| Autor: |
E Vincent, Friedrich Heller, M Borkovec, T Forster, J Hammann, M Sartori |
| Rok vydání: |
1999 |
| Předmět: |
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| Zdroj: |
Physics of the Earth and Planetary Interiors. 116:53-64 |
| ISSN: |
0031-9201 |
| DOI: |
10.1016/s0031-9201(99)00118-1 |
| Popis: |
The approximately 50-m thick loess/palaeosol sequence at Paks brickyard (Hungary) was deposited largely during the Brunhes normal polarity chron and its magnetic properties resemble those of similar sections in Europe, Central Asia and China. In order to get information on the grain size dependence of some of the magnetic parameters, two loess and two palaeosol samples were separated into a number of grain size fractions. The separation method employs consecutive sedimentation and centrifugation steps performed on bulk samples suspended in water and diluted with Calgon. Ten grain size fractions were obtained, ranging from 50 μm down to 10 nm. Several magnetic parameters of the different grain size fractions have been measured, at room temperature (low field susceptibility, hysteresis parameters) and at low temperature (susceptibility and thermoremanent magnetisation). They show a strong grain size dependence for the ferromagnetic minerals. Low temperature measurements allow discrimination of the paramagnetic vs. the ferromagnetic signal and give information on the grain size distribution of the very fine ferromagnetic minerals and on the mineral types carrying the magnetic signal. Strong relationships between weathering processes, destruction of paramagnetic minerals and possibly iron-hydroxides, and enhancement of the ferromagnetic signal are observed. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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