Strike-slip faulting in the Kielce Unit, Holy Cross Mountains, central Poland

Abstract

Strike-slip faults and associated tectonic structures have been investigated in the Holy Cross Mountains fold belt (HCM), which is located eastwards of the Variscan foreland basin. The strike-slip fault sets form a complex network, which developed during two faulting stages: in Late Palaeozoic (I) and Maastrichtian/Palaeocene (II) times.

The Late Palaeozoic fault pattern formed as a result of at least two strike-slip events: I-1 and I-2. During the first event (I-1), a N–S-striking dextral strike-slip fault set and a NNE–SSW to NE–SW-striking sinistral strike-slip fault set developed. During the next event (I-2), dextral strike slip occurred along the WNW–ESE-striking longitudinal master faults and formed a NW–SE to NNW–SSE-striking sinistral secondary strike-slip fault set. During this event, in zones north and south of the Holy Cross Fault, faultbounded blocks developed which were rotated dextrally as a result of further displacements. The strikeslip fault network was overprinted during the Maastrichtian/Palaeocene second strike-slip stage (II).