Multi-isotope (Ba,C, O) partitioning during experimental carbonatization of a hyper-alkaline solution     

Michael E. Böttcher  Nadja Neubert  Peter Escher  Katja von Allmen  Elias Samankassou  Thomas F. Nägler 《Chemie der Erde / Geochemistry》2018,78(2):241-247

Carbonates formed from hyperalkaline aqueous solutions at the Earth?s surface are known to bear the most extreme disequilibrium isotope signatures reported so far in nature. We present here the results for stable carbon (C), oxygen (O), and barium (Ba) isotope fractionation during the precipitation of witherite (BaCO₃) induced by the chemical absorption of atmospheric carbon dioxide (CO₂) into an aqueous hyper-alkaline solution (at 4° and 21?°C; 1?atm total pressure). Independent from temperature, the barium carbonate formation was associated with a substantial enrichment of the lighter C and O isotopes in the solid compared to the atmosphere (C, O), close to previous results found in experiments and nature. A new approach is introduced to explain oxygen isotope fractionation upon hydroxylation of CO₂. With Ba isotope enrichment factors between ?0.45 and ?0.53‰ (^138/134ε) or ?0.34 and ?0.40‰ (^137/134ε), respectively, the synthesized BaCO₃ displays the highest kinetic enrichment of the light Ba isotope in the carbonate solid reported so far.  相似文献   

Using environmental isotopes in the study of the recharge-discharge mechanisms of the Yarmouk catchment area in Jordan     

Elias?SalamehEmail author 《Hydrogeology Journal》2004,12(4):451-463

The recharge sources, the flow mechanisms and discharge areas of the different groundwater bodies underlying the Yarmouk River catchment area in Jordan, have, until now, not been adequately explained, although a wide range of hydrological, hydrogeological, and hydrochemical studies have been done. Along the Jordanian part of the catchment area of the Yarmouk River, groundwater issues from different aquifers with a variety of chemistries and types within the same aquifer and in between the different aquifers. Conventional recharge/discharge mechanisms, water balances and chemical analyses did not adequately explain the chemical variations and the different water types found in the area. Applying environmental isotopic tools combined with their altitude effects due to topographic variations (250–1,300 m a.s.l. within a distance of 20 km), and taking into consideration re-evaporation effects on the isotopic depletion and enrichment of rainwater, has greatly helped in understanding the recharge discharge mechanisms of the different aquifers. Precipitation along the highlands of an average of 600 mm/year is found to be depleted in its isotopic content of O¹⁸ = –7.0 to –7.26 and D = –32.2 to –33.28, whereas that of the Jordan Valley of 350 mm/year is highly enriched in isotopes with O¹⁸ = –4.06 and D = –14.5. The groundwater recharged along the highlands is depleted in isotopes (O¹⁸ = ~ –6, D = ~ –30), groundwater at the intermediate elevations is enriched (O¹⁸ = ~ –5, D = ~ –23) and that of the Jordan Valley aquifers containing meteoric water is highly enriched (O¹⁸ ~ –3.8, D = ~ –18). The deep aquifers in the Jordan Valley foothills are depleted in isotopes (O¹⁸ –18 = –6, D = –30) and resemble those of the highland aquifers. Only through using isotopes as a tool, were the sources of the different groundwater bodies and recharge and discharge mechanisms unambiguously explained. It was found that recharge takes place all over the study area and produces groundwater, which, from the highlands towards the Jordan Valley, shows increasing enrichment in isotopes. The highlands aquifer, with its groundwater depleted in isotopes, becomes confined towards the Jordan Valley; and, due to its confining pressure, leaks water upwards into the overlying aquifers causing their water to become less enriched in isotopes. Water depleted in its isotopic composition also seeps upward to the ground surface at the mountain foothills through faults and fissures.

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Resumen Las fuentes de recarga, los mecanismos de flujo y las áreas de descarga de los diferentes cuerpos de agua subterránea que subyacen el área de la cuenca del Río Yarmouk en Jordania, se han explicado de manera no ambigua únicamente mediante la aplicación de los isótopos como herramienta. A lo largo de la parte Jordana del área de la cuenca del Río Yarmouk el agua subterránea emerge de diferentes acuíferos con una variedad de tipos y composiciones, ya sea que provengan del mismo acuífero o de diferentes acuíferos. Los mecanismos convencionales de recarga/descarga, balances hídricos y variaciones químicas no han podido explicar las variaciones químicas y los diferentes tipos de aguas. La aplicación de herramientas de isótopos ambientales combinadas con los efectos de altitud derivados de variaciones topográficas (250 hasta 1,300 m s.n.m. en una distancia de 20 km) y tomando en consideración los efectos de re-evaporación en el empobrecimiento de isótopos y enriquecimiento del agua de lluvia han ayudado fuertemente en el entendimiento de los mecanismos de recarga/descarga de los diferentes acuíferos. La precipitación en el área varía de 600 mm/año, a lo largo de las tierras altas, a 350 mm/año en el área del Valle Jordán. El flujo de agua subterránea ocurre de las tierras altas hacia el Valle Jordán. El agua subterránea de las tierras altas está empobrecida en isótopos (O¹⁸ =~ –6, D =~ –30), el agua subterránea de elevaciones intermedias está enriquecida (O¹⁸ =~ –5, D =~ –23), y el agua de los acuíferos del Valle Jordan contiene agua meteórica que se encuentra altamente enriquecida (O¹⁸ =~ –3.8, D =~ –18). Los acuíferos profundos que se localizan al pie de las tierras altas del Valle Jordán están empobrecidos en isótopos (O¹⁸ =~ –6, D =~ –30) y son similares a los acuíferos de las tierras altas. Solo al aplicar los isótopos ambientales como herramienta pudo explicarse de manera inequívoca las fuentes de los diferentes cuerpos de agua subterránea y los mecanismos de recarga y descarga.

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Résumé Les zones de recharge, les mécanismes découlement et les zones de décharges des différentes masses deau souterraine sous le bassin versant de la rivière Yarmouk en Jordanie, étaient expliquées de manière ambiguë par les seuls outils isotopiques. Le long de la parti Jordanienne du bassin versant de la rivière Yarmouk leau souterraine provient de différents aquifères et se distinguent par leur type et leur composition chimique, selon que leau provient du même ou des différents aquifères. Les mécanismes conventionnels de recharge et de décharge, bilan hydrologique ne donnaient pas dexplications satisfaisantes concernant les variations chimiques et les différents types deau. En appliquant les isotopes environnementaux combinés aux effets de laltitude sur les variations des teneurs isotopiques (laltitude varie de 250 à 1,300 m sur une distance de 20 km.) et en prenant en considération les effets de ré-évaporation sur lappauvrissement et lenrichissement isotopique des eaux pluviales ont fortement contribués à une meilleure compréhension des mécanismes de recharge des différents aquifères. Les précipitations annuelles sont comprises entre 600 mm dans les zones en altitude et 350 mm dans la vallée de la Jordanie. Les écoulements de leau souterraine sont dirigés des zones en altitude vers la vallée de la Jordanie. Les eaux souterraines des zones en altitude sont isotopiquement appauvries (O¹⁸ = ~ –6, D = ~ –30), les eaux souterraines des zones de moyenne altitude sont enrichies (O¹⁸ = ~ –5, D = ~ –23) et les eaux de la vallée très enrichies (O¹⁸ ~ –3.8, D = ~ –18). Les aquifers profonds dans la vallée de la Jordanie sont appauvris (O¹⁸ –18 = –6, D = –30) et se confondent avec les eaux des zones situées en altitude. En appliquant uniquement les isotopes environnementaux comme des outils de compréhension des phénomènes hydrogéologiques, la source des différentes masses deau souterraines, les mécanismes de la recharge et de la décharge pourraient être expliqués de manière ambiguë.

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Structure of Saturn's Mesosphere from the 28 Sgr Occultations     

W.B. Hubbard  C.C. Porco  D.M. Hunten  G.H. Rieke  M.J. Rieke  D.W. McCarthy  V. Haemmerle  J. Haller  B. McLeod  L.A. Lebofsky  R. Marcialis  J.B. Holberg  R. Landau  L. Carrasco  J. Elias  M.W. Buie  E.W. Dunham  S.E. Persson  T. Boroson  S. West  R.G. French  J. Harrington  J.L. Elliot  W.J. Forrest  J.L. Pipher  R.J. Stover  A. Brahic  I. Grenier 《Icarus》1997,130(2):404-425

We analyze an extensive data set of immersion and emersion lightcurves of the occultation of 28 Sgr by Saturn's atmosphere on 3 July 1989. The data give profiles of number density as a function of altitude at a variety of latitudes, at pressures ranging from about 0.5 to about 20 μbar. The atmosphere is essentially isothermal in this range, with a temperature close to 140 K for an assumed mean molecular weight of 2.135. Owing to favorable ring geometry, an accurate radial scale is available for all observations, and we confirm the substantial equatorial bulge produced by zonal winds of ∼450 m/s first observed in the Voyager radio-occultation experiments. The fact that the bulge is still present at microbar pressures suggests that the equatorial winds persist to high altitudes. According to our radial scale, the 2.4-μbar level, which corresponds to half-flux in the stellar occultations, is at an equatorial radius of 60,960 km. This radial scale is in good agreement with the Voyager radio-occultation data at mbar pressures and allows smooth interpolation of the isothermal structure between the stellar-occultation and radio-occultation regions. We do not have such a smooth interpolation between our data and Voyager ultraviolet occultation data, unless we discard the lowest 200 km of Voyager ultraviolet data. When this is done, we obtain a complete atmospheric model from an equatorial radius of 61,500 km down to an equatorial radius of 60,500 km. This model gives excellent agreement between all 28 Sgr, Voyager, and Pioneer 11 data.  相似文献   

Fluctuation of rainfall in attica during the years of the erection of the Parthenon     

Elias G. Mariolopoulos 《Pure and Applied Geophysics》1962,51(1):243-250

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A New Species of Amsassia from the Ordovician of Korea and South China: Paleobiological and Paleogeographical Significance     

Mirinae Lee  Heeju Park  Nguyen Viet Tien  Suk-Joo Choh  Robert J. Elias  Dong-Jin Lee 《《地质学报》英文版》2016,90(3):796-806

A new species of the probable calcareous alga Amsassia, A. koreanensis, is recognized from the Duwibong Formation (Middle Ordovician, Darriwilian) of the Taebaeksan Basin in mid-eastern Korea. This is the first report of the genus from the Korean Peninsula, expanding its geographical range to the eastern Sino-Korean Block. The new species also occurs in the Xiazhen Formation (Upper Ordovician, Katian) at Zhuzhai in the South China Block. Amsassia koreanensis is the smallest species of this modular genus, having a maximum module diameter of 0.28 mm. Module increase is by bipartite, tripartite and quadripartite types of longitudinal axial fission, but unlike other species of the genus, quadripartite fission is common. The types of fission are comparable to those in some Tetradiida (now Prismostylales, florideophycean rhodophyte algae), although the processes of fission are different. The distribution of A. koreanensis further strengthens the biogeographical connection between the Sino-Korean and South China blocks, suggesting that these two paleocontinents were located closer together during the Middle to Late Ordovician than previously speculated.  相似文献   

Sources of groundwater salinity along the flow path,Disi–Dead Sea/Jordan     

Elias Salameh  Rania Hammouri 《Environmental Geology》2008,55(5):1039-1053

The groundwater along the eastern escarpment of the Dead Sea shows a variety of chemical compositions with EC values ranging between 500 and a few thousand μS/cm. In this article the different groundwaters were correlated to the aquifers from where they originate and the water–rock interactions were elaborated at. It was found that the start of intercalations of Permo-Triassic and Jurassic rocks in the area and the basaltic dykes and sills are the sources, which cause a drastic increase in the salinity of the water. These rocks contents of residual evaporites, contact metamorphism products, sills, dykes and secondary altered mineral assemblage of plagioclase-, pyroxenes- and Fe-, Mn- minerals cause also drastic changes in ionic ratios, saturation indices and groundwater types. Fresh groundwater flows entering the area become, gradually, after a few kilometres highly salinized and of earthalkali type with prevailing chloride and sulfate instead of being bicarbonate waters.  相似文献   

HI observations ofHII-galaxies     

Elias Brinks  Ulrich Klein 《Astrophysics and Space Science》1989,156(1-2):183-187

High-resolution observations of the star forming dwarf galaxies Haro 21 and Markarian 314 are presented and are compared with a set of narrow band (H) CCD images. TheHi system related to Haro 21 measures about 12 kpc in diameter and is much more extended than the optical emission. The optical light follows that of an exponential disk and has a scale length of only 600 pc. TheHi distribution shows a lack of neutral gas near its centre where most of the H emission is found. The velocity field is regular and shows the characteristics of a disk in differential rotation. The rotation curve is rising out to the last measured point and the total mass is estimated to be about 1.5×10¹⁰ M . This implies that Haro 21 is a galaxy which is dominated by Dark Matter.Partly based on observations collected at the European Southern Observatory, La Silla, Chile.  相似文献   

Assessing the impacts of human activities and soil erosion on the water quality of Plastira mountainous Mediterranean Lake,Greece   总被引：1，自引：0，他引：1  

Vassiliki Markogianni  Angeliki Mentzafou  Elias Dimitriou 《Environmental Earth Sciences》2016,75(10):915

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Dimensional analysis of yielding and pounding structures for records without distinct pulses     

Elias Dimitrakopoulos  Andreas J. Kappos  Nicos Makris 《Soil Dynamics and Earthquake Engineering》2009

The seismic response of two fundamental mechanical configurations of earthquake engineering, the elastic–plastic system and the pounding oscillator, is revisited with the aid of dimensional analysis. Starting from the previous work of the authors which focused on pulse-type excitations, the paper offers an alternative, yet physically motivated, way to present the response of yielding and pounding structures under excitations with arbitrary time history. It is shown, that when the appropriate time and length scales are adopted, dimensional analysis can be implemented and remarkable order emerges in the response. Regardless of the acceleration level and frequency content of the excitation, all response spectra become self-similar and when expressed in dimensionless terms, resulting from dimensional analysis, follow a single master curve. The study proposes such scales together with the associated selection criteria among the available in literature strong ground motion parameters and shows that the proposed approach reduces drastically the scatter in the response.  相似文献   

The 2014 seismic hazard model of the Middle East: overview and results     

Karin Şeşetyan  Laurentiu Danciu  Mine B. Demircioğlu Tümsa  Domenico Giardini  Mustafa Erdik  Sinan Akkar  Levent Gülen  Mehdi Zare  Shota Adamia  Anooshiravan Ansari  Avetis Arakelyan  Ayşegül Askan  Mher Avanesyan  Hektor Babayan  Tamaz Chelidze  Raffi Durgaryan  Ata Elias  Hossein Hamzehloo  Khaled Hessami  Doğan Kalafat  Özkan Kale  Arkady Karakhanyan  Muhammad Asif Khan  Tahir Mammadli  Mahmood Al-Qaryouti  Mohammad Sayab  Nino Tsereteli  Murat Utkucu  Otar Varazanashvili  Muhammad Waseem  Hilal Yalçın  Mustafa Tolga Yılmaz 《Bulletin of Earthquake Engineering》2018,16(8):3535-3566

The Earthquake Model of Middle East (EMME) Project aimed to develop regional scale seismic hazard and risk models uniformly throughout a region extending from the Eastern Mediterranean in the west to the Himalayas in the east and from the Gulf of Oman in the south to the Greater Caucasus in the North; a region which has been continuously devastated by large earthquakes throughout the history. The 2014 Seismic Hazard Model of Middle East (EMME-SHM14) was developed with the contribution of several institutions from ten countries. The present paper summarizes the efforts towards building a homogeneous seismic hazard model of the region and highlights some of the main results of this model. An important aim of the project was to transparently communicate the data and methods used and to obtain reproducible results. By doing so, the use of the model and results will be accessible by a wide community, further support the mitigation of seismic risks in the region and facilitate future improvements to the seismic hazard model. To this end all data, results and methods used are made available through the web-portal of the European Facilities for Earthquake Hazard and Risk (www.efehr.org).  相似文献