(Oral, André et al.) Palaeoenvironment reconstruction of a medieval embankment at Sint Anna ter Muiden based on the ecology of palynomorphs and diatoms

Onderzoeksoutput: Hoofdstuk in Boek/Rapport/CongresprocedureC3: Congres abstractpeer review

  • Coralie Andre
  • Wim De Clercq
  • Annelies Storme
  • Dante de Ruijsscher
  • Maxime Poulain
  • Frieda Bogemans
  • Koen Sabbe
  • Bart Van de Vijver
  • Stephen Louwye
It is generally assumed in the literature that a violent storm in 1134 was responsible for the formation of a large tidal inlet, the Zwin. Afterwards, man reclaimed the landscape via the massive construction of dikes and canals. The region of Bruges, connected to the sea via a network of outer ports, became a major axis of maritime circulation. However, after its heyday, due to the collapse of the economy and the silting up of the Zwin, the harbours fell into disuse and disappeared. A multidisciplinary project now aims the reconstruction of the ecological palaeoenvironment during the Roman and medieval periods in the northern coastal plain of Belgium and the Netherlands.
Two pollen boxes were recently taken at the lost harbour of Sint Anna ter Muiden (Zeeland, the Netherlands), one located in an embankment, and the other including a waste layer dated from the 13th-14th century. A total of 66 samples were studied for palynological and diatom analyses.
The first pollen box shows disturbed mudflat sediments, referred to as clay-sods and dug by man in the coastal plain and used as a levelling layer on which the embankment was subsequently constructed. The terrestrial palaeoenvironment reflects a woodland-dominated landscape and the nearby presence of the coastal plain. The diatom spectrum is dominated by tychoplanktonic marine-brackish species (e.g., Cymatosira belgica and Paralia sulcata), which indicate a marine influence. Sediment holding a large number of shells was then deposited by man on top of the clay-sods to increase the height of the embankment. This layer holds abundant palynomorphs associated with anthropogenic activities. The tychoplanktonic marine-brackish diatoms remain dominant, and benthic brackish-freshwater species (e.g., Navicula cincta and Hantzschia amphyoxis) become more abundant and reflect dry supratidal conditions, such as a saltmarsh. These results are compared with the diatom analysis from a dike at Stene (Flanders, Belgium) dated to the Roman period, where dry supratidal conditions predominate.
The second pollen box holds undisturbed mudflat sediments, in which terrestrial and aquatic palaeoenvironments are recorded that are similar to those in the clay-sods. The waste layer overlying these mudflat sediments holds many palynomorphs linked to anthropogenic activities. Epontic and benthic brackish-freshwater species (e.g., Halamphora coffeiformis and Nitzschia capitellata) become dominant and reflect intertidal conditions, such as a mudflat. Thus, the conditions were wetter towards the waste layer, and although dry supratidal conditions are recorded in the embankment, the dominance of tychoplanktonic marine-brackish diatoms suggest that it was still impacted by the sea.
Originele taal-2Engels
Titel14th European Diatom Meeting Abstractbook
StatusGepubliceerd - 2023
Event14th Euroepan Diatom Meeting - Meise Botanic Garden, Meise
Duur: 8-mei-202311-mei-2023
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