In the summer of 2000, ten deep magnetotelluric soundings were carried out in northeastern Poland. These observations were organized along the 250-km profile crossing the East European Craton (EEC) and the Tornquist-Teisseyre zone (TTZ) up to the Holy Cross Mountains. These data extended by the ultralong period ones obtained at the geomagnetic observatories Minsk (at the EEC) and Belsk (at the TTZ) have allowed estimating the mantle conductivity down to 1000 km depths. The satisfactory analysis of these data has been made by means of the 1D spherical inversions in the context of the reliable conductance distributions. On the background of relatively low conductances of sediments (10-600 S) along the profile it has been revealed that the upper mantle conductivity is increasing from the EEP towards the TTZ. The main conductive property bas been detected at the asthenosphere depths of about 150-300 km beneath the TTZ. A good correlation exists between the present result and the previous one obtained beneath the parallel profile situated 150 km towards the northwest.
Geomagnetic data from the Polish Antarctic Station Arctowski were analyzed to estimate the geoelectrical mid mantle structure for the West Antarctic. Response functions were obtained at periods from 11 to 65 days by using Dst variations. The original inversion in the spherical geometry was applied to establish the 1D structure. This first deep geoelectrical sounding in the Antarctic has shown the existence of a mid mantle conductive layer, of 850 kS conductance, at a depth of about 700 km. This result has confirmed the idea of the global character of that layer over the Earth.
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