Immiscible separation of metalliferous Fe/ Ti-oxide melts from fractionating alkali basalt: P-T-f O2 conditions and two-liquid elemental partitioning     

Vratislav Hurai  Klaus Simon  Uwe Wiechert  Jochen Hoefs  Patrik Konečný  Monika Huraiová  Jacques Pironon  Jozef Lipka 《Contributions to Mineralogy and Petrology》1998,133(1-2):12-29

Globules of iron-dominated (59–69 wt% FeO_tot) and titanium-dominated (43.5 wt% TiO₂) oxide melts have been detected in igneous xenoliths from Pliocene-to-Pleistocene alkali basalts of the Western Carpathians. Fluid inclusion and mineral composition data indicate immiscible separation of the high-iron-oxide melt (HIM) at magmatic temperatures. The HIM separation occurred during clinopyroxene (augite) accumulation in an alkali trachybasalt and continued during crystallization of amphibole (kaersutite) and K-feldspar (anorthoclase), the latter coexisting with trachyte and alkalic rhyolite residual melts. Some HIM was also expelled from sub-alkalic rhyolite (70–77% SiO₂), coexisting with An_27–45 plagioclase and quartz in granitic (tonalite-trondhjemite) xenoliths. Oxygen fugacities during HIM separation range from −1.4 to +0.6 log units around the QFM buffer. A close genetic relationship between HIM-hosted xenoliths and mantle-derived basaltic magma is documented by mineral ¹⁸O values ranging from 4.9 to 5.9‰ V-SMOW. δD values of gabbroic kaersutite between −61 and −86‰ V-SMOW are in agreement with a presumed primary magmatic water source. Most trace elements, except Li, Rb and Cs, have preferentially partitioned into the HIM. The HIM/Si-melt partition coefficients for transition elements (Sc, V, Cr, Co, Ni) and base metals (Zn, Cu, Mo) are between 2–160, resulting in extreme enrichment in the HIM. La and Ce also concentrate in the silicic melt, whereas Tb-Tm in the HIM. Hence, the immiscible separation causes REE fractionation and produces residual silicic melt enriched in LREE and depleted in HREE. The weak fractionation among Tb-Tm and Yb, Lu can be attributed to recurrent extraction of the HIM from the magmatic system, while flat HREE chondrite-normalized patterns are interpreted to indicate no or little loss of the HIM. Received: 30 September 1997 / Accepted: 23 March 1998  相似文献   

Contrasting origin of post-collisional high-K calc-alkaline and shoshonitic versus alkaline and peralkaline granitoids. The use of sliding normalization   总被引：41，自引：0，他引：41  

Jean-Paul Ligeois  Jacques Navez  Jan Hertogen  Russell Black 《Lithos》1998,45(1-4):1-28

Abundant high-K calc-alkaline (HKCA) magmatism appears to be post-collisional and often shifts to shoshonitic or alkaline–peralkaline compositions in the final stages of orogeny. The nature and the causes of this transition are studied on the basis of 308 major element and of 86 unpublished trace element (including REE) analyses of the Pan-African granitoids from the Tuareg shield (Adrar des Iforas, Mali and Aïr, Niger). This database covers a wide variety of magmas from subduction-related to intraplate-type including abundant HKCA batholiths. Literature data from geodynamically well-constrained cases are also included. In addition to a conventional geochemical approach of the studied magmatism, the sliding normalization method is proposed. This tool aims at comparing magmatic series: each studied rock is normalized to the interpolated composition of the reference series that has the same SiO₂ content as the sample. This method amplifies differences in sources and in fractionation processes and allows comparison of rocks from basic to acid composition. Two distinct juvenile sources are proposed: a previously enriched phlogopite-K richterite bearing lithospheric mantle or a lower juvenile crustal equivalent for HKCA-shoshonitic magmas, and a lowest lithospheric-upper asthenospheric OIB-type mantle for alkaline-peralkaline magmatism. The first source is melted only shortly after its generation when the lithosphere was still hot, which restricts HKCA magmatism mainly to post-collisional settings. The second asthenospheric/lowest lithosphere source is by definition close to its melting temperature and can generate magma ubiquitously both in space and time. The main melting triggers are lithospheric major structures which are not only operative in a post-collisional setting but also in other environments such as intraplate setting. Geochemistry thus gives indications about the nature of the source and on geotectonic settings. However, the latter is a second rank information, which is partly model-dependant. The post-collisional period differs from other settings by a propensity to generate large amounts of magma of various kinds, among which HKCA magmatism is volumetrically the most prominent.  相似文献   

Determination of cirrus radiative parameters from combination between active and passive remote sensing measurements during FRENCH/DIRAC 2001     

Grard Brogniez  Frdric Parol  Laurianne Bcu  Jacques Pelon  Olivier Jourdan  Jean-Franois Gayet  Frdrique Auriol  Christian Verwaerde  Jean-Yves Balois  Bahaiddin Damiri 《Atmospheric Research》2004,72(1-4):425

In the context of the next AQUA Train satellite experiment, airborne measurements were carried out to simulate satellite measurements. They were conducted between September 25 and October 12, 2001, off the coast of southern France over the Atlantic Ocean and over the Mediterranean Sea, respectively. During the intensive Field Radiation Experiment on Natural Cirrus and High-level clouds (FRENCH/DIRAC 2001), natural ice clouds were sampled from in situ and remote sensing measurements. On October 5 and 7, 2001, cirrus cloud decks were described by a complete data set acquired by: (i) in situ microphysical instruments onboard the TBM-700 aircraft: PMS probe, and Polar Nephelometer (ii) and downward-looking radiative instruments onboard the Mystère 20 aircraft: an infrared radiometer, a lidar, a visible imager with polarisation capabilities, and a middle infrared radiometer. Moreover, classical thermodynamical measurements were carried out onboard the Mystère 20. Mean microphysical characteristics of cirrus deck are derived from interpretation of remote sensing measurements. These properties are compared with those derived from in situ microphysical measurements in order to evaluate the radiative impact of natural cirrus clouds.  相似文献   

On the Structural Link Between Variables in Kriging with External Drift   总被引：3，自引：0，他引：3  

Jacques Rivoirard 《Mathematical Geology》2002,34(7):797-808

Kriging with external drift allows one to estimate a target variable, accounting for a densely sampled auxiliary variable. Contrary to cokriging, kriging with external drift does not make explicit the structural link between target variable and auxiliary variable, for the latter is considered to be deterministic. In this paper, we show that kriging with external drift assumes implicitly an absence of spatial dependence between the auxiliary variable and the residual of the linear regression of target variable on auxiliary variable at same point. This is the simple model with orthogonal residual, where cokriging is collocated and coincides with kriging of the residual. In this model, the cross-structure is proportional to the structure of the auxiliary variable, and the linear regression of target variable on auxiliary variable does not depend on the support.  相似文献   

MELIMEX,an experimental heavy metal pollution study: Effects of increased heavy metal load on crustacea plankton     

Jacques Urech 《Aquatic Sciences - Research Across Boundaries》1979,41(2):247-260

The crustacea plankton of three artificial model lakes in Lake Baldegg was observed during 15 months. Two were loaded continuously with low concentrations of five heavy metals (Hg, Cu, Cd, Zn, Pb). It was attempted to explain the significant lower abundances of the loaded limno-corrals. The results suggest that the decrease was not, or only partially, caused by the lower food supply in the loaded limnocorrals, but directly by the heavy metals. Accompaning laboratory tests show significantly increased egg-development-times for two species of those animals from the loaded limno-corrals. Two other species show a decrease of the egg production/♀. It cannot be determined if increased mortality of particular animal stages was caused by heavy metals.

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Résumé On a observé pendant 15 mois les crustacés planctoniques des trois modèles de lac installés dans le lac de Baldegg. Dans deux de ceux-ci, une charge constante de cinq métaux lourds (Hg, Cu, Cd, Zn, Pb) de faible concentration a été maintenue. On a essayé d'expliquer la faible concentration significative de plancton dans les bassins limnologiques chargés. Les résultats montrent que la diminution n'était que partiellement ou pas du tout causée par le faible approvisionnement en nourriture dans les bassins chargés, mais directement par les métaux lourds. Les tests de laboratoire montrent significativement l'augmentation du temps de développement des œufs pour deux espèces animales des bassins chargés. Deux autres espèces montrent une diminution de la production d'œufs/♀. On ne peut pas déterminer l'augmentation de la mortalité des animaux causée par les métaux lourds à des stades particuliers de développement.

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Copper,zinc and lead minerals suspended in ocean waters     

Jacques Jedwab 《Geochimica et cosmochimica acta》1979,43(1):101-110

Individual particles of malachite, tenorite, paratenorite, laurionite and sphalerite, as well as several intermediate compounds of Cu, Zn, Pb, Cl, S, OH and CO₃ have been identified among paniculate matter filtered from Atlantic and Pacific deep water samples. These particulate matter samples were provided mainly by the GEOSECS 1972 and 1974 cruises. The detection and the identification of the individual heavy metal compounds were made by a combination of light microscopy, SEM, EMP and XRD. The highest frequency of heavy metal compounds has been found at several North Atlantic, and at one Antarctic stations. Their origin can, at least partly, be ascribed to technological influences, since metallic copper and brass particles are sometimes found associated with, or included in the heavy metal compounds. Others, however, result clearly from growth in the water.  相似文献   

Sur lesStaurastrum du lac Léman     

Dr Jacques Naef  Prof. Dr Pierre Bourrelly  Paul Martin  Denis Mack 《Aquatic Sciences - Research Across Boundaries》1978,40(1):51-59

Among the Desmids which have been observed in the plankton of the lake of Geneva, organisms having 4 processes have been discovered. Their frequency in the water samples and the results of in vitro studies on their progeny when cultivated in several environmental conditions, allow us to consider these organisms as a form ofStaurastrum sebaldi. The triradiate organisms have been incorrectly named and one must now consider three different species.   相似文献   

Garnet—biotite gneiss in ‘Système du Graphite’ (Madagascar): Petrology and fluid inclusions     

Liliane Berglund  Jacques Touret 《Lithos》1976,9(2):139-148

Primary ‘carbonic’ fluid inclusions filled with nearly pure high density CO₂ occur in garnet in a garnet—biotite gneiss from ‘Système du Graphite’, Komajia, Madagascar (Malagasy). They have been formed during syntectonic growth of the garnet under granulite facies conditions. Most of the biotite appears to have crystallized later than the garnet under the influence of more water rich fluids.  相似文献   

The Amsterdam-St. Paul volcanic province,and the formation of low Al tholeiitic andesites     

Bernard M. Gunn  Norman D. Watkins  Walter E. Trzcienski  Jacques Nougier 《Lithos》1975,8(2):137-149

The island of St. Paul in the Indian Ocean is located on the axis of the southeastern branch of the Indian Ocean Rise, as is the similar volcano of Amsterdam, 80 km to the north. Both volcanoes and possibly part of the local ridge are formed of a high-alumina plagioclase tholeiite making this a distinctive volcanic province. Lavas with Al₂O₂ contents of 12 to 22% are directly related by plagioclase fractionation. Residual rocks are a distinctive low silica, low alumina, potassic andesite with andesine and even olligoclase feldspar. Parallel lines of evolution exist in the sea floor plagioclase tholeiites, which differ only in slightly lower tenor of Sr and potassium group elements, and in the Steens Mountain tholeiites of Oregon, which differ in their significantly higher Sr and K group elements  相似文献   

The subalkaline potassic magmatism of the Ballons massif (Southern Vosges,France): shoshonitic affinity     

Maurice Pagel  Jacques Leterrier 《Lithos》1980,13(1):1-10

A systematic geochemical study of the Ballons plutonic complex (Southern Vosges, France) indicates that the border facies of the massif are composed of two continuous differentiation series ranging from gabbros to quartz monzonites and very similar to the shoshonitic associations (high K₂O/Na₂O ratios as well as high Ba, Sr, U and Th contents). The existence of a geochemical discontinuity between the two series and the monzogranite, which is the principal component of the massif, argues against the monzogranite being directly related to the two differentiation series by fractional crystallization. The zoned structure of the monzogranite can be attributed to in situ crystal fractionation.  相似文献