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T8
Late-Middle to Late Pleistocene deposits of the lower River Nene, eastern England,
and implications for stratigraphical interpretation
H. E. Langford
Department of Geography, Environment and Development Studies, Birbeck University of London, Malet
Street, London WC1E 7HX, United Kingdom
Correlation of British Pleistocene fluvial deposits historically relied upon subjective
altitudinal qrouping of disparate sand and gravel bodies on valley sides, valley floors and
interfluves. Over recent decades this has been supplemented by lithological,
biostratigraphical and age-estimate data (mostly amino acid racemization and optically
stimulated luminescence), generally within the established terrace systems. Detailed
sedimentary facies analysis of fluvial deposits has been the exception rather than the rule.
Likewise, the three-tier terrace system of the River Nene is based on historical altitudinal
grouping representing temporally distinct periods of aggradation. More recently proposed
revisions have questioned this simplistic triparte division and recognized greater
complexity within the terrace system, but without amending the altitudinal parameters or
components of the historical grouping. Sedimentological, palaeoecological and ageestimate
studies on the sedimentary succession at Whittlesey, eastern England, have
been carried out over the past 20 years. This succession records complex late-Middle to
Late Pleistocene fluvial aggradation extending back to at least marine oxygen isotope
stage 8, and represents two interglacial and three glacial stages. A similarly complex
sequence, possibly representing the same time span, at Sutton Cross occupies a River
Nene 2nd Terrace some 15 km upstream of the 1st Terrace at Whittlesey. Evidence for
the preservation of possibly temporally equivalent fluvial sequences within separate
terraces therefore challenges the established tripartite terrace system, as well as recently
proposed revisions. The various terrace stratigraphical schemes are presented here and
the impoverishment of the database and the difficulty of subjectively distinguishing
separate altitudinal groups are demonstrated. Various proposals for the formation and
preservation of terrace systems are also discussed. A brief description of the sedimentary
succession at Whittlesey is provided and some implications for Pleistocene stratigraphy
discussed. An alternative terrace stratigraphy scheme capturing the data from Whittlesey
and Sutton Cross is presented but rejected because the rationale for such schemes is
fundamentally flawed. Instead a combination of detailed sedimentology combined with
geomorphological considerations demonstrates that the disparate sand and gravel bodies
of the River Nene catchment are post-Anglian remnants of fluvial activity on a palimsest
landscape. It is also recommended that in future cartoons depicting catchment-wide
terrace stratigraphy should be replaced by a sequence of cross-sections that would be
spatially more meaningful and also demonstrate the impoverishment or otherwise of the
supporting database.
Keywords: sedimentology; geomorphology; sedimentary succession; terrace stratigraphy;
late Middle to Late Pleistocene; River Nene; Whittelsey.