Magnetic characterization and Mössbauer spectroscopy of magnetic concentrates from Greek lake sediments |
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| Authors: | S Papamarinopoulos PW Readman Y Maniatis A Simopoulos |
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| Institution: | Department of Geophysics, University of Edinburgh, Edinburgh Scotland;N.R.C. “Demokritos”, Aghia Paraskevi, Athens Greece |
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| Abstract: | Bulk magnetic properties of three Greek lake sediments indicated that the main magnetic constituent was predominantly pseudo-single-domain magnetite. This was confirmed by successfully extracting and directly identifying the magnetite. The majority of the magnetite in the magnetic concentrates is present as grains of about 2–3 μm in size, the overall size ranging from < 1to～ 10 μm with occasional grains up to ～ 20 μm. The grains are roughly equidimensional and angular in form indicating that they are of primarily detrital origin, although an authigenic origin for the very fine grains must be a possibility. Mössbauer spectra of the magnetic concentrates suggest that either the magnetite is slightly non-stoichiometric to a similar degree in the three lakes, or contains impurity ions. Haematite was also found in the concentrates but its abundance is only ～10–15% that of magnetite and its is not detectable in any of the magnetic properties of the sediments. |
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