Estimation of clay content in soil based on resistivity modelling and laboratory measurements     

Vladimir Shevnin  Aleksandr Mousatov  Albert Ryjov  Omar Delgado-Rodriquez 《Geophysical Prospecting》2007,55(2):265-275

The determination of clay content in near‐surface formations is crucial for geotechnical, hydrogeological and oil‐contamination studies. We have developed a technique for estimating clay content that consists of the minimization of the difference between the theoretically calculated and measured soil resistivities as a function of water salinity. To calculate the resistivity, we used a model that takes into account the electrochemical processes in the clay micropores. The experimental measurements of soil resistivity were performed on soil samples, completely saturated by brines at different concentrations of NaCl salt in the range 0.6–100 g/l, to obtain the resistivity versus salinity curve. The parameters obtained with this curve inversion are the clay content, the total porosity and the cation exchange capacity. To verify the new technique, we determined clay concentrations of artificial mixtures of calibrated sand and clay. The relative mean error in the clay content does not exceed 20% for a 5% fitting error of the resistivity versus salinity curves. Such evaluations allow the correct separation of the main lithological groups (sand, sandy loam, loam, and light, medium and heavy clay). We applied this technique to estimate the petrophysical parameters of soils (clay content, porosity and cation exchange capacity) at various sites in Mexico. The results improved the interpretation of the vertical electrical soundings, the lithological soil characterization and the delineation of oil‐contaminated areas.  相似文献   

Assimilation-fractional crystallization of Polvadera Group rocks in the northwestern Jemez Volcanic Field,New Mexico     

Bradley S. Singer  Albert M. Kudo 《Contributions to Mineralogy and Petrology》1986,94(3):374-386

Pliocene Polvadera Group rocks in the northwestern Rio Grande rift-marginal portion of the Jemez Volcanic Field record the rapid transition from weakly alkaline Lobato Basalt magmatism (48–52% SiO₂; 7.9 Ma) through calc-alkaline Lobato andesite and dacite (53–64% SiO₂) and Tschicoma dacite-rhyodacite magmatism (63–69% SiO₂; 7.4 Ma). Petrologically, Lobato andesite and dacite and Tschicoma dacite-rhyodacite represent a cogenetic suite of differentiates (the La Grulla Plateau or LGP suite) distinctive from the bulk of Polvadera Group rocks including Tschicoma andesite. Increasing (⁸⁷Sr/⁸⁶Sr)_O ratios with differentiation within the LGP suite from 0.7051 (54% SiO₂) to 0.7064 (68% SiO₂), trace element variations, and disequilibrium mineral assemblages suggest open system differentiation involving ⁸⁷Sr-enriched upper crust. A likely parental magma is the voluminous Lobato Basalt ((⁸⁷Sr/⁸⁶)_O= 0.7043–0.7050) which was erupted predominantly earlier and to the east toward the rift axis. The best model for petrogenesis involves bulk assimilation of locally wide-spread Proterozoic (1.4–1.6 Ga) upper crustal granite by fractionally crystallizing Lobato Basalt. Assimilation-fractional crystallization (AFC) modeling of Sr-isotope and trace element variation (DePaolo 1981) indicates that 40% crystallization of Lobato Basalt accompanied by 10% addition of granite reproduces the observed geochemical and Sr-isotopic diversity. Neither magma mixing, nor mafic recharge have complicated the magmatic evolution of the LGP suite. Crustal thickness and/or retarded tectonism could have facilitated conditions necessary for evolution by AFC to occur within the upper crust.  相似文献   

Aswan telemetered seismograph network     

D.W. Simpson  R.M. Kebeasy  C. Nicholson  M. Maamoun  R.N.H. Albert  E.M. Ibrahim  A. Megahed  A. Gharib  A. Hussain 《Journal of Geodynamics》1987,7(3-4)

A telemetered network of 8 short-period seismograph stations was installed at Aswan Reservoir in July 1982 to monitor induced seismicity near the site of a magnitude 5 earthquake which occurred in November 1981. A continuous monitor of the seismicity is provided by pen and ink recording of 4 stations. An event detector is used to identify events of interest, for which all of the stations are recorded on magnetic tape. Approximate displacement magnifications are 40, 000 at 1 hz with a maximum of 500, 000 at 20 hz.  相似文献   

A microearthquake survey in the Abu-Simbel area in Egypt     

S.J. Gibowicz  Z. Droste  R.M. Kebeasy  E.M. Ibrahim  R.N.H. Albert 《Engineering Geology》1983,19(2):95-109

From the middle of January to the middle of March, 1981 a microearthquake survey was conducted jointly by Polish and Egyptian seismologists in the Abu-Simbel area, about 230 km upstream from the Aswan High Dam. A small seismic array composed of six stations and a magnetic-tape digital recording system was operated during the survey. Altogether 63 microearthquakes at epicentral distances of up to 50 km and 12 local earthquakes at distances of up to 200 km were recorded, but only 16 microearthquakes could be properly located. All of them originated either directly under the High Dam Reservoir or close to its shores, thus implying their association with its water level fluctuations.It was deduced that under the Abu-Simbel array a deep fracture zone or deep fault extending in the NNE—SSW direction, 1–3 km wide and several kilometers deep, must be present to explain the observed effects of heavy attenuation and scattering of seismic waves under the array. This fracture zone might be a deep expression of the western edge of the Nile Valley in the Abu-Simbel area.  相似文献   

Geochemistry of modern seawater and brines from salt pans: Main components and bromine distribution     

Albert Günter Herrmann  Doris Knake  Jürgen Schneider  Heide Peters 《Contributions to Mineralogy and Petrology》1973,40(1):1-24

Seawater at different stages of evaporation from the salt works of Seovlje near Portoro (Yugoslavia) was analyzed geochemically. The seawater there passes through 20 stages of concentration until the first halite crystallizes. All important parameters were determined at all stages: concentrations of Cl, SO₄, Na, K, Ca, Mg, and Br, temperature, pH, Eh, oxygen content and titration alkalinity. With increasing evaporation calcium carbonate crystallizes first followed by calcium sulphate as gypsum and after these halite. All three components crystallize from supersaturated solutions. The pH of the initial seawater is 8.32; it falls abruptly to 6.65 when the first calcium carbonate precipitates. Eh in the original seawater is +393 mv; negative values were found in the halite crystallization pans, which contain an anaerobic mud as a reducing agent. The oxygen content of the solution decreases parallel to the drop in Eh. In the pans in which NaCl crystallizes Eh is zero. Apparently the mud also adsorbs K, as can be inferred from a change in the Mg/K ratio.The bromine partition between crystallizing halite and the brine in the salt pans of Seovlje is discussed with regard to some genetic problems of marine salt deposits. In the conditions in the salt pans the bromine partition coefficient at the beginning of NaCl crystallization from seawater—expressed as b=wt.-% Br (mineral)/wt.-% Br (solution)—is 0.12 to 0.14 or—expressed as D=Br/Cl(mineral)/Br/Cl(solution)—0.030 to 0.034 at temperatures between 33° C and 42° C. The conclusion is that a Br content of about 60 to 75 ppm is to be expected for the first halite that crystallizes from evaporating seawater.  相似文献   

Atmosphärische und ozeanische lange Wellen und Wirbelstörungen und ihre Ähnlichkeit mit Trägheitsbewegungen     

Albert Defant 《Ocean Dynamics》1956,9(2):49-55

Zusammenfassung Die völlige Gleichheit der für die äquatoriale Zone der Erde abgeleiteten Trägheitsbewegungen bei F. J. W. Whipple mit den C. G. Rossbyschen langen Wellen in einem breiten stabilen Oststrom und mit den Wirbelstörungen in einer nach W gehenden instabilen Strömung erfordert eine Erklärung, um so mehr als die physikalischen Grundlagen in beiden Fällen völlig verschieden liegen. Eine solche Erklärung wird hier gegeben. Außerdem wird die Trägheitsbewegung auf der rotierenden Erde von solchen Bewegungen abgeleitet, die sich ganz auf einer Hemisphäre abspielen. Sie gelingt in mathematisch einfacher Form. Schließlich wird auf die verschiedene Strömungsstabilität westwärts und ostwärts gehender ozeanischer Ströme hingewiesen und ihr Zusammenhang mit den erwähnten langen Wellen und Wirbelstörungen nach Rossby hervorgehoben.

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Long waves and vorticity in the atmosphere and in the ocean and their resemblance to inertia motions

Summary The complete correspondence of the inertia motions, as derived by F. J. W. Whipple for the equatorial zone of the earth, with Rossby's long waves in a broad stable eastward setting current and with the vorticity phenomena in a westward directed instable current calls for an explanation, especially so as in both cases the underlying physical conditions are of a different nature. This explanation is given in the present paper. Besides, the inertia motion on the revolving earth is derived from motions occurring on one hemisphere only and a mathematically simple formula of this is given. Finally, in drawing attention to the different current stability of westward and eastward setting currents, emphasis is laid on their relation to the afore mentioned long waves and vorticity phenomena after Rossby.

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Ondes longues et le phénomène de vorticity dans l'atmosphère et dans l'océan et leur ressemblance avec des mouvements d'inertia

Résumé Il s'est montré nécessaire d'éclaircir la correspondance entre les mouvements d'inertia dérivés par F. J. W. Whipple pour la zone équatoriale de la terre d'une part, et les ondes longues d'après C. G. Rossby dans un large et stable courant orienté vers l'Est et entre le phénomène devorticity dans un courant instable orienté vers l'ouest, d'autre part. Cette explanation est d'autant plus nécessaire que les conditions physiques fondamentales en sont tout à fait différentes. Le travail suivant offre une telle explanation. En outre, on dérive des mouvements qui ne se produisent que sur un seul hémisphère le mouvement d'inertia sur la terre rotatoire et on réussit à trouver une solution mathématiquement simple. Enfin, on discute la forte différence en stabilité qui se présente dans des courants océaniques orientés vers l'Est et ceux orientés vers l'Ouest en soulignant leur relation avec des ondes longues et le phénomène devorticity d'après. Rossby.

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Herrn Professor Dr. Gerhard Schott zum 90. Geburtstag gewidmet.  相似文献   

Die Strömungen in Meeresstraßen     

Albert Defant 《Ocean Dynamics》1955,8(1):1-15

Zusammenfassung In folgender Zusammenfassung unserer Kenntnisse der Ozeanographie der Meeresstraßen wird ein kurzer Überblick über den Aufbau und die Bewegungen der Wassermassen in Meeresstraßen gegeben und versucht, letztere als eine Auswirkung eines thermodynamischen Systems aufzufassen. Dies ergibt die Möglichkeit, in einfacher Weise aus dem Dichteunterschied der Wassermassen beim Ein- und Austritt in die Meeresstraße und den Dimensionen derselben die mittlere Stromstärke des Wasseraustausches zwischen beiden Meeren zu ermitteln. Für eine genauere Bestimmung der Stromverhältnisse muß man auf die antitriptischen Bewegungsgleichungen zurückgehen. Eine Lösung derselben wird gegeben und ein Vergleich der theoretischen Ergebnisse mit den Strombeobachtungen ergibt eine recht befriedigende Übereinstimmung. Der Einfluß der Corioliskraft, der Morphologie der Meeresstraße, besonders des Meeresbodens in ihr, sowie jener der Gezeiten wird kurz besprochen.In einem Endteil wird die große Beeinflussung des thermohalinen Aufbaues vor der Mündung der Meeresstraße in den freien Ozean durch den Ausfluß salzreicher und warmer Wassermassen des Unterstromes näher behandelt und eine Theorie der Ausbreitung dieses Wassereinschubes als Austauschproblem gegeben. Die Anwendung derselben auf die Verhältnisse im Atlantischen Ozean vor der Straße von Gibraltar führt zu einem Wert des seitlichen Austauschkoeffizienten, wie er bei anders gearteten Meeresströmungen gefunden wurde.

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On the nature of water movements passing through straits

Summary In the following paper summarizing our knowledge of the oceanography of straits, the stratification and passage of water masses through straits is outlined and their occurrence is interpreted as being the effect of the thermodynamic system. This conception permits to determine the mean strength of current of the water interchange between two oceans by simply deducing it from the dimensions of the straits and from the difference in density of the water masses on their passage through the mouths of the straits. A precise determination of the current conditions calls for the application of the equations of movement leaving, however, friction out of account. A solution of these equations is given and a comparison between the results arrived at by theory and those obtained from current observations shows a good correspondence. The combined effects of the deflecting force of the earth's rotation, of the morphology of the straits, and, in particular, of that of their floor as well as the influence of the tides are discussed in a concise manner.In conclusion, the great influence is treated the outflowing water masses of the undertow with their high temperature and salinity exert on the thermohaline stratification of the water body in the open ocean near the mouth of the straits. A theory is developed treating the distribution of the intercalated water body as a problem of interchange. The application of the theory to the conditions dominating in the Atlantic Ocean before the Straits of Gibraltar yields a value for the lateral mixing coefficient which comes very near to that one arrived at when calculating ocean currents of a different character.

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Sur la nature des courants d'eau à travers les détroits

Résumé Dans le présent résumé de nos connaissances de l'océanographie de détroits on donne un aperçu de la stratification et des mouvements des eaux à travers des détroits, phénomènes, que l'on essaie d'attribuer au système thermodynamique. Cette interprétation permet de conclure, d'une manière simple, des dimensions du détroit et de la différence en densité des eaux au moment de leur passage par les ouvertures du détroit à l'intensité moyenne du courant d'échange entre les deux océans. Une précision des conditions de courant exige l'application des éqations de mouvements sans, cependant, tenir compte de la friction; une solution en est donnée. La comparaison des résultats théoriques avec des observations de courant montre que l'accord en est satisfaisant. L'ensemble des influences de la rotation terrestre, de la morphologie des détroits, particulièrement de celle de leur fond, ainsi que l'effet des marées est brièvement discuté.Enfin, on traite le grand effet que l'écoulement des eaux à haute température et salinité du courant sous-marin exerce sur la stratification thermohaline des eaux qui se trouvent dans l'océan ouvert devant l'ouverture du détroit. On développe une théorie d'après laquelle on considère la distribution de ce corps intercalé d'eau comme problème de l'échange des eaux. L'application de cette théorie aux conditions dans l'océan Atlantique devant l'ouverture du détroit de Gibraltar conduit à une valeur du coefficient latéral de mélange qui est très voisine de celle que l'on obtient en faisant le calcul des courants marins d'un caractère différent.

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Herrn Professor Dr. Georg Wüst, Kiel, zu seinem 65. Geburtstage zugeeignet.

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Nach einem Vortrag im Geophysikalischen Kolloquium der Universität Hamburg am 10. Februar 1955.  相似文献   

A paleoclimate model of Northern Hemisphere ice sheets     

G.E. Birchfield  Johannes Weertman  Albert T. Lunde 《Quaternary Research》1981,15(2):126-142

A model for predicting the growth and decay of ice sheets based on the astronomical theory of climate change is presented. The purpose of the study in part is to isolate the role of the ice-sheet physics and earth response under varying ice load by simplifying to the extreme the role of the hydrosphere-atmosphere. Ice sheet physics and the response of the lithosphere-asthenosphere under the ice load are modeled explicitly. Insolation anomalies (taken at a fixed latitude) directly force latitudinal displacement of the snow line. Accumulation rate a, and ablation rate a′ evaluated at mean sea level are specificed as external constants; a,a′ decrease linearly with ice sheet elevation. Rough tuning of the model to the general shape of the ice-volume record of the last two major glacials determines the external constants. Model predictions of the ages of several events in the last major glaciation compare well with the radiological ages. The six glacial terminatios (I–VI) over the last 600,000 yr are identified and the predicted ages compare reasonably well with the δ¹⁸O record for two deep-sea cores. A direct comparison of model power spectra of ice volume as a function of period with spectra of the δ¹⁸O record shows apparent underprediction of power near 100,000 yr. When a quantitative but heuristic method for taking into account the “red noise” spectrum evident in the geological records is used, a much more favorable comparison is possible. The model prediction lends support to the hypothesis that the nonlinearity of the ice-sheet physics is responsible for the 100,000-yr periodicity in the geological record of the late Pleistocene.  相似文献   

Seasonal prevailing surface winds in Northern Serbia     

Tošić  Ivana  Gavrilov  Milivoj B.  Marković  Slobodan B.  Ruman  Albert  Putniković  Suzana 《Theoretical and Applied Climatology》2018,131(3-4):1273-1284

Theoretical and Applied Climatology - Seasonal prevailing surface winds are analyzed in the territory of Northern Serbia, using observational data from 12 meteorological stations over several...  相似文献   

Recent Trends in Satellite-Derived Chlorophyll and Aerosol Optical Depth Together with Simulated Dimethylsulfide in the Eastern China Marginal Seas     

QU Bo  GABRIC Albert J 《中国海洋大学学报(英文版)》2022,21(2):486-498

The biogenic compound dimethylsulfide(DMS)produced by a range of marine biota is the major natural source of re-duced sulfur to the atmosphere and plays a major role in the formation and evolution of aerosols,potentially affecting climate.The spatio-temporal distribution of satellite-derived chlorophyll_a(CHL)and aerosol optical depth(AOD)for the recent years(2011-2019)in the Eastern China Marginal Seas(ECMS)(25°-40°N,120°-130°E)are studied.The seasonal CHL peaks occurred during late April and the CHL distribution displays a clear zonal gradient.Elevated CHL was also observed along the northern and western coastlines during summer and winter seasons.Trend analysis shows that mean CHL decreases by about 10%over the 9-year study period,while AOD was higher in south and lower in north during summertime.A genetic algorithm technique is used to calibrate the key model parameters and simulations are carried out for 2015,a year when field data was available.Our simulation results show that DMS seawater concentration ranges from 1.56 to 5.88 nmol L^?1 with a mean value of 2.76 nmol L^?1.DMS sea-air flux ranges from 2.66 to 5.00mmol m^?2 d^?1 with mean of 3.80mmol m^?2 d^?1.Positive correlations of about 0.5 between CHL and AOD were found in the study region,with higher correlations along the coasts of Jiangsu and Zhejiang Provinces.The elevated CHL concentration along the west coast is correlated with increased sea-water concentrations of DMS in the region.Our results suggest a possible influ-ence of DMS-derived aerosol in the local ECMS atmosphere,especially along the western coastline of ECMS.  相似文献