{"id":7535,"date":"2025-11-12T13:33:26","date_gmt":"2025-11-12T13:33:26","guid":{"rendered":"https:\/\/www.bgs.ac.uk\/groundwater\/?page_id=7535"},"modified":"2025-11-27T10:16:14","modified_gmt":"2025-11-27T10:16:14","slug":"chalk-kellaways-oxford-clay-and-osgodby-formations-separation-map","status":"publish","type":"page","link":"https:\/\/www.bgs.ac.uk\/groundwater\/energy\/shale-gas-and-groundwater\/aquifers-and-shales\/aquifer-shale-separation-maps\/chalk-kellaways-oxford-clay-and-osgodby-formations-separation-map\/","title":{"rendered":"Chalk\/Kellaways, Oxford Clay and Osgodby formations separation map"},"content":{"rendered":"\t\t\t<section class=\"hero-section hero-section-with-social\">\n\t\t\t\t\t\t\t\t<div class=\"hero-info-wrap\">\n\t\t\t\t\t<div class=\"container\">\n\t\t\t\t\t\t<div class=\"row\">\n\t\t\t\t\t\t\t<div class=\"col-12\">\n\t\t\t\t\t\t\t\t<div class=\"hero-info\">\n\t\t\t\t\t\t\t\t\t<h1>Chalk\/Kellaways, Oxford Clay and Osgodby formations separation map<\/h1>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\n\t\t\t<div class=\"social-wrap social-wrap-inline-them\">\n\t\t\t\t<div class=\"sea-background-f\">\n\t\t\t\t\t<span>Share this article<\/span><a target=\"_blank\"  href=\"https:\/\/www.facebook.com\/sharer\/sharer.php?u=https:\/\/www.bgs.ac.uk\/groundwater\/energy\/shale-gas-and-groundwater\/aquifers-and-shales\/aquifer-shale-separation-maps\/chalk-kellaways-oxford-clay-and-osgodby-formations-separation-map\/\"><span class=\"icon-facebook\"><span class=\"hidden\">Facebook<\/span><\/span><\/a><a target=\"_blank\"  href=\"https:\/\/twitter.com\/intent\/tweet?text=Chalk\/Kellaways,%20Oxford%20Clay%20and%20Osgodby%20formations%20separation%20map&#038;url=https:\/\/www.bgs.ac.uk\/groundwater\/energy\/shale-gas-and-groundwater\/aquifers-and-shales\/aquifer-shale-separation-maps\/chalk-kellaways-oxford-clay-and-osgodby-formations-separation-map\/\"><span class=\"icon-twitter\"><span class=\"hidden\">Twitter<\/span><\/span><\/a><a   onclick=\"javascript:void( (function() {var e=document.createElement('script' );e.setAttribute('type','text\/javascript' );e.setAttribute('charset','UTF-8' );e.setAttribute('src','\/\/assets.pinterest.com\/js\/pinmarklet.js?r='+Math.random()*99999999);document.body.appendChild(e)})());\"  href=\"javascript:void(0);\"><span class=\"icon-pinterest\"><span class=\"hidden\">Pinterest<\/span><\/span><\/a><a target=\"_blank\"  href=\"https:\/\/wa.me?text=https:\/\/www.bgs.ac.uk\/groundwater\/energy\/shale-gas-and-groundwater\/aquifers-and-shales\/aquifer-shale-separation-maps\/chalk-kellaways-oxford-clay-and-osgodby-formations-separation-map\/\"><span class=\"icon-whatsapp\"><span class=\"hidden\">WhatsApp<\/span><\/span><\/a><a   href=\"mailto:?subject=Chalk\/Kellaways,%20Oxford%20Clay%20and%20Osgodby%20formations%20separation%20map&#038;body=%20(https:\/\/www.bgs.ac.uk\/groundwater\/energy\/shale-gas-and-groundwater\/aquifers-and-shales\/aquifer-shale-separation-maps\/chalk-kellaways-oxford-clay-and-osgodby-formations-separation-map\/)\"><span class=\"icon-mail\"><span class=\"hidden\">Email<\/span><\/span><\/a><a href=\"#\" data-copy=\"https:\/\/www.bgs.ac.uk\/groundwater\/energy\/shale-gas-and-groundwater\/aquifers-and-shales\/aquifer-shale-separation-maps\/chalk-kellaways-oxford-clay-and-osgodby-formations-separation-map\/\" class=\"copy-url-on-click\"><span class=\"icon-link\"><span class=\"hidden\">Copy Link<\/span><\/span><\/a><\/div><\/div>\t\t\t\t\t\t\t<\/section>\n\t\t\t\n\n\n<section class=\"wp-block-bgs-blocks-content-container content-section\"><div class=\"container\"><div class=\"row\"><div class=\"col-12\">\t\t\t<div id=\"wysiwyg-1623-block_030ed613233a56b6b61fc0ce5d80edaf\" class=\"  \" >\n\t\t\t<h2>Chalk\/Kellaways, Oxford Clay and Osgodby formations separation map<\/h2>\n<div class=\"col-12 responsive-table\"><table>\n<tbody>\n<tr>\n<td>Area where aquifer and shale\/clay are present<\/td>\n<td>\n<ul>\n<li>North Yorkshire<\/li>\n<li>Around the Humber and Lincolnshire<\/li>\n<li>Norfolk and Cambridgeshire<\/li>\n<li>Bedfordshire to Dorset<\/li>\n<li>Around the Weald<\/li>\n<li>Note that, for the purposes of drafting this separation map the maximum depth of the Chalk aquifer is taken to be 400 mbgl based on the recommendations in the <a href=\"http:\/\/www.wfduk.org\/resources%20\/defining-and-reporting-groundwater-bodies\" target=\"_blank\" rel=\"noopener\">UK TAG report<\/a>. More information about this can be found in the\u00a0<a href=\"https:\/\/www.bgs.ac.uk\/groundwater\/energy\/shale-gas-and-groundwater\/aquifers-and-shales\/methods\/\">methods<\/a> section<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n<tr>\n<td>Thickness of intervening strata<\/td>\n<td>\n<ul>\n<li>North Yorkshire: 150 to 300 m<\/li>\n<li>Around the Humber and Lincolnshire: up to about 450 m, generally increasing south-eastwards<\/li>\n<li>Norfolk and Cambridgeshire: 30 to 250 m decreasing south and eastwards<\/li>\n<li>Bedfordshire to Dorset; around the Weald: 30 to 1500 m; thickest adjacent to the Weald and south-eastwards on the Isle of Wight<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n<tr>\n<td>Lithology of intervening strata<\/td>\n<td><!-- wp:list --><\/p>\n<ul class=\"wp-block-list\">\n<li style=\"list-style-type: none\">\n<ul class=\"wp-block-list\"><!-- wp:list-item --><\/ul>\n<\/li>\n<\/ul>\n<ul>\n<li>North Yorkshire: permeable <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=CR\">Corallian Group<\/a> (principal aquifer); low permeability <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=KC\">Kimmeridge Clay Formation<\/a> (clay); low permeablitiy <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=AMC\">Ampthill Clay Formation<\/a> (clay); low permeability <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=SPC\">Speeton Clay Formation<\/a>; mixed permeability Lower Cretaceous sedimentary rocks<\/li>\n<li>Around the Humber and Lincolnshire: low permeability <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=KC\">Kimmeridge Clay Formation<\/a> (clay); <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=AMC\">Ampthill Clay Formation<\/a> (clay); permeable <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=SYS\">Spilsby Sandstone Formation<\/a> (principal aquifer); permeable <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=W\">Wealden Group<\/a> sandstone; low permeability <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=W\">Wealden Group<\/a> limestone; permeable <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=LGS\">Lower Greensand Group<\/a> (principal aquifer)<\/li>\n<li>Norfolk and Cambridgeshire: low permeability <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=KC\">Kimmeridge Clay Formation<\/a> (clay); <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=AMC\">Ampthill Clay Formation<\/a> (clay); permeable <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=W\">Wealden Group<\/a> sandstone; permeable <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=LGS\">Lower Greensand Group<\/a> (principal aquifer); mixed permeability <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=GLT\">Gault Formtion<\/a> (clay); <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=UGS\">Upper Greensand Formation<\/a><\/li>\n<li>Bedfordshire to Dorset and around the Weald: permeable <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=CR\">Corallian Group<\/a> (principal aquifer); low permeability <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=WWB\">West Walton Formation<\/a> (clay); low permeability <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=KC\">Kimmeridge Clay Formation<\/a> (clay); low permeability <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=AMC\">Ampthill Clay Formation<\/a> (clay); permeable <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=PL\">Portland Group<\/a>; permeable <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=PB\">Purbeck Group<\/a>; low permeability <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=W\">Wealden Group<\/a>; <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=LGS\">Lower Greensand Group<\/a> (principal aquifer); mixed permeability <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=UGS\">Upper Greensand Formation<\/a>; <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=GLT\">Gault Formation<\/a> (clay)<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n<tr>\n<td>Other major aquifers in the area<\/td>\n<td>\n<ul>\n<li>North Yorkshire: Triassic sandstone; Magnesian limestone (both below)<\/li>\n<li>Around the Humber and Lincolnshire: Oolites; Triassic sandstone; Magnesian limestone; Carboniferous limestone (all below)<\/li>\n<li>Norfolk and Cambridgeshire: Crag; Oolites; Permian sandstone; Triassic sandstone; Carboniferous limestone (all below)<\/li>\n<li>Bedfordshire to Dorset; around the Weald: Oolites; Permian sandstone; Triassic sandstone; Carboniferous limestone (all below)<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n<tr>\n<td>Other shales or clays in the area<\/td>\n<td>\n<ul>\n<li>North Yorkshire: <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=LI\">Lias Group<\/a>; <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=BOHI\">Bowland High Group<\/a>; <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=CRAV\">Craven Group<\/a> (all below)<\/li>\n<li>Around the Humber and Lincolnshire; Norfolk to Cambridgeshire; Bedfordshire to Dorset; around the Weald: <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=LI\">Lias Group<\/a> (below)<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n<tr>\n<td>Aquifer map<\/td>\n<td>\n<ul>\n<li><a href=\"https:\/\/www.bgs.ac.uk\/groundwater\/energy\/shale-gas-and-groundwater\/aquifers-and-shales\/aquifer-occurrence-maps#chalk\">Chalk<\/a> principal aquifer<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n<tr>\n<td>Shale\/clay map<\/td>\n<td>\n<ul>\n<li><a href=\"https:\/\/www.bgs.ac.uk\/groundwater\/energy\/shale-gas-and-groundwater\/aquifers-and-shales\/shale-and-clay-occurrence-maps#kocofmns\">Kellaways, Oxford Clay and Osgodby formations<\/a> shale\/clay unit<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<p>&nbsp;<\/p>\n\t\t\t<\/div>\n\t\t\t\n\n<figure  class=\"img-wrap\"><a href=\"https:\/\/www.bgs.ac.uk\/groundwater\/wp-content\/uploads\/sites\/4\/2025\/11\/ch-koo.png\" data-toggle=\"lightbox\" data-footer=\"&lt;p&gt;Chalk\/Kellaways, Oxford Clay and Osgodby formations separation map. BGS \u00a9 UKRI.&lt;\/p&gt;\n\" data-gallery=\"gallery_93860\"><img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/groundwater\/wp-content\/uploads\/sites\/4\/2025\/11\/ch-koo.png\" class=\"lazy-blur\" alt=\"ch-koo\" data-src=\"https:\/\/www.bgs.ac.uk\/groundwater\/wp-content\/uploads\/sites\/4\/2025\/11\/ch-koo.png\" \/><\/a><figcaption class=\"caption sm-line\">\n\t\t\t\t\t<div class=\"caption-icon\">\n\t\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/groundwater\/wp-content\/themes\/bgs\/img\/info-caption.svg\" alt=\"Information icon\">\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<div class=\"caption-text\"><p>Chalk\/Kellaways, Oxford Clay and Osgodby formations separation map. BGS \u00a9 UKRI.<\/p>\n<\/div>\n\t\t\t\t\t<div class=\"expand-box expand-box-top\"><a href=\"https:\/\/www.bgs.ac.uk\/groundwater\/wp-content\/uploads\/sites\/4\/2025\/11\/ch-koo.png\" ><img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/groundwater\/wp-content\/themes\/bgs\/img\/expand.svg\" alt=\"Expand icon\"><\/a><\/div>\n\t\t\t\t<\/figcaption><\/figure><\/div><\/div><\/div><\/section>\n\n\n<section class=\"cta-section  sea-background-e \">\n\t<div class=\"container\">\n\t\t<div class=\"row md-row\">\n\t\t\t<div class=\"col-12\">\n\t\t\t\t<h2>Need more information?<\/h2>\t\t\t\t\t\t\t\t<div class=\"btn-wrap\"><a href=\"https:\/\/www.bgs.ac.uk\/contact-the-person\/?employee=smedley-pauline\"  class=\"button primary-background   \">Contact Pauline Smedley<\/a><\/div>\t\t\t<\/div>\n\t\t<\/div>\n\t<\/div>\n<\/section>\n\t\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":7,"featured_media":0,"parent":2639,"menu_order":1,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"_relevanssi_hide_post":"","_relevanssi_hide_content":"","_relevanssi_pin_for_all":"","_relevanssi_pin_keywords":"","_relevanssi_unpin_keywords":"","_relevanssi_related_keywords":"","_relevanssi_related_include_ids":"","_relevanssi_related_exclude_ids":"","_relevanssi_related_no_append":"","_relevanssi_related_not_related":"","_relevanssi_related_posts":"1","_relevanssi_noindex_reason":"","footnotes":""},"tags":[],"class_list":["post-7535","page","type-page","status-publish","hentry"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.2 - 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