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   

Fractionation of dissolved organic matter affected by polyvalent metal cations     

Klaus Kaiser 《Organic Geochemistry》1998,28(12):849-854

The purpose of the study was to evaluate the influence of polyvalent cations known to form complexes with natural organic substances on the operational fractionation of dissolved organic matter (DOM) using XAD-8 adsorber resin. Dissolved organic matter solutions from a forest floor were treated with increasing concentrations of polyvalent metal cations (Ca²⁺, Al³⁺, Fe³⁺) at different pH levels. Then the concentrations of total dissolved organic carbon (DOC) and the distribution between hydrophilic and hydrophobic DOC were determined. The concentrations of total DOC decreased slightly when the C/metal ratio was less than 10, especially for Al and Fe. Hydrophilic DOC increased and hydrophobic DOC decreased with increasing concentrations of metal cations. Effects increased in the order Ca<Al<Fe and were more pronounced at low DOC concentrations and high pH values. The reason for the reduction of the DOC concentrations seemed to be the formation of insoluble metal–DOM complexes, while soluble metal–DOM complexes may induce an alteration of the distribution between hydrophilic and hydrophobic DOC. Thus, the polyvalent cations and their concentration need to be considered when DOM fraction distributions, determined with XAD-8 resin, of different waters are compared, especially at low DOC contents and high pH.  相似文献   

Bruthabitatmodellierung für den Drosselrohrsänger (Acrocephalus arundinaceus L.) als Bestandteil eines integrativen Managementsystems für Seeufer     

Annette Woithon  Klaus Schmieder 《Limnologica》2004,34(1-2):132

Within the context of the European legislative (e.g. Water Framework Directive, Natura 2000 network) monitoring and assessment of wetland areas are of great significance. This research points out the relevance of spatially explicit habitat models as an essential part of a decision support system for lake shore management. The Great Reed Warbler (Acrocephalus arundinaceus L.) was selected as a key species of aquatic reed structures. Many results of investigation about breeding behaviour of this German Red List species are available. The factors of selecting a breeding range were modelled in a Geographic Information System (GIS) using indices that quantify the corresponding spatial characteristics of patches in the ecosystem (e.g. shape complexity or distance to other vegetation structures). A habitat suitability map was created for a nature conservation area at Lake Constance, Germany. The observed breeding places in the investigation area showed a great coincidence with the modelled habitat ranges. This modelling approach of integrating spatial indicators is an important basis to provide automated monitoring systems based on remote sensing methods.  相似文献   

Fifty thousand galaxies at a glance     

Klaus Meisenheimer  Christian Wolf 《Astronomy& Geophysics》2002,43(3):3.15-3.21

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An in situ attenuance meter for very turbid waters     

Klaus Ohm 《Ocean Dynamics》1979,32(2):70-76

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The German Geoscientific Airborne Remote Sensing Srogramme: Background,aims, and organization     

Dipl.-Geogr. Klaus Strübing 《Ocean Dynamics》1979,32(1):1-2

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Infra-red radiometry in the German Bight     

Dipl.-Oz. Gerd Axel Becker  Dr. Klaus Huber  Dipl.-Oz. Hans Krause 《Ocean Dynamics》1979,32(1):19-26

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Pyroxenes in Serra de Magé: cooling history in comparison with Moama and Moore County     

George E. Harlow  C.E. Nehru  Martin Prinz  G. Jeffrey Taylor  Klaus Keil 《Earth and Planetary Science Letters》1979,43(2):173-181

Single-crystal X-ray, optical, and microprobe study of pyroxenes in the Serra de Magéfeldspar cumulate eucrite indicate complex exsolution features from a slow cooling history. Two pyroxenes now exist: “low” orthohypersthene ( P2₁ca) as host ( ～82 vol.%) and augite ( C2/c) in four distinct habits. This pyroxene pair yields an apparent “equilibration” temperature of ～900°. These relations are typical for orthopyroxene of both the Stillwater and Kintoki-San types, indicating an original pigeonite pyroxene with a bulk composition En₅₁Fs₃₉Wo₁₀. Variations in augite-hypersthene textural relationships suggest variable initial compositions from about Wo₈ to Wo₁₁. The bulk composition is intermediate to those of initial pigeonites in Moama and Moore County but the augite-hypersthene tie line is longer suggesting a slower cooling history. Our examinations of all three meteorites show that Serra de Magéaugite lamellae are as thick or thicker than those in the other meteorites, contrary to the measurement of Miyamoto and Takeda. The compositional data, textural relations, and existence of P2₁ca hypersthene suggest at least a comparable if not slower cooling history for Serra de Magé.  相似文献   

The structure and development of greater Lagos     

Dr. Klaus Grenzebach 《GeoJournal》1978,2(4):295-310

In the period between 1965 and 1976, when German geographers carried out their fieldwork for the Afrika-Kartenwerk under the sponsorship of the German Research Society, remarkable progress in urban development especially in Lagos could be observed. The cooperation with the Federal Survey Department of Nigeria gave the opportunity for collecting several series of aerial photographs which bring into focus some stages of the overwhelming urban expansion.The materials presented here have been selected to demonstrate some regional structures of the Nigerian capital. — In the geography of today the scientific evaluation of aerial photographs together with findings from local observation and historical as well as statistical data is still undervalued. Through this technique, the more classical and conservative method of geographical analysis, relying on subjective judgement, may regain some of its importance, which it once had in the age of exploration of new territories.Where data is scarce and written records of urban expansion are not available or difficult to extract, aerial photographs can give an impression of certain stages of urban growth. A functional analysis under geographical aspects has to be regarded by changes within spatial units in order to the factors of influence. Those factors are numerous, their influence will cause changes in a series of pushes arising from economic developments of the vast hinterland as well as from social conditions of certain groups of the population. In a metropolitan center, as Lagos, the highest ranking central place of Africa's most populous nation, heterogenous events and a confusing number of planning decisions must be taken into consideration. One consequence of nationwide regional interactions with the metropolis is migratory population dynamics. In pursuing lines of interaction, which originate from economic power, population density, and natural resources, one can hardly isolate a single element of influence because all factors are closely interrelated. For Lagos, there is only limited data available on the social and economic standard of the population, valid basic demographic figures of some value are not available.One still has to accept very rough estimates on population figures, number of industrial workers, the standards of housing and the social and economic hierarchy of the population. The present retrospective analysis of aerial photographs gives an interpretation of the regional structure of the town and indicate possible future development.  相似文献   

Radar measurements of wind and waves     

Klaus Hasselmann  W. Alpers  D. Barick  D. Crombie  C. Flachi  A. Fung  H. van Hutten  W. Jones  G. P. De Loor  B. Lipa  R. Long  D. Ross  C. Rufenach  W. Sandham  O. Shemdin  C. Teague  D. Trizna  G. Valenzuela  E. Walsh  F. Wentz  J. Wright 《Boundary-Layer Meteorology》1978,13(1-4):405-412

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