Mnin restraining stepover – evidence of significant Cretaceous–Cenozoic dextral strike-slip faulting along the Teisseyre-Tornquist Zone?

摘要

A newly recognized Mnin restraining stepover is identified in the Permo-Mesozoic cover of the western part of the Late Palaeozoic Holy Cross Mountains Fold Belt (Poland), within a fault pattern consisting of dextral strikeslip faults. The formation of a large contractional structure at the Late Cretaceous – Cenozoic transition displays the significant role of strike-slip faulting along the western border of the Teisseyre-Tornquist Zone, in the foreland of the Polish part of the Carpathian Orogen. Theoretical relationships between the maximum fault offsets/mean step length, as well as between the maximum fault offsets/mean step width allowed the estimation of the values of possible offsets along the Snochowice and Mieczyn faults forming the Mnin stepover. The estimated values suggest displacements of as much as several tens of kilometres. The observed offset along the Tokarnia Fault and theoretical calculations suggest that the strike-slip faults west of the Late Palaeozoic Holy Cross Mountains Fold Belt belong to a large strike-slip fault system.We postulate that the observed significant refraction of the faults forming the anastomosing fault pattern is related also to the interaction of the NW-SE-striking faults formed along the western border of the Teisseyre-Tornquist Zone and the reactivated WNW-ESE-striking faults belonging to the fault systems of the northern margin of the Tethys Ocean.