of homogenized sediments and are interpreted to be formed by liquefaction flows generated by subduction-related earthquakes of the nearby plate-boundary. The uppermost TUs are related to the historical well known major earthquakes which occurred in 1762, 1897 and 1950. Using the TUs as time marks the mean annual storage rates for the intervals could be assessed. A direct comparison of echosounder data gathered in 1994, 1997 and 2006 is used as another method to estimate the last decade mean annual storage rate.In general, the averaged decadal to centennial mean annual storage rates in the foreset beds have significantly decreased within the last ∼300 years from 22% to 18% and down to 13.8% of the present total annual fluviatile suspension supply to the delta (10⁹ t a⁻¹). This decrease, however, is not evenly distributed along the foreset beds. In the western clinoform mean annual storage rates slightly decreased during the last ∼300 years, whereas in the eastern clinoform the mean annual storage rate of the last decade is one-third of the initial value in the late eighteenth century.The variation of clinoform slope angles generally coincides with the local accumulation rates but a variable degree of asymmetry gives some new insights in the future trend of the subaqueous delta development. The sink of sediment in the western clinoform depocentre landward of the inflection point, where shape changes from convex to concave, is producing an increase in concavity.The decline in monsoon precipitation over the last centuries is assumed to have significantly contributed to the decreased mean annual storage rate in the eastern clinoform where the convexity of the clinoform increases seaward of the inflection point. It is very likely that the whole depocentre of the fluvial sediment load is shifting toward the western subaqueous delta and to the Swatch of No Ground Canyon and, thereby, increasing the export to the deep-sea fan.  相似文献   

Complex fault structure interactions of crustal shear zones revealed by seismic anisotropy: an example in the eastern betic cordillera (Spain)     

Luisa Buontempo  Andreas Wuestefeld 《地学学报》2013,25(1):57-64

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Overwintering of terrestrial Arctic arthropods: the fauna of Svalbard now and in the future     

María Luisa Ávila-Jiménez  Stephen J. Coulson  Torstein Solhøy  & Anna Sjöblom 《Polar research》2010,29(1):127-137

There are over 500 species of arthropods recorded from Svalbard. These animals overwinter either within the soil or on the ground surface, and have to tolerate an environment where the ground is frozen for over 9 months each year. Three cold-tolerance strategies have been described from Svalbard invertebrates: freeze avoidance, freeze tolerance and desiccation. Once in a cold-tolerant state the animals can be extremely cold tolerant in terms of both minimum exposure temperature and period of exposure. How the overwintering capabilities of these animals will be affected by climate changes during the next 100 years, as predicted by climate models, is not yet known. Four principle factors with an impact on overwintering of the terrestrial arthropod fauna are outlined here: (1) warmer winter temperatures, with an increased frequency of extreme events such as freeze–thaw cycles and surface icing; (2) changes in snow fall and snow lie; (3) pollutant load; and (4) dispersal of invertebrates to Svalbard. Finally, areas where further research is required are highlighted: including the development of controlled multi-season field experiments; effect of freeze–thaw cycles; changes in thickness and distribution of snow lie, with the subsequent effects on duration of the summer period; chill susceptibility of soil arthropods; assessing potential colonizing species and the likelihood of these species becoming established; assessing the effect of gene flow from surrounding populations; interactions between pollution and cold tolerance; anoxia stress; and the genetics of cold tolerance.  相似文献