Pre-Ordovician polyphase tectonics of the Cambrian sequences in the Kielce Unit, Holy Cross Mts. (Central Poland)

On a basis of tectonic mesostructures, the pre-late Tremadocian tectonic event (Sandomirian "phase"), believed to account for deformation of the Cambrian system in the Kielce Unit (Holy Cross Mts., Central Poland), has been subdivided into 3 successive tectonic episodes of different kinematics. During the first stage ($D_{1}$), flat, westerly vergent thrusts originated, giving rise to gravitational sliding. Subsequently, during $D_{2}$, the entire sequence was imbricated by the northerly vergent thrusts. In the terminal phase ($D_{3}$), map-scale folds developed, changing inclinations of previously formed structures. Mode of deformation during the $D_{2}$ stage is typical for thrust and fold belts. Absolute dating of these events remains speculative, but the pre-late Tremadocian age of the $D_{1}$ and $D_{2}$ phases is evident. The $D_{3}$ is considered as a continuation of the $D_{2}$, but alternative concepts are also acceptable in the light of the presented data.