985 resultados para 330.1[82]


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3 Briefe zwischen Graf Lazy Henckel von Donnersmarck und Max Horkheimer, 1968; 2 Briefe zwischen Gräfin Nina Henckel von Donnersmarck und Max Horkheimer, 1968; 4 Briefe zwischen der Sängerin Carla Henius und Max Horkheimer, 1970-1971; 1 Brief an K. H. Hennings von Max Horkheimer, 1967; 4 Briefe zwischen Professor Wilhelm Hennis und Max Horkheimer, 1971; 1 Brief an Professor Dieter Henrich von Max Horkheimer, 1964; 2 Briefe zwischen Caroline Hergert und Max Horkheimer, 1970; 1 Brief von Professor Fred Herman an Max Horkheimer, 1959; 2 Briefe zwischen der Fachschülerin Dora Herrmann und Max Horkheimer, 1972; 2 Briefe zwischen Professor Franz Herrmann und Max Horkheimer, 1970; 6 Briefe zwischen Dr. phil. Gert-Julius Herrmann und Max Horkheimer, 1968; 2 Briefe zwischen Dipl. Kfm. Dr. Dr. Otto O. Herz und Max Horkheimer, 1969; 4 Briefe zwischen Professor und Museumsdirektor Erich Herzog und Max Horkheimer, 1970; 2 Briefe zwischen Hans Eberhard Hess und Max Horkheimer, 1970; 16 Briefe zwischen Professor Eugen Hess-Baer und Max Horkheimer, 1966-1971; 3 Briefe zwischen Karl Hess und Max Horkheimer, 1969-1971; 1 Drucksache von Pfarrer Walter Hess, 1971; 6 Briefe zwischen dem Bankier Walter Hesselbach und Max Horkheimer, 1971-1973; Drucksachen vom Hessischen Kreis, 1968; Briefe zwischen dem Hessischen Landesmuseum Darmstadt und Max Horkheimer, 1969; 25 Briefe zwischen Professor Heinz Joachim Heydorn und Max Horkheimer, 1965-1973; 2 Briefe zwischen Dr. Karl Heymann und Max Horkheimer, 1970; 1 Brief an den Hippokrates-Verlag von Max Horkheimer, 1971; 9 Briefe zwischen Walter Hirschmann und Max Horkheimer, 1969-1971;

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Seventeen whole-rock samples, generally taken at 25-50 m intervals from 5 to 560 m sub-basement in Hole 504B, drilled in 6.2 m.y. old crust, were analysed for 87Sr/86Sr ratios, Sr and Rb concentrations, and 18O/16O ratios. Sr isotope ratios for 8 samples from the upper 260 m of the hole range from 0.70287 to 0.70377, with a mean of 0.70320. In the 330-560 m interval, 5 samples have a restricted range of 0.70255-0.70279, with a mean of 0.70266, the average value for fresh mid-ocean ridge basalts (MORB). In the 260-330 m interval, approximately intermediate Sr isotopic ratios are found. Delta18O values (?) range from 6.4 to 7.8 in the upper 260 m, 6.2-6.4 in the 270-320 m interval, and 5.8-6.2 in the 320-560 m interval. The values in the upper 260 m are typical for basalts which have undergone low-temperature seawater alteration, whereas the values for the 320-560 m interval correspond to MORB which have experienced essentially no oxygen isotopic alteration. The higher 87Sr/86Sr and 18O/16O ratios in the upper part of the hole can be interpreted as the result of a greater overall water/rock ratio in the upper part of the Hole 504B crust than in the lower part. Interaction of basalt with seawater (87Sr/86Sr = 0.7091) increased basalt 87Sr/86Sr ratios and produced smectitic alteration products which raised whole-rock delta18O values. Seawater circulation in the lower basalts may have been partly restricted by the greater number of relatively impermeable massive lava flows below about 230 m sub-basement. These flows may have helped to seal off lower basalts from through-flowing seawater.

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The aim of DSDP Leg 82 was to decipher the temporal and spatial evolution of Azores Plume. The Pb-isotopic results of this leg are rather complex, and can be summarized as follows: 1. At a given site (561, 558), variations of Pb isotopic compositions are generally accompanied by major changes in trace-element ratios, indicating significant heterogeneity of the source region. There is a correlation between Pb isotopes and trace elements. 2. In contrast, if all the data (i.e., all studied sites) of Leg 82 are considered together, no correlation can be discerned between Pb isotopes and trace elements. Site 556, especially, shows abnormal behavior. 3. Leg 82 samples not only cover the entire range of Pb isotopic composition previously established for the Atlantic Ocean, but extend this field to more radiogenic values. 4. The data are compatible with the hot-spot model proposed by Schilling (1975), if one considers that the Azores Plume itself is isotopically heterogeneous, and that it has been progressively contaminated to various degrees by upper mantle material.

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The sulfur contents of 21 basalt samples from four DSDP Leg 82 holes were determined and the isotopic compositions of sulfur were measured on 15 of them. Most of the basalts are altered and have sulfur contents of about 100 ppm. Isotopic ratios for sulfate and total sulfur range from +0.7 to +10.5 per mil, indicating almost complete leaching of the igneous sulfide in low-sulfur samples by alteration. Total sulfur content of some samples ranges between 960 and 1170 ppm, somewhat higher than expected for tholeiitic basalts. The isotope ratios of total sulfur in these samples are slightly shifted to values heavier than the generally assumed mantle ratio of zero, and this shift is thought to result from a secondary source of sulfur.