Late Cainozoic evolution of the Nysa Kłodzka river system between Kłodzko and Kamieniec Ząbkowicki, Sudetes Mts, southwestern Poland

Abstract

The Nysa Kłodzka river drainge basin in the Sudetes Mts, SW Poland, preserves a complex late Cainozoic sequence that includes eight fluvial series/terraces and deposits from two glacial episodes as well as locally volcanic rocks, slope covers and loess. Sedimentation took place during the late Pliocene and since early Middle Pleistocene (Cromerian), with a long erosion phase (hiatus) during the Early Pleistocene. Fluvial series occur in the late Pliocene, Cromerian, Holsteinian, late Saalian/Eemian, Weichselian and the Holocene. Glacial deposits are represented in the early Elsterian and early Saalian stages. The main tectonic uplift and strong erosion was during the Early Pleistocene, with displacement about 60-70 m. Tectonic uplift was documented also for the post-Elsterian and the post-early Saalian time, and these uplift phases are most probably due to glacio-isostatic rebound. The Quaternary terrace sequence has been formed due to base level changes, epigenetic erosion after glaciations and neotectonic movements. The Cromerian fluvial deposits/terraces do not reveal any tectonic influence. However, all other Quaternary terraces indicate clear divergence, and the post-early Saalian terraces also offset by fault scarps. The total Late Pleistocene displacement along the fault scarps is about 25 m. The fluvial pattern is stable, once formed during the Pliocene, it continued in the same place until recently, with only minor changes along the uplifted block surrounding the Bardo gorge which infers the antecedent origin of the Bardo gorge. During the post-glacial times, epigenetic incisions have only slightly modified the valley.