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1.
On three nights in February 1976 we carried out polarimetric measurements, in V, of the short periodic eclipsing binary XY UMa, covering a complete cycle. The results are as follows:
- Within all phase intervals the linear polarization does not exceed 0.1%.
- In the phase range 0 p .95–1 p .35 the scatter of the Stokes parametersQ andU is about twice that within the phase interval 0 p .35–0 p .95.
- A periodogram analysis of these data revealed a period of 21000 s, which is equal to half the orbital periodP o=0d.47899 within 1.5%.
2.
Reactive surface area is one of the key parameters for studying the kinetics of mineral dissolution. The common practice in experimental kinetics is to normalize the dissolution rate to the surface area measured by the BET method. The relationship between BET surface area and the reactive surface area is not trivial in minerals such as smectites, which possess both internal and external surface areas, and in which the dissolution is controlled by the chemical attack on the edge surface. The present study examines two proxies for the reactive surface area of the Clay Mineral Society reference smectite SAz-1: BET surface area and the edge surface area measured using AFM.Since smectites are very microporous, their BET surface area is strongly influenced by the degassing procedure. It is demonstrated that outgassing the smectite powder at 135°C in a 15 mL min−1 N2 gas flow for at least 24 hours minimizes contribution from micropores to less than 11% of the BET surface area.Following dissolution experiments in solutions with a low electrolyte concentration, the BET surface area increased from 34 ± 2 m2 g−1 in raw SAz-1 to 127 ± 13 m2 g−1 in SAz-1 sample recovered from dissolution experiments. This increase in BET surface area is explained by a decrease in the average size of the smectite aggregates, and by an increase in microporosity due to the depletion in the major interlayer cation, i.e., Ca2+. As the BET surface area of the raw smectite sample includes considerably less microporosity compared to the BET surface area of the smectite recovered from dissolution experiments, the former is a better approximation of the external surface area of the dried sample powder.AFM measurements show that there is no correlation between the specific external surface area of the sample and its specific edge surface area. This observation is explained by the platy morphology of the smectite particle in which the specific external surface area depends linearly on the height reciprocal, whereas the specific edge surface area is independent of the particles height and depends linearly on the sum of the reciprocals of the length of the axes. Therefore, there is no reason to expect a correlation between the BET and the edge surface area. Our results show that the edge surface area (4.9 ± 0.7 m2 g−1) of the smectite particles cannot be predicted based on its external surface area (136 ± 20 m2 g−1). Therefore, the BET surface area cannot serve as a proxy for the reactive surface area. We suggest using AFM measurements of the specific edge surface area as an alternative proxy for the reactive surface area of smectite. 相似文献
3.
Prof. Dr. K. Metz 《International Journal of Earth Sciences》1962,52(1):210-226
Zusammenfassung Die Niederen Tauern sind ein Teil der großen Masse des ostalpinen Altkristallins. Zwei ihrer Anteile haben in altalpidischer Zeit durchaus verschiedenartige tektonische Prägungen erlitten: Die Gesteine der Seckauer Tauern unterlagen damals einer intensiven Teilbewegung im Gefüge und überdies einer Metamorphose, deren Typus als Seckauer Kristallisation durchaus der Tauern-Kristallisation der Hohen Tauern vergleichbar ist. Die westlich benachbarten Wölzer Tauern erfuhren zu gleicher Zeit lediglich eine starke Deformation, aber keine Metamorphose.Eingefaltete und mit den kristallinen Gesteinen geschuppte triadische Sedimente ermöglichen zusammen mit dem Auftreten von Jungtertiär eine zeitliche Unterteilung alpidischer Prägungsakte. In diesem Zusammenhang werden 2 Systeme tertiärer Bruchstörungen kurz beschrieben.Im vortertiären alpidischen Orogen waren die hier behandelten Kristallinmassen Angehörige von drei verschiedenen tektonischen Stockwerken: das tiefste mit einer starken alpidischen Metamorphose, darüber ein Stockwerk mit Faltungs- und Überschiebungstektonik und schließlich im Süden (Zirbitz-Sau- u. Koralm) ein oberstes Stockwerk mit Bruchtektonik unter Erhaltung aller voralpidischen Strukturelemente.Dieser Befund ist schlecht in Übereinstimmung zu bringen mit einer Auffassung, welche dieses Altkristallin lediglich als eingeschobene Riesenmasse kristalliner Gesteine ohne Differenzierung gegenüber dem tektonischen Geschehen betrachtet.
The Niedere Tauern as a part of the big mass of the ostalpines Altkristallin can be subdivided in various sections. Two of them show very different tectonic development during the pretertiary alpidic tectogenesis: In the Seckauer Tauern (gneisses and granites of various types) a rock deformation of high intensity took place and the rocks were metamorphosed in a specific type (Seckau crystallisation, comparable with the Tauern crystallisation of the Hohe Tauern). In the neighboured Wölzer Tauern at the same time only cinematic deformation without metamorphism was induced in the ancient mica schists.The presence of triassic sediments, infolded and imbricated in the cristalline series, as well as coal bearing tertiary sediments allow a chronological subdivision of the alpidic movements. Two arcs of tertiary fault-systems are described.The cristalline masses considered here were representing three different levels of the ancient-alpidic (pretertiary) Orogen: a deepest level with metamorphism and local gneissification, a level of folding and thrusting without metamorphism, a superficial level of ancient crystallins (Zirbitzkogel) with movements en bloc and complete preservation of all pre-alpidic rock features.Hence the author concludes that the eastalpine mass of cristallins, considered in the paper, was not a giant overthrusted nappe of uniform level, undifferentiated in respect to the eastalpine orogen.
Résumé Le massif des Niedere Tauern constitue une partie de la grande masse du vieux socle cristallin des Alpes orientales. Deux de leur parties ont subi des empreintes tectoniques différentes à la période la plus ancienne de la formation des Alpes: Les roches des Tauern de Seckau ont été soumises à cette époque à un mouvement intensif et en plus à une métamorphose dont le type, sous le nom de «cristallisation de Seckau», est tout à fait comparable à la «cristallisation de Tauern» dans la région des Hohe Tauern. Les Wölzer Tauern, situées à l'Ouest, n'ont subi à la même époque qu'une forte déformation, mais pas de métamorphose.Des sédiments triassiques, plissés et charriés avec les roches cristallines, ont permis grâce à la présence des couches du Tertiaire supérieur d'établir une division chronologique des phases tectoniques alpines. A ce sujet deux systèmes de fractures tertiaires sont décrits par la suite.A l'orogène prétertiaire les masses cristallines en question ont fait partie de trois étages structuraux différents: à la base un étage à forte métamorphose alpine, au milieu un étage à tectonique caractérisée par des plissements et des charriages et enfin au Sud un étage supérieur à tectoniques à fractures radiales conservant tous les éléments de la structure préalpine.Ces constatations peuvent difficilement s'accorder avec la théorie qui considère ce vieux socle cristallin comme une grosse masse des roches cristallines implantée sans différenciation vis à vis des processus tectoniques.
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4.
For the reaction: 1 diopside+3 dolomite ?2 forsterite+4 calcite+2 CO2 (14) the following P total?T-brackets have been determined experimentally in the presence of a gasphase consisting of 90 mole%CO2 and 10 mole%H2O∶1 kb, 544°±20° C; 3kb, 638°±15° C; 5kb, 708°±10° C; 10kb, 861°±10° C. The determination was carried out with well defined synthetic minerals in the starting mixture. The MgCO3-contents of the magnesian calcites formed by the reaction in equilibrium with dolomite agree very well with the calcite-dolomite miscibility gap, which can be recalculated from the activities and the activity coefficients of MgCO3 as given by Gordon and Greenwood (1970). The equilibrium constant K 14b was calculated with respect to the reference pressure P 0=1 bar using the experimentally determined \(P_{total} TX_{CO_2 }\) brackets, the activities of MgCO3 and CaCO3 (Gordon and Greenwood 1970; Skippen 1974) and the fugacities of CO2 Holloway (1977) considering the correction of Flowers (1979). Results are plotted as function of the absolute reciprocal temperature in Fig. 1. For the temperature range of 530° to 750° C the following linear expression can be given for the natural logarithm of K14b: (g) $$[ln K_{14b} ]_T^P = - \frac{{18064.43}}{{T\left( {^\circ K} \right)}} + 38.58 + \frac{{0.308(P - 1 bar)}}{{T\left( {^\circ K} \right)}}$$ where P is the total pressure in bars and T the temperature in degrees Kelvin. Combining Equation (g) with the activities of MgCO3 and CaCO3 gives the equilibrium fugacity \(f_{CO_2 }\) : (i) $$[ln f_{CO_2 } ]_T^P = - \frac{{11635.44}}{{T\left( {^\circ K} \right)}} + 21.09 + \frac{{0.154(P - 1 bar)}}{{T\left( {^\circ K} \right)}}$$ Equation (i) and the fugacities of CO2 permit to calculate the equilibrium data in terms of \(P_{CO_2 }\) and T (see Fig. 3) or P total, T and \(X_{CO_2 }\) (see Fig. 5). Combining the \(P_{total} TX_{CO_2 }\) equilibrium data of the above reaction with those of the previously investigated reaction (Metz 1976): 1 tremolite+11 dolomite ?8 forsterite+13 calcite+9 CO2+1 H2O yields the stability conditions of the four-mineral assemblage: diopside+calcian dolomite+forsterite +magnesian calcite and the stability conditions of the five-mineral assemblage: tremolite+calcian dolomite+forsterite +magnesian calcite+diopside both shown in Fig. 6. Since these assemblages are by no means rare in metamorphic siliceous dolomites (Trommsdorff 1972; Suzuki 1977; Puhan 1979) the data of Fig. 6 can be used to determine the pressure of metamorphism and to estimate the composition of the CO2-H2O fluid provided the temperature of the metamorphic event was determined using the calcite-dolomite geothermometer. 相似文献
5.
H. Wieseneder H. Heritsch K. Metz J. Zemann E. Schroll K. Becherer 《Mineralogy and Petrology》1969,13(2):191-200
Ohne Zusammenfassung 相似文献
6.
K. Metz 《International Journal of Earth Sciences》1952,40(2):261-275
Zusammenfassung Aus der Kombination üblicher stratigraphischer und tektonischer Geländearbeit mit gefügekundlichen Methoden (B.Sander) in paläozoischen Gebieten der Ostalpen ergaben sich klarere Einblicke in die voralpidische Baugeschichte dieser Gebirgsstücke.Die Arbeit bringt übersichtsweise eine Zusammenfassung der bisherigen Ergebnisse und daraus ableitbare Folgerungen für benachbarte Gebirgsstücke. Es wird ein mächtiger bretonischer Gebirgsstamm in den Zentralalpen vermutet, der für die spätere alpidische Strukturgestaltung in den östlichen Ostalpen von Bedeutung wurde.Einige vergleichende Ausblicke in die westlichen Alpenteile wurden gegeben. 相似文献
7.
Robert Metz 《Central European Journal of Geosciences》2012,4(1):3-8
Mudstones of the Triassic Passaic Formation, near Milford, New Jersey, have yielded the first evidence of an arthropod impression in that formation. Associated trace fossils include Helminthoidichnites, Lockeia, Scoyenia, Spongeliomorpha, and the reptile footprint Rhynchosauroides, representing the Scoyenia ichnofacies. Associated sedimentary structures include desiccation cracks and raindrop impressions. The Passaic sediments were deposited under shallow water lacustrine shoreline conditions subject to periodic subaerial exposure. 相似文献
8.
High concentrations of naturally occurring radium pose environmental and health concerns in natural and industrial systems. The adsorption of Ra2+ in saline water is limited compared to its adsorption in fresh water, but the process of co-precipitation may be effective in decreasing its concentration. However, despite its importance, Ra co-precipitation has rarely been studied in high ionic strength environments such as those in evaporitic systems.The fate of Ra in the reject brine of a desalination plant was studied via evaporation batch experiments at ionic strengths (I) ranging from 0.7 to 7.0 mol kg−1. Precipitation sequences revealed that Ra co-precipitated with barite, even though the latter was a trace mineral compared to the precipitated gypsum. The concentration-based effective partition coefficient, , for the co-precipitation reaction was 1.04 ± 0.01. This value of is significantly lower than the value for relatively diluted solutions (1.8 ± 0.1). This low value of is mainly the result of a kinetic effect but is also slightly affected by the ionic strength.Both effects are quantitatively examined in the present paper. It is suggested that a kinetic effect influences the nucleation of (Ra,Ba)SO4, reducing the value of the partition coefficient. This kinetic effect is caused by the favorable nucleation of a more soluble phase (i.e., a phase with a higher BaSO4 fraction). An additional decrease in the partition coefficient results from the ionic strength effect. Considering the activity of Ra2+ and Ba2+ in the solution (rather than their concentration) makes it possible to determine the activity-based partition coefficient (), which accounts for the ionic strength effect. was calculated empirically from the experiments and theoretically via a kinetic model. The two derived values are consistent with one another and indicate the combined effect of ionic strength and precipitation kinetics.Finally, the common assumption that γRa2+/γBa2+=1 was re-examined using a numerical model to predict the experimental results. As the ionic strength increases, this assumption becomes less appropriate for predicting the change in as calculated in the experiments. Understanding the co-precipitation of Ra in such systems is crucial for risk assessments in which both Ra concentration and ionic strength are relatively high. 相似文献
9.
Basing on calculations and experiments the equilibrium curves of 15 reactions occuring during metamorphism of siliceous dolomites are presented. In a T—XCO 2 diagram these curves intersect at four isobaric invariant points. This is consistent with the fact, that different reaction sequences are known from the nature. 相似文献
10.
Prof. Dr. K. Metz 《International Journal of Earth Sciences》1972,61(1):87-96
Zusammenfassung Es wird ein kurzer Überblick über den komplexen Gesteinsbestand eines Gebietes im arabischen Grundgebirge des südlichen Hedjaz gegeben. Es zeigte sich, daß die tektonischen, stark überprägten und metamorphen Serien heute noch nicht in das Schema der in der Literatur genannten Serien eingebaut werden können. Diese scheinen sowohl hinsichtlich ihres stofflichen Bestandes wie auch des Zusammenhanges ihrer strukturellen und metamorphen Prägung noch zu wenig gekennzeichnet zu sein.Die im Grundgebirge weit verbreiteten Seitenverschiebungen werden kurz beschrieben und ihr Alter als wahrscheinlich spät-präkambrisch aufgefaßt.
The paper gives a general view of the different rock series occurring in a mapped area of the basement complex in the southern Hedjaz. The predominant masses of strongly tectonized and epimetamorphic series cannot be correlated with some series, which are named already in the literature of Arabia. These latter series seem defined not sufficiently in their composition and in the relation to their structural and metamorphic development.The wrench movements, wide spread in the Arabian basement, are briefly described and defined as being probably late-precambrian.
Résumé L'auteur donne un bref aperçu de la composition géologique complexe d'une région du soubassement arabe de l'Hedjaz du Sud. Il s'est avéré qu'à l'heure actuelle les séries fortement tectonisées et métamorphiques ne peuvent encore être intégrées au schéma des séries mentionnées par la littérature. Ces séries semblent être encore trop peu caractérisées en ce qui concerne leur composition ainsi que le rapport entre leurs caractéristiques structurelles et métamorphiques.Les failles horizontales de décrochement, qui sont très répandues dans le soubassement, sont décrites brièvement et définies comme datant probablement de la fin de l'antécambrien.
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