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Climate and related controls on
interglacial river sedimentation in lowland Britain

by Philip Gibbard 1 & John Lewin2

1. Godwin Institute of Quaternary Research, Department of Geography, University of Cambridge, Downing Street, CAMBRIDGE CB2 3EN, England, UK
2. Institute of Geography & Earth Sciences, University of Wales, ABERYSTWYTH SY23 2DB, Wales, UK
. Institute of Geography and Earth Sciencies, University of Wales, Aberystwyth SY23 2DB, Wales, U.K.

Based on: Gibbard, P.L. & Lewin J. 2002 Climate and related controls on interglacial fluvial sedimentation in lowland Britain. Sedimentary Geology 151 , 187-210 .

The diagrams

Phase i  

Phase ii , Phase iii

 Phase iii and Phase iv
Phase iv  
Full glacial
Phase i  

The block diagrams are available for viewing from the individual pages listed here. They are accompanied by short explanations. For more detail, readers should consult the further reading list below.  Feel free to copy/paste images from these pages.
  1. Interglacial fluvial sediments
  2. Alluvial sedimentation styles  
  3. Identification and subdivision of interglacial fluvial sequences
  4. Devensian (Weichselian) Late-glacial -Holocene (Flandrian) fluvial sequences as an analogue  
  5. The pattern and implications of Interglacial fluvial sedimentation
  6. Fph i.  Late-glacial – interglacial transition (Substages late-glacial to I)
  7. Fph ii. Full interglacial  (Substage II)
  8. Fph iii. Full interglacial  (Substages late II – III)
  9. Fph iv. Late interglacial rejuvenation and dissection (late Substage III to Early-glacial)
  10. Full-glacial .
  11. Discussion and Conclusions

The figures were drawn by Owen Tucker of the Cartography and Reprographics Unit of the Department of Geography, University of Cambridge.


Interglacial fluvial sediment sequences are common in lowland Britain where their palaeontology has been considerably studied but their sedimentology is poorly known.  By contrast, Holocene (Flandrian) sequences have yielded important insights into river, and thus environmental, evolution. This paper examines the nature of the interglacial fluvial sedimentary record in southern Britain, showing similarities and differences in the sedimentary record.  A four-phase pattern of fluvial behavior through an interglacial cycle is presented. The utility of using Holocene sequences as analogues for previous interglacial sedimentation is discussed and an attempt is made to explain the proposed four-phase pattern in terms of predictable fluvial responses to an interglacial climate cycle.  Finally, the implications of the pattern for alluvial unit preservation and the stratigraphical interpretation of Pleistocene temperate events from river sediments are highlighted.  It is shown that British lowland rivers normally adopt three major behavioural modes in the Pleistocene: braided or wandering gravel-dominated mode, fine sediment-dominated stable meandering to anastomosing mode, and incision or non-depositional mode..


Throughout Britain, Quaternary fluvial sediments occur in lowland areas as extensive valley fills or as dissected deposits on hillsides and hilltops.  They may or may not underlie substantial terrace or modern floodplain surfaces.  By far the most abundant fluvial accumulations are gravels and sands, thought to have been deposited under predominantly cold Pleistocene climates.  Temperate interglacial deposits are much rarer.  Nevertheless, by comparison with neighbouring areas of Europe, interglacial deposits are remarkably common throughout lowland southern Britain, being particularly well known from regions of low valley gradient and subdued topography ins eastern, southern and south-eastern England, the English Midlands and the Welsh borderlands.

Although interglacial fluvial sediments have been studied in detail, in particular to understand their stratigraphical significance for subdivision of fluvial and related sequences in general, most of the research has been undertaken by palaeontologists.  This is because the sediments are often highly fossiliferous and therefore hold important implications for biostratigraphical and palaeoenvironmental reconstruction.  With all these studies, it is surprising perhaps that the sediments themselves have received relatively little attention.  This is less true of Holocene (Flandrian; post-glacial) sequences which, often in association with archaeological investigations, have yielded important insights into sedimentation controls and timing.

Whilst the importance of interglacial fluvial sediments cannot be overestimated for subdivision of Quaternary successions both within and beyond glaciated areas, the character of the sedimentary record at any one locality is markedly discontinuous, and shows high lateral facies variability.  This includes a strong local ‘overprinting’ on any regional climate and environmental changes and, although often richly fossiliferous, sections frequently fail to provide unequivocal evidence of age.  Preservation of materials from different parts of interglacial stages also appears to be markedly unequal.

Therefore, setting aside questions concerning the number and correlation of interglacial (temperate) sequences in the region, these considerations point to the need to examine processes of interglacial sedimentation.  They include both the likely changes in sedimentation style as interglacials proceed, and the effects they may have on preservation potential of earlier deposits.  Some channel patterns involve extensive valley-floor reworking of alluvial sediments by laterally-mobile channels, as in the case of many braided streams.  Others involve rivers of restricted mobility, together with overbank sedimentation which may blanket but not remove prior alluvial channels and deposits, as in the case of stable meandering or anastomosing rivers.  The sequence of channel styles is important, because this determines both their amounts of vertical and lateral sedimentation within valleys, and the extent to which earlier materials are removed or remain to dominate later,  less extensive depositional domains.

This paper attempts a reconstruction of the sequence of fluvial sedimentation styles produced by rivers responding to cool temperate events repeatedly represented in the Pleistocene, to see if general patterns may be discerned.  This is seen as especially important in that sedimentary styles and their sequences play a decisive role in determining the availability of a palaeontological record at any locality and time.  The paper focuses on lowland Britain and its interglacial fluvial record, highlighting similarities and differences between events.   

Since the present interglacial period (Holocene or Flandrian) is apparently similar in most respects to those of at least the last 0.75 My, it is reasonable to seek Pleistocene analogues in Holocene floodplain sequences.  The use of Holocene analogues for previous interglacial sedimentation patterns is therefore also discussed.

For the purposes of this work, discussion is restricted to freshwater sequences, i.e. those sediments laid down entirely under a ‘normal’ middle-reach fluvial regime, downstream of predominantly erosional headwaters and upstream of any estuarine influences.  The latter impose considerable modifications on fluvial sedimentary patterns, resulting from sea-level, tidal and water-mass interactions that impact on the entire sedimentary regime .  Moreover, the volume of sediment deposited and therefore potentially likely to be preserved in estuarine situations is much increased.  An example of interglacial estuarine sedimentation in the region is discussed by Gibbard (1994).

Further reading

The full paper:

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