The chemical composition of surface water in the influence zone of the Severonikel smelter     

V. A. Dauval’ter  M. V. Dauval’ter  N. V. Saltan  E. N. Semenov 《Geochemistry International》2009,47(6):592-610

This paper reports data on the chemical composition of surface waters (predominant ions and trace elements: approximately 40 parameters and elements) in the influence zone of the Severonikel Cu-Ni smelter in the town of Monchegorsk, Murmansk oblast. The long-continued discharge of waste waters has increased the mineralization and changed the proportions of ions in surface waters in the area: water in the sewage pond of the smelter is classed with brackish waters of the S ₄ ^2? class, Na⁺ group. The sequence of major ions in water bodies under aerotechnogenic load retains the natural succession of major cations, but their concentrations slightly increase. The maximum concentration of ions in the surface waters of the Monchegorsk testing area were detected in wintertime, and the minimum contents occur during the high water period. Water bodies under aerotechnogenic load are characterized by average mineralization values much higher than is natural. The highest concentrations of Ni and Cu (two to three orders of magnitude higher than the assumed background values) and practically all trace elements were found in water bodies receiving waste waters from the smelter. The concentrations of Ni and other heavy metals in the Moncha River are much lower than in other water bodies but more than one order of magnitude higher than the assumed background concentrations.  相似文献   

On the accuracy of the ground force estimated in vibroseis acquisition   总被引：1，自引：0，他引：1  

Christos Saragiotis  Péter Scholtz  Claudio Bagaini 《Geophysical Prospecting》2010,58(1):69-80

For a linear elastic Earth the time derivative of the ground force is considered proportional to the far-field wavelet. Under the assumption that the baseplate is stiff and the bending forces of the baseplate are negligible, the ground force is also approximated by the sum of the accelerations of the baseplate and the reaction mass weighted by the respective masses. Combining these two assumptions, the time derivative of the weighted sum is considered proportional to the far-field wavelet. This result, often referred to as the far-field wavelet assumption, although convenient and most often employed is not always valid. We explore its validity using the spectral harmonic ratios of recorded data, which are used extensively in data filtering and analysis of vibratory data. We show that the far-field wavelet assumption fails particularly for harmonic components of even order. More compact soil after repeated shots further invalidates this assumption. Non-linear modelling of the ground under the vibrator point may provide a direction towards solving this discrepancy. Finally, we describe a method for the estimation of the harmonic spectral ratios.  相似文献   

Dynamics of grains falling on a sloping granular medium: application to the evolution of a talus          下载免费PDF全文

Fabio Vittorio De Blasio  May‐Britt Sæter 《地球表面变化过程与地形》2015,40(5):599-609

Numerous field surveys have provided quantitative information on the characteristics of talus deposits. Much less has been done to quantify the basic dynamics processes of blocks involved in talus evolution. In this work, we perform a set of experiments at the reduced scale of some metres using an inclined board covered with a loose granular medium. The complexity of the processes forming a talus is simplified by studying the interaction of only two kinds of grain sizes at a time. Grains of one class size are dropped from a fixed height onto the board covered by a layer of grains of a different class size, and their final distribution is recorded. We find that when small grains fall on large grains, the granular abundance decreases rapidly as a function of the distance from the fall point, which is explained by the effect of multiple bouncing on the irregular surface. In contrast, large grains falling on a bed of smaller grains lose much more energy at impact. They may stop at once, or roll down slope, often reaching the whole board length; as a consequence, their abundance peaks in the fall zone and at the change of slope. Experiments also show that grains travel longer with increasing fall height and sloping angle. The results clarify in a physical manner one mechanism that might explain why large blocks are typically found in the distal part of a talus slope, while smaller blocks remain near the fall zone. Based on these and previous experiments, a schematic view of talus evolution is discussed. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Single element and competitive sorption of copper, zinc and lead onto a Luvisol profile     

Péter Sipos 《Central European Journal of Geosciences》2009,1(4):404-415

The sorption parameters of Cu, Zn and Pb are related to the composition of the different genetic horizons of a Luvisol profile in batch sorption experiments. The affinities of metals towards the soil samples from different horizons followed the same sequence, e.g. Pb≥C>>Zn. By far the highest metal retention was found in the C_k horizon due to the alkaline conditions. It is followed by the A horizon with its high organic matter content, while the lowest sorption capacity was found in the Bt horizon. In the horizons free of carbonate, primarily Pb and Cu were immobilized. The studied soil can be characterized by high amount of organic matter, clay accumulation horizon, as well as calcareous subsoil. This kind of profile development makes soils able to immobilize a significant metal pollution.  相似文献   

Distribution and sorption of potentially toxic metals in four forest soils from Hungary     

Péter Sipos 《Central European Journal of Geosciences》2009,1(2):183-192

Metals of natural and anthropogenic origin behave differently in soils mostly due to their different mobility. In this study, sequential extractions and batch sorption experiments were performed to relate the fractionation of native Ni, Cu, Zn and Pb to the sorption properties of added metals in four soils with contrasting physiochemical characteristics. A significant effect due to sample composition on both the mobility and sorption characteristics of these metals was found. The efficiency of soil components in metal immobilization was in the order of carbonate > organic matter > swelling clay minerals. The partitioning of native metals together with the information gained through the sorption isotherms allows a deeper insight on the fate and behavior of metals in soils with various compositions.  相似文献   

Regional and global effects of southern ocean constraints in a global model     

Michael P. Schodlok  Manfred Wenzel  Jens G. Schröter  Hartmut H. Hellmer 《Ocean Dynamics》2008,58(3-4):155-168

Global ocean circulation models do not usually take high-latitude processes into account in an adequate form due to a limited model domain or insufficient resolution. Without the processes in key areas contributing to the lower part of the global thermohaline circulation, the characteristics and flow of deep and bottom waters often remain unrealistic in these models. In this study, various sections of the Bremerhaven Regional Ice Ocean Simulation model results are combined with a global inverse model by using temperature, salinity, and velocity constraints for the Hamburg Large Scale Geostrophic ocean general circulation model. The differences between the global model with and without additional constraints from the regional model demonstrate that the Weddell Sea circulation exerts a significant influence on the course of the Antarctic Circumpolar Current with consequences for Southern Ocean water mass characteristics and the spreading of deep and bottom waters in the South Atlantic. The influence of the Ross Sea is found to be less important in terms of global influences. However, regional changes in the Pacific sector of the Southern Ocean are found to be of Ross Sea origin. The additional constraints change the hydrographic conditions of the global model in the vicinity of the Antarctic Circumpolar Current in such a way that transport values, e.g., in Drake Passage no longer need to be prescribed to obtain observed transports. These changes not only improve the path and transport of the Antarctic Circumpolar Current but affect the meso- and large-scale circulation. With a higher (lower) mean Drake Passage transport, the mean Weddell Gyre transport is lower (higher). Furthermore, an increase (decrease) in the Antarctic Circumpolar Current leads to a decrease (increase) of the circum-Australian flow, i.e., a decrease (increase) of the Indonesian Throughflow.  相似文献   

Very precise orbits of 1998 Leonid meteors     

Hans BETLEM  Peter JENNISKENS  Jaap van &#x;t LEVEN  Casper ter KUILE  Carl JOHANNINK  Haibin ZHAO  Chenming LEI  Guanyou LI  Jin ZHU  Steve EVANS  Pavel SPURNÝ 《Meteoritics & planetary science》1999,34(6):979-986

Abstract— Seventy-five orbits of Leonid meteors obtained during the 1998 outburst are presented. Thirty-eight are precise enough to recognize significant dispersion in orbital elements. Results from the nights of 1998 November 16/17 and 17/18 differ, in agreement with the dominant presence of different dust components. The shower rate profile of 1998 November 16/17 was dominated by a broad component, rich in bright meteors. The radiant distribution is compact. The semimajor axis is confined to values close to that of the parent comet, whereas the distribution of inclination has a central condensation in a narrow range. On the other hand, 1998 November 17/18 was dominated by dust responsible for a more narrow secondary peak in the flux curve. The declination of the radiant and the inclination of the orbit are more widely dispersed. The argument of perihelion, inclination, and the perihelion distance are displaced. These data substantiate the hypothesis that trapping in orbital resonances is important for the dynamical evolution of the broad component.  相似文献   

Mineralogy,chemistry, and noble gas contents of Adzhi-Bogdo– an LL3–6 chondritic breccia with L-chondritic and granitoidal clasts     

A. Bischoff  T. Geiger  H. Palme  B. Spettel  L. Schultz  P. Scherer  J. Schlüter  J. Lkhamsuren 《Meteoritics & planetary science》1993,28(4):570-578

Abstract— Adzhi-Bogdo is an ordinary chondrite regolith breccia (LL3–6) which fell on 1949 October 30 in Gobi Altay, Mongolia. The rock consists of submm- to cm-sized fragments embedded in a fine-grained clastic matrix. The polymict breccia contains various types of clasts, some of which must be of foreign origin. Components of the breccia include chondrules, melt rock clasts (some of which are K-rich), highly recrystallized rock fragments (“granulites”), breccia clasts, pyroxene-rich fragments with achondritic textures, and alkali-granitoids. The composition of olivine in most fragments is in the range of LL-chondrites. However, olivine in some components has significantly lower fayalite contents, characteristic of L-chondrites. The bulk meteorite is very weakly shocked (S2). Based on the bulk chemical composition, Adzhi-Bogdo is an ordinary chondrite. The concentrations of Fe and Ni are somewhat intermediate between L- and LL-chondrites. The contents of solar gases indicate that Adzhi-Bogdo is a regolith breccia. Most of the solar He and probably a part of the solar Ne of Adzhi-Bogdo has been lost. It is suggested that Adzhi-Bogdo experienced an (impact-induced) thermal event early in its history, because most of the radiogenic ⁴⁰Ar is retained.  相似文献   

On the centre-to-limb variation and latitude dependence of the asymmetry and wavelength shift of the solar line λ 5576     

P. N. Brandt  E. H. Schröter 《Solar physics》1982,79(1):3-18

Low noise photoelectric measurements of the line profile of the g = 0 Fe line gl 5576.097 combined with determinations of the wavelength shift of its centre calibrated by use of an I ₂ absorption tube are reported. Measurements taken at various limb distances (1.0 cos 0.2) and along 4 different diameters of the Sun are used to investigate the behaviour of the line asymmetry (C-shape) and wavelength shift of the line centre as functions of cos and of latitude and to search for possible pole-equator differences.An accuracy of approx. 0.8 mÅ r.m.s. is achieved for the determination of the centre of the solar line relative to the iodine lines and of 0.3 mÅ to 1 mÅ r.m.s. for the relative variations of the C-shape. The analysis shows a significant difference between the limb-effect curves along polar and equatorial diameters for cos 0.4 and changes of the C-shape for 0.9 cos 0.6 with a rather strong indication of a latitude dependence of the C-shape. This latitude dependence may account for the so-called ears observed by Howard et al. (1980) who used the well-known Doppler compensator method which integrates the line asymmetry from the line wings to the core.Mitteilungen aus dem Kiepenheuer-Institut Nr. 207.  相似文献   

Combination of common-midpoint-refraction seismics with the generalized reciprocal method     

Dirk Orlowsky  Horst Rüter  Lothar Dresen 《Journal of Applied Geophysics》1998,39(4):221-235

A useful method for increasing the signal/noise ratio of refracted waves is Common-Midpoint (CMP)-refraction seismics. With this technique the shallow underground can be described in detail using all information (amplitude, frequency, phase characteristics) of the wavetrain following the first break (first-break phase). Thus, the layering can be determined and faults, weak zones, and clefts can be identified. This paper deals with the optimization of CMP-refraction seismics used in combination with the Generalized Reciprocal Method (GRM). Theoretical studies show a close relationship of both methods to the kinematics of wave propagation. Velocities and optimum offsets determined by the GRM can be used directly in the partial Radon transformation in CMP-refraction seismics. The integration of refracted waves leads to an increase in the signal/noise ratio but simultaneously the integration boundaries must be restricted to deal only with selective parts of the investigated refractor. The result of this process is an intercept-time section which can be converted directly to a depth section using standard refraction seismic techniques. Another possibility of depth conversion is the transformation of this intercept-time section to a `pseudo-zero-offset section', known from reflection seismics. Thus, zero-offset sections can be migrated using wave-equation techniques such as Kirchhoff migration.  相似文献