Abstract: Miocene Tectonic Development of the Polish Carpathian Foredeep Basin

KRZYWIEC PIOTR

Polish Carpathian Foredeep (PCF) basin developed in Miocene times in front of the advancing Carpathian thrust belt. Recently completed interpretation of dense coverage of seismic reflection profiles provided new information on tectonic development of the PCF. In the western part only small normal faults can be observed within the Mesozoic basement of the PCF. They are partly older faults reactivated in Miocene times. It can be shown that prominent lows observed within the PCFs' Mesozoic basement can be attributed to either erosional or tectonic (normal faulting) processes. Immediately in front of the Carpathians, particulary between Bochnia and Tarnow, series of detachment faults developed within the foredeep sediments. These faults are solely detached within the middle Badenian evaporites and do not show any correlation with basement deformations. Gentle flexure of the basement in this part of the PCF suggest that bending of the lithosphere below the thrust belt was dominant process that has created present-day large-scale architecture of the PCF.

Very different results were obtained for the eastern part of the study area. Seismic data located between Rzeszow and Przemysl revealed large amount of tectonic deformations present within the Paleozoic basement of the PCF. They consist of either horst-and-graben structures or systems of large normal faults and rotated blocks. Normal faults present in the easternmost part of the PCF developed partly as synsedimentary features. Some of these faults were slightly inverted during Sarmatian (or younger) times. This inversion can be attributed to last stages of shortening within the Carpathian thrust belt.

AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria