Neuere Veröffentlichungen     

G. Dietrich  G. Tomczak  H. C. Freiesleben  Erich Lange  H. G. Macht 《Ocean Dynamics》1954,7(1-2):66-72

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Petrographie des minerais de fer de la Fosse du Labrador     

Erich Dimroth  Jean-Jacques Chauvel 《International Journal of Earth Sciences》1972,61(1):97-115

Résumé Les textures des minerais de fer précambriens de type «jaspilite» sont semblables à celles des calcaires. Les éléments texturels suivants sont décrits: 1. orthochems: a) fémicrite, b) matrice siliceuse, c) ciment siliceux; 2. allochems: a) pellets, b) intraclastes, c) oolithes et pisolithes, d) échardes. Les types pétrographiques sont définis par la combinaison des éléments de texture, comme pour la classification des calcaires. Les types de faciès sont caractérisés par une séquence de bancs correspondant à un ou plusieurs types pétrographiques et par certaines structures sédimentaires. Ils forment la base de l'interprétation des conditions de dépôt et de la paléogéographie du bassin.Les transformations épigénétiques sont les suivantes: 1. dessication, fissuration, cimentation et compaction. 2. Cristallisation du gel de silice: a) quartz à cristallisation primaire, calcédonite et quartzine, b) quartz micropolygonal, c) quartz recristallisé. 3. Cristallisation de la poussière d'hématite, migration du fer et cristallisation de la spéculante et de la magnétite. 4. Cristallisation et recristallisation de la sidérite, de la minnesotaïte, de la stilpnomélane, de la riebeckite et du talc. La migration du fer et la cristallisation de la spécularite, de la magnétite et de la sidérite prennent place avant la compaction complète du sédiment et avant ou pendant la cristallisation primaire du quartz. Le quartz recristallisé, la minnesotaïte et peut-être le talc et la stilpnomélane, sont des minéraux tardidiagénétiques. La riebeckite se forme pendant le métamorphisme. Les phénomènes de recristallisation se poursuivent pendant le métamorphisme régional.

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Textures of Precambrian cherty ironstones are similar to those of limestones. The following textural elements have been recognized: 1. Orthochems: a) femicrite, b) matrix chert, c) cement chert. 2. Allochems: a) pellets, b) intraclasts, c) oolites and pisolites, d) shards. Textural lithotypes are defined by the combination of the textural elements they contain, analogous to the classification of limestones. Textural faciès consist of beds of one or several lithotypes in characteristic sequence. They commonly contain distinguishing sedimentary structures. Textural facies are the basis of the interpretation of the depositional environment and basin configuration.The following types of epigenetic transformations have been recognized: 1. Dessication, shrinkage, cementation and compaction. 2. Crystallization of silicagel in the following sequence: a) primocrystalline quartz and chalcedony (normal and lengthslow), b) micro-polygonal quartz, c) recrystallized quartz. 3. Crystallization of hematite dust, migration of iron and crystallization of specular hematite and of magnetite. 4. Crystallization and recristallization of siderite, minnesotaite, stilpnomelane, riebeckite and talc. Migration of iron and the recristallization of speculante, magnetite and siderite take place essentially before the complete compaction of the rock and before and during the primo-cristallization of quartz. Recrystallized quartz, minnesotaite, and may be stilpnomelane and talc are essentially late diagenetic minerals. Riebeckite formed during metamorphism. A certain recrystallization occured during regional metamorphism.

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Zusammenfassung Texturen der präkambrischen, kieseligen Eisensteine (Jaspilite) sind ähnlich denen von Kalken. Folgende Texturelemente wurden erkannt: 1. Orthocheme: a) Femikrit, b) Quarzmatrix (matrix chert), c) Quarzzement (cement chert). 2. Allocheme: a) Pellets, b) Intraklasten, c) Oolithe und Pisolithe, d) Scherden. Texturelle Lithotypen werden definiert durch die Kombination ihrer Texturelemente, wie in Kalken. Texturelle Fazies bestehen aus einem oder mehreren Lithotypen in regelmäßiger Folge. Sie besitzen oft kennzeichnende Strukturen. Texturfazien sind die Grundlage der Rekonstruktion der Bildungsbedingungen, Umwelt und Paläogeographie der Eisensteine.Folgende Arten epigenetischer Veränderungen wurden unterschieden: 1. Trocknung, Schrumpfung, Zementation und Kompaktion. 2. Kristallisation von Silikagel in der Reihenfolge: a) Primärquarz, Chalzedon und Quarzin, b) Kristallisation von Hämatitstaub, Wanderung von Eisen und Kristallisation von Spekulant und Magnetit. 4. Kristallisation und Rekristallisation von Siderit, Minnesotait, Stilpnomelan, Riebeckit und Talk. Wanderung von Eisen sowie Kristallisation von Spekulant, Magnetit und Siderit erfolgen im wesentlichen während der Kompaktion der Gesteine und vor (z. T. während) der Primärkristallisation von Quarz. Rekristallisierter Quarz, Minnesotait und vielleicht Stilpnomelan und Talk bilden sich weitgehend im spätdiagenetischen Stadium. Regionalmetamorphe Reaktionen führen zur Entstehung von Riebeckit und gelegentlich zu weiterer Kornvergröberung aller Minerale.

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Publié avec l'autorisation du Ministre, Ministère des Richesses Naturelles du Québec.  相似文献   

Spin-cast ZERODUR mirror substrates of the 8 m class and lightweight substrates for secondary mirrors     

Hartmut W. Hoeness  Rudolf Mueller  Erich W. Rodeck  Friedrich B. Siebers 《Astrophysics and Space Science》1989,160(1-2):193-197

For about 20 years SCHOTT has been supplying the glass ceramic ZERODUR, a material with very low thermal expansion. Besides many other applications, ZERODUR is excellently suited for the manufacture of mirror substrates for telescopes. About 80% of all telescopes in the western world with mirror diameters >1.8 m have been equipped with ZERODUR during the last 10 years. The development of modern astronomical telescopes is aimed at larger primary mirrors and lighter secondary mirrors.New techniques have been developed by SCHOTT for manufacture of thin monolithic mirror blanks of more than 8 m in diameter. The development of thin meniscus shaped shells using the spin-casting technique was successfully completed last year. During a test production several mirror substrates up to 4.1 m in diameter and down to 57 mm in thickness could be produced. The know-how has been acquired for the fabrication of mirror substrates of more than 8 m in diameter by the spin-casting technique.SCHOTT has also performed considerable developmental work in the field of lightweighted ZERODUR mirror substrates which can be generated using different techniques: forming of the lightweighted structure during casting, fusion of individual components to a total structure and lightweighting of a massive block by various mechanical machining methods.Paper presented at the Symposium on the JNLT and Related Engineering Developments, Tokyo, November 29–December 2, 1988.Registered trademark of SCHOTT Glaswerke, Mainz.  相似文献   

Solar flares: High-energy radiation and particles     

Erich Rieger 《Solar physics》1989,121(1-2):323-345

Due to the Sun's proximity flares can be investigated in the gamma-ray regime and flare generated particles can be measured in space and related to particular events. In this review paper we focus on the problem of particle acceleration by using as observational ingredients: the fluxes and spectra of particles inferred from gamma-ray measurements and observed in interplanetary space, the temporal characteristics of flares at high-energy X- and gamma-rays and the distribution of gamma-ray flares over the solar disc.  相似文献   

Limonit vom Hohen Sarstein,Oberösterreich     

Erich Johann Zirkl 《Mineralogy and Petrology》1965,10(1-4):256-264

Zusammenfassung Von einem Limonit aus der Umgebung der Steinhüttelalm am Hohen Sarstein im Dachsteingebiet (Oberösterreich) werden die Ergebnisse der Durchlicht-, Auflicht-und Elektronenmikroskopie, der DTA, Röntgen- und chemischen Untersuchungen mitgeteilt. Das Hauptmineral ist Nadeleisenerz, -FeOOH. Die Entstehung wird kurz erörtert.

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Summary Limonite from the environment of Steinhüttelalm at Hoher Sarstein in the Dachstein area (Upper Austria) is described. The results of microscopy in transmitted and reflected light, electron microscopy, DTA, X-ray, and chemical investigations are communicated. The main mineral is goethite, -FeOOH. The genesis is discussed.

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Herrn Professor Dr.F. Machatschki zum 70. Geburtstag gewidmet.  相似文献   

Über das Vorkommen einiger Spurenmetalle in Blei-Zink-Erzen der ostalpinen Metallprovinz     

Erich Schroll 《Mineralogy and Petrology》1955,5(3):183-208

Zusammenfassung Die Spurenanalyse ostalpiner Bleiglanze und Zinkblenden ergibt unabhängig von minerogenetischen Faktoren regionale Unterschiede in der Mikroparagenese. Die Pb-Zn-führenden Erzvorkommen der Ostalpen werden in nachstehend angeführte Erzbezirke gegliedert (vgl. auch Abb. 8): Mit 10 Textabbildungen.  相似文献   

Untersuchungen zum Mechanismus von Blastesis und Syntexis in Phylliten und Hornfelsen des südwestlichen Fichtelgebirges     

Erich Dimroth 《Mineralogy and Petrology》1963,8(3):361-402

Ohne ZusammenfassungMit 14 Textabbildungen  相似文献   

Untersuchungen zum Mechanismus von Blastesis und Syntexis in Phylliten und Hornfelsen des südwestlichen Fichtelgebirges     

Erich Dimroth 《Mineralogy and Petrology》1963,8(4):475-522

Ohne ZusammenfassungMit 22 Textabbildungen  相似文献   

Numerical investigations of shear localization in a micro‐polar hypoplastic material     

Wenxiong Huang  Erich Bauer 《国际地质力学数值与分析法杂志》2003,27(4):325-352

In this paper a micro‐polar continuum approach is proposed to model the essential properties of cohesionless granular materials like sand. The model takes into account the influence of particle rotations, the mean grain size, the void ratio, the stresses and couple stresses. The constitutive equations for the stresses and couple stresses are incrementally non‐linear and based on the concept of hypoplasticity. For plane strain problems the implementation of the model in a finite element program is described. Numerical studies of the evolution of micro‐polar effects within a granular strip under plane shearing are presented. It is shown that the location and evolution of shear localization is strongly influenced by the initial state and the micro‐polar boundary conditions. For large shearing the state quantities tend towards a stationary state for which a certain coupling between the norm of the stress deviator and the norm of the couple stress tensor can be derived. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

The haze and methane distributions on Neptune from HST-STIS spectroscopy     

Erich Karkoschka  Martin G. Tomasko 《Icarus》2011,211(1):780-797

We analyzed a data cube of Neptune acquired with the Hubble STIS spectrograph on August 3, 2003. The data covered the full afternoon hemisphere at 0.1 arcsec spatial resolution between 300 and 1000 nm wavelength at 1 nm resolution. Navigation was accurate to 0.004 arcsec and 0.05 nm. We constrained the vertical aerosol structure with radiative transfer calculations. Ultraviolet data confirmed the presence of a stratospheric haze of optical depth 0.04 at 370 nm wavelength. Bright, discrete clouds, most abundant near latitudes −40° and 30°, had their top near the tropopause. They covered 1.7% of the observed disk if they were optically thick. The methane abundance above the cloud tops was 0.0026 and 0.0017 km-am for southern and northern clouds, respectively, identical to earlier observations by Sromovsky et al. (Sromovsky, L.A., Fry, P.M., Dowling, T.E., Baines, K.H., Limaye, S.S., [2001b]. Icarus 149, 459-488). Aside from these clouds, the upper troposphere was essentially clear. Below the 1.4-bar layer, a vertically uniform haze extended at least down to 10 bars with optical depth of 0.10-0.16/bar, depending on the latitude. Haze particles were bright at wavelengths above 600 nm, but darkened toward the ultraviolet, at the equator more so than at mid and high latitudes. A dark band near −60° latitude was caused by a 0.01 decrease of the single scattering albedo in the visible, which was close to unity. A comparison of methane and hydrogen absorptions contradicted the current view that methane is uniformly mixed in latitude and altitude below the ∼1.5-bar layer. The 0.04 ± 0.01 methane mixing ratio is only uniform at low latitudes. At high southern latitudes, it is depressed roughly between the 1.2 and 3.3-bar layers compared to low-latitude values. The maximum depression factor is ∼2.7 at 1.8 bars. We present models with 2° latitude sampling across the full sunlit globe that fit the observed reflectivities to 2.8% rms.  相似文献