Recharge and salinization in the Madrid Basin     

A. S. Issar  R. M. Llamas  I. Herraez 《Environmental Geology》1993,21(1-2):55-61

The purpose of this work was to reinvestigate the existing hydrogeological conceptual model of the basin of Madrid, Spain. A cumulative chemical isotopic diagram which enabled the distinction between different groups of water as well as calculation of the mode of their blending was used for this investigation. It was found that the groups of discharge were lighter in their isotopic composition than that of recharge. The previous explanation of this fact, backed by carbon-14 dating, was the long residence time due to flow lines going down to depths of more than 1000 m. This flow model assumes homogenous conditions to these depths. This assumption can not be supported by evidence from deep wells. Thus a modified model is suggested which maintains homogenous conditions only to about 300 m and a deep confined aquifer below containing paleowater. The higher degree of depletion of this water has been explained by a colder climate on top of an altitude effect. Another interesting observation was the correlation between the isotopic composition of the rains, the month of the rain event and the composition of the recharge group groundwater. It could be seen that the winter rains resemble the groundwater composition, which shows that practically all the spring and summer rains were evapotranspirated.  相似文献   

Influence of the Load Wavelength on the Permeability of a Viscosity Interface in the Mantle     

Čížková  Hana  Čadek  Ondřej  van den berg  Arie P. 《Studia Geophysica et Geodaetica》1997,41(1):64-72

Assuming a radially stratified Newtonian mantle in a steady-state approximation, we demonstrate that the permeability of a viscosity interface at 660-km depth strongly depends on the wavelength of buoyancy forces driving the flow. The flow induced by long-wavelength loads penetrates through the boundary freely even if the viscosity increases by two orders. In contrast, the boundary is practically impermeable for short-wavelength loads located in the upper mantle. Thus, a stepwise increase of viscosity is a significant obstacle for small descending features in the upper mantle, but huge upper mantle downwellings, or upwellings formed in the-lower mantle can overcome it easily. This indicates that certain care is necessary in interpreting the seismic structure of the mantle by means of flow models. The global tomographic image includes only the first few degrees of the harmonic series and, consequently, its interpretation in terms of a present-day flow field results in a predominantly whole-mantle circulation even for extreme viscosity contrasts.  相似文献   

Direct probabilistic description of arrival times of Runoff events within the year     

Arie Ben-Zvi  Lev Meirovich 《Stochastic Environmental Research and Risk Assessment (SERRA)》1997,11(6):511-521

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November 2004     

Arie Issar 《Environmental Geology》2004,46(8):1134-1135

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Salt accumulation in the loessial sequence in the Be'er Sheva Basin,Israel     

Mordeckai Magaritz  Haim Gvirtzman  Arie Nadler 《Environmental Geology》1988,11(1):27-33

Evidence of climatic changes is recorded in the salt content of the surface sediments in arid zones. In wetter periods airborne salts are removed downward by leaching to the groundwater, whereas in drier periods they accumulate. The period of salt accumulation in the loessial sediments of the northern Negev is about 10,000 yr. This period represents the recent aridification phase. The beginning of this stretch of time followed the last humid period in the region. Top paleo soil (calcic horizon) found in the region and dated 12,000 yr B.P. is an indicator of this humid period. This article is a contribution from the Agricultural Research Organization, The Volcani Center, Bet Datan, Israel, No. 1751E, 1986 series.  相似文献   

The effect of urbanization in an arid region: Formation of a perched water table that causes environmental damages   总被引：1，自引：0，他引：1  

A. Karnieli  A. Issar  M. Wolf 《Environmental Geology》1984,6(1):51-63

Construction in a new neighborhood in the israeli town of Dimona, situated in an arid region in the south of the country (150 mm average annual rainfall), resulted in a rise in groundwater levels during the subsequent rainy seasons This caused flooding of shelter basements, soil sliding, and sagging which permanently damaged walls and buildings The neighborhood had been built on continental sands and marls blanketed by loess, on a valley slope near a rocky anticlinal dip-slope Subsurface studies, using piezometer holes and groundwater analyses, revealed the presence of sand lenses alternating with plastic marls, which act as seasonal aquifers with perched water tables Groundwaters obtain high SO ₄ ⁻² and Cl⁻ corrosivity through contact with these nonflushed marls of the Neogene valley fill (Hazeva Formation) The reasons for the rising of groundwater were found to be (a) artificial interference with the natural (pre-construction) drainage system—interception of the hillside runoff by building plots, roads, etc, (b) partial denudation of the loess blanket, increasing the local infiltration and the build-up of local, perched water tables, and (c) corrosion of concrete and steel pipelines, as well as foundations, by prolonged contact with corrosive groundwater, resulting in haphazard but massive leakage Guidelines are proposed for an environmental improvement plan, which would include terracing and planting of the watershed above town to increase evapotranspiration, lowering of the water table by pumping, and diverting the water to suburban parks (groves of saltresistant trees), and replacement of steel and cement pipes by a non-corrodable plastic pipe system  相似文献   

Whose forecast will be verified in 2025: Malthus’ or Condorcet’s?     

Arie S. Issar 《Hydrogeology Journal》2007,15(2):419-422

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Latent heat effects of the major mantle phase transitions on low-angle subduction     

Jeroen van Hunen  Arie P van den Berg  Nico J Vlaar 《Earth and Planetary Science Letters》2001,190(3-4):125-135

Very low to zero shallow dip angles are observed at several moderately young subduction zones with an active trenchward moving overriding plate. We have investigated the effects of latent heat for this situation, where mantle material is pushed through the major mantle phase transitions during shallow low-angle subduction below the overriding plate. The significance of the buoyancy forces, arising from the latent heat effects, on the dynamics of the shallowly subducting slab is examined by numerical modeling. When a 32-Ma-old slab is overridden with 2.5 cm/yr by a continent, flat subduction occurs with a 4–5 cm/yr convergence rate. When latent heat is included in the model, forced downwellings cause a thermal anomaly and consequently thermal and phase buoyancy forces. Under these circumstances, the flat slab segment subducts horizontally about 350 km further and for about 11 Ma longer than in the case without latent heat, before it breaks through the 400-km phase transition. The style of subduction strongly depends on the mantle rheology: increasing the mantle viscosity by one order of magnitude can change the style of subduction from steep to shallow. Similarly, an overriding velocity of less than 1 cm/yr leads to steep subduction, which gradually changes to flat subduction when increasing the overriding velocity. However, these model parameters do not change the aforementioned effect of the latent heat, provided that low-angle subduction occurs. In all models latent heat resulted in a substantial increase of the flat slab length by 300–400 km. Varying the olivine–spinel transition Clapeyron slope γ from 1 to 6 MPa/K reveals a roughly linear relation between γ and the horizontal length of the slab. Based on these results, we conclude that buoyancy forces due to latent heat of phase transitions play an important role in low-angle subduction below an overriding plate.  相似文献   

Foreword     

Sol R. Silverman  Arie Nissenbaum 《Organic Geochemistry》1979,1(4):189

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Chemical reactions of sea water with rocks and freshwater: Experimental and field observations on brackish waters in Israel     

Arie Nadler  Mordeckai Magaritz  Emanuel Mazor 《Geochimica et cosmochimica acta》1980,44(6):879-886

Four major processes are observed to take place in the coastal aquifer of Israel, detectable even in the short times of water contact with the carbonate-containing host rocks. Three are chemical reactions, Ca²⁺-Mg²⁺ exchange, Na⁺-Ca²⁺ or Na⁺-Mg²⁺ base exchange, SO^2?₄ reduction and the fourth is dilution by freshwater. These reactions and their effects on the chemical composition of the waters were demonstrated experimentally. The range of chemical changes observed in the laboratory experiments overlap the range of the studied natural waters. This indicates that simulation of geologically long-term rock-water interaction could be achieved in laboratory experiments even at low temperatures.  相似文献