Flood clay

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As Hochflutlehm fine-grained, are fluvial sediments called. Flood loams are composed of sandy, clayey, mostly carbonate-free silts . They are sedimented in phases of increased soil erosion in the catchment area, which are related to climatic fluctuations in the Pleistocene .

Genesis and Stratigraphy

Flood loam as well as flood sands have been deposited both inside and in the lying and hanging walls of the Ice Age low terrace . The youngest high-tide loams on the Lower Rhine are known from the early Holocene ( Preboreal ). Flood deposits differ from the actual Pleistocene terrace bodies in that they are very fine-grained. The literature often does not differentiate between flood loam and flood loam ( Holocene ); sometimes the terms flood clay, flood loam and flood sediment are used synonymously. Flood sediments are always in morphologically higher positions than the floodplain loams and are characterized by the development of parabrown earth formations, while brown soils are usually formed from the floodplain loam deposits .

Flood loam in the Lower Rhine Bay

Flood deposits in the Lower Rhine Bay are considered to be a complex genetic and stratigraphic rock formation. In the Rhine - Maas area, a distinction is made between older high-tide deposits (formed before the Alleröd Interstadial ) and more recent high-tide deposits (deposited at the turn of the Pleistocene / Holocene). In the Meuse area, high-tide loams are known whose sedimentation began in the oldest Dryas period and ended in the Bölling Interstadial (11,850 to 11,590 years BC). In the area of Arcen en Velden there are also known high-tide loams that were already 13,000 years BC. Were created. Also from the area south of Cologne , partly mollusc- bearing high-tide loams and sands are known, which were sedimented before the Alleröd Interstadial. Most of the high-tide loams were deposited at the turn of the Younger Dryas Period to the Preboreal (10,000 to 9500 years BC). Flood deposits in the Lower Rhine Bay are deposits that formed when the overgrown river systems deepened when the climate began to improve at the end of the Ice Age. Flood loam is known in the Lower Rhine Bay in three petrographic facies: Flood loam in the narrower sense, sandy flood loam and silty flood loam. The composition varies depending on the flow velocity and the distance to the main flow channel. Various petrographic compositions can be formed within a flood body. While flood sands indicate higher flow velocities and a short distance to the main stream channel, high flood loams are sedimented on flat flood plains in the area of ​​low flow velocities.

supporting documents

  1. ↑ Günther Reichelt The layers of the flood clay
  2. ↑ Litholex of the Federal Institute for Geosciences and Raw Materials, interactive, regional search , accessed on December 29, 2012
  3. ^ Geological State Office North Rhine-Westphalia: Geologie am Niederrhein , Krefeld 1988, p. 58
  4. ↑ Klaus Kern: Settlement history and floodplain clay formation in Germany . In: Basics of near-natural water design . Springer DE, 1994, ISBN 9783540575382 , p. 101.
  5. ^ A b Josef Klostermann: Geology of the Lower Rhine Bay. Geological Service NRW, Krefeld 1992, ISBN 978-3860299258 , p. 153
  6. ^ Josef Klostermann: Geology of the Lower Rhine Bay , Geological Service NRW, Krefeld 1992, ISBN 978-3860299258 , pp. 153-154
  7. ^ Josef Klostermann: Geology of the Lower Rhine Bay. Geological Service NRW, Krefeld 1992, ISBN 978-3860299258 , p. 154

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