Neotectonically controlled fluvial features, Wałbrzych Upland, Middle Sudeten Mts, southwestern Poland

The landscape of the Wałbrzych Upland, Sudeten Mts, southwestern Poland, has developed over a long time involving three main stages: (I) the Oligocene-Early Pliocene, (II) the Late Pliocene-Early Pleistocene, and (III) the Middle-Late Pleistocene. Stage III is neotectonically controlled and is discussed in detail. The entire Wałbrzych Upland was covered by a continuous ice cover during the early Saalian and at least in its marginal part during the Elsterian. The pre-early Saalian fluvial landscape shows no evidence of tectonic activity in contrast with that of post-early Saalian time. The post-early Saalian valleys have been formed during the intensive and short-term uplift of the mountain upland with simultaneous re-activation of fault zones. The main geomorphological effects of this uplift are: abandonment of valleys; formation of deep river valleys cut within bedrock; varying shapes of newly incised valleys; highly irregular longitudinal profiles of channels; varying numbers of terraces and their heights along the valleys; tilting of terraces; and formation of fault scarps at some fault lines. The main geological effects are: variable thicknesses of alluvial deposits caused by rotation of bedrock blocks; synsedimentary increases of thickness of alluvial deposits at some fault lines; and breaking of the continuity of some alluvial surfaces at the major fault lines. The uplift of the Wałbrzych Upland was controlled by glacio-isostatic rebound after the early Saalian glaciation supplemented by localised extensional tectonics. Total tectonic uplift was about 40–50 m.