The Structure of the Central Part of Transeuropean Suture Zone and the Basement of Neighbouring Platforms Based On Regional Magnetotelluric Survey

Michal Stefaniuk¹, Jedrzej Pokorski², Tomasz Czerwinski¹, and Marek Wojdyla^1
1PBG Geophysical Exploration Company, Warsaw, Poland
²Polish Geological Institute, Warsaw, Poland

The magnetotelluric survey was made during 2005-2006 years along a regional profile, which runs across Poland from south-west to north-east. The profile crosses major geological structures of Central Poland, including the Variscan Externides and Varscian foredeep, the Transeuropean Suture Zone and the marginal zone of East European Craton. The length of the profile is about 700 km; 161 deep magnetotelluric sounding sites were designed with a medium spacing of about 4 km. The main objectives of the project include identification of sub-Zechstein sedimentary structures and evaluation of resistivity distribution within the deep crust, especially at the contact of East European Precambrian Craton and Central Europe and Paleozoic structures. Geophysical interpretation of MT sounding data was made based on 1D and 2D inversion. The upper part of the geological section is built of relatively flat layers, hence a 1D interpretation model could by effectively applied. Starting models for 1D inversion were constructed based on results of electromagnetic well-logging. Some well-documented seismic horizons were taken as constraints in 1D inversion. Initial models for 2D inversion were constructed with the use of results of 1D magnetotelluric sounding inversion and structural model of the upper part of cross-section based on seismic data interpretation. A resistivity distribution model along the measurement profile was obtained as a result of geophysical interpretation. Of great interest is varied resistivity of the formation resting between the Zechstein evaporate complex, and the crystalline basement and differentiation of the East European Craton basement.

AAPG Search and Discovery Article #90072 © 2007 AAPG and AAPG European Region Conference, Athens, Greece