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    Rainer Altherr

    The Canadian Mineralogist. Skip to main page content. ...
    A total of 43 apatite fission-track ages, together with track length measurements (36 on confined tracks, 7 on projected tracks) are reported from the crystalline basement rocks of Kenya (Pan-African Mozambique Belt and late Archean/... more
    A total of 43 apatite fission-track ages, together with track length measurements (36 on confined tracks, 7 on projected tracks) are reported from the crystalline basement rocks of Kenya (Pan-African Mozambique Belt and late Archean/ early Proterozoic Nyanza Shield). The ...
    ABSTRACT
    U---Pb isotopic analyses of discordant zircons from undeformed Miocene I-type granitoids from the central Aegean, Greece, have identified an example of post-igneous Pb loss from clear, non-metamict zircons which cannot be related to any... more
    U---Pb isotopic analyses of discordant zircons from undeformed Miocene I-type granitoids from the central Aegean, Greece, have identified an example of post-igneous Pb loss from clear, non-metamict zircons which cannot be related to any post-igneous thermal overprint. It is ...
    The new tomographic image of the mantle beneath the French Massif Central reaching a depth of 270 km is interpreted in terms of mantle temperature, considering effects of anharmonicity and anelasticity on seismic velocities as well as... more
    The new tomographic image of the mantle beneath the French Massif Central reaching a depth of 270 km is interpreted in terms of mantle temperature, considering effects of anharmonicity and anelasticity on seismic velocities as well as effects of mineral reactions, composition and partial melt. For every block of the tomographic model we calculate the absolute temperature required to fit
    Abstract Concentrations of Li, Be and B and the isotopic composition of lithium have been measured in minerals from a suite of dry and metasomatised spinel peridotite and pyroxenite xenoliths from Harrat Uwayrid, a Pliocene–Quaternary... more
    Abstract Concentrations of Li, Be and B and the isotopic composition of lithium have been measured in minerals from a suite of dry and metasomatised spinel peridotite and pyroxenite xenoliths from Harrat Uwayrid, a Pliocene–Quaternary volcanic field in the NW part of the Arabian peninsula, developed during formation of the Red Sea. In most peridotites, Li concentrations in pyroxene and olivine grains show significant systematic zoning, with a core-to-rim decrease in pyroxene but a minor increase in olivine. δ 7 Li tends to show a rim-ward increase in clinopyroxene, while it is constant or decreases slightly in olivine. These variations indicate a diffusive transfer of Li from clinopyroxene to olivine during cooling, implying that the partition coefficients K Li Ol/Cpx and K Li Ol/Opx are temperature-dependent and increase with falling temperature. K Li Cpx/Opx , stays nearly constant at ∼ 1. δ 7 Li values measured in virtually unmodified cores of olivine, orthopyroxene and clinopyroxene from three peridotites are similar within individual xenoliths but vary among the xenoliths, with individual values ranging from + 1.1 to + 9.7‰. In marked contrast to Li, the concentrations of Be and B are nearly constant in mineral grains, and apparent inter-mineral partition coefficients for these elements are independent of concentrations and xenolith equilibration temperature. Concentrations of Li, Be and B in minerals of un-metasomatized peridotites are relatively low and are similar to values reported previously. Relative abundances of the three light elements in minerals of xenoliths affected by metasomatism have been used to constrain the nature of metasomatic agents. A preferential enrichment of both Li and B relative to Be that is observed in some xenoliths suggests metasomatism by a hydrous fluid, well below the critical point of the solvus between hydrous fluid and silicate melt. A uniform enrichment of all three light elements shown by other xenoliths points to either a silicate melt at subcritical conditions or a supercritical liquid as metasomatic agent.
    ... surface heat flow values, suggesting that surface heat flow has not yet equilibrated with mantle temperatures ([Kuo and Essene, 1986], [Nasir and Al-Fuqha, 1988], [Stein and Katz, 1989], [Nasir, 1992], [Stein et al., 1993], [McGuire,... more
    ... surface heat flow values, suggesting that surface heat flow has not yet equilibrated with mantle temperatures ([Kuo and Essene, 1986], [Nasir and Al-Fuqha, 1988], [Stein and Katz, 1989], [Nasir, 1992], [Stein et al., 1993], [McGuire, 1998a], [McGuire, 1998b], [Medaris and Syada ...
    ... FP Furlong, W. Spakman and R. Wortel, Thermal structure of the continental lithosphere: constraints from seismic tomography, Tectonophysics 244 (1995), pp. 107–117. ... S. Karato, Importance of anelasticity in the interpretation of... more
    ... FP Furlong, W. Spakman and R. Wortel, Thermal structure of the continental lithosphere: constraints from seismic tomography, Tectonophysics 244 (1995), pp. 107–117. ... S. Karato, Importance of anelasticity in the interpretation of seismic tomography, Geophys. Res. Lett. ...
    ABSTRACT
    ... n 87-142 MgO % I I I I I 40 41 42 43 44 CDOB Iherzolites 9 Banija 9 Vrbanja-Celinac-Skatavica-~njegotinja 9 Ljubi(~-(~avka A Bosanski Ozren o Borja [] Krivaja-Konjuh o Varda-Tara-Zlatibor Primitive mantle estimates + Jagoutz et al. ...
    A total of 43 apatite fission-track ages, together with track length measurements (36 on confined tracks, 7 on projected tracks) are reported from the crystalline basement rocks of Kenya (Pan-African Mozambique Belt and late Archean/... more
    A total of 43 apatite fission-track ages, together with track length measurements (36 on confined tracks, 7 on projected tracks) are reported from the crystalline basement rocks of Kenya (Pan-African Mozambique Belt and late Archean/ early Proterozoic Nyanza Shield). The ...