Geomorphology and palaeoecology of the Mark valley (southern Netherlands): palaeoecology, palaeohydrology and climate during the Weichselian Late Glacial

Bohncke, Sjoerd, Vandenberghe, Jef, Coope, Russell & Reiling, Rudo 1987 03 01: Geomorphology and palaeoecology of the Mark valley (southern Netherlands): palaeoecology, palaeohydrology and climate during the Weichselian Late Glacial. Boreas, Vol. 16, pp. 69–85. Oslo. ISSN 0300–9483.A backswamp peat, located on an Upper Pleniglacial terrace, has been analysed in detail with respect to its pollen content, its macroscopic plant remains and its fossil insect fauna. The analyses permitted a detailed reconstruction of the Late Glacial palaeoenvironment besides an estimation of fluctuations in the local humidity and fluctuations in the palaeotemperatures. The main boundaries in the sequence have been radiocarbon dated, indicating a peat accumulation from c.12,600 B.P. to 10,970 B.P. The Bölling s.l. shows a clear migration of vegetation belts, starting with a shrub vegetation and passing into a birch wood. This progressive vegetation development culminates in a short lasting Pinus maximum early in the Alleröd, without being hampered by events during the Older Dryas. Up to and including the Alleröd no serious climate deterioration is registered. The humidity curve reveals a semiterrestrial phase in the local hydrosere that correlates with the Older Dryas and that is explained by the geomorphological evolution of the adjacent river system. The transition to the Younger Dryas coincides with a return to fluvial conditions and a marked change in the pollen record and insect fauna, indicating a decline in the average July temperature from between 18 and 15°C to 11 and 10°C.