A Geological Model of the Chalk of East Kent Volume 1 of 2 : Report Integrated Geoscience Surveys (South) Programme Commissioned Report CR/04/092N
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A geological model of the Chalk of East Kent Volume 1 of 2 : Report Integrated Geoscience Surveys (South) Programme Commissioned Report CR/04/092N BRITISH GEOLOGICAL SURVEY COMMISSIONED REPORT CR/04/092N A geological model of the Chalk of East Kent Volume 1 of 2 : Report D T Aldiss, J R Bloomfield, D K Buckley, S K Doran, D J Evans, P M Hopson, K R Royse and M A Woods The National Grid and other Ordnance Survey data are used with the permission of the Controller of Her Majesty’s Stationery Office. Ordnance Survey licence number GD 272191/1999 “This report contains commercially sensitive data from Folkestone Key words and Dover Water Services, Mid Kent Water and Southern Water. Kent; Great Stour; North Downs; Any person or organisation who has a copy of this report should not Chalk; Palaeogene; structure; geological model. make it available to others without written permission from Folkestone and Dover Water Services, Mid Kent Water, Southern Front cover Water and the Environment Agency.” Seaford Chalk in Denne’s Chalk Pit, Canterbury [TR148 566], in 1960. Three courses of flint are Volume 2 of this report comprises an Appendix of geophysical log offset by small faults. Brown suites with hydrogeological interpretations silty sand partly chokes the fissures and has also washed along the flint beds, where it infills irregular cavities. BGS Photograph A09664 Bibliographical reference ALDISS, D T, BLOOMFIELD, J R, BUCKLEY, D K, DORAN, S K, EVANS, D J, HOPSON, P M, ROYSE, K R AND WOODS, M A. 2004. A geological model of the Chalk of East Kent. Volume 1 of 2: Report. British Geological Survey Commissioned Report, CR/04/092. 97pp © NERC 2004 Keyworth, Nottingham British Geological Survey 2004 BRITISH GEOLOGICAL SURVEY The full range of Survey publications is available from the BGS Keyworth, Nottingham NG12 5GG Sales Desks at Nottingham and Edinburgh; see contact details 0115-936 3241 Fax 0115-936 3488 below or shop online at www.thebgs.co.uk e-mail: [email protected] The London Information Office maintains a reference collection www.bgs.ac.uk of BGS publications including maps for consultation. Shop online at: www.thebgs.co.uk The Survey publishes an annual catalogue of its maps and other publications; this catalogue is available from any of the BGS Sales Murchison House, West Mains Road, Edinburgh EH9 3LA Desks. 0131-667 1000 Fax 0131-668 2683 The British Geological Survey carries out the geological survey of e-mail: [email protected] Great Britain and Northern Ireland (the latter as an agency service for the government of Northern Ireland), and of the London Information Office at the Natural History Museum surrounding continental shelf, as well as its basic research (Earth Galleries), Exhibition Road, South Kensington, London projects. It also undertakes programmes of British technical aid in SW7 2DE geology in developing countries as arranged by the Department for International Development and other agencies. 020-7589 4090 Fax 020-7584 8270 020-7942 5344/45 email: [email protected] The British Geological Survey is a component body of the Natural Environment Research Council. Forde House, Park Five Business Centre, Harrier Way, Sowton, Exeter, Devon EX2 7HU 01392-445271 Fax 01392-445371 Geological Survey of Northern Ireland, 20 College Gardens, Belfast BT9 6BS 028-9066 6595 Fax 028-9066 2835 Maclean Building, Crowmarsh Gifford, Wallingford, Oxfordshire OX10 8BB 01491-838800 Fax 01491-692345 Parent Body Natural Environment Research Council, Polaris House, North Star Avenue, Swindon, Wiltshire SN2 1EU 01793-411500 Fax 01793-411501 www.nerc.ac.uk CR/04/092: Volume 1; Version 1.0 Confidential Last modified: 2004/05/24 17:21 Acknowledgements This report was produced as part of a project funded by the Environment Agency, and supported by Mid-Kent Water, Southern Water and (on behalf of Folkestone and Dover Water Services) Veolia Water. The project was also assisted by the provision of water borehole records by these four organisations, and the authors would like to thank in particular Michael Cheetham (Environment Agency), Lee Dance (Mid-Kent), Trevor Muten and Jon Ticehurst (Southern Water), and Lucy Lytton and Jessica Randle (Veolia Water). “This report contains commercially sensitive data from Folkestone and Dover Water Services, Mid Kent Water and Southern Water. Any person or organisation who has a copy of this report should not make it available to others without written permission from Folkestone and Dover Water Services, Mid Kent Water, Southern Water and the Environment Agency.” i CR/04/092: Volume 1; Version 1.0 Confidential Last modified: 2004/05/24 17:21 Contents Acknowledgements.........................................................................................................................i Contents..........................................................................................................................................ii Summary.......................................................................................................................................vi 1 Introduction............................................................................................................................ 1 2 Data sources and data acquisition ........................................................................................ 2 2.1 1:50 000 scale geological maps and other publications ................................................. 2 2.2 Field slips and standards................................................................................................. 3 2.3 Borehole Logs (Lithological) ......................................................................................... 3 2.4 Borehole Logs (Geophysical)......................................................................................... 4 2.5 Seismic data.................................................................................................................... 4 2.6 Biostratigraphical data.................................................................................................... 4 2.7 Topographic maps and digital terrain models ................................................................ 5 3 The Chalk Group ................................................................................................................... 5 3.1 Introduction .................................................................................................................... 5 3.2 Grey Chalk Subgroup ..................................................................................................... 6 3.2.1 West Melbury Marly Chalk Formation.......................................................................6 3.2.2 Zig Zag Chalk Formation............................................................................................7 3.3 White Chalk Subgroup ................................................................................................... 8 3.3.1 Holywell Nodular Chalk Formation............................................................................9 3.3.2 New Pit Chalk Formation..........................................................................................10 3.3.3 Lewes Nodular Chalk Formation ..............................................................................11 3.3.4 Seaford Chalk Formation ..........................................................................................13 3.3.5 Margate Chalk Member (Newhaven Chalk Formation) ...........................................14 4 The Palaeogene..................................................................................................................... 15 4.1 Thanet Sand Formation ................................................................................................ 15 4.2 Upnor Formation (Lambeth Group) ............................................................................. 15 4.3 Harwich Formation (Thames Group) ........................................................................... 16 4.4 London Clay Formation (Thames Group).................................................................... 16 5 Superficial Deposits.............................................................................................................. 16 6 Geological Modelling ........................................................................................................... 17 6.1 The modelling process.................................................................................................. 17 6.2 Mapping the new Chalk lithostratigraphy .................................................................... 18 6.2.1 General procedure.....................................................................................................18 6.2.2 Base of West Melbury Marly Chalk Formation........................................................19 ii CR/04/092: Volume 1; Version 1.0 Confidential Last modified: 2004/05/24 17:21 6.2.3 Base of Zig Zag Chalk Formation.............................................................................20 6.2.4 Base of Holywell Nodular Chalk Formation.............................................................20 6.2.5 Base of New Pit Chalk Formation.............................................................................21 6.2.6 Base of Lewes Nodular Chalk Formation.................................................................22 6.2.7 Base of Seaford Chalk Formation .............................................................................22 6.2.8 Base of Margate Chalk Member