贼鸥用于南极环境大型指示生物种的初步研究

对南极长城站附近棕贼鸥(C.s.lonnberg)、灰贼鸥(C.maccormicki)和两者的混合配对(hybrid)的食性与考察站环境质量的相关性进行研究,结果表明,贼鸥的食物结构受站区人类废弃物的直接影响。贼鸥食性构成同时与人类活动和动物生态习性相关而起到双重信息载体作用,可作为南极环境生态评价的重要指标之一,对推动实现南极环境生态评价的量化有重要意义。     

Kanonaite-rich viridines from the Venn-Stavelot Massif,Belgian Ardennes

In highly oxidized Mn- and Al-rich layers of the low-grade metamorphic metasediments north of Salmchâteau, Belgium, three types of viridine porphyroblasts can be distinguished: (a) single-phase porphyroblasts, (b) composite porphyroblasts with a core consisting of very fine-grained kaolinite, which is interpreted as a pseudomorph after andalusite, and a rim of viridine and, (c) composite porphyroblasts with a viridine core, a first mantle of kaolinite (as a pseudomorph after andalusite) and a second rim of viridine. These grains form an assemblage with muscovite, paragonite, Mg-chlorite, piemontite, braunite, hematite, quartz, rutile, and apatite. In the single-phase porphyroblasts the chemical composition of the core, (Mn _0.51 ³⁺ Al_0.44Fe _0.04 ³⁺ )Al(O/SiO₄), grades continuously into (Mn _0.79 ³⁺ Al_0.15Fe _0.06 ³⁺ )Al(O/SiO₄) of the rim. The outer zones of the analyzed grains are thus richer in kanonaite-component, MnAl(O/SiO₄), than the original kanonaites described recently by Vrána et al. (1978) from the type locality in Zambia. Taking into consideration also other chemical data of viridines of the Salmchâteau locality there exists a complete solid solution series in the system Al₂SiO₅ (And)-MnAlSiO₅ (Kan)-FeAlSiO₅ at least from And₆₁Kan₃₇(FeAlSiO₅)₂ to And₁₅Kan₇₉(FeAl-SiO₅)₆ for the P-T conditions verified here ( 400 ° C/1–2 kb). The oxygen fugacity of the rocks is estimated to correspond to f _O2 of the MnO₂/ Mn₂O₃-buffer or to exceed it. Single-phase and composite porphyroblasts of the andalusite-type minerals contain S-shaped internal structures, which, in the marginal parts of the grains, are always oriented perpendicular to the schistosity planes. Together with the zoning of the composite grains these structures give clear evidence, that the andalusite formation is preceded by viridine growth in suitable rocks high in manganese. Thus, the viridines of the cores are formed under P-T conditions of less than 360–380 ° C/1–2 kb. The recurrent availability of Mn to form the kanonaite-rich rims in all three types of porphyroblasts may be explained by Mn release out of the recrystallizing hematites along the schistosity planes during decreasing temperatures.Although the Commision on New Minerals and Mineral Names, IMA, has deleted the classical name viridine it is preferred here and used as a varietal name for all intermediate members of the solid solution series between andalusite, Al₂(O/SiO₄), and the recently described kanonaite, MnAl(O/SiO₄) (Vrána et al., 1978). This is done with special regard to the petrographie purpose of this investigation, since it is impracticable and by simple optical methods in strongly zoned crystals even impossible to distinguish between manganian andalusite [Al(6)>Mn] and aluminous kanonaite [Al(6)相似文献   

Beobachtungen zur Stratigraphie des Schilfsandsteins im ost-lippischen Bergland

Zusammenfassung Die sandige Fazies des Schilfsandsteins ist in Ost-Lippe rhythmisch aufgebaut. Diese Abfolge ist so konstant, daß sie als stratigraphische Gliederung verwendbar ist. Einzelne Schichtglieder lassen sich bis maximal 2500 m Erstreckung verfolgen und als Leithorizonte benutzen. Das gilt auch beim Übergang in andere Faziesbereiche. Die Sandsteine selbst sind ebenfalls (z. T. undeutlich) rhythmisch entwickelt; die Zuordnung von Rhythmen ist in einigen Fällen möglich. Modalbestands-Analysen, Korngrößen- und Karbonat-Bestimmungen ergeben keine feinere Untergliederungsmöglichkeit der Schichtfolge. Sie vermögen die makroskopische Schichtgliederung teilweise zu stützen bzw. zu ergänzen. - Ausblick auf Sedimentationsverhältnisse im Untersuchungsgebiet und arbeitsmethodische Fragen.

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The sandstone-facies of the Schilfsandstein (km₂) in the eastern part of Lippe (eastern Westphalia) shows a rhythmic sedimentation, which may be used as a stratigraphic subdivision. Some layers continue on distances up to 2500 m and partly give the possibility to connect the silty and the sandstone-facies. The lithologic subdivision is only in some degree controlled by means of modal analysis, mechanical and carbonate analysis. - Short review of sedimentary and methodic problems.

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Résumé Le faciès gréseux du Schilfsandstein (km₂) dans la partie de l'est de Lippe (Westphalie orientale) est sédimenté rhythmiquement. Cette manière de sédimentation peut être usée à une subdivision stratigraphique. Quelques bancs peuvent être suiviès jusqu' à une distance de 2500 mètres; cela rend possible en partie une corrélation des faciès de silt et de grès. On peut contrôler la subdivision lithostratigraphique seulement en partie à l'aide d'analyses minérales et granulométriques et par détermination du carbonate. - Aperçu des problèmes sédimentologiques et méthodiques.

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The coticule rocks (spessartine quartzites) of the Venn-Stavelot Massif,Ardennes, a volcanoclastic Metasediment?

Thin spessartine-quartzite layers (coticules) are interstratified with Ordovician (Salmian) shales of the Venn-Stavelot Massif, Ardennes. These coticules indicate sudden interruptions in the sedimentation process of the shales. The lower contact of the coticules represents an abrupt change in the chemical composition from the underlying shales. In contrast, the upper limit of the coticules is chemically more diffuse. Phase relations of the phengitebearing spessartine-quartzites including paragonite, chlorite, and chloritoid or kaolinite as subordinate phases give evidence for a manganese-montmorillonitic source material of the coticules. This is in good agreement with the internal structures observed in the coticule layers (swelling and sliding effects, Liesegang structures). Since there is a positive correlation between the oxidation ratio of the enclosing shales and the chemical composition of the coticules, it is proposed that the source material of the coticules developed in situ by halmyrolysis out of tuffs. High oxidation ratios of the shales with iron fixed in the trivalent state but with divalent and thus mobile manganese led to the formation of coticule starting material, dominantly a manganese-montmorillonite. Halmyrolysis products formed under low oxidation ratio conditions of the enclosing shales are characterized by hydrosilicates rich in iron. The Obrochishte manganese deposit, Bulgaria, is discussed as a nonmetamorphic equivalent of the coticules of the Ardennes.     

Beiträge zur Limnologie des Walen-, Zürich-Ober-und Zürichsees

Chemical and physical conditions of the Walensee are discussed on the basis of values analyzed during an investigation period in the years 1972–1975. Thereby values of selected parameters have been compared with data of other Swiss lakes to estimate the trophic condition of the lake.      

Isotopenuntersuchungen zum Kalkumsatz im Löß

The ratio of oxygen and carbon isotopes is a criterion for the carbonate-genesis with distinct differences between marine, freshwater, soil and loess carbonates. In addition it becomes clear that there is a number of carbonate soils within the loess of the mediterranean region with distinguishable isotopic compositions. The components affecting the relation of the isotopes in these loesses and the intercalated soils are discussed. The carbonate-turnover during the sedimentation of the loess with carbonate-precipitation from remnant solutions seems to be of some importance. The relatively small participation of biogenic CO₂ in the carbonate-turnover ist evident.     

Henry's law and hydrolysis-rate constants for peroxyacyl nitrates (PANs) using a homogeneous gas-phase source

The solubilities and hydrolysis rates of PAN (peroxyacetyl nitrate) and its homologues PPN (peroxypropionyl nitrate), PnBN (peroxy-n-butyl nitrate), PiBN (peroxy-isobutyl nitrate) and MPAN (peroxymethacryloyl nitrate) in liquid water have been studied at 20 °C. Temperature dependencies were measured for PAN and PPN. The solubilities of peroxyacyl nitrates decrease smoothly with increasing carbon-chain length fromH (293 K)=4.1 M atm^–1 (PAN) toH (293 K)=1.0 M atm^–1 (PiBN). Hydrolysis-rate constants, which cover the range fromk _h (293 K)=(2.4–7.4)×10^–4 s^–1, do not show a systematic chain-length dependency. Solubilities of PAN and PPN in solutions which mimic the composition and ionic strength of sea water are 15% and 20% lower than in pure water. The hydrolysis rate constants are not affected.     

Seasonal variations of zinc in a eutrophic lake

Depth profiles of dissolved zinc were measured monthly over one year in Lake Greifen, a eutrophic lake. The concentrations are in the range 10–40 nM and show systematic variations over time and depth. Due to the increased binding to particles and subsequent settling, concentrations of zinc in the epilimnion decrease during summer stagnation. Clear correlations between Zn and major nutrients (P, Si) are, however, not observed in the water column. No accumulation of Zn occurs in the anoxic hypolimnion. The Zn sedimentation is related to the sedimentation of algae and of manganese oxide. A mass-balance calculation shows that 87% of the Zn input is retained in the sediments of Lake Greifen.     

Spectral mapping of rock weathering degrees on granite using hyperspectral DAIS 7915 spectrometer data

Rocks are weathered by chemical and physical processes into a mixture of loose material that produces soil. Mineralogical and textural changes are involved, which can be detected by imagery through digital image processing based on rock spectral behaviour as recorded by ground and laboratory spectrometers. Different densities of vegetation cover can be mapped qualifying further evolution of the area in terms of erosion, transport and sedimentation. Hyperspectral imagery helps to map the weathering front and different degrees of weathering on granite rock through mineralogical and textural associations related to the geomorphological processes in the area on various granitic facies. Abundance of feldspar and porfidic texture on the fresh rock are the critical parameters conditioning intensity of weathering in the area. Maps spectrally elaborated gather information on lithologies, mineralogical changes produced by geomorphological processes associated to landforms, topography and climate. Such maps contribute to estimating the spatial controls of erosion, suggesting soil particle size distribution, soil aggregation, soil depth, and consequently, helping to elaborate soil loss and soil conservation maps.     

Chronology and correlation of Quaternary magnetostratigraphy and nannofossil biostratigraphy in Norwegian-Greenland Sea sediments

Paleomagnetic analyses of a series of sediment cores from the Norwegian—Greenland Sea document the existence of seven short-lived geomagnetic events during the last about 500.000 years. Calcareous nannofossil biostratigraphy, correlated to oxygen isotope chronostratigraphy, provides a time framework to infer age and duration of these periods of extreme divergence of the earth's magnetic paleofield from the regular normal polarity configuration of the Brunhes Chron. The geomagnetic events typically extend over 5 to 10 kyr. Two events are observed within the oxygen isotope stage 2–4 interval. A short event is recorded at the stage 4/5 boundary and another just below the stage 5/6 boundary. Additional three geomagnetic events are identified in oxygen isotope stage 6, at the stage 9/10 boundary and near the top of oxygen isotope stage 13, respectively.

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Zusammenfassung Paläomagnetische Analysen einer Serie von Sedimentkernen aus der Norwegisch-Grönländischen See dokumentieren die Existenz von sieben kurzen geomagnetischen Ereignissen innerhalb der letzten etwa 500.000 Jahre. Alter und Dauer dieser extrem von der regulären Konfiguration normaler Polarität des erdmagnetischen Feldes der Brunhes Epoche abweichenden Episoden werden im Zeitrahmen von Biostratigraphien kalkiger Nannofossilien bestimmt, die mit einer Sauerstoffisotopen-Chronostratigraphie korreliert sind. Die geomagnetischen Ereignisse erstrecken sich typischerweise über Zeiträume von 5 bis 10 tausend Jahren. Zwei Ereignisse werden im Intervall der Sauerstoffisotopen Stadien 2–4 beobachtet. Ein kurzes Ereignis fällt in etwa mit der Stadien 4/5 Grenze zusammen, ein weiteres findet sich knapp unterhalb der Stadien 5/6 Grenze. Drei weitere geomagnetische Ereignisse sind im Sauerstoffisotopen Stadium 6, an der Stadien 9/10 Grenze und nahe dem Ende des Stadiums 13 identifiziert worden.

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Résumé Des analyses paléomagnétiques pratiquées dans une série de carottes de sédiments de la mer de Norvège-Groenland montrent l'existence de sept événements géomagnétiques de courte durée, au cours des derniers 500.000 ans. Ces événements sont marqués par une extrême divergence du champ paléomagnétique terrestre par rapport à la configuration régulière de la polarité normale de Brunhes. La biostratigraphie des nannofossiles calcaires, correlée à la chronostratigraphie des isotopes de l'oxygène, fournit un cannevas temporel qui permet d'en préciser l'âge et la durée. Ils s'étendent typiquement sur 5 000 à 10 000 ans. Deux événements sont observés dans l'intervalle 2–4 des stades des isotopes de l'oxygène. Un événement court est enregistré à la limite des stades 4/5 et un autre juste sous la limite 5/6. Les trois autres événements se situent respectivement dans le stade 6, à la limite des stades 9/10 et près du sommet du stade 13.

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