Na 1 Nachlass Max Horkheimer, 553 - Korrespondenzen mit Leo Löwenthal (p. VI 22, 1-206)

126 Briefe zwischen Max Horkheimer und Leo Löwenthal, Januar - August 1948; 1 Brief von J. D. Scott an Max Horkheimer, 28.04.1948; 1 Telegramm von Fred May an Leo Löwenthal, 22.04.1948; 2 Briefe zwischen David Riesmann und Leo Löwenthal, Februar - März 1948; 1 Brief von Max Horkheimer an Herbert Macuse, 1948; 1 Brief von Leo Löwenthal an William Dieterle, 27.02.1948; 2 Briefe zwischen Theodor W. Adorno und Leo Löwenthal, 1948; 1 Brief von Max Horkheimer an Samuel H. Flowerman, 20.02.1948; 1 Brief von Irving Howe an Leo Löwenthal, 02.09.1948; 3 Briefe zwischen Erich Preiser und Leo Löwental, 1948; 1 Brief von Walter Hallstein an Max Horkheimer, 02.07.1948; 1 Brief von Max Horkheimer an M. Fiske Lissance, 05.02.1948; 1 Brief und 1 Memorandum an John Slawson von Max Horkheimer, 10.01.1948;

Ausst. 206 - De vitanda vsvra ex Greco in Latinvm tradvctvs

Vorbesitzer: Heinrich Anton Cornill-d'Orville (Exlibris im Vorderdeckel)

Ms. lat. oct. 206 - Annotata ad Burkhardi Gotthelfi Struvii Bibliothecam iuris selectam

Vorbesitzer: Familie von Holzhausen;

In-situ Iron isotope measurements and mineral compositions from ODP Hole 206-1256D and IODP Hole 335-U1256D

In-situ Fe isotope measurements have been carried out to estimate the impact of the hydrothermal metamorphic overprint on the Fe isotopic composition of Fe-Ti-oxides and Fe-sulfides of the different lithologies of the drilled rocks from IODP Hole 1256D (eastern equatorial Pacific; 15 Ma crust formed at the East Pacific Rise). Most igneous rocks normally have a very restricted range in their 56Fe/54Fe ratio. In contrast, Fe isotope compositions of hot fluids (> 300 °C) from mid-ocean-ridge spreading centers define a narrow range that is shifted to lower delta 56Fe values by 0.2 per mil - 0.5 per mil as compared to igneous rocks. Therefore, it is expected that mineral phases that contain large amounts of Fe are especially affected by the interaction with a fluid that fractionates Fe isotopes during exsolution/precipitation of those minerals. We have used a femtosecond UV-Laser ablation system to determine mineral 56Fe/54Fe ratios of selected samples with a precision of < 0.1 per mil (2 sigma level) at micrometer-scale. We have found significant variations of the delta 56Fe (IRMM-014) values in the minerals between different samples as well as within samples and mineral grains. The overall observed scale of delta 56Fe (magnetite) in 1256D rocks ranges from - 0.12 to + 0.64 per mil, and of delta 56Fe (ilmenite) from - 0.77 to + 0.01 per mil. Pyrite in the lowermost sheeted dike section is clearly distinguishable from the other investigated lithological units, having positive delta 56Fe values between + 0.29 and + 0.56 per mil, whereas pyrite in the other samples has generally negative delta 56Fe values from - 1.10 to - 0.59 permil. One key observation is that the temperature dependent inter-mineral fractionations of Fe isotopes between magnetite and ilmenite are systematically shifted towards higher values when compared to theoretically expected values, while synthesized, well equilibrated magnetite-ilmenite pairs are compatible with the theoretical predictions. Theoretical considerations including beta-factors of different aqueous Fe-chlorides and Rayleigh-type fractionations in the presence of a hydrous, chlorine-bearing fluid can explain this observation. The disagreement between observed and theoretical equilibrium fractionation, the fact that magnetite, in contrast to ilmenite shows a slight downhole trend in the delta 56Fe values, and the observation of small scale heterogeneities within single mineral grains imply that a general re-equilibration of the magnetite-ilmenite pairs is overprinted by kinetic fractionation effects, caused by the interaction of magnetite/ilmenite with hydrothermal fluids penetrating the upper oceanic crust during cooling, or incomplete re-equilibration at low temperatures. Furthermore, the observation of significant small-scale variations in the 56Fe/54Fe ratios of single minerals in this study highlights the importance of high spatial-resolution-analyses of stable isotope ratios for further investigations.

Major element oxides of minerals from a lava pond at ODP Site 206-1256

At Ocean Drilling Program Site 1256 (6°44.2'N, 91°56.1'W), during Leg 206, a thick massive unit was cored in two neighboring penetrations of the uppermost basement, Holes 1256C and 1256D. This thick massive lava flow, commonly referred to as the "Lava Pond," is identified as Unit 18 (>30 m thick) in Hole 1256C and Unit 1 (>74.2 m thick) in Hole 1256D (Wilson et al., 2003, doi:10.2973/odp.proc.ir.206.2003). In the coarse-grained basalt that comprises this lithological unit, low-temperature "background" alteration events are present. This report provides microprobe analyses of both primary and secondary minerals present in this massive lava pond. The analyses of typically magmatic minerals (titanomagnetite, plagioclase, and clinopyroxene) are given for comparison with secondary minerals.