Wyniki interpretacji strukturalnej utworów triasu i paleozoiku przedgórza Karpat opartej na nowych danych sejsmicznych

The main purpose of the article was to reconstruct the structural details of the Triassic and Palaeozoic formations of the central part of the Carpathian Foreland based on interpretation of new 3D seismic data. The interpretation included the analysis of seismic attributes, among them Time Gain, Relative acoustic impedance, First derivative, Dominant frequency and Instantaneous bandwidth were the most useful. Previous knowledge on the geological structure of the Palaeozoic complex in this area was derived mainly from the interpretation of 2D seismic sections, regional concepts and data from the only deep well drilled in the late 1950s and early 1960s. The results of the seismic image analysis show that the Jurassic sub-surface is composed of a number of tectonic blocks of various sizes, separated by dislocation zones. Most of them are tilted blocks which are the remnants of the Caledonian-Variscan tectonic system. Palaeozoic sediments with clearly arranged continuous seismic reflectors strongly contrast in the seismic image with the complex of anchimetamorphic rocks of the uppermost Ediacaran characterized by disarranged, homogeneous record. Clastic formations of the Lower Triassic fill primarily the deeper parts of the tectonic half-grabens. Based on the seismic image analysis, the complex is divided into two series: the lower one, with significantly lower amplitude values and noticeably lower continuity of seismic reflectors and the upper one with diversified dynamics and greater continuity of reflectors. The highest analyzed complex is the carbonate formation of Roetian and Muschelkalk, characterized by high amplitude values and high continuity of reflectors so that it can be easily identified on seismic sections. The analysis carried out with the use of seismic attributes allowed to determine the seismic characteristics of individual lithostratigraphic complexes of the Triassic and Palaeozoic formations and provided more detailed information on the geological structure of the research area.