CINXE.COM
EMD Column Archives
<!--NumRecords: 87--><!--PageCount: 8--><!--FILENAME: e:\webs\DNN_AAPG_Production_9_11_3\Portals\0\PackFlashItemImages\WebReady\common-wording-vs-historical-terminology-2012-08aug-hero.jpg--><!--IssueArticleID: 3390--><!--IssueTitle: August 2012--><!--FILENAME: e:\webs\DNN_AAPG_Production_9_11_3\Portals\0\PackFlashItemImages\WebReady\EXPLORER-cover-2012-05may-thumb.jpg--><!--IssueArticleID: 3269--><!--IssueTitle: May 2012--><!--FILENAME: e:\webs\DNN_AAPG_Production_9_11_3\Portals\0\PackFlashItemImages\WebReady\EXPLORER-cover-2012-02feb-thumb.jpg--><!--IssueArticleID: 3532--><!--IssueTitle: February 2012--><!--FILENAME: e:\webs\DNN_AAPG_Production_9_11_3\Portals\0\PackFlashItemImages\WebReady\EXPLORER-cover-2011-11nov-thumb.jpg--><!--IssueArticleID: 3065--><!--IssueTitle: November 2011--><!--FILENAME: e:\webs\DNN_AAPG_Production_9_11_3\Portals\0\PackFlashItemImages\WebReady\EXPLORER-cover-2011-08aug-thumb.jpg--><!--IssueArticleID: 3059--><!--IssueTitle: August 2011--><!--FILENAME: e:\webs\DNN_AAPG_Production_9_11_3\Portals\0\PackFlashItemImages\WebReady\adapting-to-lower-cost-natural-gas-fig1.jpg--><!--IssueArticleID: 3053--><!--IssueTitle: May 2011--><!--FILENAME: e:\webs\DNN_AAPG_Production_9_11_3\Portals\0\PackFlashItemImages\WebReady\EXPLORER-cover-2011-02feb-thumb.jpg--><!--IssueArticleID: 2586--><!--IssueTitle: February 2011--><!--FILENAME: e:\webs\DNN_AAPG_Production_9_11_3\Portals\0\PackFlashItemImages\WebReady\tapping-into-geothermal-a-hot-idea-fig1.gif--><!--IssueArticleID: 3149--><!--IssueTitle: November 2010--><!--FILENAME: e:\webs\DNN_AAPG_Production_9_11_3\Portals\0\PackFlashItemImages\WebReady\oil-shales-making-cautious-progress-fig1.jpg--><!--IssueArticleID: 3034--><!--IssueTitle: August 2010--><!--FILENAME: e:\webs\DNN_AAPG_Production_9_11_3\Portals\0\PackFlashItemImages\WebReady\hydrates-face-key-test-on-north-slope-emd-johnson-mdcjpg.jpg--><!--IssueArticleID: 2990--><!--IssueTitle: May 2010--><!--FILENAME: e:\webs\DNN_AAPG_Production_9_11_3\Portals\0\PackFlashItemImages\WebReady\EXPLORER-cover-2010-02feb-thumb.jpg--><!--IssueArticleID: 2922--><!--IssueTitle: February 2010--><!--FILENAME: e:\webs\DNN_AAPG_Production_9_11_3\Portals\0\PackFlashItemImages\WebReady\EXPLORER-cover-2009-11nov-thumb.jpg--><!--IssueArticleID: 1805--><!--IssueTitle: November 2009--><!DOCTYPE html> <html lang="en-US"> <head id="Head"><!-- Google Tag Manager --><script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K4KHX626');</script><!-- End Google Tag Manager --><meta content="text/html; charset=UTF-8" http-equiv="Content-Type" /><title> EMD Column Archives </title><meta id="MetaDescription" name="description" content="AAPG's Energy Minerals Division (EMD) is dedicated to addressing the special concerns of energy resource geologists working with energy resources other than conventional oil and gas, providing a vehicle to keep abreast of the latest developments in the geosciences and associated technology. EMD works in concert with the Division of Environmental Geosciences to serve energy resource and environmental geologists." /><link href="/Resources/Shared/stylesheets/dnndefault/7.0.0/default.css?cdv=1092" type="text/css" rel="stylesheet"/><link href="/Resources/Search/SearchSkinObjectPreview.css?cdv=1092" type="text/css" rel="stylesheet"/><link href="/Portals/_default/Skins/Explorer/skin.css?cdv=1092" type="text/css" rel="stylesheet"/><link href="/Portals/20/portal.css?cdv=1092" type="text/css" rel="stylesheet"/><link href="/Portals/_default/Skins/Explorer/css/font-awesome.min.css?cdv=1092" type="text/css" rel="stylesheet"/><link href="/Portals/_default/Skins/Explorer/iba.css?cdv=1092" type="text/css" rel="stylesheet"/><script src="/Resources/libraries/jQuery/03_05_01/jquery.js?cdv=1092" type="text/javascript"></script><script src="/Resources/libraries/jQuery-Migrate/03_04_00/jquery-migrate.js?cdv=1092" type="text/javascript"></script><link id="DNNGo_StyleSwitch_CSS_jquery.fancybox.css" rel="stylesheet" type="text/css" href="/DesktopModules/DNNGo_SkinPlugin/Resource/css/jquery.fancybox.css?cdv=xxx.1814" /><!--[if LT IE 9]><link id="IE6Minus" rel="stylesheet" type="text/css" href="/Portals/_default/Skins/Explorer/ie.css" /><![endif]--><meta name="robots" content="noindex,noarchive,follow"> <link rel="canonical" href="https://explorer.aapg.org/archives/emd-column/currentpage/5" id="AAPGTab-4605"> <link href="https://explorer.aapg.org/Portals/_default/Skins/Explorer/explorer-ads.css" type="text/css" rel="stylesheet"> <script src="https://explorer.aapg.org/js/custom-js/jquery.dfp.min.js" type="text/javascript"></script> <script src="https://explorer.aapg.org/js/custom-js/explorer-ads.js" type="text/javascript"></script><link rel='SHORTCUT ICON' href='/Portals/20/explorer-favicon.ico?ver=HiLByN5hD80A-KkTmQmwFQ%3d%3d' type='image/x-icon' /><meta name="google-site-verification" content="9W9qvsC4ITEdg-Osm6qvdjpK7hvc_dNv6jncJ2JXkew" /><meta name="viewport" content="width=device-width,height=device-height, minimum-scale=1.0, maximum-scale=1.0" /><meta http-equiv="X-UA-Compatible" content="IE=edge" /></head> <body id="Body"> <!-- Google Tag Manager (noscript) --><noscript><iframe src=https://www.googletagmanager.com/ns.html?id=GTM-K4KHX626 height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript><!-- End Google Tag Manager (noscript) --> <form method="post" action="/archives/emd-column/currentpage/5" id="Form" enctype="multipart/form-data"> <div class="aspNetHidden"> <input type="hidden" name="__EVENTTARGET" id="__EVENTTARGET" value="" /> <input type="hidden" name="__EVENTARGUMENT" id="__EVENTARGUMENT" value="" /> <input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="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" /> </div> <script type="text/javascript"> //<![CDATA[ var theForm = document.forms['Form']; if (!theForm) { theForm = document.Form; } function __doPostBack(eventTarget, eventArgument) { if (!theForm.onsubmit || (theForm.onsubmit() != false)) { theForm.__EVENTTARGET.value = eventTarget; theForm.__EVENTARGUMENT.value = eventArgument; theForm.submit(); } } //]]> </script> <script src="/WebResource.axd?d=pynGkmcFUV0SzJJIonnsOWligjRH68pVwIBEXTiRJ2zV4CK5i2znpjlNqaM1&t=638568424745067788" type="text/javascript"></script> <script src="/DesktopModules/DNNGo_SkinPlugin/Resource/js/jquery.fancybox.r.js?cdv=xxx.1814" type="text/javascript"></script> <script src="/ScriptResource.axd?d=NJmAwtEo3IrB17bAIo7l5cSEMbNxIgkgBAmNL0KCpseGm73kYRB_RAoh19pQ3dj8dha4j6DlTTtGStIznboL99mnla6ee6pbu-NoTKtHEfsb-GFEqzduVj5fjGW19dkWVPQOSA2&t=ffffffffc820c398" type="text/javascript"></script> <script src="/ScriptResource.axd?d=dwY9oWetJoKiET5hsTdUgOCxax8jT0bYaoFTXyOQkg-_1nfHKY-4Wsung6A5ChGwQKxnzsQ5veXp0icKsvg-P6ZOAWhY8x8iFQU6HITezyfLWdyTfttIJCo69i0i7AKVduUyEEPM8eltZ8Wc0&t=ffffffffc820c398" type="text/javascript"></script> <div class="aspNetHidden"> <input type="hidden" name="__VIEWSTATEGENERATOR" id="__VIEWSTATEGENERATOR" value="CA0B0334" /> <input type="hidden" name="__VIEWSTATEENCRYPTED" id="__VIEWSTATEENCRYPTED" value="" /> <input type="hidden" name="__EVENTVALIDATION" id="__EVENTVALIDATION" value="dUndePLRIFK4iBLYhrJyUk1hoVJMOpLrBnDwinsrMUZOSuuIt6JXNBYDTkrNJwn6+ZalrdPvehcUsRe5ivAOVSuZa90Wpiz+ETCvQnNpA4v8dY99qFAwc9YRKAFZi2MobQPANj2nUplEmD+7R9YN6LBuW1oKHlRHeG86mlPaOu4IsJ7cyTDi6GrMkDg+gEOW7o7zpA==" /> </div><script src="/js/dnn.js?cdv=1092" type="text/javascript"></script><script src="/js/custom-js/slimmage.min.js?cdv=1092" type="text/javascript"></script><script src="/js/dnncore.js?cdv=1092" type="text/javascript"></script><script src="/Resources/Search/SearchSkinObjectPreview.js?cdv=1092" type="text/javascript"></script><script src="/js/dnn.servicesframework.js?cdv=1092" type="text/javascript"></script> <script type="text/javascript"> //<![CDATA[ Sys.WebForms.PageRequestManager._initialize('ScriptManager', 'Form', [], [], [], 180, ''); //]]> </script> <div class="SkinPlugin_icon"> </div> <script type="text/javascript"> jQuery(".SkinPlugin_icon a#dnn_SKINPLUGIN1_ctl00_hlLink").attr('rel', 'gallery').fancybox_r({ type: 'iframe', autoSize: false, modal: true, width: 900,height:600 }); function CloseFancybox() { jQuery.fancybox_r.close(); } </script> <!--[if lt IE 9]> <script src="https://html5shim.googlecode.com/svn/trunk/html5.js"></script> <![endif]--> <!-- <link href="https://www.aapg.org/Portals/_default/Skins/ACE2015new/Skin.css" type="text/css" rel="stylesheet"/> --> <link href="https://www.aapg.org/Portals/_default/Skins/Explorer/ACE2015HomePage.css" type="text/css" rel="stylesheet"/> <link href="https://www.aapg.org/Portals/_default/Skins/Explorer/aapg.css" type="text/css" rel="stylesheet"/> <!--<link href="https://www.aapg.org/js/custom-js/obfusc8or.css" type="text/css" rel="stylesheet"/> <script src="https://www.aapg.org/js/custom-js/obfusc8or.js" type="text/javascript"></script> --> <!--CDF(Css|/Portals/_default/Skins/Explorer/css/font-awesome.min.css?cdv=1092|DnnPageHeaderProvider|100)--> <!--CDF(Css|/Portals/_default/Skins/Explorer/iba.css?cdv=1092|DnnPageHeaderProvider|100)--> <style> #dnngo_megamenu0c0775403a { display: none; } </style> <noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-KHX35B" height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript> <div class="body_bg"> <div id="dnn_wrapper"> <div class="navigation navigation_mobile visible-xs visible-sm visible-md"> <div class="searchBox2 " id="search2" style="display:none;"> <span id="dnn_dnnSEARCH5_ClassicSearch"> <span class="searchInputContainer" data-moreresults="See More Results" data-noresult="No Results Found"> <input name="dnn$dnnSEARCH5$txtSearch" type="text" maxlength="255" size="20" id="dnn_dnnSEARCH5_txtSearch" class="NormalTextBox" aria-label="Search" autocomplete="off" placeholder="Search..." /> <a class="dnnSearchBoxClearText" title="Clear search text"></a> </span> <a id="dnn_dnnSEARCH5_cmdSearch" class="search" href="javascript:__doPostBack('dnn$dnnSEARCH5$cmdSearch','')">GO</a> </span> <script type="text/javascript"> $(function() { if (typeof dnn != "undefined" && typeof dnn.searchSkinObject != "undefined") { var searchSkinObject = new dnn.searchSkinObject({ delayTriggerAutoSearch : 400, minCharRequiredTriggerAutoSearch : 2, searchType: 'S', enableWildSearch: true, cultureCode: 'en-US', portalId: -1 } ); searchSkinObject.init(); // attach classic search var siteBtn = $('#dnn_dnnSEARCH5_SiteRadioButton'); var webBtn = $('#dnn_dnnSEARCH5_WebRadioButton'); var clickHandler = function() { if (siteBtn.is(':checked')) searchSkinObject.settings.searchType = 'S'; else searchSkinObject.settings.searchType = 'W'; }; siteBtn.on('change', clickHandler); webBtn.on('change', clickHandler); } }); </script> </div> <div id="mobile_menu" > <div class="menu_main"> <div id="multi_menu9be45a2b71" class="multi_menu"> <ul id="gomenu9be45a2b71" class="dropdown "><li class="current Item-1 dir"><a href="https://explorer.aapg.org/archives" class="menuitem " title="Archives" ><span class='menu_arrow arrow_closed'>-</span><span>Archives</span></a><ul><li class=" SunItem-1 "><a href="https://explorer.aapg.org/archives" title="Issue Archives" ><span>Issue Archives</span></a></li><li class=" SunItem-2 "><a href="https://explorer.aapg.org/archives/presidents-column" title="President’s Column Archives" ><span>President’s Column</span></a></li><li class=" SunItem-3 "><a href="https://explorer.aapg.org/archives/directors-corner" title="Director’s Corner Archives" ><span>Director’s Corner</span></a></li><li class=" SunItem-4 "><a href="https://explorer.aapg.org/archives/geophysical-corner" title="Geophysical Corner Archives" ><span>Geophysical Corner</span></a></li><li class=" SunItem-5 "><a href="https://explorer.aapg.org/archives/policy-watch" title="Policy Watch Archives" ><span>Policy Watch</span></a></li><li class=" SunItem-6 "><a href="https://explorer.aapg.org/archives/historical-highlights" title="Historical Highlights Archives" ><span>Historical Highlights</span></a></li><li class=" SunItem-7 "><a href="https://explorer.aapg.org/archives/regions-sections" title="Regions/Sections Archives" ><span>Regions/Sections</span></a></li><li class=" SunItem-8 "><a href="https://explorer.aapg.org/archives/foundation-update" title="Foundation Update Archives" ><span>Foundation Update</span></a></li><li class=" SunItem-9 "><a href="https://explorer.aapg.org/archives/dpa-column" title="DPA Column Archives" ><span>DPA Column</span></a></li><li class="current SunItem-10 "><a href="https://explorer.aapg.org/archives/emd-column" title="EMD Column Archives" ><span>EMD Column</span></a></li><li class=" SunItem-11 "><a href="https://explorer.aapg.org/archives/deg-column" title="DEG Column Archives" ><span>DEG Column</span></a></li><li class=" SunItem-12 "><a href="https://explorer.aapg.org/archives/protracks" title="ProTracks Archives" ><span>ProTracks</span></a></li><li class=" SunItem-13 "><a href="https://explorer.aapg.org/archives/making-a-difference" title="Making a Difference Archives" ><span>Making a Difference</span></a></li><li class=" SunItem-14 "><a href="https://explorer.aapg.org/archives/spotlight-on" title="Spotlight On ... Archives" ><span>Spotlight On</span></a></li><li class=" SunItem-15 "><a href="https://explorer.aapg.org/archives/a-look-back" title="A Look Back Archives" ><span>A Look Back</span></a></li><li class=" SunItem-16 "><a href="https://explorer.aapg.org/archives/business-side-of-geology" title="Business Side of Geology Archives" ><span>Business Side of Geology</span></a></li><li class=" SunItem-17 "><a href="https://explorer.aapg.org/archives/wildcat-recollections" title="Wildcat Recollections Archives" ><span>Wildcat Recollections</span></a></li></ul></li><li class=" Item-2 "><a href="https://explorer.aapg.org/advertise" class="menuitem " title="Advertise in AAPG EXPLORER" ><span>Advertise</span></a></li><li class=" Item-3 "><a href="https://explorer.aapg.org/search" class="menuitem " title="Search" ><span>Search</span></a></li><li class=" Item-4 "><a href="http://www.aapg.org" class="menuitem " title="aapg.org" target="_blank"><span>aapg.org</span></a></li></ul> </div> </div> <script type="text/javascript"> jQuery(function ($) { $("#multi_menu9be45a2b71").accordionpromulti({ accordion: true, speed: 300, closedSign: '+', openedSign: '-' }); }); </script> </div> </div> <div class="wrapper"> <div class="visible-xs visible-sm visible-sm visible-md"> <header> <div class=" phoneHeadTop clearfix"> <a href="https://explorer.aapg.org"><img src="https://img.aapg.org/Portals/20/ExplorerAAPGorg-logo-500px.png"></a> <span class="switchOpen glyphicons"> </span> </div> <div class="phoneHeadBottom"> <div class="HeadPane_mobile "></div> <div class="Login "> <span class="sep">|</span> </div> <div class="languageBox "> <div class="language-object" > </div> </div> </div> </header> </div> <div class=" light-model "> <!-- hidden-xs --> <!-- header3 --> <!-- header3 End --> <div id="header4" class="hidden-xs hidden-sm hidden-md"> <header> <div class="roll_menu"> <div class="dnn_layout "> <div class="head_mid clearfix"> <div class="row"> <div class="col-sm-9"> <div class="dnn_logo "> <a href="https://explorer.aapg.org"><img src="https://img.aapg.org/Portals/20/ExplorerAAPGorg-logo-500px.png"></a> </div> <!-- <div class="phone_box"> <div class="pulldownsearch hidden-xs " style="display:none;"> <div class="searchbut"><span class="glyphicons glyph-search"></span></div> <div class="searchBox" id="search" style="display:none;"> <span class="searchArrow"> </span> <span id="dnn_dnnSEARCH_ClassicSearch"> <span class="searchInputContainer" data-moreresults="See More Results" data-noresult="No Results Found"> <input name="dnn$dnnSEARCH$txtSearch" type="text" maxlength="255" size="20" id="dnn_dnnSEARCH_txtSearch" class="NormalTextBox" aria-label="Search" autocomplete="off" placeholder="Search..." /> <a class="dnnSearchBoxClearText" title="Clear search text"></a> </span> <a id="dnn_dnnSEARCH_cmdSearch" class="search" href="javascript:__doPostBack('dnn$dnnSEARCH$cmdSearch','')">GO</a> </span> <script type="text/javascript"> $(function() { if (typeof dnn != "undefined" && typeof dnn.searchSkinObject != "undefined") { var searchSkinObject = new dnn.searchSkinObject({ delayTriggerAutoSearch : 400, minCharRequiredTriggerAutoSearch : 2, searchType: 'S', enableWildSearch: true, cultureCode: 'en-US', portalId: -1 } ); searchSkinObject.init(); // attach classic search var siteBtn = $('#dnn_dnnSEARCH_SiteRadioButton'); var webBtn = $('#dnn_dnnSEARCH_WebRadioButton'); var clickHandler = function() { if (siteBtn.is(':checked')) searchSkinObject.settings.searchType = 'S'; else searchSkinObject.settings.searchType = 'W'; }; siteBtn.on('change', clickHandler); webBtn.on('change', clickHandler); } }); </script> </div> </div> </div> --> <div class="Head_right"> <nav> <div class="dnn_menu "> <div id="dnngo_megamenu"> <div class="dnngo_gomenu" id="dnngo_megamenu7af91755cc"> <ul class="primary_structure"> <li class="dir current item-1"> <a href="https://explorer.aapg.org/archives" title="Archives" ><span>Archives</span></a> <div class="dnngo_menuslide"> <ul class="dnngo_slide_menu "> <li > <a href="https://explorer.aapg.org/archives" title="Issue Archives" ><span>Issue Archives</span></a> </li> <li > <a href="https://explorer.aapg.org/archives/presidents-column" title="President’s Column Archives" ><span>President’s Column</span></a> </li> <li > <a href="https://explorer.aapg.org/archives/directors-corner" title="Director’s Corner Archives" ><span>Director’s Corner</span></a> </li> <li > <a href="https://explorer.aapg.org/archives/geophysical-corner" title="Geophysical Corner Archives" ><span>Geophysical Corner</span></a> </li> <li > <a href="https://explorer.aapg.org/archives/policy-watch" title="Policy Watch Archives" ><span>Policy Watch</span></a> </li> <li > <a href="https://explorer.aapg.org/archives/historical-highlights" title="Historical Highlights Archives" ><span>Historical Highlights</span></a> </li> <li > <a href="https://explorer.aapg.org/archives/regions-sections" title="Regions/Sections Archives" ><span>Regions/Sections</span></a> </li> <li > <a href="https://explorer.aapg.org/archives/foundation-update" title="Foundation Update Archives" ><span>Foundation Update</span></a> </li> <li > <a href="https://explorer.aapg.org/archives/dpa-column" title="DPA Column Archives" ><span>DPA Column</span></a> </li> <li > <a href="https://explorer.aapg.org/archives/emd-column" title="EMD Column Archives" ><span>EMD Column</span></a> </li> <li > <a href="https://explorer.aapg.org/archives/deg-column" title="DEG Column Archives" ><span>DEG Column</span></a> </li> <li > <a href="https://explorer.aapg.org/archives/protracks" title="ProTracks Archives" ><span>ProTracks</span></a> </li> <li > <a href="https://explorer.aapg.org/archives/making-a-difference" title="Making a Difference Archives" ><span>Making a Difference</span></a> </li> <li > <a href="https://explorer.aapg.org/archives/spotlight-on" title="Spotlight On ... Archives" ><span>Spotlight On</span></a> </li> <li > <a href="https://explorer.aapg.org/archives/a-look-back" title="A Look Back Archives" ><span>A Look Back</span></a> </li> <li > <a href="https://explorer.aapg.org/archives/business-side-of-geology" title="Business Side of Geology Archives" ><span>Business Side of Geology</span></a> </li> <li > <a href="https://explorer.aapg.org/archives/wildcat-recollections" title="Wildcat Recollections Archives" ><span>Wildcat Recollections</span></a> </li> </ul> </div> </li> <li class=" item-2"> <a href="https://explorer.aapg.org/advertise" title="Advertise in AAPG EXPLORER" ><span>Advertise</span></a> </li> <li class=" item-3"> <a href="https://explorer.aapg.org/search" title="Search" ><span>Search</span></a> </li> <li class=" item-4"> <a href="http://www.aapg.org" title="aapg.org" target="_blank"><span>aapg.org</span></a> </li> </ul> </div> <script type="text/javascript"> jQuery(document).ready(function ($) { $("#dnngo_megamenu7af91755cc").dnngomegamenu({ slide_speed: 200, delay_disappear: 500, popUp: "vertical",//level delay_show:150, direction:"ltr",//rtl ltr megamenuwidth:"box",//full box WidthBoxClassName:".dnn_layout" }); }); jQuery(document).ready(function () { jQuery("#dnngo_megamenu7af91755cc").has("ul").find(".dir > a").attr("aria-haspopup", "true"); }); </script> </div> </div> </nav> </div> </div> <div class="col-sm-3"><div id="dnn_PageMessagePane" class="PageMessage"><div class="DnnModule DnnModule-DNN_HTML DnnModule-22568 DnnVersionableControl"><a name="22568"></a><div id="dnn_ctr22568_ContentPane"><!-- Start_Module_22568 --><div id="dnn_ctr22568_ModuleContent" class="DNNModuleContent ModDNNHTMLC"> <div id="dnn_ctr22568_HtmlModule_lblContent"><p>EMD <strong>Column</strong> </p></div> </div><!-- End_Module_22568 --></div> </div></div></div> </div> </div> </div> <div class="header_top"> <div class="dnn_layout"> <div class="dnn_layout"> <div class="head_mid clearfix"> <div id="dnn_HeadPane" class="HeadPane DNNEmptyPane"></div> <div class="Login "> <span class="sep">|</span> </div> <div class="languageBox "> <div class="language-object" > </div> </div> </div> </div> </div> </div> </header> </div> </div> <div id="dnn_BannerPane" class="BannerPane DNNEmptyPane"></div> <div class="dnn_layout "> <div id="dnn_BannerPaneA" class="BannerPaneA"><div class="DnnModule DnnModule-DNN_HTML DnnModule-22567 DnnVersionableControl"><a name="22567"></a><div id="dnn_ctr22567_ContentPane"><!-- Start_Module_22567 --> <div class="adslot adunit explorer-ad-desktop" data-dimensions="970x90" data-adunit="Explorer_Desktop_0" id="Explorer_Desktop_0"> </div> <div class="adslot adunit explorer-ad-tablet" data-dimensions="728x90" data-adunit="Explorer_Tablet_0" id="Explorer_Tablet_0"> </div> <div class="adslot adunit explorer-ad-mobile" data-dimensions="320x50" data-adunit="Explorer_Mobile_0" id="Explorer_Mobile_0"> </div><div id="dnn_ctr22567_ModuleContent" class="DNNModuleContent ModDNNHTMLC"> <div id="dnn_ctr22567_HtmlModule_lblContent"><!--<div class="container">--> <!--<div><img src="/Portals/0/PackFlashItemImages/WebReady/explorer-cover-2017-10oct.jpg" /></div>--> <style> .sponsored-content-label { color: #aaa; font-size: 0.7em; text-transform: uppercase; padding-left: 5px; } span.d p { display: inline-block; } </style> <div class="col-sm-12"> <h1> Division Column EMD Archives</h1> <div><p>The Energy Minerals Division (EMD), a division of AAPG, is dedicated to addressing the special concerns of energy resource geologists working with energy resources other than conventional oil and gas, providing a vehicle to keep abreast of the latest developments in the geosciences and associated technology. EMD works in concert with the Division of Environmental Geosciences to serve energy resource and environmental geologists.</p></div> <div class="row articles"><div style="position: relative;" class=" PFID-1993 col-sm-3 aapg-floating-box "><a class="ContentTypeVisible" href="/story/articleid/1993/common-wording-vs-historical-terminology" target="_blank"><span class="ContentTypeName vertical">August 2012</span><div class="photo_box img_zoom ico_right_enter box_border_padding "><div class="pic_box"><img class="img-responsive" src="/Portals/0/PackFlashItemImages/WebReady/common-wording-vs-historical-terminology-2012-08aug-hero.jpg?width=480&height=320&mode=crop&anchor=topcenter&encoder=freeimage&progressive=true&quality=90&scale=both" ></div><div class="text_sytle_1"><h3>Common Wording vs. Historical Terminology</h3><p><p>For more than 100 years, shale oil has referred to the p...</p></div></div></a></div><div style="position: relative;" class=" PFID-1901 col-sm-3 aapg-floating-box "><a class="ContentTypeVisible" href="/story/articleid/1901/oh-fraque-changing-public-perceptions" target="_blank"><span class="ContentTypeName vertical">May 2012</span><div class="photo_box img_zoom ico_right_enter box_border_padding "><div class="pic_box"><img class="img-responsive" src="/Portals/0/PackFlashItemImages/WebReady/EXPLORER-cover-2012-05may-thumb.jpg?width=480&height=320&mode=pad&anchor=middlecenter&encoder=freeimage&progressive=true&quality=90&scale=both&bgcolor=ffffff" ></div><div class="text_sytle_1"><h3>Oh, Fraque! Changing Public Perceptions</h3><p><p>Hydraulic fracturing technology was pioneered in the mid...</p></div></div></a></div><div style="position: relative;" class=" PFID-1851 col-sm-3 aapg-floating-box "><a class="ContentTypeVisible" href="/story/articleid/1851/when-is-unconventional-conventional" target="_blank"><span class="ContentTypeName vertical">February 2012</span><div class="photo_box img_zoom ico_right_enter box_border_padding "><div class="pic_box"><img class="img-responsive" src="/Portals/0/PackFlashItemImages/WebReady/EXPLORER-cover-2012-02feb-thumb.jpg?width=480&height=320&mode=pad&anchor=middlecenter&encoder=freeimage&progressive=true&quality=90&scale=both&bgcolor=ffffff" ></div><div class="text_sytle_1"><h3>When Is Unconventional Conventional?</h3><p><p>If you have a pulse and have been to an AAPG Annual Conv...</p></div></div></a></div><div style="position: relative;" class=" PFID-2453 col-sm-3 aapg-floating-box "><a class="ContentTypeVisible" href="/story/articleid/2453/itaposs-the-environment-stupid" target="_blank"><span class="ContentTypeName vertical">November 2011</span><div class="photo_box img_zoom ico_right_enter box_border_padding "><div class="pic_box"><img class="img-responsive" src="/Portals/0/PackFlashItemImages/WebReady/EXPLORER-cover-2011-11nov-thumb.jpg?width=480&height=320&mode=pad&anchor=middlecenter&encoder=freeimage&progressive=true&quality=90&scale=both&bgcolor=ffffff" ></div><div class="text_sytle_1"><h3>It's the Environment, Stupid</h3><p><p>It's a green energy world we currently live and work in,...</p></div></div></a></div><div style="position: relative;" class=" PFID-2360 col-sm-3 aapg-floating-box "><a class="ContentTypeVisible" href="/story/articleid/2360/remaining-relevant--not-a-problem" target="_blank"><span class="ContentTypeName vertical">August 2011</span><div class="photo_box img_zoom ico_right_enter box_border_padding "><div class="pic_box"><img class="img-responsive" src="/Portals/0/PackFlashItemImages/WebReady/EXPLORER-cover-2011-08aug-thumb.jpg?width=480&height=320&mode=pad&anchor=middlecenter&encoder=freeimage&progressive=true&quality=90&scale=both&bgcolor=ffffff" ></div><div class="text_sytle_1"><h3>Remaining Relevant – Not a Problem!</h3><p><p>It’s a new year, with a new EMD Executive Committe...</p></div></div></a></div><div style="position: relative;" class=" PFID-2167 col-sm-3 aapg-floating-box "><a class="ContentTypeVisible" href="/story/articleid/2167/adapting-to-lower-cost-natural-gas" target="_blank"><span class="ContentTypeName vertical">May 2011</span><div class="photo_box img_zoom ico_right_enter box_border_padding "><div class="pic_box"><img class="img-responsive" src="/Portals/0/PackFlashItemImages/WebReady/adapting-to-lower-cost-natural-gas-fig1.jpg?width=480&height=320&mode=pad&anchor=middlecenter&encoder=freeimage&progressive=true&quality=90&scale=both&bgcolor=ffffff" ></div><div class="text_sytle_1"><h3>Adapting to Lower Cost Natural Gas</h3><p><p>EMD’s Energy Economics and Technology Committee is...</p></div></div></a></div><div style="position: relative;" class=" PFID-2072 col-sm-3 aapg-floating-box "><a class="ContentTypeVisible" href="/story/articleid/2072/seeing-some-good-news" target="_blank"><span class="ContentTypeName vertical">February 2011</span><div class="photo_box img_zoom ico_right_enter box_border_padding "><div class="pic_box"><img class="img-responsive" src="/Portals/0/PackFlashItemImages/WebReady/EXPLORER-cover-2011-02feb-thumb.jpg?width=480&height=320&mode=pad&anchor=middlecenter&encoder=freeimage&progressive=true&quality=90&scale=both&bgcolor=ffffff" ></div><div class="text_sytle_1"><h3>Seeing Some Good News</h3><p><p>My first six months as president of the AAPG Energy Minerals Division has brought both ...</p></div></div></a></div><div style="position: relative;" class=" PFID-2939 col-sm-3 aapg-floating-box "><a class="ContentTypeVisible" href="/story/articleid/2939/tapping-into-geothermal-a-hot-idea" target="_blank"><span class="ContentTypeName vertical">November 2010</span><div class="photo_box img_zoom ico_right_enter box_border_padding "><div class="pic_box"><img class="img-responsive" src="/Portals/0/PackFlashItemImages/WebReady/tapping-into-geothermal-a-hot-idea-fig1.gif?width=480&height=320&mode=crop&anchor=topcenter&encoder=freeimage&progressive=true&quality=90&scale=both&bgcolor=ffffff" ></div><div class="text_sytle_1"><h3>Tapping Into Geothermal a Hot Idea</h3><p><p>The last 10 years has witnessed an expansion by the oil ...</p></div></div></a></div><div style="position: relative;" class=" PFID-2796 col-sm-3 aapg-floating-box "><a class="ContentTypeVisible" href="/story/articleid/2796/oil-shales-making-cautious-progress" target="_blank"><span class="ContentTypeName vertical">August 2010</span><div class="photo_box img_zoom ico_right_enter box_border_padding "><div class="pic_box"><img class="img-responsive" src="/Portals/0/PackFlashItemImages/WebReady/oil-shales-making-cautious-progress-fig1.jpg?width=480&height=320&mode=crop&anchor=topcenter&encoder=freeimage&progressive=true&quality=90&scale=both&bgcolor=ffffff" ></div><div class="text_sytle_1"><h3>Oil Shales Making Cautious Progress</h3><p><p>Despite discouraging economic conditions over the last t...</p></div></div></a></div><div style="position: relative;" class=" PFID-2882 col-sm-3 aapg-floating-box "><a class="ContentTypeVisible" href="/story/articleid/2882/hydrates-face-key-test-on-north-slope" target="_blank"><span class="ContentTypeName vertical">May 2010</span><div class="photo_box img_zoom ico_right_enter box_border_padding "><div class="pic_box"><img class="img-responsive" src="/Portals/0/PackFlashItemImages/WebReady/hydrates-face-key-test-on-north-slope-emd-johnson-mdcjpg.jpg?width=480&height=320&mode=crop&anchor=topcenter&encoder=freeimage&progressive=true&quality=90&scale=both&bgcolor=ffffff" ></div><div class="text_sytle_1"><h3>Hydrates Face Key Test on North Slope</h3><p><p>Gas hydrate, a crystalline compound of water and natural...</p></div></div></a></div><div style="position: relative;" class=" PFID-2753 col-sm-3 aapg-floating-box "><a class="ContentTypeVisible" href="/story/articleid/2753/divisions-to-cooperate-on-renewables" target="_blank"><span class="ContentTypeName vertical">February 2010</span><div class="photo_box img_zoom ico_right_enter box_border_padding "><div class="pic_box"><img class="img-responsive" src="/Portals/0/PackFlashItemImages/WebReady/EXPLORER-cover-2010-02feb-thumb.jpg?width=480&height=320&mode=pad&anchor=middlecenter&encoder=freeimage&progressive=true&quality=90&scale=both&bgcolor=ffffff" ></div><div class="text_sytle_1"><h3>Divisions to Cooperate on Renewables</h3><p><p>It was refreshing to meet recently with Frank Walles, th...</p></div></div></a></div><div style="position: relative;" class=" PFID-747 col-sm-3 aapg-floating-box "><a class="ContentTypeVisible" href="/story/articleid/747/lots-of-potential-lots-of-hurdles" target="_blank"><span class="ContentTypeName vertical">November 2009</span><div class="photo_box img_zoom ico_right_enter box_border_padding "><div class="pic_box"><img class="img-responsive" src="/Portals/0/PackFlashItemImages/WebReady/EXPLORER-cover-2009-11nov-thumb.jpg?width=480&height=320&mode=pad&anchor=middlecenter&encoder=freeimage&progressive=true&quality=90&scale=both&bgcolor=ffffff" ></div><div class="text_sytle_1"><h3>Lots of Potential, Lots of Hurdles</h3><p><p>As North America tries to obtain energy security it will...</p></div></div></a></div></div> <div class="loading-indicator"> <div class="loading infinite-scroll-request"> <div class="loading-container container1"> <div class="circle1"></div> <div class="circle2"></div> <div class="circle3"></div> <div class="circle4"></div> </div> <div class="loading-container container2"> <div class="circle1"></div> <div class="circle2"></div> <div class="circle3"></div> <div class="circle4"></div> </div> <div class="loading-container container3"> <div class="circle1"></div> <div class="circle2"></div> <div class="circle3"></div> <div class="circle4"></div> </div> </div> <div class="infinite-scroll-last">End of content</div> <div class="infinite-scroll-error">No more pages to load</div> </div> </div> <!-- <div class="page-load-status"> <p class="infinite-scroll-request">Loading...</p> <p class="infinite-scroll-last">End of content</p> <p class="infinite-scroll-error">No more pages to load</p> </div> --> <!--</div>--> <nav class=" row article_paging" itemscope itemtype="http://schema.org/SiteNavigationElement"><a class="first" href="/Default.aspx?TabId=4605&language=en-US">❮❮ </a> <a class="previous" href="/Default.aspx?TabId=4605¤tpage=4&language=en-US">❮ </a><span class="pipe">|</span> <a class="page" href="/Default.aspx?TabId=4605&language=en-US">1</a><a class="page" href="/Default.aspx?TabId=4605¤tpage=2&language=en-US">2</a><a class="page" href="/Default.aspx?TabId=4605¤tpage=3&language=en-US">3</a><a class="page" href="/Default.aspx?TabId=4605¤tpage=4&language=en-US">4</a><span class="current">5</span><a class="page" href="/Default.aspx?TabId=4605¤tpage=6&language=en-US">6</a><a class="page" href="/Default.aspx?TabId=4605¤tpage=7&language=en-US">7</a><a class="page" href="/Default.aspx?TabId=4605¤tpage=8&language=en-US">8</a> <span class="pipe">|</span><a class="next pagination__next" href="/Default.aspx?TabId=4605¤tpage=6&language=en-US"> ❯</a> <a class="last" href="/Default.aspx?TabId=4605¤tpage=8&language=en-US"> ❯❯</a></nav> <!-- <link href="/js/custom-js/lightbox/css/lightbox.min.css" rel="stylesheet"> <script defer src="/js/custom-js/lightbox/js/lightbox.min.js" type="text/javascript"></script> <script defer src="/js/custom-js/aapg-social-share.js" type="text/javascript"></script> --> <script defer src="https://unpkg.com/infinite-scroll@3/dist/infinite-scroll.pkgd.min.js"></script> <script defer src="https://www.aapg.org/js/custom-js/jquery.matchHeight-min.js" type="text/javascript"></script> <!--<script defer src="https://unpkg.com/infinite-scroll@3/dist/infinite-scroll.pkgd.min.js"></script>--> <script> $(document).on("ready",function(){ // $(".divPFMainShortCode a").each(function(){ // $(this).attr('data-lightbox', $(this).attr("rel")).attr('data-title', $(this).attr("title")); // }); $('.row.articles').infiniteScroll({ // options path: '.pagination__next', append: '.row.articles', history: 'push', hideNav: '.article_paging', status: '.loading-indicator' }); }); </script> <script> $(document).ready(function(){ $(".col-sm-3.aapg-floating-box .photo_box").matchHeight().addClass("matchedHeight"); }); //$('.row.articles').on( 'load.infiniteScroll', function() { // $(".col-sm-3.aapg-floating-box .photo_box").not(".matchedHeight").matchHeight(); // console.log("Re-ran matchHeight()"); //}); var scrolls = 0; document.addEventListener("scroll", function() {scrolls+=1; if(scrolls%7 === 0) {$(".col-sm-3.aapg-floating-box .photo_box").not(".matchedHeight").matchHeight().addClass("matchedHeight");}} ); </script></div> </div><!-- End_Module_22567 --></div> </div></div> </div> <div id="dnn_BannerPaneB" class="BannerPaneB DNNEmptyPane"></div> <div class="Banner_bg"> <div class="dnn_layout "> <div style="height:0px ; overflow:hidden"> </div> <div id="dnn_BannerPaneC" class="BannerPaneC DNNEmptyPane"></div> </div> </div> <div class="dnn_layout"> <div class="content_mid clearfix"> <div class="row"> <div class="col-sm-12"> <div id="dnn_TopPaneA" class="TopPaneA DNNEmptyPane"></div> </div> </div> </div> </div> <div class="Content_bg_2"> <div class="Content_line"> <div class="dnn_layout"> <div class="content_mid clearfix"> <section class="row"> <div class="col-sm-6"> <div id="dnn_TopPaneB" class="TopPaneB DNNEmptyPane"></div> </div> <div class="col-sm-6"> <div id="dnn_TopPaneC" class="TopPaneC DNNEmptyPane"></div> </div> </section> </div> </div> </div> </div> <div class="dnn_layout"> <div class="content_mid clearfix"> <div class="row"> <div class="col-sm-12"> <div id="dnn_TopPaneD" class="TopPaneD DNNEmptyPane"></div> </div> </div> </div> </div> <div class="Content_bg_3"> <div class="dnn_layout"> <div class="content_mid clearfix"> <div class="row"> <div class="col-sm-12"> <div id="dnn_TopPaneE" class="TopPaneE DNNEmptyPane"></div> </div> </div> </div> </div> <div id="dnn_TopPaneF" class="TopPaneF DNNEmptyPane"></div> </div> <div class="dnn_layout"> <div class="content_mid clearfix"> <div class="row"> <div class="col-sm-12"> <div id="dnn_TopPaneG" class="TopPaneG DNNEmptyPane"></div> </div> </div> </div> </div> <div class="Content_bg"> <div class="dnn_layout"> <div class="content_mid clearfix"> <div id="dnn_TopOutPane" class="TopOutPane DNNEmptyPane"></div> </div> </div> </div> <section id="dnn_content"> <div id="dnn_Full_Screen_PaneA" class="Full_Screen_PaneA DNNEmptyPane"></div> <div class="dnn_layout"> <div class="content_mid clearfix"> <div class="pane_layout"> <div class="row"> <div class="col-sm-12"> <div id="dnn_TopPane" class="TopPane DNNEmptyPane"></div> </div> </div> </div> </div> </div> <div id="dnn_Full_Screen_PaneB" class="Full_Screen_PaneB DNNEmptyPane"></div> <div class="dnn_layout"> <div class="content_mid clearfix"> <div class="pane_layout"> <div class="row"> <div class="col-sm-3"> <div id="dnn_RowOne_Grid3_Pane" class="RowOne_Grid3_Pane DNNEmptyPane"></div> </div> <div class="col-sm-9"> <div id="dnn_RowOne_Grid9_Pane" class="RowOne_Grid9_Pane DNNEmptyPane"></div> </div> </div> <div class="row"> <div class="col-sm-4"> <div id="dnn_RowTwo_Grid4_Pane" class="RowTwo_Grid4_Pane DNNEmptyPane"></div> </div> <div class="col-sm-8"> <div id="dnn_RowTwo_Grid8_Pane" class="RowTwo_Grid8_Pane DNNEmptyPane"></div> </div> </div> <div class="row"> <div class="col-sm-5"> <div id="dnn_RowThree_Grid5_Pane" class="RowThree_Grid5_Pane DNNEmptyPane"></div> </div> <div class="col-sm-7"> <div id="dnn_RowThree_Grid7_Pane" class="RowThree_Grid7_Pane DNNEmptyPane"></div> </div> </div> <div class="row"> <div class="col-sm-6"> <div id="dnn_RowFour_Grid6_Pane1" class="RowFour_Grid6_Pane1 DNNEmptyPane"></div> </div> <div class="col-sm-6"> <div id="dnn_RowFour_Grid6_Pane2" class="RowFour_Grid6_Pane2 DNNEmptyPane"></div> </div> </div> <div class="row"> <div class="col-sm-7"> <div id="dnn_RowFive_Grid7_Pane" class="RowFive_Grid7_Pane DNNEmptyPane"></div> </div> <div class="col-sm-5"> <div id="dnn_RowFive_Grid5_Pane" class="RowFive_Grid5_Pane DNNEmptyPane"></div> </div> </div> <div class="row"> <div class="col-sm-8"> <div id="dnn_RowSix_Grid8_Pane" class="RowSix_Grid8_Pane DNNEmptyPane"></div> </div> <div class="col-sm-4"> <div id="dnn_RowSix_Grid4_Pane" class="RowSix_Grid4_Pane DNNEmptyPane"></div> </div> </div> <div class="row"> <div class="col-sm-9"> <div id="dnn_RowSeven_Grid9_Pane" class="RowSeven_Grid9_Pane DNNEmptyPane"></div> </div> <div class="col-sm-3"> <div id="dnn_RowSeven_Grid3_Pane" class="RowSeven_Grid3_Pane DNNEmptyPane"></div> </div> </div> </div> </div> </div> <div id="dnn_Full_Screen_PaneC" class="Full_Screen_PaneC DNNEmptyPane"></div> <div class="dnn_layout"> <div class="content_mid clearfix"> <div class="pane_layout"> <div class="row"> <div class="col-sm-4"> <div id="dnn_RowEight_Grid4_Pane1" class="RowEight_Grid4_Pane1 DNNEmptyPane"></div> </div> <div class="col-sm-4"> <div id="dnn_RowEight_Grid4_Pane2" class="RowEight_Grid4_Pane2 DNNEmptyPane"></div> </div> <div class="col-sm-4"> <div id="dnn_RowEight_Grid4_Pane3" class="RowEight_Grid4_Pane3 DNNEmptyPane"></div> </div> </div> <div class="row"> <div class="col-sm-3"> <div id="dnn_RowNine_Grid3_Pane1" class="RowNine_Grid3_Pane1 DNNEmptyPane"></div> </div> <div class="col-sm-6"> <div id="dnn_RowNine_Grid6_Pane" class="RowNine_Grid6_Pane DNNEmptyPane"></div> </div> <div class="col-sm-3"> <div id="dnn_RowNine_Grid3_Pane2" class="RowNine_Grid3_Pane2 DNNEmptyPane"></div> </div> </div> <div class="row"> <div class="col-sm-3"> <div id="dnn_RownTen_Grid3_Pane1" class="RownTen_Grid3_Pane1 DNNEmptyPane"></div> </div> <div class="col-sm-3"> <div id="dnn_RowTen_Grid3_Pane2" class="RowTen_Grid3_Pane2 DNNEmptyPane"></div> </div> <div class="col-sm-3"> <div id="dnn_RowTen_Grid3_Pane3" class="RowTen_Grid3_Pane3 DNNEmptyPane"></div> </div> <div class="col-sm-3"> <div id="dnn_RowTen_Grid3_Pane4" class="RowTen_Grid3_Pane4 DNNEmptyPane"></div> </div> </div> </div> </div> </div> <div id="dnn_Full_Screen_PaneD" class="Full_Screen_PaneD DNNEmptyPane"></div> <div class="dnn_layout"> <div class="content_mid clearfix"> <div class="pane_layout"> <div class="row"> <div class="col-sm-12"> <div id="dnn_ContentPane" class="ContentPane DNNEmptyPane"></div> </div> </div> </div> </div> </div> <div id="dnn_Full_Screen_PaneE" class="Full_Screen_PaneE DNNEmptyPane"></div> <div class="dnn_layout"> <div class="content_mid clearfix"> <div class="pane_layout"> <div class="row"> <div class="col-sm-3"> <div id="dnn_RownEleven_Grid3_Pane1" class="RownEleven_Grid3_Pane1 DNNEmptyPane"></div> </div> <div class="col-sm-3"> <div id="dnn_RowEleven_Grid3_Pane2" class="RowEleven_Grid3_Pane2 DNNEmptyPane"></div> </div> <div class="col-sm-3"> <div id="dnn_RowEleven_Grid3_Pane3" class="RowEleven_Grid3_Pane3 DNNEmptyPane"></div> </div> <div class="col-sm-3"> <div id="dnn_RowEleven_Grid3_Pane4" class="RowEleven_Grid3_Pane4 DNNEmptyPane"></div> </div> </div> <div class="row"> <div class="col-sm-3"> <div id="dnn_RowTwelve_Grid3_Pane1" class="RowTwelve_Grid3_Pane1 DNNEmptyPane"></div> </div> <div class="col-sm-6"> <div id="dnn_RowTwelve_Grid6_Pane" class="RowTwelve_Grid6_Pane DNNEmptyPane"></div> </div> <div class="col-sm-3"> <div id="dnn_RowTwelve_Grid3_Pane2" class="RowTwelve_Grid3_Pane2 DNNEmptyPane"></div> </div> </div> <div class="row"> <div class="col-sm-4"> <div id="dnn_RowThirteen_Grid4_Pane1" class="RowThirteen_Grid4_Pane1 DNNEmptyPane"></div> </div> <div class="col-sm-4"> <div id="dnn_RowThirteen_Grid4_Pane2" class="RowThirteen_Grid4_Pane2 DNNEmptyPane"></div> </div> <div class="col-sm-4"> <div id="dnn_RowThirteen_Grid4_Pane3" class="RowThirteen_Grid4_Pane3 DNNEmptyPane"></div> </div> </div> </div> </div> </div> <div id="dnn_Full_Screen_PaneF" class="Full_Screen_PaneF DNNEmptyPane"></div> <div class="dnn_layout"> <div class="content_mid clearfix"> <div class="pane_layout"> <div class="row"> <div class="col-sm-9"> <div id="dnn_RowFourteen_Grid9_Pane" class="RowFourteen_Grid9_Pane DNNEmptyPane"></div> </div> <div class="col-sm-3"> <div id="dnn_RowFourteen_Grid3_Pane" class="RowFourteen_Grid3_Pane DNNEmptyPane"></div> </div> </div> <div class="row"> <div class="col-sm-8"> <div id="dnn_RowFifteen_Grid8_Pane" class="RowFifteen_Grid8_Pane DNNEmptyPane"></div> </div> <div class="col-sm-4"> <div id="dnn_RowFifteen_Grid4_Pane" class="RowFifteen_Grid4_Pane DNNEmptyPane"></div> </div> </div> <div class="row"> <div class="col-sm-7"> <div id="dnn_RowSixteen_Grid7_Pane" class="RowSixteen_Grid7_Pane DNNEmptyPane"></div> </div> <div class="col-sm-5"> <div id="dnn_RowSixteen_Grid5_Pane" class="RowSixteen_Grid5_Pane DNNEmptyPane"></div> </div> </div> <div class="row"> <div class="col-sm-6"> <div id="dnn_RowSeventeen_Grid6_Pane1" class="RowSeventeen_Grid6_Pane1 DNNEmptyPane"></div> </div> <div class="col-sm-6"> <div id="dnn_RowSeventeen_Grid6_Pane2" class="RowSeventeen_Grid6_Pane2 DNNEmptyPane"></div> </div> </div> <div class="row"> <div class="col-sm-5"> <div id="dnn_RowEighteen_Grid5_Pane" class="RowEighteen_Grid5_Pane DNNEmptyPane"></div> </div> <div class="col-sm-7"> <div id="dnn_RowEighteen_Grid7_Pane" class="RowEighteen_Grid7_Pane DNNEmptyPane"></div> </div> </div> <div class="row"> <div class="col-sm-4"> <div id="dnn_RowNineteen_Grid4_Pane" class="RowNineteen_Grid4_Pane DNNEmptyPane"></div> </div> <div class="col-sm-8"> <div id="dnn_RowNineteen_Grid8_Pane" class="RowNineteen_Grid8_Pane DNNEmptyPane"></div> </div> </div> <div class="row"> <div class="col-sm-3"> <div id="dnn_RowTwenty_Grid3_Pane" class="RowTwenty_Grid3_Pane DNNEmptyPane"></div> </div> <div class="col-sm-9"> <div id="dnn_RowTwenty_Grid9_Pane" class="RowTwenty_Grid9_Pane DNNEmptyPane"></div> </div> </div> </div> </div> </div> <div id="dnn_Full_Screen_PaneG" class="Full_Screen_PaneG DNNEmptyPane"></div> <div class="dnn_layout"> <div class="content_mid clearfix"> <div class="pane_layout"> <div class="row"> <div class="col-sm-12"> <div id="dnn_BottomPane" class="BottomPane DNNEmptyPane"></div> </div> </div> </div> </div> </div> <div id="dnn_Full_Screen_PaneH" class="Full_Screen_PaneH DNNEmptyPane"></div> </section> <div class="Content_bg_4"> <div class="dnn_layout"> <div class="content_mid clearfix"> <div id="dnn_BottomOutPane" class="BottomOutPane DNNEmptyPane"></div> </div> </div> </div> <!-- Footer --> <div id="footer1"> <footer> <div class="Footer_Topbg "> <div class="dnn_layout"> <div class="footer_mid clearfix"> <div id="dnn_FooterOutPane" class="FooterOutPane DNNEmptyPane"></div> </div> </div> </div> <div class="Footer_Contentbg "> <div class="dnn_layout"> <div class="footer_mid clearfix"> <div class="row"> <div class="col-sm-3"> <div id="dnn_FootPaneA" class="FootPaneA DNNEmptyPane"></div> </div> <div class="col-sm-3"> <div id="dnn_FootPaneB" class="FootPaneB DNNEmptyPane"></div> </div> <div class="col-sm-3"> <div id="dnn_FootPaneC" class="FootPaneC DNNEmptyPane"></div> </div> <div class="col-sm-3"> <div id="dnn_FootPaneD" class="FootPaneD DNNEmptyPane"></div> </div> </div> </div> </div> </div> <div class="Footer_Bottombg "> <div class="dnn_layout"> <div class="footer_mid clearfix"> <div class="copyright_style"> <span id="dnn_dnnCOPYRIGHT_lblCopyright" class="footer ">Copyright 2025 AAPG</span> <span class="sep ">|</span> <a id="dnn_dnnPRIVACY_hypPrivacy" class="terms " rel="nofollow" href="https://explorer.aapg.org/privacy">Privacy Statement</a> <span class="sep ">|</span> <a id="dnn_dnnTERMS_hypTerms" class="terms " rel="nofollow" href="https://explorer.aapg.org/terms">Terms Of Use</a> <span class="sep ">|</span> <a href="https://www.aapg.org/advertise" target="_blank">Media Kit</a> <span class="sep ">|</span> <span class="social-icons "> <span class="sep "><a href="https://www.facebook.com/AAPGeologists" target="_blank"><span class="social social-facebook"></span></a></span> <span class="sep "><a href="https://www.linkedin.com/company/american-association-of-petroleum-geologists-aapg/" target="_blank"><span class="social social-linked-in"></span></a></span> <span class="sep "><a href="https://twitter.com/AAPG" target="_blank"><span class="social social-twitter"></span></a></span> <span class="sep "><a href="https://www.youtube.com/user/aapgweb" target="_blank"><span class="social social-youtube"></span></a></span> <!-- <span class="sep "><a href="https://plus.google.com/b/103177223533885807388/+AapgOrg/posts" target="_blank"><span class="social social-google-plus"></span></a></span>--> </span> </div> <div id="dnn_FooterPane" class="FooterPane DNNEmptyPane"></div> <div id="to_top" class=" "><span> </span></div> </div> </div> </div> </footer> </div> <!-- Footer End --> </div> </div> </div> <script type="text/javascript" src="https://www.aapg.org/Portals/_default/Skins/Explorer/scripts/script.js"></script> <script type="text/javascript" src="https://www.aapg.org/Portals/_default/Skins/Explorer/scripts/custom.js"></script> <!--<script type="text/javascript" src="https://www.aapg.org/js/custom-js/analytics-downloads.js"></script> --> <!--CDF(Javascript|/js/custom-js/slimmage.min.js?cdv=1092|DnnBodyProvider|99)--> <script defer src="/js/custom-js/ga-gtm-explorer.js" type="text/javascript"></script> <script defer src="/DesktopModules/AAPG/PackFlash/PFIncrementViewsJS.aspx" type="text/javascript"></script> <!-- <script defer src="/js/custom-js/fingerprint2.min.js" type="text/javascript"></script> <script defer src="/DesktopModules/AAPG/UserTracking/TrackViewsJS.aspx" type="text/javascript"></script> --> <script type="text/javascript"> $(document).ready(function(){ // BEGIN IncrementViews // var PageURL = window.location.href; // var PageTitle = document.title; // var UserID = ''; // var Username = "[User:Username]"; // var Displayname = "[User:DisplayName]"; // var Useremail = "[User:Email]"; // // console.log("PageURL = " + PageTitle); // console.log("PageTitle = " + PageTitle); // console.log("UserID = " + UserID); // console.log("Username = " + Username); // console.log("Displayname = " + Displayname); // console.log("Useremail = " + Useremail); // END IncrementViews if (window.location.href.indexOf("login.aapg.org") !== -1) { var currentButton = $('a[href*=www\\.aapg\\.org\\/register\\?refUrl\\=https\\%3A\\%2F\\%2Fexplorer\\.aapg\\.org]'); var currentButtonHreftest = $(currentButton).attr("href"); //console.log("currentButtonHreftest = " + currentButtonHreftest ); if (typeof currentButton !== 'undefined') { var currentButtonHref = $('a[href*=www\\.aapg\\.org\\/register\\?refUrl\\=https\\%3A\\%2F\\%2Fexplorer\\.aapg\\.org]').attr("href"); var newButtonHref = currentButtonHref.replace("refUrl=https%3A%2F%2Fexplorer.aapg.org","refUrl=http%3A%2F%2Fwww.aapg.org").replace("refUrl=http%3A%2F%2Fexplorer.aapg.org","refUrl=http%3A%2F%2Fwww.aapg.org"); $(currentButton).attr("href",newButtonHref); //console.log("newButtonHref = " + newButtonHref); } } }); </script> <input name="ScrollTop" type="hidden" id="ScrollTop" /> <input name="__dnnVariable" type="hidden" id="__dnnVariable" autocomplete="off" value="`{`trackLinks`:`false`,`__scdoff`:`1`,`sf_siteRoot`:`/`,`sf_tabId`:`4605`,`evoq_TabId`:`4605`,`evoq_PageLanguage`:`en-US`,`evoq_ContentItemId`:`-1`,`evoq_UrlReferrer`:``,`evoq_UrlPath`:`https%3a%2f%2fexplorer.aapg.org%2farchives%2femd-column%2fcurrentpage%2f5`,`evoq_UrlQuery`:`%3fTabId%3d4605%26currentpage%3d5%26language%3den-US`,`evoq_ContentItemReferrer`:`-1`,`evoq_PersonalizedUrlReferrer`:`-1`,`evoq_DisableAnalytics`:`False`}" /> <input name="__RequestVerificationToken" type="hidden" value="lV8NXehB7TpnhSPGNehq2S4tcESWzfI5JZz0SLPOhl7EdnQ7hDSga-E4rqoIeoGJgUdhOg2" /> <script type="text/javascript" src="/DesktopModules/DNNGo_Megamenu/Resource/js/dnngo-megamenu.js"></script></form> <!--CDF(Javascript|/js/dnncore.js?cdv=1092|DnnBodyProvider|100)--><!--CDF(Css|/Resources/Shared/stylesheets/dnndefault/7.0.0/default.css?cdv=1092|DnnPageHeaderProvider|5)--><!--CDF(Css|/Portals/_default/Skins/Explorer/skin.css?cdv=1092|DnnPageHeaderProvider|15)--><!--CDF(Css|/Portals/20/portal.css?cdv=1092|DnnPageHeaderProvider|35)--><!--CDF(Css|/Resources/Search/SearchSkinObjectPreview.css?cdv=1092|DnnPageHeaderProvider|10)--><!--CDF(Javascript|/Resources/Search/SearchSkinObjectPreview.js?cdv=1092|DnnBodyProvider|100)--><!--CDF(Css|/Resources/Search/SearchSkinObjectPreview.css?cdv=1092|DnnPageHeaderProvider|10)--><!--CDF(Javascript|/Resources/Search/SearchSkinObjectPreview.js?cdv=1092|DnnBodyProvider|100)--><!--CDF(Javascript|/js/dnn.js?cdv=1092|DnnBodyProvider|12)--><!--CDF(Javascript|/js/dnn.servicesframework.js?cdv=1092|DnnBodyProvider|100)--><!--CDF(Javascript|/Resources/libraries/jQuery/03_05_01/jquery.js?cdv=1092|DnnPageHeaderProvider|5)--><!--CDF(Javascript|/Resources/libraries/jQuery-Migrate/03_04_00/jquery-migrate.js?cdv=1092|DnnPageHeaderProvider|6)--> <!-- Start of HubSpot Embed Code --> <script type="text/javascript" id="hs-script-loader" async defer src="//js.hs-scripts.com/42500357.js"></script> <!-- End of HubSpot Embed Code --> <script>(function(){function c(){var b=a.contentDocument||a.contentWindow.document;if(b){var d=b.createElement('script');d.innerHTML="window.__CF$cv$params={r:'912dcefdfabb604b',t:'MTczOTcxMTc0OS4wMDAwMDA='};var a=document.createElement('script');a.nonce='';a.src='/cdn-cgi/challenge-platform/scripts/jsd/main.js';document.getElementsByTagName('head')[0].appendChild(a);";b.getElementsByTagName('head')[0].appendChild(d)}}if(document.body){var a=document.createElement('iframe');a.height=1;a.width=1;a.style.position='absolute';a.style.top=0;a.style.left=0;a.style.border='none';a.style.visibility='hidden';document.body.appendChild(a);if('loading'!==document.readyState)c();else if(window.addEventListener)document.addEventListener('DOMContentLoaded',c);else{var e=document.onreadystatechange||function(){};document.onreadystatechange=function(b){e(b);'loading'!==document.readyState&&(document.onreadystatechange=e,c())}}}})();</script></body> </html>