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Datasets with PANGAEA technical keyword @moridge

Mostrando recursos 1 - 20 de 863

  1. First results from the Arctic Mid-Ocean Ridge Expedition with POLARSTERN and HEALY

    Thiede, Jörn; Barrais, Jörg; Drachev, Sergej; Gauger, Steffen; Haas, Christian; Hartmann, Thomas; Hatzky, Jörn; König-Langlo, Gert; Lieser, Jan L; Niessen, Frank; Schenke, Hans Werner; Shevchenko, Vladimir P; Snow, Jonathan E; Spielhagen, Robert F

  2. First results from the Arctic Mid-Ocean Ridge Expedition with POLARSTERN and HEALY

    Thiede, Jörn; Barrais, Jörg; Drachev, Sergej; Gauger, Steffen; Haas, Christian; Hartmann, Thomas; Hatzky, Jörn; König-Langlo, Gert; Lieser, Jan L; Niessen, Frank; Schenke, Hans Werner; Shevchenko, Vladimir P; Snow, Jonathan E; Spielhagen, Robert F

  3. Nd and Pb isotopes in ferromanganese crusts

    Frank, Martin; Whiteley, N; Kasten, Sabine; Hein, James R; O'Nions, R K
    The intensity of North Atlantic Deep Water (NADW) production has been one of the most important parameters controlling the global thermohaline ocean circulation system and climate. Here we present a new approach to reconstruct the overall strength of NADW export from the North Atlantic to the Southern Ocean over the past 14 Myr applying the deep water Nd and Pb isotope composition as recorded by ferromanganese crusts and nodules. We present the first long-term Nd and Pb isotope time series for deep Southern Ocean water masses, which are compared with previously published time series for NADW from the NW Atlantic...

  4. Nd and Pb isotopes in ferromanganese crusts

    Frank, Martin; Whiteley, N; Kasten, Sabine; Hein, James R; O'Nions, R K
    The intensity of North Atlantic Deep Water (NADW) production has been one of the most important parameters controlling the global thermohaline ocean circulation system and climate. Here we present a new approach to reconstruct the overall strength of NADW export from the North Atlantic to the Southern Ocean over the past 14 Myr applying the deep water Nd and Pb isotope composition as recorded by ferromanganese crusts and nodules. We present the first long-term Nd and Pb isotope time series for deep Southern Ocean water masses, which are compared with previously published time series for NADW from the NW Atlantic...

  5. Geochemistry of sediments from the mid-oceanic Kolbeinsey Ridge

    Lackschewitz, Klas S; Wallrabe-Adams, Hans-Joachim; Garbe-Schönberg, Carl-Dieter
    In order to assess recent submarine volcanic contributions to the sediments from the active Kolbeinsey Ridge, surface samples were analyzed chemically. The contribution of major and trace elements studied differ within the study area. A statistical analysis of the geochemical variables using factor analysis and cluster method allows to distinguish possible sample groups. Cluster method identifies three distinct sediment groups located in different areas of sedimentation. Group 1 is characterized by highest contents of Fe2O3, V, Co, Ni, Cu and Zn demonstrating the input of volcaniclastic material. Group 2 comprises high values of CaCO3, CaO and Sr representing biogenic carbonate. Group 3...

  6. Geochemistry of sediments from the mid-oceanic Kolbeinsey Ridge

    Lackschewitz, Klas S; Wallrabe-Adams, Hans-Joachim; Garbe-Schönberg, Carl-Dieter
    In order to assess recent submarine volcanic contributions to the sediments from the active Kolbeinsey Ridge, surface samples were analyzed chemically. The contribution of major and trace elements studied differ within the study area. A statistical analysis of the geochemical variables using factor analysis and cluster method allows to distinguish possible sample groups. Cluster method identifies three distinct sediment groups located in different areas of sedimentation. Group 1 is characterized by highest contents of Fe2O3, V, Co, Ni, Cu and Zn demonstrating the input of volcaniclastic material. Group 2 comprises high values of CaCO3, CaO and Sr representing biogenic carbonate. Group 3...

  7. Sedimentology of the Reykjanes Ridge, Southeast Greenland

    Lackschewitz, Klas S; Baumann, Karl-Heinz; Gehrke, B; Wallrabe-Adams, Hans-Joachim; Thiede, Jörn; Bonani, Georges; Endler, Rudolf; Erlenkeuser, Helmut; Heinemeier, Jan
    Marine records from the Reykjanes Ridge indicate ice sheet variations and abrupt climate changes. One of these records, ice-rafted detritus (IRD), serves as a proxy for iceberg discharges that probably indicates ice sheet fluctuations. The IRD records suggest that iceberg discharge 68,000-10,000 yr B.P. happened more frequently than the 7000- to 10,000-yr spacing of the Heinrich events. An IRD peak 67,000 to 63,000 yr B.P. further suggests that the Middle Weichselian glaciation started about 12,000 yr earlier in the North Atlantic than in the Norwegian Sea. Several later IRD events, in contrast, correlate with Norwegian Sea IRD-rich layers and imply...

  8. Sedimentology of the Reykjanes Ridge, Southeast Greenland

    Lackschewitz, Klas S; Baumann, Karl-Heinz; Gehrke, B; Wallrabe-Adams, Hans-Joachim; Thiede, Jörn; Bonani, Georges; Endler, Rudolf; Erlenkeuser, Helmut; Heinemeier, Jan
    Marine records from the Reykjanes Ridge indicate ice sheet variations and abrupt climate changes. One of these records, ice-rafted detritus (IRD), serves as a proxy for iceberg discharges that probably indicates ice sheet fluctuations. The IRD records suggest that iceberg discharge 68,000-10,000 yr B.P. happened more frequently than the 7000- to 10,000-yr spacing of the Heinrich events. An IRD peak 67,000 to 63,000 yr B.P. further suggests that the Middle Weichselian glaciation started about 12,000 yr earlier in the North Atlantic than in the Norwegian Sea. Several later IRD events, in contrast, correlate with Norwegian Sea IRD-rich layers and imply...

  9. Geochemistry of Fe-Mn crusts in sediments of the Central Indian Ridge

    Kuhn, Thomas; Bau, M; Blum, Nevin; Halbach, Peter
    Layered Fe-Mn crusts from the off-axis region of the first segment of the Central Indian Ridge north of the Rodrigues Triple Junction were studied geochemically and mineralogically. Vernadite (delta-MnO2) is the main mineral oxide phase. 230Thxs and Co concentrations suggest high growth rates of up to 29 mm/Myr and a maximum age of the basal crust layer of 1 Ma. Whereas most of the major and minor elements show concentrations which are typical of hydrogenetic formation, Co, Pb, Ni and Ti concentrations are strikingly lower. Concentrations and distribution of the strictly trivalent rare-earths and yttrium (REY) are typical of hydrogenetic...

  10. Geochemistry of Fe-Mn crusts in sediments of the Central Indian Ridge

    Kuhn, Thomas; Bau, M; Blum, Nevin; Halbach, Peter
    Layered Fe-Mn crusts from the off-axis region of the first segment of the Central Indian Ridge north of the Rodrigues Triple Junction were studied geochemically and mineralogically. Vernadite (delta-MnO2) is the main mineral oxide phase. 230Thxs and Co concentrations suggest high growth rates of up to 29 mm/Myr and a maximum age of the basal crust layer of 1 Ma. Whereas most of the major and minor elements show concentrations which are typical of hydrogenetic formation, Co, Pb, Ni and Ti concentrations are strikingly lower. Concentrations and distribution of the strictly trivalent rare-earths and yttrium (REY) are typical of hydrogenetic...

  11. Element composition in various minerlas of ODP Hole 209-1274A peridotites, Mid-Atlantic

    Seyler, Monique; Lorand, J-P; Dick, Henry J B; Drouin, Marion
    ODP Leg 209 Site 1274 mantle peridotites are highly refractory in terms of lack of residual clinopyroxene, olivine Mg# (up to 0.92) and spinel Cr# (~0.5), suggesting high degree of partial melting (>20%). Detailed studies of their microstructures show that they have extensively reacted with a pervading intergranular melt prior to cooling in the lithosphere, leading to crystallization of olivine, clinopyroxene and spinel at the expense of orthopyroxene. The least reacted harzburgites are too rich in orthopyroxene to be simple residues of low-pressure (spinel field) partial melting. Cu-rich sulfides that precipitated with the clinopyroxenes indicate that the intergranular melt was...

  12. Element composition in various minerlas of ODP Hole 209-1274A peridotites, Mid-Atlantic

    Seyler, Monique; Lorand, J-P; Dick, Henry J B; Drouin, Marion
    ODP Leg 209 Site 1274 mantle peridotites are highly refractory in terms of lack of residual clinopyroxene, olivine Mg# (up to 0.92) and spinel Cr# (~0.5), suggesting high degree of partial melting (>20%). Detailed studies of their microstructures show that they have extensively reacted with a pervading intergranular melt prior to cooling in the lithosphere, leading to crystallization of olivine, clinopyroxene and spinel at the expense of orthopyroxene. The least reacted harzburgites are too rich in orthopyroxene to be simple residues of low-pressure (spinel field) partial melting. Cu-rich sulfides that precipitated with the clinopyroxenes indicate that the intergranular melt was...

  13. Rare earth and trace elements in igneous and metamorphic minerals of oceanic gabbros from the Mid-Atlantic Ridge

    Cortesogno, Luciano; Gaggero, Laura; Zanetti, Alberto
    SIMS analyses have been carried out on clinopyroxenes, plagioclases and amphiboles of six gabbroic samples from Holes 921-924 of the Ocean Drilling Program Leg 153 sited in the MARK area of the Mid-Atlantic Ridge at the ridge-transform intersection, to investigate the rare earth, trace and volatile element distribution in the lower ocean crust during igneous crystallization and higher grade metamorphic conditions. The metagabbros underwent granulite to subgreenschist facies conditions through three main tectono-metamorphic phases: (1) ductile regime (750 < T < 1000 °C and P = 0.3 GPa); (2) transitional regime (600 < T < 700 °C and P =...

  14. Rare earth and trace elements in igneous and metamorphic minerals of oceanic gabbros from the Mid-Atlantic Ridge

    Cortesogno, Luciano; Gaggero, Laura; Zanetti, Alberto
    SIMS analyses have been carried out on clinopyroxenes, plagioclases and amphiboles of six gabbroic samples from Holes 921-924 of the Ocean Drilling Program Leg 153 sited in the MARK area of the Mid-Atlantic Ridge at the ridge-transform intersection, to investigate the rare earth, trace and volatile element distribution in the lower ocean crust during igneous crystallization and higher grade metamorphic conditions. The metagabbros underwent granulite to subgreenschist facies conditions through three main tectono-metamorphic phases: (1) ductile regime (750 < T < 1000 °C and P = 0.3 GPa); (2) transitional regime (600 < T < 700 °C and P =...

  15. (Table 5) Rare earth and trace element concentrations of amphibole from ODP Hole 153-923A

    Cortesogno, Luciano; Gaggero, Laura; Zanetti, Alberto

  16. (Table 5) Rare earth and trace element concentrations of amphibole from ODP Hole 153-923A

    Cortesogno, Luciano; Gaggero, Laura; Zanetti, Alberto

  17. (Table 5) Rare earth and trace element concentrations of amphibole from ODP Site 153-921

    Cortesogno, Luciano; Gaggero, Laura; Zanetti, Alberto

  18. (Table 5) Rare earth and trace element concentrations of amphibole from ODP Site 153-921

    Cortesogno, Luciano; Gaggero, Laura; Zanetti, Alberto

  19. (Table 4) Rare earth and trace element concentrations of plagioclase from ODP Hole 153-924B

    Cortesogno, Luciano; Gaggero, Laura; Zanetti, Alberto

  20. (Table 4) Rare earth and trace element concentrations of plagioclase from ODP Hole 153-924B

    Cortesogno, Luciano; Gaggero, Laura; Zanetti, Alberto

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