Contributions of groundwater conditions to soil and water salinization

 Salinization is the process whereby the concentration of dissolved salts in water and soil is increased due to natural or human-induced processes. Water is lost through one or any combination of four main mechanisms: evaporation, evapotranspiration, hydrolysis, and leakage between aquifers. Salinity increases from catchment divides to the valley floors and in the direction of groundwater flow. Salinization is explained by two main chemical models developed by the authors: weathering and deposition. These models are in agreement with the weathering and depositional geological processes that have formed soils and overburden in the catchments. Five soil-change processes in arid and semi-arid climates are associated with waterlogging and water. In all represented cases, groundwater is the main geological agent for transmitting, accumulating, and discharging salt. At a small catchment scale in South and Western Australia, water is lost through evapotranspiration and hydrolysis. Saline groundwater flows along the beds of the streams and is accumulated in paleochannels, which act as a salt repository, and finally discharges in lakes, where most of the saline groundwater is concentrated. In the hummocky terrains of the Northern Great Plains Region, Canada and USA, the localized recharge and discharge scenarios cause salinization to occur mainly in depressions, in conjunction with the formation of saline soils and seepages. On a regional scale within closed basins, this process can create playas or saline lakes. In the continental aquifers of the rift basins of Sudan, salinity increases along the groundwater flow path and forms a saline zone at the distal end. The saline zone in each rift forms a closed ridge, which coincides with the closed trough of the groundwater-level map. The saline body or bodies were formed by evaporation coupled with alkaline-earth carbonate precipitation and dissolution of capillary salts. Received, May 1998 · Revised, July 1998 · Accepted, September 1998     

Estimating groundwater recharge rates in the southeastern Holstein region, northern Germany

In the southeastern Holstein region, located to the east of the metropolitan zone of Hamburg, northern Germany, a groundwater investigation program was conducted from 1984 to 2000 by the State Agency for Nature and Environment (Landesamt für Natur und Umwelt, LANU) of Schleswig-Holstein, Germany, with the aim of providing long-term, ecologically acceptable groundwater management plans for the region. The focal point of the investigation comprised the determination of groundwater recharge rates. The investigation method was based on the transfer of available lysimeter results from other regions to comparable regions within the area studied. With the help of lysimeter equations, potential amounts of percolation water were calculated. The groundwater recharge rate was then determined after subtraction of the surface runoff which was calculated for the entire area. All computations were performed with a spreadsheet program. Groundwater recharge rates were calculated for two areas. One consisted of roughly determining groundwater recharge rates for the total region (1,392 km²) of southeastern Holstein. The overall goal of these investigations was to identify potential areas of water exploitation. Areas in which groundwater recharge rates are high and groundwater outflow is low are particularly suited to water exploitation, since inflow rates into deeper aquifers are high. These areas are located on the flanks of the Elbe and Stecknitz River valleys. Subsurface groundwater runoff to these lowlands would be reduced through groundwater withdrawal. However, the resulting decline in shallow groundwater tables would be so small that it would have no detrimental ecological effects. Groundwater recharge rates were also calculated for a 110-km² area in the outskirts of Hamburg (Grosshansdorf model area) which is intensively developed for water supply. These investigations showed that the amount of groundwater recharge is already being withdrawn to a large extent. Approximately 65% of the recharge rate is currently withdrawn by the waterworks in this area, thus making further increases in exploitation rates unjustifiable from an ecological point of view. Electronic Publication     

Studie über Höhenschwankungen der F2-Schicht: III

Zusammenfassung Es muss unterschieden werden zwischen den (scheinbaren) Minimalhöhen der F2-Schicht und jenen Höhen, in denen sich das Miximum der Elektronenkonzentration befindt. Es wird gezeist, dass sich für Statinen in Aequatornähe diese beiden Gebiete der F2-Schicht ganz verschieden verhalten; aus der Tatsache, dass die untere Begrenzung mit zunehmender Sonnentätigkeit abwts sinkt, während gleichzeitig die Höhe für die maximale Elektronenkonzentration anwächst, wird auf eine Veränderung der Schichtdicke geschlossen, die von der wechselnden Sonnenaktivität étroite avec l'activité solaire.

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Résumé La distinction entre la hauteur virtuelle minimum de la couche F2 et la hauteur vituelle où se trouve le maximum de la concentration 'eléctronique est nécessaire. On Montre que ces deux régions sont tré différentes pour les stations situées près de l'équateur. Etant donné que la base de la couche F2 s'abaisse pendant la période de croissance du cycle solaire, tandis que la hauteur de la concentraion éléctronique du maximmum augmente, on en conclu que l'épaisseur est soumis à des variations en relation étroite avec l'activité solaire.

     

Geochemistry and petrography of basalt grindstones from the Karak Plateau,central Jordan

Seventeen basalt grindstone fragments from central Jordan's Karak Plateau were studied. Most of these artifacts are vesicular or amygdaloidal with calcite as the dominant mineral filling the voids. The major minerals are olivine (with iddingsite rims), plagioclase, clinopyroxene, magnetite, and apatite. Glass is present in some samples. One basalt fragment is quite different in appearance and composition and may have come from flows closer to the Dead Sea. Grindstone fragment compositions plot in the tephrite‐basanite and basalt fields. A plot of the concentrations of niobium, zirconium, and yttrium reveal that the sample compositions plot in the “within‐plate alkali basalt” and “within‐plate tholeiite” fields. The acquisition of basalts for preparing such implements appears to have been random. Some may have been introduced through trade and migration. Archaeological and environmental studies on the Karak Plateau are urgently needed because Jordan's population growth and economic development are destroying many sites and their environmental contexts. © 2004 Wiley Periodicals, Inc.     

400 Jahre Mathematik und Astronomie an der Universität Würzburg: Alma Julia Herbipolensis 1582–1982

Ohne Zusammenfassung

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400 years mathematics and astronomy at the Wurzburg University: Alma Julia herbipolensis 1582–1982

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s. O. Volk, Mathematik, Astronomie und Physik in der Vergangenheit der Universität Würzburg, Festschrift 1982.

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Paper presented at the 1981 Oberwolfach Conference on Mathematical Methods in Celestial Mechanics.     

Einiges zur Geometrie der Lagekugelbesetzung

Ohne ZusammenfassungMit 3 Textabbildungen.