The mobilisation of Platinum-Group Elements in altered oceanic crust from ODP-borehole 1256D for tracing the noble metal flux in the crust
Final Report Abstract
We have carried out a pilot study in order to test systematically, for the first time, whether the platinum-group elements (PGE) are fractionated by hydrothermal alteration of the oceanic crust and which mechanisms might be responsible for their fractionation. For this purpose we have selected samples, altered to different degrees, from the at present only intact sequence drilled through the upper oceanic crust. Thin sections were prepared and investigated, rock powders were used to analyse them for major and trace element (including PGE) compositions as well as for Cu and S isotopes. Although our results do show significant Pt–Pd fractionations and variations in Cu and S isotopic compositions, this pilot study has not been detailed enough in order to offer firm interpretations due to the lack of systematic correlations. We feel that different processes must be held responsible for the elemental and isotopic variations. Identifying and separating them was not possible within our pilot study.
Publications
- (2008) Petrography of the dike–gabbro transition at IOPD Site 1256 (equatorial Pacific): The evolution of the granoblastic dikes. Geochem. Geophys. Geosyst. 9, 29 Seiten
J. Koepke, D. M. Christie, W. Dziony, W. Holtz, D. Lattard, J. Maclennan, S. Park, B. Scheibner, T. Yamasaki & S. Yamazaki
(See online at https://doi.org/10.1029/2008GC001939) - (2009) Chalkophile Elemente in der Ozeankruste von ODP Hole 1256D, 87. Jahrestagung der DMG, Halle, Hallesches Jahrbuch für Geowissenschaften 31, 213 (Kurzfassung)
B. Scheibner, H.-G. Stosch & D. Garbe-Schönberg
- (2009): Chalcophile element budget in the ocean crust: First results from the complete section of upper oceanic crust at borehole 1256D (ODP-Leg 206, Exp. 309, Exp. 312). IODP/ICDP-Kolloquium Potsdam 2009, pp. 318.
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Scheibner, B., Stosch, H.-G.
- (2009): Chalcophile element budget in the upper crust (ODP Hole 1256D). Geochimica et Cosmochimica Acta, Vol. 73, 13, A1170-A1170 [Goldschmidt Conference Davos (abstract)]
Scheibner, B., Stosch, H.-G., Garbe-Schönberg, D.
