A stratigraphical framework for the Lower Cretaceous of England Research Report RR/08/03 HOW TO NAVIGATE THIS DOCUMENT Bookmarks The main elements of the table of contents are book- marked enabling direct links to be followed to the principal section headings and sub- headings, figures, plates and tables irrespective of which part of the document the user is viewing. In addition, the report contains links: from the principal section and subsection headings back to the contents page, from each reference to a figure, plate or table directly to the corresponding figure, plate or table, from each figure, plate or table caption to the first place that figure, plate or table is mentioned in the text and from each page number back to the contents page. RETURN TO CONTENTS PAGE BRITISH GEOLOGICAL SURVEY RESEARCH REPORT RR/08/03 The National Grid and other Ordnance Survey data are used with the permission of the Controller of Her Majesty’s Stationery Office. Licence No: 100017897/2008. Keywords A stratigraphical framework for the United Kingdom, England, Yorkshire, Lincolnshire, East Anglia, Southern England. Lower Cretaceous of England Geology, Stratigraphy, Lower Cretaceous, Early Cretaceous. P M Hopson, I P Wilkinson and M A Woods Front cover Ferruginous Sand Formation exposed above a significant landslide founded in the Atherfield Clay Formation, Red Cliff, Sandown Bay, Isle of Wight (P683788). Bibliographical reference HOPSON , P M, WILKINSON , I P, and WOODS , M A. 2008. A stratigraphical framework for the Lower Cretaceous of England. British Geological Survey. British Geological Survey Research Report, RR/08/03. ISBN 0 85272 623 5 Copyright in materials derived from the British Geological Survey’s work is owned by the Natural Environment Research Council (NERC) and/or the authority that commissioned the work. You may not copy or adapt this publication without first obtaining permission. 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Stratigraphy Commission and their reviewers for comment Peter Rawson formerly of University College London and suggestions incorporated in this document. is thanked for his views and comments of various early drafts of this document. John Cope of the National Museum Peter Hopson, Ian Wilkinson and Mark Woods. iii British Geological Survey Research Report RR/08/04 Contents Summary vi 5.16 Wealden Group 56 5.17 Lower Greensand Group 56 1 Introduction 1 5.18 Selborne Group 61 1.1 The base of the Cretaceous in onshore basins 1 1.2 Offshore correlation 2 6 Cleveland/Yorkshire Basin 62 1.3 Other considerations 2 6.1 Speeton Clay Formation 62 2 Palaeogeography and Basin Definition 3 6.2 Hunstanton Formation 64 3 Wessex Basin (Wealden Basin) 5 Overview 67 3.1 Purbeck Basin 5 References 69 3.2 Wealden Group 8 3.3 Lower Greensand Group 14 3.4 Selborne Group 22 FIGURES 4 Wessex Basin (Vectian Basin) 25 4.1 Purbeck Group 25 1 The palaeogeography at various times throughout the 4.2 Wealden Group 28 Early Cretaceous 4 4.3 Lower Greensand Group 31 2 The relationship of the lithologies within the East 4.4 Selborne Group 35 Midlands Shelf area 42 5 East Midlands Shelf (including ‘Bedfordshire Straits’) 41 5.1 Sandringham Sands Formation 45 TABLES 5.2 Dersingham Formation 48 5.3 Roach Formation 49 1 The relationship between the Boreal and Tethyan 5.4 Carstone Formation 49 stages 1 5.5 Selborne Group 50 2 Lithostratigraphical scheme for the Wealden 5.6 Spilsby Sandstone Formation 50 Basin 6 5.7 Claxby Ironstone Formation 51 3 Lithostratigraphical scheme for the Vectian 5.8 Tealby Formation 52 Basin 26 5.9 Roach Formation 53 4 Lithostratigraphical scheme for the East Midlands 5.10 Skegness Clay Formation 53 Shelf 43 5.11 Sutterby Marl Formation 54 5 Deposits of the ‘Bedfordshire Straits’ and related 5.12 Carstone Formation 54 areas 44 5.13 Hunstanton Formation 55 6 Lithostratigraphical scheme for the Cleveland/ 5.14 Sandringham Sands Formation 55 Yorkshire Basin 63 5.15 Purbeck Group 55 7 Overview of the Lower Cretaceous 68 v British Geological Survey Research Report RR/08/03 Summary This report describes the Lower Cretaceous strata of Clear terminology and relationships exist over the East England appearing on maps and major texts from the British Midlands Shelf and needs little adjustment at formation and Geological Survey and seeks to clarify the lithostratigraphical member level. terminology, relationships and distribution of the various In the marginal area of the Wessex Basin from north units. The report considers the successions in England Wiltshire to Bedfordshire, a number of new terms (at formation within defined sedimentological basins: the Wessex Basin level) are proposed for the thin isolated units encountered; more (including the Wealden Basin and Vectian Basin — sub- research may clarify their relationships and require a further basins of some authors), the East Midlands Shelf covering reappraisal of these terms used herein and in the literature. Lincolnshire, South Yorkshire and Norfolk (strictly not a The Whitchurch Sand Formation is now considered to be of basin in its own right) and the Cleveland–Yorkshire Basins Valanginian age and includes those beds formerly described are described. The marginal basin successions of north as the Shotover Ironsands. The isolated outcrops attributed to Wiltshire to Bedfordshire (the ‘Bedfordshire Straits’) are the Lower Greensand Group are all given formation status. included in the descriptions for the East Midlands Shelf The terms ‘Calne Sand’ and ‘Seend Ironstone (Ironsand of area. some authors)’ are firmly emplaced within the literature The base of the Lower Cretaceous is taken at the base and are retained. The Faringdon Sand Formation has been of the Berriasian Stage that occurs in the lower part of the introduced and includes the Faringdon Sponge Gravels Purbeck Group of the English succession. Consequently the Member, Baulking Sand Member and Fernham Sand Member. Lulworth Formation is described herein as it is principally Terms such as the ‘Red Sands’ of Uffington, ‘Junction Beds’ of Berriasian age. The Haddenham Formation, a new term and ‘Transition Beds’ have been abandoned and the unnamed proposed herein, covers those beds formerly called the outcrops around Clifton Hampden incorporated into the newly Purbeck Limestone Formation within the marginal basin defined Baulking Sand Member, Fernham Sand Member and areas in Wiltshire, Oxfordshire and Buckinghamshire. Munday’s Hill Phosphatic Sandstone Formation; the latter These are probably of latest Jurassic, Portlandian Stage, but including the Shenley Limestone Member. show strong lithological affinities to the restricted salinity The term ‘Selborne Group’ is formally introduced environments of the Purbeck Group rather than the open to include the Gault Formation and Upper Greensand marine conditions of the Portland Group. The Purbeck Formation.