Metamorphic rocks in the deep boreholes near Maribor

Abstract

Six research-captive boreholes for thermal water passed through a pile of metamorphic rocks near Maribor (Eastern Slovenia) that is on average about 1000 m thick. The succession of metamorphic rocks is characteristic for the Pohorje Mt. and eastern Kobansko region. In the area of the boreholes two tectonic zones are more pronounced: the upper one, at a depth of about 510 to 550 m at the contact of the Štelenska Gora and Phyllite formations and the deeper one at a depth of about 460 to 590 m, indicating the reverse fault junction of the Phyllite and Kobansko formations. They belong to the second and the third thrust unit of the accretionary wedge formed at the collision of the European and African plates. Four Alpine nappe units are proven in the Slovenian part of the Eastern Alps.