In: Geologica Carpathica, vol. 43, no. 5
Oto Orlicky - Frantisek Cano - Jozef Lipka - Anna Mihalikova - Boris Toman
Detaily:
Rok, strany: 1992, 287 - 293
Jazyk: eng
O článku:
The magnetic Fe-Ti oxides of basaltic rocks of different ages from Central Slovakia, Bohemian Massif, Syria and Nigeria have been studied by electron-microprobe analysis, X-ray powder diffraction, Mössbauer spectroscopy, and by fully automated measurements of the change of magnetic susceptibility (κ) of the samples in the range -196 to 620 °C. The compositions of dominant magnetic phases, also oxidation parameter z of Fe-Ti oxides of basaltic rocks under study have been evaluated and derived, comparing our laboratory data with those published by other authors. A following compositions and oxidation parameters z of Fe-Ti oxides of four selected groups of basaltic rocks are supposed to be actual:
— Fe2.3Ti0.7O4–Fe2.4Ti0.6O4 (z ≈ 0.15–0.35)
— Fe2.28Ti0.72O4–Fe2.62Ti0.38 O4<'sub> (z ≈ 0.12–0.32)
— Fe2.95Ti0.05O4–Fe3O4 (+ Fe2O3)
A solution of the nature of Fe-Ti oxides is supposed to be very problematic. In true multi-domain particles of the samples k should be approximately constant over a rather extended temperature interval. Many authors have concluded that the properties of all compositions are consistent with multi-domain structure. Surprisingly, titanomagnetites with low Curie temperatures exhibit a variation of κ with temperature. These titanomagnetites have shown a characteristic cusps behaviour, which is typical for spin-glasses. It means that actual temperature dependence of κ for coarse-grained high-titanium titanomagnetites is quite different from that, expected for large multi-domain grains.
— Fe2.3Ti0.7O4–Fe2.4Ti0.6O4 (z ≈ 0.15–0.35)
— Fe2.28Ti0.72O4–Fe2.62Ti0.38 O4<'sub> (z ≈ 0.12–0.32)
— Fe2.95Ti0.05O4–Fe3O4 (+ Fe2O3)
A solution of the nature of Fe-Ti oxides is supposed to be very problematic. In true multi-domain particles of the samples k should be approximately constant over a rather extended temperature interval. Many authors have concluded that the properties of all compositions are consistent with multi-domain structure. Surprisingly, titanomagnetites with low Curie temperatures exhibit a variation of κ with temperature. These titanomagnetites have shown a characteristic cusps behaviour, which is typical for spin-glasses. It means that actual temperature dependence of κ for coarse-grained high-titanium titanomagnetites is quite different from that, expected for large multi-domain grains.
Ako citovať:
ISO 690:
Orlicky, O., Cano, F., Lipka, J., Mihalikova, A., Toman, B. 1992. Fe-Ti MAGNETIC MINERALS OF BASALTIC ROCKS: A STUDY OF THEIR NATURE AND COMPOSITION. In Geologica Carpathica, vol. 43, no.5, pp. 287-293. 1335-0552.
APA:
Orlicky, O., Cano, F., Lipka, J., Mihalikova, A., Toman, B. (1992). Fe-Ti MAGNETIC MINERALS OF BASALTIC ROCKS: A STUDY OF THEIR NATURE AND COMPOSITION. Geologica Carpathica, 43(5), 287-293. 1335-0552.