Acta Geodaetica, Geophysica et Montanistica 12. (1977)
1–3. szám - VIII. Laboratory studies of the temperature dependence of the conductivity of rocks - Laštovičková, M.: The temperature dependence of the electrical conductivity of basaltic rocks from Bohemian Massif
418 м. laStoviCková In order to test this theory, comparative measurements of samples of magnetite, hematite and a set of basaltic rocks from the Bohemian Massif were made. The electrical conductivity and its temperature dependence were measured by means of the double electrode method in an argon atmosphere with a continuous record of the variations of the electrical conductivity [4]. The values of the Curie temperature were determined with the aid of the temperature dependence of the saturated magnetization, which was determined by means of a magnetic balance in a magnetic field of 10 000 Oe [5]. The samples of basaltic rocks used contained titanomagnetites at different degrees of oxidation and of different concentrations of the ferrimagnetic component. The ferrimagnetics concentration ranged from 5 to 16%. With some samples of basalts titanomagnetites were present as the ferrimagnetic Fig. 1. Thermomagnetic spectrum of sample No. 230. Separation in steps of 2 0 °C; P(% gives the percentage mass representation of the fraction Fig. 2. lg a =f(l/T) for magnetites: ItO No. 41; OOOONo. 30. Curie temperature marked by arrow Acta Geodaetica, Geophysica et Alontanistica Acad. Sei. Hung. 12, 1977