Flandrian sea-level changes in the fenland

Abstract

Micropalaeontological, stratigraphic, radiocarbon, and published data have been assessed to elucidate sea-level changes in the Fenland during the Plandrian Stage. Up to 8 periods characterised by positive tendencies in sea-level movement have been identified, Wash I - VIII, separated by up to 7 periods, Fenland I - VII, dominated by negative tendencies in sea-level movement. 102 (>14) C dates form the chronological framework on which this scheme is based. Negative tendencies cannot yet be confirmed as absolute falls in sea-level due to the errors involved in the assessment of sea-level indicators. These errors relating to age and altitude have been quantified wherever possible. The variation in stratigraphic surfaces has been briefly assessed and the statistical limitations of pollen analyses have been shown by the application of confidence limits to the pollen diagrams. A computer program, NEWPLOT, has been developed to draw the pollen diagrams, including pollen concentration, from 6 sites at Bourne Fen, Cowbit Wash and Adventurers’ Land. Models have been suggested to assess the stratigraphic and micropalaeontological changes at the salt marsh-freshwater fen transition and to identify tendencies of sea-level movement. Problems relating to the existing methodology of sea-level studies have been noted from the difficulty in objectively correlating the data and results of various authors. The errors identified in the collection, interpretation and correlation of sea-level data have repercussions for the planning of sea-defences and land-use in low-lying coastal areas.