The period of rotation and the photoelectric lightcurve of the minor planet 79 eurynome     

Hans Josef Schober 《Icarus》1976,28(3):415-420

The minor planet 79 Eurynome was observed during the 1974 opposition for four nights in November, using a photoelectric photometer attached to the 60 cm telescope at the Observatoire de Haute Provence, France. A synodic period of P_syn = 5^h 58^m46^s ± 6^s m.e. was derived. The total amplitude of the lightcurve is only 0.05 mag. The lightcurve shows a double maximum and double minimum. Both minima appear to be at the same level. Observations were carried out in an instrumental filter system (UBV)' Results are shown only for V′, but U′ and B′ measurements supplement the conclusions concerning the rotation. The phase angle α, covered by the observations, ranges from 3 to 5°. The present results for 79 Eurynome rule out the longer period of 0^d.49830 derived by F. Scaltriti and V. Zappalà in favor of their possible period of 0^d.24915.  相似文献   

Pre-Cenozoic intra-plate magmatism along the Central Andes (17–34°S): Composition of the mantle at an active margin     

Friedrich Lucassen  Gerhard Franz  Rolf L. Romer  Frank Schultz  Peter Dulski  Klaus Wemmer 《Lithos》2007,99(3-4):312-338

Sr–Nd–Pb isotope ratios of alkaline mafic intra-plate magmatism constrain the isotopic compositions of the lithospheric mantle along what is now the eastern foreland or back arc of the Cenozoic Central Andes (17–34°S). Most small-volume basanite volcanic rocks and alkaline intrusive rocks of Cretaceous (and rare Miocene) age were derived from a depleted lithospheric mantle source with rather uniform initial ¹⁴³Nd/¹⁴⁴Nd ( 0.5127–0.5128) and ⁸⁷Sr/⁸⁶Sr ( 0.7032–0.7040). The initial ²⁰⁶Pb/²⁰⁴Pb ratios are variable (18.5–19.7) at uniform ²⁰⁷Pb/²⁰⁴Pb ratios (15.60 ± 0.05). A variety of the Cretaceous depleted mantle source of the magmatic rocks shows elevated Sr isotope ratios up to 0.707 at constant high Nd isotope ratios. The variable Sr and Pb isotope ratios are probably due to radiogenic growth in a metasomatized lithospheric mantle, which represents the former sub-arc mantle beneath the early Palaeozoic active continental margin. Sr–Nd–Pb isotope signatures of a second mantle type reflected in the composition of Cretaceous (one late Palaeozoic age) intra-plate magmatic rocks (¹⁴³Nd/¹⁴⁴Nd  0.5123, ⁸⁷Sr/⁸⁶Sr  0.704, ²⁰⁶Pb/²⁰⁴Pb  17.5–18.5, and ²⁰⁷Pb/²⁰⁴Pb  15.45–15.50) are similar to the isotopic composition of old sub-continental lithospheric mantle of the Brazilian Shield.

Published Nd and Sr isotopic compositions of Mesozoic to Cenozoic arc-related magmatic rocks (18–40°S) represent the composition of the convective sub-arc mantle in the Central Andes and are similar to those of the Cretaceous (and rare Miocene) intra-plate magmatic rocks. The dominant convective and lithospheric mantle type beneath this old continental margin is depleted mantle, which is compositionally different from average MORB-type depleted mantle. The old sub-continental lithospheric mantle did not contribute to Mesozoic to Cenozoic arc magmatism.  相似文献   

Volcanic plume simulation on large scales     

Josef M. Oberhuber  Michael Herzog  Hans-F. Graf  Karsten Schwanke 《Journal of Volcanology and Geothermal Research》1998,87(1-4)

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On the volcanology of the Gibeon Kimberlite Field, Namibia     

S. Kurszlaukis  L. Franz  V. Lorenz   《Journal of Volcanology and Geothermal Research》1998,84(3-4)

Kimberlite volcanism in the Upper Cretaceous Gibeon Kimberlite Field, southern Namibia, consisting of at least 42 diatremes and a number of associated dykes, is closely related to carbonatitic and ultrabasic volcanic and intrusive activity which occurred at the margin of the Field. The volcanology of the diatremes and dykes as well as their structural setting is reported here. Because of the paleohydrogeological setting, and since juvenile kimberlite occurring in dykes, intrusive plugs, and spherical lapilli is devoid of vesicles, a phreatomagmatic eruption mechanism is proposed for the genesis of the kimberlite diatremes. Karoo dolerite, basalt and sediment xenoliths in the diatremes provide evidence for the former extent of Karoo strata at the time of eruption.  相似文献   

A comment on determining the induced magnetic field in bodies of arbitrary shape     

Josef Bochníček  Tomáš Zelinka  Reviewer T. Kolbenheyer 《Studia Geophysica et Geodaetica》1981,25(4):411-412

Summary The authors prove that the solution of Laplace's equation under Neumann's boundary conditions can be transformed to an advantage into determining the field which is generated by charges, induced by the external field at surfaces of discontinuity.  相似文献   

Physiologische Wirkungen von Carotinoiden bei Salmoniden     

Dr. Josef Deufel 《Aquatic Sciences - Research Across Boundaries》1975,37(2):244-248

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The use of laboratory measurements of electric resistivity of rocks for evaluating the magnetotelluric method     

Marcela Laštovičková  Josef Pek  Reviewer M. Hvoždara 《Studia Geophysica et Geodaetica》1979,23(1):94-98

Summary A profile model of electric resistivity as a function of depth was compiled, the initial parameters being the values of the electric resistivity determined experimentally for basaltic and eclogitic rocks from the Bohemian Massif. The curves of the apparent resistivity were computed for this model and the measure of information evaluated for the various model layers. The dominant influence of the subsurface layer was proved.  相似文献   

Stenols and stanols in the oxic and anoxic waters of the Black Sea     

Robert B. Gagosian  Franz Heinzer 《Geochimica et cosmochimica acta》1979,43(4):471-486

Water samples collected from a slope station and two deep stations in the western basin of the Black Sea were analyzed for stenols and stanols by glass capillary gas chromatography. These results were used in conjuction with hydrographic, particulate organic carbon, and chlorophyll a data to better understand sterol sources and their transport and transformation mechanisms in anoxic basins.The total free sterol concentrations found in the surface waters were 450–500 ng/l dropping rapidly to values well below 100 ng/l at depths below the $\text{O}{}_2\text{H}{}_2\text{S}$ interface. In the upper 200 m of the water column a strong association of sterols with particulate matter is suggested. Structural elucidation by a gas chromatograph-mass spectrometer-computer system revealed the presence of at least sixteen different stenols and stanols in the surface waters of the Black Sea. Cholesterol, 24-methylenecholesterol and 24-methylcholesta-5,22-dien-3β-ol were the major sterols in the surface waters. Cholesterol and 24-ethylcholesterol both exhibited a subsurface maximum at the $\text{O}{}_2\text{H}{}_2\text{S}$ interface. In the anoxic deep waters (200–2000 m) only cholesterol and 24-ethylcholesterol were found. Two stenols were found that have not been reported in seawater: a C₂₆ stenol with a saturated C₇H₁₅ side chain (presumably 24-norcholesterol) and 24-ketocholesterol. At least six 5α-stanols could be identified in the surface samples, each of them comprising about 10–20% of the concentration of the corresponding Δ5-stenol. From these comparatively high surface values the stanol concentrations drop rapidly to values near zero at the $\text{O}{}_2\text{H}{}_2\text{S}$ interface. Except for very low concentrations of 5α-cholestanol (< 4ng/l) no other stanols could be detected in the anoxic zone.From this data it appears that no detectable stenol → stanol conversion is occurring at the $\text{O}{}_2\text{H}{}_2\text{S}$ interface or in the deep anoxic waters of the Black Sea.  相似文献   

Day-time ionospheric disturbances of corpuscular origin in the midlatitudeD-region     

Jan Laštovička  Josef Boška  Reviewer L. Křivský 《Studia Geophysica et Geodaetica》1980,24(2):191-196

¶rt;m uu nau mu m a nu a¶rt;u ¶rt; D-amu u. a¶rt; m nu u u. u¶rt;a a a mu nma u nma mu m (20 ¶rt; 150 ).  相似文献   

Heidornit Na2Ca3[Cl · (SO4)2 · B5O8(OH)2] ein neues Bormineral aus dem Zechsteinanhydrit Mit einer röntgenographischen Untersuchung     

Prof. Dr. Wolf v. Engelhardt  Hans Füchtbauer  Josef Zemann 《Contributions to Mineralogy and Petrology》1956,5(3):177-186

Ohne Zusammenfassung  相似文献