Blind prediction of the site effects at Ashigara Valley,Japan, and its comparison with reality

Weak and strong ground motions were numerically predicted for three stations of the Ashigara Valley test site. The prediction was based on the records from a rock-outcrop station, one weak-motion record from a surface-sediments station, and the standard geotechnical model. The data were provided by the Japanese Working Group on the Effects of Surface Geology as a part of an international experiment. The finite-difference method for SH waves in a 2-D linear viscoelastic medium (a causalQ model) was employed.Comparison with the real records shows that at two stations the predictions fit better than at the third one. Strangely, the two better predictions were for stations situated at larger distances from the reference rock station (one station was on the surface, the other in a borehole). The strong ground motion (the peak acceleration of about 200 cm s^–2) was not predicted qualitatively worse than the weak motion (8 cm s^–2). A less sophisticated second prediction (not submitted during the experiment), in which we did not attempt to fit the available weak-motion record at the sedimentary station, agrees with the reality significantly better.     

Thermodynamic data from redox reactions at high temperatures. IV. Calibration of the Re-ReO2 oxygen buffer from EMF and NiO+Ni-Pd redox sensor measurements

The chemical potential of oxygen defined by the equilibrium:

The shoshonite porphyry Cu-Au association in the Goonumbla District,N.S.W., Australia

Summary The Goonumbla porphyry copper-gold deposit in N.S.W., Australia, is hosted by late Ordovician (439.2 ± 1.2 Ma)shoshonitic igneous rocks. In terms of their petrography, the rocks vary from andesitic to dacitic lavas and tuffs which are partly intruded by monzonite stocks; they are characterized by high and variable Al₂O₃ (13.4–19.9 wt%), very high K₂O values (up to 6.8 wt%), and high K₂O/Na₂O ratios (0.58–1.48), which are typical for the shoshonite association. The rocks also have enriched LILE concentrations (Ba up to 1200 ppm, Sr up to 1350 ppm), low HFSE (TiO₂ < 0.67 wt%, Zr < 125 ppm, Nb < 10 ppm, Hf < 3.4 ppm), and very low LREE (La < 22.4 ppm, Ce < 31 ppm), which are typical for potassic volcanic rocks formed in alate oceanic-arc setting.Mineral chemistry of selected magmatic mica and apatite phenocrysts from host rocks reveals relatively high SrO and BaO contents (micas: 0.15 wt% and up to 0.28 wt%, respectively; apatites: up to 0.28 wt% and 0.19 wt%, respectively) and very high halogen concentrations. Micas are characterized by up to 3.9 wt% F and 0.14 wt% Cl, whereas apatites have up to 3.6 wt% F and 0.68 wt% Cl. These very high halogen contents compared to those from barren intrusions imply that the shoshonitic magmatism was the source of mineralization.Copper-gold mineralization consists mainly of bornite, chalcopyrite, chalcocite and minor pyrite and tetrahedrite. Native gold occurs mainly as minute grains within silicates of the host rocks, and more rarely as fine inclusions in the sulphides. Mineralization is accompanied by wallrock alteration comprising a spatially restricted potassic type and a regional propylitic alteration type.Thus, the porphyry copper-gold deposit in the Goonumbla district can be viewed as an additional example of a worldwide association between potassic/shoshonitic magmatism and base- and precious-metal mineralization. More specifically, it appears to be the oldest recorded example of a shoshontie-associated porphyry Cu-Au deposit from a late oceanic-arc setting, a possible modern analogue being Ladolam at Lihir Island, Papua New Guinea

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Die Shoshonit Porphyry Cu-Au Assoziation im Goonumbla Distrikt, N.S.W., Australien

Zusammenfassung Die Porphyry Cu-Au Vererzung im Goonumbla Distrikt in New South Wales, Australien, sitzt in oberordovizischen (ca. 439.2 ± 1.2 Ma) Shoshoniten auf. Das petrographische Spektrum dieser Gesteine reicht von andesitischen bis dazitischen Laven und Tuffen, die lokal von Monzonit-Stöcken intrudiert werden; die Gesteine besitzen hohe, aber variable Al₂O₃ Gehalte (13.4–19.9 Gew%), sehr hohe K₂O Gehalte (bis zu 6.8 Gew%) und hohe K₂O/Na₂O Verhältnisse (0.58–1.48), die typisch sind für Shoshonite. Außerdem weisen sie hohe Konzentrationen an LILE Elementen (Ba bis 1200 ppm, Sr bis 1350 ppm) auf und geringe Konzentrationen an HFSE (TiO₂ < 0.67 Gew%, Zr < 125 ppm, Nb < 10 ppm, Hf < 3.4 ppm) sowie an LREE (La < 22.4 ppm, Ce < 31 ppm), die als typisch gelten für potassische Vulkanite von ozeanischen Plattengrenzen.Die Mineralchemie von repräsentativen Glimmer- und Apatit-Phänokristallen ist charakterisiert durch hohe SrO und BaO Gehalte (Glimmer: 0.15 Gew%, bzw. bis 0.28 Gew%; Apatite: bis 0.28 Gew%, bzw. 0.19 Gew%). Sie enthalten ferner sehr hohe Halogen-Konzentrationen. Die Glimmer enthalten beispielsweise bis zu 3.9 Gew% F und 0.14 Gew% Cl, während Apatite bis zu 3.6 Gew% F und 0.68 Gew% Ci aufweisen. Dies erscheint nicht ungewöhnlich, weil Glimmer und Apatite von vererzten Mag matiten zumeist deutlich höhere Halogengehalte besitzen, als solche von unvererzten Magmatiten. Die hohen Halogen-Gehalte in Phänokristallen aus den Shoshoniten legen nahe, die Vulkanite als den Ursprung der Vererzung zu interpretieren.Die Cu-Au Vererzung besteht überwiegend aus den Sulfiden Bornit, Kupferkies, Kupferglanz und vereinzelt auftretendem Pyrit und Tetrahedrit. Gediegen Gold wird in der Regel nur als kleine Partikel innerhalb von Silikaten der shoshonitischen Wirtsgesteine und seltener als feine Einschlüsse in Sulfiden gefunden.Die Vererzung wird von hydrothermaler Alteration der Wirtsgesteine begleitet und zwei Alterationsarten lassen sich unterscheiden: eine potassische sowie eine regional zu beobachtende propylitische Alteration.Die Porphyry Cu-Au Lagerstätte im Goonumbla Gebiet ist ein Beispiel für die weltweit beobachtete Assoziation von Bunt- und Edelmetallvererzungen und potassisch/shoshonitischem Magmatismus. Der Goonumbla Distrikt stellt die älteste bisher bekannte Porphyry Cu-Au Lagerstätte aus einerspätgenetischen ozeanischen Plattengrenze dar. Einmodernes Beispiel für eine Cu-Au Lagerstätte vergleichbaren Typs ist Ladolam auf Lihir Island, Papua New Guinea.

     

Once more on quasar periodicities

In an earlier paper Arp, Bi, Chu and Zhu investigated various quasar samples and recognized a periodicity of remarkable degree in them. Their conclusion was that the existence of such a periodicity is a counterevidence against the cosmological origin of quasar redshifts. Since this question is of great importance in a cosmological context, here we reanalyze some of the samples together with a galaxy sample of the pencil-beam survey of Broadhurstet al. Our result is that on the plane of cosmological parameters (₀, ₀) there is a non-negligible region where two quasar samples and the galaxy sample are simultaneously fairly periodic. Pure periodicity is still compatible with cosmological principles, at least on length scales much longer than the period length. So the regularities can fit into a cosmological context.     

Cosmic-ray modulation and long-duration solar flare events

The correlation between the long-term intensity variations of cosmic rays at neutron monitor energies and the LDE index measure of solar flares with long-lasting soft X-ray emissions is reported. Three subsequent solar cycles, 20–22, are taken into account and half-monthly data are analyzed. Possible explanation of this correlation is discussed in terms of the recent concepts of cosmic-ray modulation, in particular with merged interaction regions affecting the cosmic-ray intensity.     

On the statistical wind rose analysis

Summary In this paper an approximation of the occurrence probability of wind direction classes by means of a mixture distribution consisting of several component distributions is described. In particular, undetermined parameter values of a mixture distribution describing a wind rose are estimated by minimizing an appropriate function. Deviations of the obtained frequencies from the wind rose data are subjected to a chi-square test. Every component of the mixture distribution is expected to have an occurrence probability equal to the probability of the corresponding airflow type. This method has been applied to approximately two hundred wind data samples based on particular parts of a day and year. Results of two characteristic examples are discussed. It is expected that the statistically obtained components can be explained by meteorological and topoclimatological parameters.With 3 Figures     

Ca X line ratios in solar flares

Theoretical Ca X electron temperature sensitive emission line ratios, derived using electron excitation rates interpolated from accurateR-matrix calculations, are presented forR ₁ =I(419.74 )/I(574.02 ,),R ₂ =I(411.65 )/I(574.02 ),R ₃ =I(419.74 )/I(557.75 ), andR ₄ =I(411.65 )/I(557.75 ). A comparison of these with observational data for three solar flares, obtained by the Naval Research Laboratory's S082A slitless spectrograph on boardSkylab, reveals good agreement between theory and observation forR ₁ andR ₃ in one event, which provides limited support for the accuracy of the atomic data adopted in the analysis. However, in the other flares the observed values ofR ₁ –R ₄ are much larger than the theoretical high-temperature limits, which is probably due to blending of the 419.74 line with Civ 419.71 , and 411.65 with possibly Ciii 411.70 .     

Thermodynamic data from redox reactions at high temperatures. II. The MnO-0Mn3O4 oxygen buffer,and implications for the thermodynamic properties of MnO and Mn3O4

The \(\mu _{O_2 } \) defined by the reaction 6 MnO+O₂ =2 Mn₃O₄ has been determined from 917 to 1,433 K using electrochemical cells (with calcia-stabilized zirconta, CSZ) of the type: Steady emfs were achieved rapidly at all temperatures on both increasing and decreasing temperature, indicating that the MnO-Mn₃O₄ oxygen buffer equilibrates relatively easily. It therefore makes a useful alternative choice in experimental petrology to Fe₂O₃-Fe₃O₄ for buffering oxygen potentials at oxidized values. The results are (in J/mol, temperature in K, reference pressure 1 bar); \(\mu _{O_2 } \) (±200)=-563,241+1,761.758T-220.490T inT+0.101819T ² with an uncertainty of ±200 J/mol. Third law analysis of these data, including a correction for the deviations in stoichiometry of MnO, impliesS _298.15 for Mn₃O₄ of 166.6 J/K · mol, which is 2.5 J/K · mol higher than the calorimetric determination of Robie and Hemingway (1985). The low value of the calorimetric entropy may be due to incomplete ordering of the magnetic spins. The third law value of Δ _r H _298.15 ⁰ is-450.09 kJ/mol, which is significantly different from the calorimetric value of-457.5±3.4 kJ/mol, calculated from Δ _f H _298.15 ⁰ of MnO and Mn₃O₄, implying a small error in one or both of these latter.     

Stratiform and vein U,Mo and Cu mineralization in the Novoveská Huta area,CSFR

U-Mo and Cu mineralization occurs in horizons as well as in veins in the Permian formations near Novoveská Huta. Ore mineralization is represented by uraninite, U-Ti oxides, coffinite, molybdenite, chalcopyrite, tennantite and pyrite. The isotopic composition of S and C displays a larger variability in the stratiform ores (³⁴S from –32.7 to +2.7 and ¹³C from –27.1 to — 0.5) These data suggest mixing of meteoric solutions with fluids of volcanic origin and a complex history. There is a narrower range of ³⁴S from –18.8 to –4.6 and ¹³C from –6.3 to –2.5% in quartz-carbonate veins with Cu mineralization suggesting a deep source of ore-bearing solutions. The Permian volcanics were a significant source of ore elements.Their contents of U, Mo, Cu and Y are from two to eight times higher than in sedimentary rocks. Accumulations of ore elements in the horizons were formed by the reduction and adsorption processes 240 ± 30 Ma ago according to U-Pb isotopic dating. Due to Alpine tectonism, these low-grade ores (U<0.1 wt%) were remobilized and higher-grade U-Mo ores (U>0.1 wt%) were formed 130 ± 20 Ma ago at temperatures ranging from 110 to 120° C, according to fluid inclusions. Younger veins with Cu mineralization were formed 115 ± 10 Ma according to the model age of Pb at temperatures ranging from 95 to 190°C.     

Some results of biogeographic research on meadows in the Dyje-Svratka basin in the Czech Republic

Some results of biogeographic research on meadows in the Dyje-Svratka basin in the Czech Republic. The paper shows one example of biogeographic inventory of natural ecosystems in an unflooded meadow in the Dyje-Svratka basin. It is part of the complex physio-geographic research of the Geographic Department of the Masaryk University in Brno aimed at gaining a basis for territorial interpretation of ecological regularities and territorial application of general ecological optimizing principles. A segment of biocenosis of Ulmi-fraxineta carpini has been analyzed (Zlatník 1956).The endeavour of Czech geographers to study geosystems of various dimensions completely gets in the limelight. In question is the understanding of mutual relationship of components of geosystems based on the exchange of mass and energy. There are two ways of studying them: spatial relations or approaches concentrated on processes. In contrast to the above unilateral concept, the endeavour to make the approaches compatible appears rarely. This complex view is made possible by geobiocenologically taken biogeography in papers of Zlatník and Rauer, their students and successors. This paper shows only one example of the results of biogeographic stock-taking of meadows in the Dyje-Svratka basin, indicating relations of eco- and geosystems which confirm the necessity of ecological orientation of the present biogeography and its potential contribution to ecology.