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71.
François Risacher Bertrand Fritz Arturo Hauser 《Journal of South American Earth Sciences》2011,31(1):153-170
Thermal waters of northern (18°–27°S) and southern (37°–45°S) Chile occur in two very different climatic, geologic and hydrologic environments: arid closed basins with abundant evaporites in the north; humid climate and well drained valleys in the south. The origin and behavior of the main components of the two groups of waters are examined and compared to each other. The modeling of the alteration of volcanic rocks leads to water compositions very different from those observed both in the north and south. In addition to hydrothermal alteration and deep emanations, the Cl/Br ratio reveals a major contribution of saline waters to the two groups: infiltrating brines from salt lakes in the north; seawater in the south.In the north, concentrations of Cl, Br, Na, K, Ca, SO4, Li, B, Si result from the mixing of alteration waters with recycled brines. Hydrothermal alteration is obscured by this massive saline input, except for Mg. δ34S values are consistent with an origin of sulfate from salar brines, which are themselves derived from deep Tertiary gypsum. In the south, two processes account for the composition of thermal waters: mixing of alteration waters with seawater and deep magmatic contribution. The mixing process controls the concentration of Cl, Br, Na, Alk, Si, K, Ca, Mg. Magmatic inputs are detectable for SO4, Li and B. δ34S suggests that sulfate stems from the mixing of alteration waters with either marine SO4 in coastal waters or with deep SO2 in inland waters. In both the north and south, the Mg concentration is drastically lowered (<1 μmol/L) by the probable formation of a chlorite-type mineral. In the south, very small amounts of seawater (<1% in volume) are sufficient to imprint a clear signature on thermal waters. Not only coastal springs are affected by seawater mixing, but also remote inland springs, as far as 150 km from the sea. Subduction of marine sediments in the accretive margin could be the source of the marine imprint in thermal waters of southern Chile. Seawater may be expelled from the subducted lithosphere and incorporated into the mantle source. 相似文献
72.
Barsiene J Lehtonen KK Koehler A Broeg K Vuorinen PJ Lang T Pempkowiak J Syvokiene J Dedonyte V Rybakovas A Repecka R Vuontisjärvi H Kopecka J 《Marine pollution bulletin》2006,53(8-9):422-436
During the EU project BEEP a battery of biomarkers was applied in flounder (Platichthys flesus) and the blue mussel (Mytilus edulis) collected at three locations off the Lithuanian coast (Baltic Sea) in June and September 2001 and 2002. The elevated biomarker responses in specimens sampled in September 2001 were apparently related to the extensive dredging activities in the Klaipeda port area and subsequent dumping of contaminated sediments. High concentrations of organic pollutants (organochlorines and PBDEs) were also measured in the tissues of both indicator species. In addition, response levels of genotoxicity, cytotoxicity, immunotoxicity as well as concentrations of PAH metabolites in the bile of flounder showed elevations in 2002 after an oil spill in the Būtinge oil terminal in November 2001. In flounder, biomarker measurements 10 months after the spill indicated recovery processes but in mussels a high level of genotoxicity could still be observed 22 months later. The present study illustrates the usefulness of the multi-biomarker approach in the detection of biological effects of pollution in this region of the Baltic Sea. 相似文献
73.
Jean René Bertrand 《GeoJournal》2006,67(4):295-306
In France the distinction between the secular and religious domains is the result of a slow evolutionary process of secularization
over a period of two centuries. A key element was the law of separation between churches and State in 1905. Secularization
also produced a pluralistic socio-cultural system, which permits an increase in religious supply, issued from outside or inside
existent churches. The religious landscape became complex due to the growth of certain groups. Nowadays, efforts to regulate
Muslim communities are leading towards a new tendency of state control of religious activities in two fields, namely places
of worship and school activities. Religious plurality is recognized by the State in the name of the freedom of beliefs. Private
organizations are used for the public practice of religion and easily obtain places of worship. However, this has necessitated
a large number of regional or local arrangements. In the name of the freedom of thought, the school system of the Republic
is ensured by public schools, or by Catholic or Jewish schools, subject to strict public control. In this matter, there is
only minimal tolerance of other denominations.
相似文献
Jean René BertrandEmail: |
74.
European Venus Explorer (EVE): an in-situ mission to Venus 总被引:1,自引:0,他引:1
E. Chassefière O. Korablev T. Imamura K. H. Baines C. F. Wilson D. V. Titov K. L. Aplin T. Balint J. E. Blamont C. G. Cochrane Cs. Ferencz F. Ferri M. Gerasimov J. J. Leitner J. Lopez-Moreno B. Marty M. Martynov S. V. Pogrebenko A. Rodin J. A. Whiteway L. V. Zasova J. Michaud R. Bertrand J.-M. Charbonnier D. Carbonne P. Raizonville 《Experimental Astronomy》2009,23(3):741-760
The European Venus Explorer (EVE) mission was proposed to the European Space Agency in 2007, as an M-class mission under the
Cosmic Vision Programme. Although it has not been chosen in the 2007 selection round for programmatic reasons, the EVE mission
may serve as a useful reference point for future missions, so it is described here. It consists of one balloon platform floating
at an altitude of 50–60 km, one descent probe provided by Russia, and an orbiter with a polar orbit which will relay data
from the balloon and descent probe, and perform science observations. The balloon type preferred for scientific goals is one
which oscillates in altitude through the cloud deck. To achieve this flight profile, the balloon envelope contains a phase
change fluid, which results in a flight profile which oscillates in height. The nominal balloon lifetime is 7 days—enough
for one full circumnavigation of the planet. The descent probe’s fall through the atmosphere takes 60 min, followed by 30 min
of operation on the surface. The key measurement objectives of EVE are: (1) in situ measurement from the balloon of noble
gas abundances and stable isotope ratios, to study the record of the evolution of Venus; (2) in situ balloon-borne measurement
of cloud particle and gas composition, and their spatial variation, to understand the complex cloud-level chemistry; (3) in
situ measurements of environmental parameters and winds (from tracking of the balloon) for one rotation around the planet,
to understand atmospheric dynamics and radiative balance in this crucial region. The portfolio of key measurements is complemented
by the Russian descent probe, which enables the investigation of the deep atmosphere and surface. 相似文献
75.
The stable isotopic composition of dissolved Cl- in rainwater was measured from a coastal and an interior location in eastern Canada. At the interior Bonner Lake, Ontario, site the δ37Cl values of dissolved Cl- in precipitation ranged from −3.5‰ to −1.2‰ (SMOC) with an amount-weighted annual average of −2.3‰. At the coastal site, Bay D’Espoir, Newfoundland, δ37Cl values of dissolved Cl- values ranged from −3.1‰ to 0.0‰ with an amount-weighted annual average of −1.3‰. These negative δ37Cl values provide evidence that atmospheric HCl is 37Cl depleted, presumably from acidification of sea-salt aerosols. Accordingly, dissolved Cl- in the headwaters of two montane rivers in Western Canada had similarly depleted δ37Cl values. These results have implications to the interpretation of the isotopic compositions of dissolved Cl- in surface waters, formation fluids, and groundwaters. 相似文献
76.
Rosanna Sordo Antonella Vallenari Rosaria Tantalo France Allard Ronny Blomme Jean-Claud Bouret Ines Brott Yves Fremat Christophe Martayan Yassine Damerdji Bengt Edvardsson Eric Josselin Bertrand Plez Oleg Kochukhov Mary Kontizas Ulisse Munari Tenay Saguner Jean Zorec Andreas Schweitzer Paraskevi Tsalmantza 《Astrophysics and Space Science》2010,328(1-2):331-335
ESA’s Gaia mission will collect low resolution spectroscopy in the optical range for ~109 objects. Complete and up-to-date libraries of synthetic stellar spectra are needed to built algorithms aimed to automatically derive the classification and the parametrization of this huge amount of data. In addition, libraries of stellar spectra are one of the main ingredients of stellar population synthesis models, aiming to derive the properties of unresolved stellar populations from their integrated light. We present (a) the newly computed libraries of synthetic spectra built by the Gaia community, covering the whole optical range (300–1100 nm) at medium-high resolution of (0.3 nm) for stars spanning the most different types, from M to O, from A-peculiar to Emission lines to White Dwarfs, and (b) the implementation of those libraries in our SSP code (Tantalo in The Initial Mass Function 50 Years Later, 327:235 2005), exploring different stellar evolution models. 相似文献
77.
Leila Djadia Djamel Machane Jean-Luc Chatelain Abdesslam Abtout Rabah Bensalem Mehdi Amine Guemache Bertrand Guillier Amar Boudella El-Hadi Oubaiche 《Environmental Earth Sciences》2010,59(5):1149-1158
Results from geophysical investigations (electrical resistivity, electromagnetic mapping and seismic refraction) on an excavated
cell of the Ouled Fayet (Algiers, Algeria) pilot landfill indicated the presence of an underground runoff and permeable soil
underneath the cell. These results contradict those obtained by a feasibility study, based, however, only on the analysis
of seventy-six 10-m drilling cores. The 1D boreholes information has been proven to be insufficient and to give biased results.
The presence of water at depth is evidenced by lower resistivity, high conductivity anomalies and increase of P-wave velocity.
Thus, to the contrary of what is claimed in the feasibility study, a threat of leachate pollution is real. This study shows
that landfill construction studies cannot give trustful results without geophysical investigations. More specifically, in
Algeria, it is imperative to elaborate a landfill construction code, which should include mandatory geophysical prospecting
and deeper drilling cores. 相似文献
78.
There are two forms of systematic error in conventional deconvolution as applied to the problem of suppressing multiples with periodicities longer than a hundred milliseconds. One of these is the windowing effect due to the assumption that a true autocorrelation function can be computed from a finite portion of data. The second form of error concerns the assumption of periodicity, which is strictly true only at zero offset for a 1D medium. The seriousness of these errors increased with the lengthening of the multiple period. This paper describes and illustrates a rigorous 2D solution to the predictive deconvolution equations that overcomes both of the systematic errors of conventional 1D approaches. This method is applicable to both the simple or trapped system and to the complex or peg-leg system of multiples. It does not require that the design window be six to ten times larger compared to the operator dimensions and it is accurate over a wide range of propagation angles. The formulation is kept strictly in the sense of the classical theory of prediction. The solution of normal equations are obtained by a modified conjugate gradient method of solution developed by Koehler. In this algorithm, the normal equations are not modified by the autocorrelation approximation. As with all linear methods, approximate stationary attitude in the multiple generating process is assumed. This method has not been tested in areas where large changes in the characteristic of the multiple-generating mechanism occur within a seismic spread length. 相似文献
79.
80.
D.Z. Piper H.H. Veeh W.G. Bertrand R.L. Chase 《Earth and Planetary Science Letters》1975,26(1):114-120
An iron-rich deposit dredged from the upper flank of Dellwood Seamount in the Northeast Pacific has been analyzed for major and trace elements, rare-earth contents and uranium isotopic composition. In terms of mineralogy and overall chemical composition, the deposit resembles other iron-rich deposits variously attributed to volcanic hydrothermal activity. Both the relative concentrations of the rare-earth elements and the isotopic composition of uranium rule out seawater as the sole source of elements in this deposit. The rare-earth element pattern indicates that these elements were derived from the underlying basalt. The234U/238U ratio is significantly higher than in seawater and can best be explained by preferential leaching of234U generated by decay from its parent238U in the underlying rock and subsequent redeposition of the excess234U together with the Fe and minor metals. These data are consistent with a model for the origin of submarine metal-rich solutions involving mobilization of elements from the interior of slowly cooling basalts by circulating seawater. 相似文献