The Magnetic Field in the Geothermal Systems of the Pauzhetka Area, Southern Kamchatka

Abstract

Our multiyear studies have enabled us to make maps showing magnetic anomalies ΔT_a for major geothermal systems in the Pauzhetka area of southern Kamchatka. Magnetic fields possess both general characteristics and individual features for each object of study. The Nizhne-Koshelev vapor-dominated geothermal field is identified on the basis of a set of linear negative magnetic anomalies confined to thermal-controlling tectonic faults. The Pauzhetka geothermal field is characterized by an inhomogeneous structure of the anomalous magnetic field ΔT_a: the northwestern area has a quiet, slightly negative magnetic field, showing that this part of the field is dominated by lateral spreading of hydrothermal fluids from the upper aquifer; the southeastern part has numerous sign-varying magnetic anomalies of high intensity confined to acid–intermediate subvolcanic bodies. The South Kambalnyi group of thermal fields is characterized by a lower absolute value of magnetic induction Т compared with the Pauzhetka and the Nizhne-Koshelev geothermal fields, showing that the rocks of the Kambalnyi volcanic range are more intensely altered by hydrothermal and metasomatic processes, probably as a result of a long-continued action of convective heat flow.