Integrated Geological and Geophysical Surveys of the Lisyansky Submarine Volcano, Kuril Island Arc

Abstract

Integrated geological and geophysical surveys of the Lisyansky submarine volcano in the Simushir volcanic zone of the Kuril island arc showed that the lower horizons of this volcanic edifice are composed of pyroxene–hornblende–plagioclase porphyritic basalts, while the upper horizons consist of pyroxene–plagioclase andesites and basaltic andesites. It was for the first time in the study of this volcano that distinct mineralogical signs of fumarolic hydrothermal activity have been identified. High values of magnetization in basalts are due to considerable concentrations of titanomagnetite grains which have a pseudo-single domain structure. The Lisyansky submarine volcano was formed during geomagnetic reversals, as was also the case with the other volcanoes at the Kuril island arc. The volcanic edifice was found to contain supply channels striking nearly vertically, northeast, and northwest, and magma chambers at depths of about 1 km and 2.5‒3 km. The maximum effective magnetization of the Lisyansky submarine volcano is 3.8 A/m.