| Abstrakt: |
Gravel pits within the Lahn valley south of Marburg (Hesse/Germany) allowed insight into the structure of the Pleistocene lower terrace of an upland river. Gravels and sands up to 10 m thick show phases of accumulation and erosion. The stratigraphy implies a more complex of the lower terrace. At the base of the valley fill interglacial muds and peats of considered Eemian age, as well as early Weichselian deposits dating to the Brörup Interstadial could be identified as relics. These are overlain by sediments of the early or middle Weichselian Pleniglacial. Other phases of fluvial incision and aggradation were detected for the middle and late Pleniglacial. The Lateglacial is already marked by a meandering river and relatively stable fluvial dynamics. A strong cycle of erosion and accumulation during the early Younger Dryas shows the effect of the late Pleistocene climatic depression on the fluvial dynamics. The results of this study indicate that the marked climatic changes during the last cold stage influenced the fluvial dynamics of upland rivers indirectly through changes of the vegetation cover, sediment load and run-off, as it is also assumed for northwest and middle European lowland rivers. However, it seems likely that the upland rivers reacted more rapidly and more pronounced than the lowland rivers to smaller scale climatic changes, as took place during the middle Pleniglacial and the Younger Dryas. |
