Paläotopographie und Kleinfazies     

Gerhard Keller 《International Journal of Earth Sciences》1956,45(1):128-134

Zusammenfassung Das mit Hilfe der paläotopographischen Betrachtungsweise bis in kleinste zeitliche und räumliche Einheiten zu erkennende Relief sinkender Erdkrustenteile bewirkt eine Aufgliederung der Faziestypen in örtliche Kleinfazies. Die Einschaltung von autochthonen Streifenkohlenflözen verleiht die Möglichkeit, die Kleinfazies mit dem Wasserspiegel paralischer Bildungsräume zu verknüpfen, so daß die Großbewegungen epirogener Undationen nicht nur in ihre kleinsten räumlichen und zeitlichen Vorgänge aufgelöst, sondern auch mit absoluten Senkungsmaßen belegt werden können. Epirogenese ist die Summe dieser Kleinstbewegungen, wobei das Maß. frühdiagenetischer Setzungen und die Reliefbelebung durch außerhalb des Sedimentationsraums ausgelöste erosive Vorgänge von jenen zu trennen ist.  相似文献   

Stratigraphy of the Kos Plateau Tuff: product of a major Quaternary explosive rhyolitic eruption in the eastern Aegean, Greece     

S. R. Allen  E. Stadlbauer  J. Keller 《International Journal of Earth Sciences》1999,88(1):132-156

 The Kos Plateau Tuff (KPT) erupted during a moderate-volume explosive rhyolitic event approximately 161 ka from a source south of Kos in the eastern Aegean sea. Six major stratigraphic units have been identified, from A at the base, to F, uppermost. Unit A is a widespread vitric ash fall layer that is thickest (1.5 m), and most extensive, southeast of the source. Unit B is a 1- to 2-m-thick, low-angle cross-stratified armoured pumice lapilli and ash layer found on Kos. Unit C resembles unit B but includes a greater abundance of lithic lapilli, less fine ash, is only diffusely stratified and is on Kos and west of the source. Unit D includes a sequence of three non-welded, 1- to 20-m-thick ignimbrites that extend radially >38 km from the source in areas of low topography. Unit E is a sequence of two non-welded, 3- to 8-m-thick ignimbrites which occur radially from the vent regardless of topography, >64 km from source. Unit F has a 6-m-thick, basal, low-angle cross-stratified armoured pumice lapilli and ash part probably deposited radially from source. The upper part of unit F is a widespread >1-m-thick vitric ash fall layer, found to at least 50 km from the source. These six units represent a change in eruptive conditions from initial and final phreatomagmatic activity depositing fallout and internally stratified pyroclastic density current deposits to "dry" explosive during the more intense phases of the eruption which generated ignimbrites. Received: 8 June 1998 / Accepted: 14 January 1999  相似文献   

Constitutive Equations for Engineering Mateials,Vol. Elasticity and Modeling | Wai-Fah Chen and Atef F. Saleb, 1982. John Wiley & Sons,New York,N.Y., xii + 580 pp., £stg. 51.75 (hardcover)     

W.D. Keller 《Earth》1983,19(2):167-168

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Radiocarbon and ²¹⁰Pb distribution in submersible-taken deep-sea cores from Project FAMOUS     

Y. Nozaki  J. Kirk Cochran  Karl K. Turekian  George Keller 《Earth and Planetary Science Letters》1977,34(2):167-173

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Scanning electron micrography of hydrothermally synthesized kaolin and parent materials during synthesis reactions     

Dr. O. Lahodny-Šarc  Dr. D. Dosen-Sver  Dr. W. D. Keller 《Mineralogy and Petrology》1981,28(4):265-276

Summary Changes in morphology of the parent solid materials, and the texture of kaolin crystals developed during hydrothermal synthesis of kaolin, may be graphically followed by scanning electron micrography (SEM) of the samples drawn during synthesis. Because the chemical conditions prevailing during synthesis are controlled and known, a possiblity arises for correlating the type of kaolin texture that is produced with the various known properties of the genetic environment. In this study, which is a first attempt toward that objective, the texture of kaolin produced by four different variations of hydrothermal synthesis using amorphous silica, allophane, and gibbsite in H₂SO₄ and H₄EDTA solutions are illustrated with SEMs.Elongate crystals of kaolin, and accordion-type mats of elongate crystals, not plates, interspersed with less dense layers of elongates are recorded.

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Raster-Elektronenmikroskopie von hydrothermal synthetisiertem Kaolin

Zusammenfassung Die morphologischen Änderungen des festen Muttermaterials und die Gefüge von Kaolinkristallen, die während der hydrothermalen Synthese von Kaolin entstehen, können graphisch mittels Rasterelektronenmikroskopie kontrolliert werden. Da die chemischen Bedingungen während der Synthese definiert und bekannt sind, ist es möglich, Kaolingefüge mit verschiedenen Eigenschaften des genetischen Milieus in Wechselbeziehung zu setzen.In dieser Arbeit wurden Gefüge von Kaolin bei vier verschiedenen Bedingungen hydrothermaler Synthese hergestellt; die Ergebnisse sind für amorphes SiO₂, Allophan und Gibbsit als Muttermaterialien in H₂SO₄ und H₄EDTA-Lösungen vorgelegt. Gelängte Kristalle von Kaolinmineralien und Akkordeon-ähnlichen Matten von verlängerten Kristallen, nicht Platten, mit zwischengelagerten, weniger dichten Schichten, werden gezeigt.

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With 23 Figures  相似文献   

Die Ladungsbilanz für eine verfeinerte Kristallstruktur von Stranskiit,Zn2 Cu(AsO4)2     

Priv. Doz. Dr. P. Keller  Prof. Dr. H. Hess  P. J. Dunn 《Mineralogy and Petrology》1979,26(3):167-174

Zusammenfassung Die Kristallstruktur des Stranskiits wurde mit neuen Meßdaten, die an einer aus Tsumeb stammenden Probe gewonnen worden waren, bis zuR=0,034 für 1239 unabhängige beobachtete Reflexe verfeinert. Von der verfeinerten Struktur wurde die Ladungsbilanz aufgestellt und besonders im Hinblick auf die Ladungsdeformation des Cu²⁺ diskutiert. Eine Mikrosondenanalyse derselben Probe ergab, daß die tatsächliche Zusammensetzung der angegebenen Formel entspricht.

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Charge balance of a refined crystal structure of stranskiite, Zn₂Cu (AsO₄)₂

Summary The crystal structure of stranskiite was refined with new intensity data obtained from a specimen from Tsumeb toR=0.034 for 1234 observed independent reflections. The charge balance was calculated and discussed particularly with respect of the charge deformation of Cu²⁺. An electron probe microanalysis gave the result that the actual composition of the specimen corresponds to the given formula.

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Die Drift und ihre ökologische Bedeutung     

Andres Keller Dr. sc. nat. ETH 《Aquatic Sciences - Research Across Boundaries》1975,37(2):294-331

With one-factor experiments, the drift of larvae ofEcdyonurus venosus has been analysed in a stream model. The distances travelled by drifting animals as a function of water velocity have been determined, as well as some drift rhythms. Drift-inducing factors are principally scarecity of food (lack of periphyton) and movement of substrate. Induction of drift by small water velocities can be caused by insufficient oxygen supply. The typical drift minimum during the final larval instar is said to be caused by a pseudo-pupal stage. After temperature shocks of ±5°C respectively, the animals acclimate within 2 days. An increase in temperature induces a decrease in drift reates and vice versa. Sex, predation and competition do not influence drift. The mean flight range of the imagoes (flight-mill) is 2,794 m, the maximum upstream movement of the larvae 140 m/24 h.  相似文献   

Fault Controlled Hydrogeology at a Waste Pile     

Barry Keller  Edward Hoylman  John Chadbourne 《Ground Water Monitoring & Remediation》1987,7(2):60-63

Geologic mapping, subsurface drilling and monitoring well data indicate the existence of a complex and irregular ground water regime in the vicinity of a cement kiln dust pile on an inactive splay of the Garlock Fault System. Artesian flow, active seeps and water levels that are substantially higher than the elevation of apparent saturated conditions encountered during drilling show that ground water flows upward in certain localized zones. Tracing of chemical indicator parameters characteristic of kiln dust leachate shows that the dust pile is not affecting the chemistry of nearby ground water.  相似文献   

The phoshate mineral associations of the Tsaobismund pegmatite,Namibia     

André -Mathieu Fransolet  Paul Keller  François Fontan 《Contributions to Mineralogy and Petrology》1986,92(4):502-517

A detailed mineralogical investigation using the classical methods of identification by X-ray diffraction and by optical properties in thin sections, has revealed thirty one phosphate minerals occurring in the Tsaobismund pegmatite. This investigation is complemented by wet chemical and, mainly, electron microprobe analyses performed on the phosphates known to be typomorphic or considered to be relevant to the hydrothermal alteration. Additionally, microprobe analyses are also given for garnet, gahnite, and ferrocolumbite associated with the phosphates. On the basis of their chemical composition, particularly in terms of their Fe, Mn, and Mg contents, three types of triphylites are distinguished. Triphylite 1 only occurs as a primary phase, triphylite 2 shows exsolution lamellae of sarcopside, and triphylite 3 is partly replaced by a fluorophosphate of the triplite-zwieselite series. These minerals constitute three generations of the parent phases, which were progressively transformed by metasomatic processes, hydrothermal alteration, and by weathering, to give finally three types of complex associations. The Li(Fe,Mn)PO₄ minerals appear to be more sensitive to such transformations than those of the (Fe,Mn)₂PO₄F series. Four main stages of hydrothermal alteration processes have been recognized in the Tsaobismund pegmatite: (i) the Mason-Quensel sequence results from a progressive oxidation of Fe and Mn, and a concomitant Li-leaching of triphylite yielding ferrisicklerite and heterosite, successively; (ii) the metasomatic exchange of Na for Li produces alluaudite; in the present case, the formation of hagendorfite from triphylite 2 is considered to be earlier than the generation of alluaudite-Na occurring in the three associations; (iii) the hydration phase mainly transforms the parent Li(Fe,Mn)PO₄ phase into grey hureaulite, associated with barbosalite and tavorite; (iv) the formation of fluorapatite, not particularly widespread, replaces alluaudite-Na, as well as zwieselite s.l. The following crystallization sequence of the initially formed phosphate minerals is proposed: triphylite 1 triphylite 2 + sarcopside (associated with garnet) triphylite 3 + zwieselite s.l. The most prominent feature of this succession is the increase in the Mg and Zn contents in the composition of the phosphates, as well as the decrease in their Li contents. The variations of the Fe/Mn ratios in this sequence are discussed. The succession triphylite-zwieselite within weakly differentiated and Li-poor pegmatites is of general significance.  相似文献   

Quaternary maar volcanism near karapinar in central Anatolia     

J. Keller 《Bulletin of Volcanology》1974,38(1):378-396

In Central Anatolia, Quaternary olivine basalts overlie the Neogene calcalkaline and sialic post-orogenic volcanic series. Crater forms, cones and lava fields generally exhibit a very fresh morphology suggesting a sub-recent age. Near the town of Karapinar, eruptions took place through the shallow waters of a lake which occupied the present Konya-Eregli plain during Quaternary times. Depending on the varying influence of phreatomagmatic effects, hyaloclastitic tuff rings and maar craters, both rich in sideromelane and its palagonitic alteration products, or subaerial red cinder cones developed. The maar phase is characterized by a large development of base surge structures. The basalts are alkaline and, mostly, Ne-normative and are distinct for their low TiO₂ content and low Fe/Mg ratio from the alkali olivine basalts from oceanic and stable continental areas.  相似文献