Bridgland, D.R. 1994. Quaternary of the Thames. Geological Conservation Review Series No. 7. JNCC, Peterborough, ISBN 0 412 48830 2.
The original source material for these web pages has been made available by the JNCC under the Open Government Licence 3.0. Full details in the JNCC Open Data Policy
D.R. Bridgland
Bridgland Earth Science Consultancy, Darlington, UK.
Scientific Editor: D. Q. Bowen GCR Editor: W. A. Wimbledon
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First edition 1994
1994 Joint Nature Conservation Committee
Typeset in 10pt ITC Garamond Book by Herrington Geoscience and Exe Valley Dataset Ltd, Exeter Printed in Great Britain at the University Press, Cambridge
ISBN 0 412 48830 2
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Contributors
Acknowledgements
Access to the countryside
Preface D.R. Bridgland and W.A. Wimbledon
1 The Pleistocene of the Thames D.R. Bridgland
The Quaternary record of the River Thames
The Thames terrace system
The diversion of the Thames
The continuation of the Thames into Essex
Classification of Thames terraces and deposits
The stratigraphical framework: Pleistocene chronostratigraphy
and correlation
Terrace formation
The stratigraphy of the Thames sequence
Evidence from Palaeolithic artefacts in Thames deposits
Correlation of Thames terraces
2 The Upper Thames basin D.R. Bridgland
The Pleistocene sequence in the Upper Thames
Sugworth Road Cutting
Long Hanborough Gravel Pit
The Wolvercote Gravel and Wolvercote Channel Deposits
Stanton Harcourt Gravel Pit and Magdalen Grove Deer Park
3 The Middle Thames D.R. Bridgland (with contributions from D.A.Cheshire)
Introduction
Part 1 — Pliocene/Lower Pleistocene deposits in the London Basin D.R. Bridgland
Little Heath D.R. Bridgland
Harrow Weald Common D.R. Bridgland
Priest's Hill, Nettlebed D.R. Bridgland
Part 2 — Pre-diversion deposits in the Middle Thames basin and the Vale of St Albans D.R. Bridgland
The Vale of St Albans Thames and its demise D.R. Bridgland
Chalfont St Giles Brick Pit and Furneux Pelham Gravel Pit D.R. Bridgland
Westwood Quarry D.R. Bridgland
Westmill Quarry D.R. Bridgland and D.A. Cheshire
Moor Mill Quarry D.R. Bridgland
Ugley Park Quarry D.A. Cheshire and D.R. Bridgland
Part 3 — The sequence post-dating the diversion of the Thames (sites in the Middle Thames and its tributary, the Kennet) D.R. Bridgland
Highlands Farm Pit D.R. Bridgland
Hamstead Marshall Gravel Pit D.R. Bridgland
Cannoncourt Farm Pit D.R. Bridgland
Fern House Gravel Pit D.R. Bridgland
Brimpton Gravel Pit D.R. Bridgland
4 The Lower Thames D.R. Bridgland (with contributions from P. Harding)
Research history
Hornchurch Railway Cutting D.R. Bridgland
Wansunt Pit, Dartford Heath D.R. Bridgland
Swanscombe (Barnfield Pit — Skull Site NNR and Alkerden Lane Allotments SSSI) D.R. Bridgland
Purfleet — Bluelands, Greenlands, Esso and Botany Pits D.R. Bridgland
Globe Pit, Little Thurrock D.R. Bridgland and P. Harding
Lion Pit Tramway Cutting (West Thurrock) D.R. Bridgland and P. Harding
Aveley, Sandy Lane Quarry D.R. Bridgland
Northfleet (Ebbsfleet valley): Baker's Hole Complex D.R. Bridgland
5 Essex D.R. Bridgland (with contributions from T Allen, G.R. Coope, P.L. Gibbard and R. Wrayton)
Introduction
Part 1 — The Kesgrave Sands and Gravels D.R. Bridgland
Newney Green Quarry D.R. Bridgland
Ardleigh (Martells Quarry) D.R. Bridgland
Little Oakley D.R. Bridgland
Wivenhoe Gravel Pit D.R. Bridgland
St Osyth Gravel Pit and Holland-on-Sea Cliff D.R. Bridgland
Part 2 — Eastern Essex D.R. Bridgland
Clacton (cliffs, foreshore and golf course) D.R. Bridgland
Cudmore Grove (East Mersea cliffs and foreshore) D.R. Bridgland
Southminster, Goldsands Road Pit D.R. Bridgland
Part 3 — Deposits of local rivers D.R. Bridgland
Maldon Railway Cutting D.R. Bridgland
East Mersea (Restaurant Site and Hippopotamus Site) D.R. Bridgland
Great Totham (Lofts Farm Pit) D.R. Bridgland, T Allen, G.R. Coope, P.L. Gibbard and R. Wrayton
References
Index
T. Allen, 30 Fourth Avenue, Romford, Essex, RM7 OUB.
Dr D.R. Bridgland, Earth Science Consultancy, 41 Geneva Road, Darlington, County Durham, DL1 4NE.
Dr D.A. Cheshire, Division of Environmental and Earth Science, University of Hertfordshire, College Lane, Hatfield, Hertfordshire, AL10 9AB.
Professor G.R. Coope, Department of Geological Sciences, Birmingham University, P.O. Box 363, Birmingham, B15 2TT.
Dr P.L. Gibbard, Sub-department of Quaternary Research, Botany School, Downing Street, Cambridge, CB2 3EA.
P. Harding, Wessex Archaeology, Portway House, South Portway Estate, Old Sarum, Salisbury, Wiltshire, SP4 6EB.
R. Wrayton, 9 Barnfield, Wickford, Essex, SS11 8HP.
D.R. Bridgland wishes to acknowledge the assistance and encouragement of a great many colleagues since the initiation of his GCR work on the Thames in 1980. He is particularly indebted to Dr W.A. Wimbledon, who was an inspiration in the early years of the project and provided much valdable discussion on stratigraphy. Professor J. Rose contributed much constructive advice and criticism as referee, which helped guide the project towards publication. Invaluable discussion and advice has also been supplied by Mr T. Allen, Professor D.J. Briggs, Dr S. Campbell, Dr D.A. Cheshire, Professor G.R. Coope, Dr P.L. Gibbard, Mr P. Harding, Dr D.T. Holyoak, Dr D.H. Keen, Mr J. Mac-Nabb, Dr D. Maddy, Dr A.J. Stuart, Dr A.J. Sutcliffe, Dr R.M. Tipping and, in particular, by Dr P. Allen, Dr D.A. Cheshire, Dr R.A. Kemp, Dr R.C. Preece, Dr C.B. Stringer, Mr F.F. Wenban-Smith, and Mr J.J. Wymer, who have all read and commented on parts of the text. He would like to thank those who have contributed photographs (these are individually attributed in their captions) and unpublished work to the volume (these are: D.A. Cheshire — Westmill Quarry and Ugley Park Quarry; P. Harding — Globe Pit and Lion Pit tramway cutting; T. Allen, G.R. Coope, P.L. Gibbard and R. Wrayton — Great Totham), as well as those who have supplied personal communications, namely P. Allen, D.Q. Bowen, J.A. Catt, A.P. Currant, M.H. Field, P.L. Gibbard, R.W. Hey, D.T. Holyoak, R.A. Kemp, M.P. Kerney, J. McNabb, R.J. MacRae, D. Maddy, R.C. Preece, H.M. Rendell, J.E. Robinson, H.M. Roe, J. Rose, A.J.R. Snelling, A.J. Sutcliffe, C. Turner, A.H. Weir, F.F. Wenban-Smith, C.A. Whiteman and J.J. Wymer.
Assistance with the bibliography, provided by Paula Bridgland and Caroline Mee, is gratefully acknowledged. Paula Bridgland also helped with word processing and proof reading at various stages of the project. Thanks are also due to the GCR Publication Production Team: Dr D. O'Halloran, Project Manager; Neil Ellis, Publications Manager; Nicholas D.W. Davey, Scientific Officer (Editorial Assistant) and Valerie Wyld, GCR Sub-editor. Diagrams were drafted initially by Paul Butler and Nicholas D.W. Davey and were subsequently completed by Lovell Johns Ltd in collaboration with the author.
This volume is not intended for use as a field guide. The description or mention of any site should not be taken as an indication that access to a site is open or that a right of way exists. Most sites described are in private ownership, and their inclusion herein is solely for the purpose of justifying their conservation. Their description or appearance on a map in this work should in no way be construed as an invitation to visit. Prior consent for visits should always be obtained from the landowner and/or occupier.
Information on conservation matters, including site ownership, relating to Sites of Special Scientific Interest (SSSIs) or National Nature Reserves (NNRs) in particular counties or districts may be obtained from the relevant country conservation agency headquarters listed below:
English Nature, Northminster House, Peterborough PE1 1UA.
Scottish Natural Heritage, 12 Hope Terrace, Edinburgh EH9 2AS.
Countryside Council for Wales, Plas Penrhos, Ffordd Penrhos, Bangor, Gwynedd LL57 2LQ.
The principal aim of this volume is to provide descriptions of Sites of Special Scientific Interest, selected as part of the Geological Conservation Review, that yield evidence for the Pleistocene history of the River Thames and its tributaries. Although defined thematically, the volume covers all Pleistocene GCR sites in the Thames valley. A number of sites in southern East Anglia are also included because they provide important evidence bearing on the history of the Thames system. The justification for a GCR volume devoted to the Thames lies in the special importance of the river in the British Quaternary. The volume is concerned with the history of Britain over approximately the last two million years of geological time, during the repeated glacial phases of the Quaternary 'Ice Age' and the warmer intervals between them. Many such climatic fluctuations are recorded in the deposits of the Thames, which can be shown to have existed as the predominant west to east drainage line in south-eastern England throughout the Pleistocene.
The Thames has left a detailed record of its earlier presence in the form of deposits, which comprise fluvially aggraded floodplain sediments (predominantly gravels) preserved on the valley sides, where they form geomorphological terrace features. The oldest deposits are at the highest levels, forming a terrace 'staircase' that records successive stages in the evolution of the valley. Thames deposits are also found in areas no longer drained by the river and are a testament to the dramatic changes that have occurred in the catchment and courses of the Thames and its tributaries through time. The deposits contain, at certain localities and stratigraphical levels, the remains of plants and animals. These have been used as the main indicators of past climates, which varied from extreme Arctic cold to conditions at least as temperate as today. In addition, the fluvial and associated sediments have yielded prolific evidence, in the form of flint tools and very rare human bones, for the activities of early humans in southern Britain. There is considerable overlap between the research by geologists and that by archaeologists on the Thames deposits laid down during the last 500,000 years, many of which yield important archaeological evidence that is of considerable value to the geologist as a potential means of dating.
The Thames terrace deposits represent a less complete record than, for example, the considerable accumulation of sediment that underlies The Netherlands, laid down at the edge of the subsiding North Sea Basin by the Rhine, but they provide what is probably the most detailed terrestrial Pleistocene sequence in the British Isles. The neighbouring East Anglia region, better established as a rich source of Quaternary information (much of which is marine) and the home of several Pleistocene stratotypes, has a less complete record of the cold stages, which are represented by the gravel terraces of the Thames. Correlation of the Thames sequence with those of East Anglia and The Netherlands is in its early stages, but promises major advances in the near future.
The Thames sequence, although based on a terrace system in which downcutting events and periods of non-deposition account for a significant (but unknown) proportion of the time represented, nevertheless benefits from a degree of continuity, in that it derives from a single continuously existing source, the river itself. It therefore promises, amongst the British terrestrial sequences, to be the most readily correlated with the global oceanic record. In recent years an oxygen isotope stratigraphy, providing a detailed record of climatic fluctuations during the Pleistocene, has been reconstructed from the more or less continuous sequence of deep-sea sediments. Its use as a chronostratigraphical and 'climato-stratigraphical' standard provides a basis for correlating the often widely separated interglacial and glacial deposits of terrestrial sections throughout the world. Relating the major terrestrial sequences, such as that in the Thames basin, to this standard thus offers the best prospect for global correlation within the Pleistocene. An improved understanding of the biostratigraphical and lithostratigraphical evidence yielded by the terrace sediments, as well as the application of geochemical dating methods, has made it possible to place the Thames sequence more precisely within the emerging global geochronological framework.
A pragmatic approach to the task of selecting Thames Pleistocene sites has been employed. Important sites that allow the demonstration of stratigraphical relations have been selected, as have sites with fossiliferous sediments that provide evidence for dating the Thames sequence, as well as sites yielding significant Palaeolithic evidence. To these have been added a number of sites that are important for tracing the early evolution of the river. No attempt has been made to grade sites according to their relative significance.
By the very nature of the geological record, it is clear that some sites will represent unique occurrences for which no parallels exist, while others are merely the best available sites in deposits of extensive and widespread interest, for which alternative localities could be substituted at a later date. It is important for those engaged in geological conservation to recognize the difference between these two types of site. On the one hand careful management and maximum protection are required, while on the other hand there is a need to recognize when a designated locality is no longer a key site and has been superseded. The latter calls for a degree of flexibility in the provision of geological sites, so that the coverage can be updated to keep abreast with both advances in the science (from continuing research) and with the creation of new sites by continued quarrying activity.
Accounts of the evolution of the Thames, as evidenced by its terrace sequence, have been required reading for generations of students. Many treatises on the Thames deposits and their fossils have become classics of the scientific literature; the Swanscombe Skull, for example, has been of particular fascination for scientists and lay readers alike. The story of the blocking and diversion of the Thames by an ice sheet some 450,000 years ago is fundamental to an understanding of the shaping of southern Britain. This volume brings together, for the first time, all the themes and debates that have figured in the many attempts to reconstruct the history of this important river.
A general introduction to the Quaternary, aimed at the less specialist reader, but also providing a succinct overview for the earth scientist, is given elsewhere in this series (Campbell and Bowen, 1989).
D.R. Bridgland and W.A. Wimbledon