Estudio magnético y paleomagnético de coladas históricas del Etna (Sicilia, Italia)

Abstract

70 basaltic lava flows from Mt. Etna erupted in 1910, 1928, 1950 and 1979 were sampled to carry out rockmagnetic studies In order to determine their magnetic mineralogy and paleomagnetic stability and to asses their suitability for paleointensity studies. Rockmagnetic studies included measurement of susceptibility versus temperature curves, vibrating sample thermomagnetometer experiments, measurement of isothermal remanence acquisition curves and determination of viscosity index V. Three different types of susceptibility versus temperature curves allowed to recognize magnetite, ilmeno-hematite and/or oxidized low-Ti titanomagnetite as main ferromagnetic phases. In some samples a fraction of grains with multidomain structure could be recognized. Nevertheless, the main part of the studied samples showed a viscosity index V<5%.A paleomagnetic study carried out on a lava flow from 1689 in order to obtain additional data for a secular variation curve for Sicily yielded the following result: D= 344.6, 1= 64.2, N=14, cc95 = 1.5 and k=737