The Fenland of East Anglia is the largest area of Holocene deposits in Britain (c. 4000 km[superscript 2]) and some successions reach a thickness of 30 m. A complex palaeoenvironmental landscape has been progressively revealed as the overlying peat has wasted away to reveal exceptionally preserved roddons. Roddons are defined as dendritic ridge systems, up to 1 m high, that meander across Fenland areas. They are interpreted as being the surface expression of silted-up tidal creeks. Three generations of East Anglian roddons have been identified, each being related to a major “transgressive” event between about 2000 and 6000 yrs BP. Soon after the tidal creeks and channels had been established, they were choked by sediment (silts and fine sands) derived from a nearby shallow marine environment, perhaps following major (storm-induced?) physiographic changes. The final stage in their formation occurred after 17th century Fenland drainage, with compaction, shrinkage and wind ablation of the surrounding salt marsh clays and peats, leaving the more resistant channel infill as topographic highs. Roddon deposits contain rich assemblages of autochthonous, low marsh foraminifera with rarer ostracods (together with allochthonous taxa and fossils reworked from bedrock); assemblages differ from trunk to tributary roddons. A late-stage channel incised into a roddon at Must Farm, near Peterborough, is filled predominantly with clays containing freshwater ostracods and molluscs, together with riparian archaeological remains. This freshwater channel, therefore, represents a distinctly different palaeoecological regime compared to that of the roddons. Any future marine transgression will take place across an anthropogenically modified Fenland where the topographically positive roddons will act as barriers and islands that will affect marine ingress.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:602657 |
| Date | January 2014 |
| Creators | Smith, Dinah Marilyn |
| Contributors | Zalasiewicz, Jan; Williams, Mark |
| Publisher | University of Leicester |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/2381/28781 |
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