Results 191 to 200 of about 6,103 (222)
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Hydrothermal stability of saponitic clays from the Madrid Basin
Applied Clay Science, 1994The hydrothermal stability of sedimentary saponites from the Madrid Basin in Spain has been investigated in the laboratory. Their usefulness as physico-chemical barriers for high-level radioactive waste repositories was determined. The study focussed on the adsorption and fixation of K+ because the uptake of this cation is known to influence the ...
J. Cuevas, S. Leguey, R. Pusch
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Ground‐Water Age Distribution in Madrid Basin, Spain
Groundwater, 1982ABSTRACT The alluvial deposits that occupy the Madrid Basin in central Spain form an aquifer system covering an area of 5,000 km 2 (2,000 mi 2 ) and with thicknesses of 2,000 m (6,600 ft) or more. Average annual precipitation is 500 mm
M. Ramon Llamas +2 more
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Gravity Modelling - a Contribution to the Knowledge of Madrid Basin Structure (Spain)
Proceedings, 1995The Bouguer anomaly pattern reflects the density variations of the crust due to the different forming rocks and geometry. Gravity procedures make possible to model the structure of the crust. In these procedures several limitations must be taken into account to start with, of geological nature ( geological mapping, structural data, boreholes,..
J. F. Bergamin, R. Tejero
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Environmental Geology, 1994
The contribution of nitrogen and phosphorus due to precipitation constitutes the second most important route after superficial runoff. The sampling carried out during a two-year period by means of a precipitation collector allows us to determine the contribution of this route both qualitatively and quantitatively.
B. Lacalle Pareja +2 more
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The contribution of nitrogen and phosphorus due to precipitation constitutes the second most important route after superficial runoff. The sampling carried out during a two-year period by means of a precipitation collector allows us to determine the contribution of this route both qualitatively and quantitatively.
B. Lacalle Pareja +2 more
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Kerolite-stevensite mixed-layers from the Madrid Basin, Central Spain
Clay Minerals, 1991AbstractStructural features of very highly disordered 2:1 trioctahedral phyllosilicates from the Madrid Basin have been studied. Application of Fourier methods to XRD patterns shows that these materials consist of random kerolite-stevensite mixed-layered phases (R = 0) with 50–80% kerolite layers, and have a very small particle size with a mean of ...
J. L. Martin de Vidales +4 more
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Isotopic paleoecology of mammals and the Middle Miocene Cooling event in the Madrid Basin (Spain)
Palaeogeography, Palaeoclimatology, Palaeoecology, 2012Abstract The Middle Miocene underwent profound climatic perturbations detected in worldwide marine and continental records. The Miocene Climatic Optimum (~ 17 to 14 Ma), a warm and humid period, was followed by the Middle Miocene Cooling (~ 14–13.8 Ma) characterized by a sharp drop in temperatures and an increase in aridity triggered by the ...
Laura Domingo +4 more
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Saponitic clays from the Madrid basin: Accessory-minerals influence in hydrothermal reactivity
Applied Clay Science, 1992Abstract Some hydrothermal alteration tests have been carried out on two selected clays which contain saponite as major component with illite or sepiolite representing the main accessory minerals in the bulk composition of saponitic clays. Both samples show an important increment of silica in solution and in removable amorphous silica when ...
J. Cuevas, J.A. Medina, S. Leguey
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The New Madrid Rift System — Its Role in the Evolution of the Illinois Basin
1995The New Madrid Rift System, underlying the Mississippi Embayment and the southern end of the Illinois Basin, consists of the Reelfoot Rift and a dog-leg extension in western Kentucky known as the Rough Creek Graben. Seismic reflection sections indicate that the rift system consists of several half-grabens linked by accommodation zones much like those ...
Dennis R. Kolata, W. John Nelson
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Journal of Sedimentary Research, 1999
ABSTRACT Massive, decimeter-thick intervals formed by mosaics of subspherical calcite crystals displaying an intracrystalline fibrous microfabric have been found in Paleocene and Miocene strata in Spain. The fibrous microfabric is marked by inclusion-defined fibers that radiate from the central parts of the crystals, which can be termed ...
C. Rossi, J. C. Canaveras
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ABSTRACT Massive, decimeter-thick intervals formed by mosaics of subspherical calcite crystals displaying an intracrystalline fibrous microfabric have been found in Paleocene and Miocene strata in Spain. The fibrous microfabric is marked by inclusion-defined fibers that radiate from the central parts of the crystals, which can be termed ...
C. Rossi, J. C. Canaveras
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Comparison of different interpolation techniques for sub-basins located in Madrid.
Soil hydrophysical properties can be very spatially and temporally heterogeneous even in small areas. Due to this spatial and temporal variability, it is impossible to obtain real data for each point of interest. Therefore, the possibility to obtain the optimal estimated value, at any desired point, is decisive. The aim is to evaluate different methodsBlanca Cuevas +3 more
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