Scientific publications

The article is devoted to the results of electrical surveying carried out in the Northern Ladoga region in 2015 and 2017 by a joint team of the Geological Institute of the Kola Science Center of the Russian Academy of Sciences and the Institute of Geology of the Karelian Research Centre RAS. The set of methods included DC electrical profiling and audio-magnetotelluric sounding (AMTS). A major part of the work was electrical profiling by the method of external sliding dipole (MESD) with a 500 m step along a 130.5 km long profile crossing the entire width of the Lake Ladoga conductivity anomaly from the village of Hijtola in the west to the village of Suistamo in the east. The average depth of penetration of the MESD profiling was 150–200 m. The MESD output has enabled identification of two well conducting objects. One of them, 200 m wide, is located in the eastern margin of the Ladoga anomaly, in the area of the Janisjarvi fault zone, situated at the contact of the Northern Ladoga Proterozoic formations and Archaean rocks of the eastern frame. The second conducting object with a visible thickness of 7 km Grand anomaly is located in the middle part of the profile, on the traverse line of the settlements Elisenvaara and Ikhala. At both objects the apparent resistivity goes down to few ohm-meters or even decimal fractions. They can therefore be classified into the electronically conducting type of conductors associated with the presence of graphite- and sulfide-bearing rocks. The area of the revealed electrical conductivity anomalies was surveyed in detailed by the methods of internal sliding contact (MISK), median gradient (MG), and audio-magnetotelluric sounding (AMTS). Some outcrops were sampled for determination of the specific electrical resistance of the rocks. The article gives a consistent description of the observation technique, the results of observations and their discussion.