The arsenic source term for an in-pit uranium mine tailings facility and its long-term impact on the regional groundwater     

Brett J. Moldovan  M. Jim Hendry  Glenn A. Harrington 《Applied Geochemistry》2008

Detailed field sampling and analyses and laboratory-based diffusion-cell experiments were used in conjunction with 3-D reactive transport modeling (MODFLOW and MT3D99) to quantify the fate and long-term (10 ka) transport of As in the Rabbit Lake In-pit Tailings Management Facility (RLITMF), northern Saskatchewan, Canada. The RLITMF (300 m × 425 m × 90 m thick) was engineered to ensure solute transport within the RLITMF is dominated by diffusion. Concentrations of As in the tailings pore fluids ranged from 0.24 to 140 mg/L (n = 43). Arsenic speciation analyses indicate 90% of this arsenic exists as As⁵⁺. This observation is supported by pH–Eh measurements of pore fluids (n = 135). Geochemical analyses yielded a strong inverse correlation between the Fe/As molar ratio in the tailings solids and the corresponding concentration of dissolved As, which is attributed to the adsorption of As to secondary 2-line ferrihydrite present in the tailings. Diffusion-cell testing yielded values for the effective diffusion coefficient, sorption coefficient, and effective porosity of As in the tailings of 4.5 × 10⁻¹⁰ m²/s, 2–4 cm³/g and 0.36, respectively. Reactive transport simulations using the field and laboratory data show adsorption of As to the tailings and diffusive transport of dissolved As in the tailings should reduce the source term concentration of As to between 40% and 70% of the initial concentrations over the 10 ka simulation period. Based on these simulations, the As concentrations in the regional groundwater, 50 m down gradient of the tailings facility, should be maintained at background concentrations of 0.001 mg/L over the 10 ka period. These findings suggest the engineered in-pit disposal of U mine tailings can provide long-term protection for the local groundwater regime from As contamination.  相似文献   

Soluble organic compounds in fog and cloud droplets: what have we learned over the past few years?     

Sandro Fuzzi  Maria Cristina Facchini  Stefano Decesari  Emanuela Matta  Mihaiela Mircea 《Atmospheric Research》2002,64(1-4)

We have recently set up a new procedure for characterising the water soluble organic compounds (WSOC) in fog water, for which information is still rather limited. Fog samples collected during the 1998–1999 fall–winter season in the Po Valley (Italy) were analysed following this procedure, which allows a quantitative determination of three main classes of organic compounds (neutral species, mono- and di-carboxylic acids, polycarboxylic acids), together accounting for ca. 85% of the total WSOC. This procedure also provides information on the main chemical characteristics of these three classes of compounds (functional groups, aliphatic vs. aromatic character, etc.). The enhanced chemical knowledge on fog/cloud chemical composition opens new scenarios as far as chemical and microphysical processes in clouds and fogs are concerned.  相似文献   

Environmental protection in the Apuseni Mountains: The role of Environmental Non-Governmental Organisations (ENGOs)     

Mircea Buza  Levente Dimen  Grigor Pop  David Turnock 《GeoJournal》2001,55(2-4):631-653

The Apuseni Mountains constitute one of the most interesting parts of the Carpathians in terms of landscape, biodiversity and culture. Yet dislocations are now severe and there are development threats which also require a significant response. On the one hand there are some severe pollution problems associated with mining areas developed in the communist period which require remedial action and the cases of Roşia Montana and Zlatna are discussed. On the other hand, there are forest and pasture zones – especially the Padiş Plateau – which are coming under heavy pressure from farmers seeking to enhance their incomes following the decline of mining and manufacturing which has left many households without salaries. At the same time, tourist pressure is growing. Actions are already being taken to limit pollution damage and develop sustainable landuse practices. There is a national park project linked with nature reserves comprising picturesque landscapes, a rare flora and fauna and distinct geological and palaeotological formations (including fossil ice). There are major tourist attractions and with proper management they could become part of a development programme of the countryside. However it is essential that all stakeholders adopt sustainable practices and this means that official programmes – including the future national park authority administration's work in environment protection and tourism management – are backed up by Environmental Non-Governmental Organisations (ENGOs). The paper reviews their diverse activities and concludes that they are making a very substantial contribution in ensuring that the potentials of isolated regions can be utilised in a manner consistent with nature conservation. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Aperçu synthétique sur la tectonique des Carpates Roumaines     

Prof. Dr. Mircea D. Ilie 《International Journal of Earth Sciences》1970,59(2):605-623

Résumé À la constitution des Carpates Roumaines participent les plissements hercyniens et carpatiques.Les déformations géométriques hercyniennes ont résulté des plissements profonds déterminés par le métamorphisme régional. Elles ont influencé d'une manière de plus en plus atténuée les plissements carpatiques. Pendant le paroxisme mésocrétacé, la tectonique carpatique a engendré des nappes de décollement et des glissements grâce à un simple mécanisme, expliqué par la pesanteur.Les nappes à vergences anticarpatiques se sont formées pendant la phase laramienne. Elles sont également le résultat de la pesanteur associée à l'action de la sous-poussée.Les nappes polygénétiques sont les nappes les plus jeunes et caractérisent les zones du Flysch des Carpates Orientales.Pendant le Tertiaire, une tectonique cassante a prédominé dans les Carpates.

---

The Romanian Carpathians consist of three subdivisions, each of them having its tectonical features, namely: Eastern Carpathians, Southern Carpathians and Apuseni Mountains.Their architecture consists of Hercynian and Carpathian foldings. The Hercynian tectonics is due to the deep foldings during the metamorphism which called forth the metanappes. The Hercynian foldings have printed their characters into the Carpathian tectonics and into the evolution of the palaeomesozoical sedimentary zones.During the mesocretaceous phase, the gravitational tectonics develop into the Carpathian realm, generating the gravitational nappes of the Metalliferous Mountains, the Raru-Hsma massif and the Perani Mountains.The overthrusts took place at the surface and are not due to the lateral contraction of the rocks in the depth.The anticarpathian vergences are characteristic for the Laramian nappes.The Flysch tectonics is characterized by polygenetic nappes, formed during a long period and developed all along the chain.The ruptural tectonics developed in the Romanian Carpathians during Tertiary.

---

Zusammenfassung Die rumänischen Karpaten lassen sich in drei Einheiten teilen, jede mit ihrer Besonderheit: Ostkarpaten, Südkarpaten und Apuseni-Gebirge. Ihr Bau besteht aus herzynischen und karpatischen Elementen. Die herzynische Tektonik ist die Folge der während der Metamorphose entstandenen Tieffaltungen, welche Metadecken hervorgebracht haben. Die herzynischen Faltungen zeigen sich im karpatischen Bau und in der Ablagerungsgeschichte. Während der mittelkretazischen Faltungsbewegungen hat die Abscherungs- und Fließtektonik das karpatische Gebiet ergriffen und das Entstehen der Schweredecken im Erzgebirge, in den Raru- und Hsma-Massiven sowie im Perani-Gebirge bedingt. Die Decken sind die Folge der in der Nähe der Erdoberfläche ablaufenden Bewegungen und keineswegs des seitlichen Druckes der Tiefgesteine. Die laramischen Decken sind durch antikarpatische Vergenzen charakterisiert und auf die Unterschiebungen der alten Blöcke zurückzuführen. Die Tektonik des Flysches zeichnet sich durch polygenetische Decken aus, die sich während mehrerer Perioden, entlang dem Faltenstreichen, entwickelt haben. Die Bruchtektonik setzte in den rumänischen Karpaten erst während des Neozoikums ein.

---

. , , . , , . . .

  相似文献   

Source parameters of intermediate-depth Vrancea (Romania) earthquakes from empirical Green's functions modeling     

Adrien Oth  Friedemann Wenzel  Mircea Radulian 《Tectonophysics》2007,438(1-4):33-56

Several source parameters (source dimensions, slip, particle velocity, static and dynamic stress drop) are determined for the moderate-size October 27th, 2004 (M_W = 5.8), and the large August 30th, 1986 (M_W = 7.1) and March 4th, 1977 (M_W = 7.4) Vrancea (Romania) intermediate-depth earthquakes. For this purpose, the empirical Green's functions method of Irikura [e.g. Irikura, K. (1983). Semi-Empirical Estimation of Strong Ground Motions during Large Earthquakes. Bull. Dis. Prev. Res. Inst., Kyoto Univ., 33, Part 2, No. 298, 63–104., Irikura, K. (1986). Prediction of strong acceleration motions using empirical Green's function, in Proceedings of the 7th Japan earthquake engineering symposium, 151–156., Irikura, K. (1999). Techniques for the simulation of strong ground motion and deterministic seismic hazard analysis, in Proceedings of the advanced study course seismotectonic and microzonation techniques in earthquake engineering: integrated training in earthquake risk reduction practices, Kefallinia, 453–554.] is used to generate synthetic time series from recordings of smaller events (with 4 ≤ M_W ≤ 5) in order to estimate several parameters characterizing the so-called strong motion generation area, which is defined as an extended area with homogeneous slip and rise time and, for crustal earthquakes, corresponds to an asperity of about 100 bar stress release [Miyake, H., T. Iwata and K. Irikura (2003). Source characterization for broadband ground-motion simulation: Kinematic heterogeneous source model and strong motion generation area. Bull. Seism. Soc. Am., 93, 2531–2545.] The parameters are obtained by acceleration envelope and displacement waveform inversion for the 2004 and 1986 events and MSK intensity pattern inversion for the 1977 event using a genetic algorithm. The strong motion recordings of the analyzed Vrancea earthquakes as well as the MSK intensity pattern of the 1977 earthquake can be well reproduced using relatively small strong motion generation areas, which corresponds to small asperities with high stress drops (300–1200 bar) and high particle velocities (3–5 m/s). These results imply a very efficient high-frequency radiation, which has to be taken into account for strong ground motion prediction, and indicate that the intermediate-depth Vrancea earthquakes are inherently different from crustal events.  相似文献   

Digitized Database of Old Seismograms Recorder in Romania     

Daniel Paulescu  Maria Rogozea  Mihaela Popa  Mircea Radulian 《Acta Geophysica》2016,64(4):963-977

The aim of this paper is to describe a managing system for a unique Romanian database of historical seismograms and complementary documentation (metadata) and its dissemination and analysis procedure. For this study, 5188 historical seismograms recorded between 1903 and 1957 by the Romanian seismological observatories (Bucharest-Filaret, Foc?ani, Bac?u, Vrincioaia, Câmpulung-Muscel, Ia?i) were used. In order to reconsider the historical instrumental data, the analog seismograms are converted to digital images and digital waveforms (digitization/ vectorialisation). First, we applied a careful scanning procedure of the seismograms and related material (seismic bulletins, station books, etc.). In a next step, the high resolution scanned seismograms will be processed to obtain the digital/numeric waveforms. We used a Colortrac Smartlf Cx40 scanner which provides images in TIFF or JPG format. For digitization the algorithm Teseo2 developed by the National Institute of Geophysics and Volcanology in Rome (Italy), within the framework of the SISMOS Project, will be used.  相似文献   

The impact of climatic and non-climatic factors on land surface temperature in southwestern Romania     

Cristina?Florina?Ro?caEmail author  Gabriela?Victoria?Harpa  Adina-Eliza?Croitoru  Ioana?Herbel  Alexandru?Mircea?Imbroane  Doina?Cristina?Burada 《Theoretical and Applied Climatology》2017,130(3-4):775-790

Land surface temperature is one of the most important parameters related to global warming. It depends mainly on soil type, discontinuous vegetation cover, or lack of precipitation. The main purpose of this paper is to investigate the relationship between high LST, synoptic conditions and air masses trajectories, vegetation cover, and soil type in one of the driest region in Romania. In order to calculate the land surface temperature and normalized difference vegetation index, five satellite images of LANDSAT missions 5 and 7, covering a period of 26 years (1986–2011), were selected, all of them collected in the month of June. The areas with low vegetation density were derived from normalized difference vegetation index, while soil types have been extracted from Corine Land Cover database. HYSPLIT application was employed to identify the air masses origin based on their backward trajectories for each of the five study cases. Pearson, logarithmic, and quadratic correlations were used to detect the relationships between land surface temperature and observed ground temperatures, as well as between land surface temperature and normalized difference vegetation index. The most important findings are: strong correlation between land surface temperature derived from satellite images and maximum ground temperature recorded in a weather station located in the area, as well as between areas with land surface temperature equal to or higher than 40.0 °C and those with lack of vegetation; the sandy soils are the most prone to high land surface temperature and lack of vegetation, followed by the chernozems and brown soils; extremely severe drought events may occur in the region.  相似文献   

L'automatisation du calcul de la déviation de la verticale     

Mircea Mihailescu 《Studia Geophysica et Geodaetica》1970,14(2):183-186

  相似文献   

Tectonique rupturale des Précarpates Roumaines     

Prof. Dr. Mircea D. Ilie 《International Journal of Earth Sciences》1973,62(2):595-611

Résumé L'application de données géologiques, géomorphologiques, géophysiques et géochimiques ont permis à l'auteur de reconnaÎtre dans l'avant-pays des Carpathes roumaines une série de types importants de systèmes de fractures, et de leurs associations. L'avant-pays consiste en un socle précambrien-calédonien-hercynien métamorphique et plissé. Son étage supérieur consiste en sédiments de différents âges qui ont été fracturés. Comme les fractures du socle se continuent dans l'étage supérieur, il est possible d'expliquer la tectonique cassante du domaine profond. Les systèmes de fractures de l'avant-pays carpathique permettent d'établir de nouvelles subdivisions en particulier une unité carpatho-transdanubienne consistant dans le bloc géthique et valachien, et une unité carpatho-pyréthique comprenant le compartiment inférieur de l'Oberland et du Niederland. Entre les unités précarpathiques et la chaÎne plissée carpathique, il existe des rapports tridimensionnels qui expliquent l'origine et l'évolution de la chaÎne carpathique.

---

The author has identified an important number of types and associations of ruptural lines in the vorland of the Romanian Carpathians, consisting of an old (Precambrian— Caledonian and Hercynian) metamorphised and strongly folded basement. The cover of this vorland is formed of Mesozoic—Tertiary slightly folded, monoclinal or quasihorizontal deposits. The disjonctive deformations of the vorland being transmitted into the superstructure have allowed the identification of the ruptural tectonics. The disjonctival systems of the Carpathian vorland have shown a new subdivision of the Pre-Carpathian units, namely: the Carpatho-Transdanubian unit consisting of the Getic block and the Valachian block and the Carpatho-Pyretheean unit formed of the subunits ara de Sus and ara de Jos. Between these units and the Carpathian realm there are tridimensional connections which explain both the origin and the evolution of the Carpathians.

---

Zusammenfassung Unter Anwendung von geologischen, geomorphologischen, geophysischen und geochemischen Ergebnissen gelang es dem Verfasser, im Vorland der rumÄnischen Karpaten eine Reihe von wichtigen Typen und Vergesellschaftungen von Bruchsystemen festzustellen. Das Vorland besteht aus einem stark gefalteten und metamorphisierten vorkambrischen, kaledonisch-herzynischen Grundgebirge. Der Oberbau desselben besteht aus Ablagerungen verschiedenen Alters, die gestört sind. Da die Brüche des Grundgebirges sich auch im Oberbau fortpflanzen, ist es möglich, die Bruchtektonik der Tiefe zu klÄren. Die Bruchsysteme des karpatischen Vorlandes erlauben eine neue Unterteilung desselben, und zwar in eine karpatisch-transdanubische Einheit, welche aus den getischen und walachischen Blöcken besteht, und in eine karpatisch-pyretische Einheit, die aus Unterabteilungen des Ober- und des Niederlandes besteht. Zwischen den vorkapatischen Einheiten und dem karpatischen Faltungssystem bestehen dreidimensionale VerhÄltnisse, welche die Entstehung und die Umgestaltung der Karpatenkette erklÄren.

---

, , . - . — , . . . , . - , , - , . , .

  相似文献   

On the period variability of GP andromedae     

Alexandru Pop  Victor Liteanu  Dan Moldovan 《Astrophysics and Space Science》2003,284(4):1207-1222

The present paper deals with the pulsation period variability of the high-amplitude δ Scuti star GP Andromedae using a data set covering a time base of 26.9 years. The possibility of a periodic component (reflecting the light-time effect induced by a hypothetic binarity) in the O-C curve is inferred. The presence of this periodicity in the period variation of GP And leads to a diminution of the discrepancy between predicted and observed relative period change rates. The hypothesis of the existence of an unseen companion is discussed. The statistical analysis of the final O-C residuals distribution, indicates their normal or close to normal character. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献