Der Pyroxentuff vom Heilsberg im Hegau

Zusammenfassung Das Tuffvorkommen vom Heilsberg bei Gottmadingen im Hegau wurde neu kartiert und mineralogisch untersucht. Die Korngrößenverteilung zeigt ein deutliches Maximum bei 0,6–1,2 mm. Der Tuff besteht aus 40% magmatogenem Material und 60% Bestandteilen des durchschlagenen Untergrundes. Die magmatogenen Komponenten sind 17% Einzehnineralien, 10% Grundmasse und 13 % Auswürflinge. Unter den Einzelmineralien wiegt der Pyroxen (Fassait) vor, daneben kommen Amphibol, Biotit und Magnetit, ferner Apatit und Analcim sowie einige seltenere Mineralien vor. Für Pyroxen, Amphibol, Biotit und Magnetit werden chemische Analyse und optische Eigenschaften mitgeteilt. Die größte Menge der magmatogenen Auswürflinge sind kugelförmige Lapilli, die hinsichtlich ihrer Entstehung genauer untersucht und chemisch analysiert wurden. Seltener sind grobkristalline, dunkle und belle Bomben, deren Mineralgehalt und chemische Zusammonsetzung genauer beschrieben werden. Sic stellen wahrscheinlich Differentiate des Heilsbergmagmas dar. Die ehemals glasige, magmatogene Grundmasse des Tuffs liegt heute als ein Gemenge von Montmorillonit und Calcit vor.Aus den nichtmagmatogenen Bestandteilen kann auf den Untergrund im Bereich des Heilsbergvulkans geschlossen werden. Aus dem Deckgebirge wurden Tertiär, Mahn, Dogger, Jura, Keuper und Muschelkalk nachgewiesen. Das Grund-gebirge besteht hauptsächlich aus granodioritischen bis granitischen Gesteinen und enthält auffallenderweise nur wenig Gneise. Der Herd der Eruption dürfte mindestens 4000 m tief liegen.Der Chemismus des Heilsbergmagmas ist hornblenditisch. Es ist dem Magma der Melilithite verwandt und leitet zu den Phonolithen des Hegau über. Das Gestein ist als hornblenditischer Pyroxen-Analcim-Tuff zu bezeichnen.Zwei unabhängige Bestimmungen nach der K-Ar-Methode ergaben für den Biotit des Tuffs ein obermiozänes Alter von 14,0 bzw. 14,5 Mill. Jahren.Mit 2 Textabbildungen     

Measurements of radio noise at 0.700 mc and 2.200 mc from a high-altitude rocket probe

Radio noise observations at frequencies of 0·700 Mc and 2·200 Mc were made at altitudes between 3000 and 11,000 km from a Blue Scout Jr. high-altitude rocket probe on 30 July 1963. A steady background flux of (7·5₋₃⁺⁶) × 10⁻¹⁹ W m⁻²)(c/s)⁻¹ at 0·700 Mc and (1·8^+1.0_−0.5 × 10⁻¹⁹ W m⁻² (c/s)⁻¹ at 2·200 Mc was observed. Assuming a galactic origin of the observed fluxes at both frequencies, the averaged sky brightnesses are b(0·700 Mc) = (6₋₃⁺⁵) × 10⁻²⁰ W m⁻² (c/s)⁻¹ sr⁻¹b(2·200 Mc) = (1.4^+1.0_−0.5 × 10⁻²⁰ W m⁻² (c/s)⁻¹ sr⁻¹ The observed brightness at 2·200 Mc is in reasonable agreement with the results of other observers. The apparent brightness at 0·700 Mc is, however, greater than was expected from previous observations. An alternative source of the 0·700 Mc flux in the terrestrial exosphere, as well as characteristics of several noise bursts observed during the flight, is briefly discussed.     

Models of the Southern Oscillation in the 300–100 mb layer and the basis of seasonal forecasting

Summary The geometry of the principal Upper High (near the Indian Occean) in the 300–100 mb layer appears to account for the Southern Oscillation (S.O.), and models of its behaviour are presented. Significant features of these models include the equatorial points of upper convergence (C) and divergence (D), a pressure discontinuity (CNDS) forming «arcs» and an «enclosure» around the high, and, lastly, encircling «crescents» both outside and inside the enclosure. The geography of the seasonal sucession can thus—in a qualitative manner—be interpreted in the light of known wind and contour patterns near the tropopause. With a few general principles, the established empirical rules of long-range forecasting then follow by deduction. The models and the terminology are useful likewise in the interpretation of solar-terrestrial relations and of climatic fluctuations.     

Correlation of atmospheric occurences over the United States with some physical and chemical parameters. Part III: Frequencies of precipitation

Summary Correlation between some physical and chemical variables, measured at 28 stations of the United States Weather Bureau Network, and seasonal and annual frequencies of precipitation, has been attempted with the aim of gaining insight into the bearing of such variables, on occurrence of precipitation. — Concurrent trends of frequencies with local temperature functions, altitude parameters, precipitable water vapour increments, and some chemical species have been found.Contribution of the «Centro Nucleazione Aerosoli» of the National Research Council of Italy, Via Vettore 4 (Monte Sacro),Roma.     

Phase Equilibria in the Metamorphic Rocks of St. Paul Island and Cape North, Nova Scotia

A suite of schists—one from the garnet zone, 19 from thestaurolite zone, 2 from the kyanite isograd, and one from thekyanite zone—were separated into their constituent minerals.Chemical analyses of one chlorite and of 23 sets of coexistingbiotites and garnets were carried out by photometric and titrametricprocedures. Plots of garnet-biotite tie-lines from divariantassemblages on appropriate phase diagrams result in intersectingtie-lines which cannot be ascribed to experimental error. Theoreticalconsiderations argue that at equilibrium, at the same pressureand temperature or at constant pressure and varying temperature,tie-lines of divariant assemblages should not intersect. Possibleexplanations require that diffusion equilibrium of Fe and Mgbe restricted to volumes smaller than that of a hand specimenor that P as well as T varies considerably. Emission spectrographicdeterminations of Fe and Mg in biotite indicate that the Fe/Mgratio varies among biotites little more than a centimeter apart.Such a variation would argue more in favor of a lack of diffusionequilibrium.     

Structure and petrology of an alpine peridotite on Cypress Island,Washington, U.S.A

A study of the structural petrology of a peridotite exposed on Cypress Island in Skagit Co., Washington, U.S.A. has been carried out. The Cypress peridotite is, by virtue of its composition, structure and associations, typical of ultramafics of the alpine type. It contains relict layering and accumulative textures which show it to have originated by crystal settling from a magma of unknown initial composition. Parallelism of lineations and b-axes of folds in the layering with well-developed [100]-maxima in the fabrics of olivine crystals is considered to have arisen through a penetrative deformation of the mass accompanied by plastic flow or recrystallization of the olivine. An indication of the minimum temperature of the deformation is provided by cross-cutting veins of pyroxenite which have not participated in the folding. The most satisfactory interpretation of the overall fabric of the peridotite is that it was deformed, possibly during intrusion, as a crystal mush, and that filter pressing due to compaction of the solid particles by plastic flow or recrystallization removed all but a small percentage of the magmatic fraction which then crystallized following cessation of the movements.     

The volcano-magnetic effect

Summary A geometrically simple volcano is considered, havig a spherical magma chamber of 2.5 km radius centred at 10 km depth. The Curie point isotherm is assumed to be a plane at 20 km depth, except for the spherical volume which is also non-magnetic. The stress pattern in the vicinity of the spherical chamber, due to regional stress of sufficient intensity to cause an eruptions, is used to calculate the change in magnetization which results from the piezomagnetic effect through the volume of solid rock. The consequent magnetic field anomaly at the surface is then obtaied by numerical integration of the dipole law of force over the stressed volume. For rocks of the type found on the volcanic island of St. Vincent (West Indies), this model gives a maximum local volcano-magnet c effect of about 7 gammas.     

Ion-exchange reactions on clay minerals and cation selective membrane properties as possible mechanisms of economic metal concentration

A series of exploratory experiments on the concentration of base metals through ion exchange reactions on clay minerals show promising results. The extraction of Pb, Zn and Cd from bentonite, illite, kaolinite and montmorillonite was successful and megascopic quantities of PbS, CdS and ZnS could be obtained at specific loci, depending essentially on the flow velocity, and the other cations present. These or similar exchange reactions are tentatively proposed as possible mechanisms of economic metal concentration during diagenesis.

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Zusammenfassung Es werden experimentelle Resultate zur Anreicherung von Schwermetallen durch Tonminerale (Montmorillonite, Illite und Kaolinite) mitgeteilt. Eine erste Anreicherung kann über den Kationenaustausch bewirkt werden. In dem darauffolgenden zweiten, sehr viel wirksameren Schritt werden die Schwermetallionen aus den Tonlagern extrahiert und in deren Nähe als schwerlösliche Sulfide oder Carbonate gefällt. Die Extraktion beruht darauf, daß Tonschichten als Kationen-permeable Membranen wirken können. Sie wird von der Art der Tonminerale und der Kationen, den Lösungsgenossen, den Konzentrationsverhältnissen, dem pH-Wert, der Reaktionstemperatur, dem Porenvolumen und der Porenverteilung im Sediment beeinflußt.