<span class="mw-page-title-main">Shale</span>

Shale

<p><b>Shale</b> is a fine-grained, <a href="/en/Clastic" title="Clastic" class="mw-redirect wl">clastic</a> <a href="/en/Sedimentary_rock" title="Sedimentary rock" class="wl">sedimentary rock</a> formed from <a href="/en/Mud" title="Mud" class="wl">mud</a> that is a mix of flakes of <a href="/en/Clay_mineral" title="Clay mineral" class="wl">clay minerals</a> (hydrous aluminium phyllosilicates, e.g. kaolin, <a href="/en/Aluminium" title="Aluminium" class="wl">Al</a><sub>2</sub><a href="/en/Silicon" title="Silicon" class="wl">Si</a><sub>2</sub><a href="/en/Oxygen" title="Oxygen" class="wl">O</a><sub>5</sub>(<a href="/en/Hydroxide" title="Hydroxide" class="wl">OH</a>)<sub>4</sub>) and tiny fragments (<a href="/en/Silt" title="Silt" class="wl">silt</a>-sized particles) of other minerals, especially <a href="/en/Quartz" title="Quartz" class="wl">quartz</a> and <a href="/en/Calcite" title="Calcite" class="wl">calcite</a>.<span class="mw-ref reference" id="cite_ref-Blatt2_1-0"><a href="#cite_note-Blatt2-1" style="counter-reset: mw-Ref 1;"><span class="mw-reflink-text">[1]</span></a></span>  Shale is characterized by its tendency to split into thin layers (<a href="/en/Lamination_(geology)" title="Lamination (geology)" class="wl">laminae</a>) less than one centimeter in thickness. This property is called <i><a href="/en/Fissility_(geology)" title="Fissility (geology)" class="wl">fissility</a></i>.<span class="mw-ref reference" id="cite_ref-Blatt2_1-1"><a href="#cite_note-Blatt2-1" style="counter-reset: mw-Ref 1;"><span class="mw-reflink-text">[1]</span></a></span> Shale is the most common sedimentary rock.<span class="mw-ref reference" id="cite_ref-RocksMaterials2_2-0"><a href="#cite_note-RocksMaterials2-2" style="counter-reset: mw-Ref 2;"><span class="mw-reflink-text">[2]</span></a></span></p>

<div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none" about="#mwt1">Fine-grained, clastic sedimentary rock</div>
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<style data-mw-deduplicate="TemplateStyles:r1066479718" typeof="mw:Extension/templatestyles mw:Transclusion">.mw-parser-output .infobox-subbox{padding:0;border:none;margin:-3px;width:auto;min-width:100%;font-size:100%;clear:none;float:none;background-color:transparent}.mw-parser-output .infobox-3cols-child{margin:auto}.mw-parser-output .infobox .navbar{font-size:100%}body.skin-minerva .mw-parser-output .infobox-header,body.skin-minerva .mw-parser-output .infobox-subheader,body.skin-minerva .mw-parser-output .infobox-above,body.skin-minerva .mw-parser-output .infobox-title,body.skin-minerva .mw-parser-output .infobox-image,body.skin-minerva .mw-parser-output .infobox-full-data,body.skin-minerva .mw-parser-output .infobox-below{text-align:center}</style><div class='mobile-collapse'><header class="mobile-collapse-header mobile-collapse-btn"><b>Quick facts: Composition...</b> <span class='arrow'>▼</span></header> <table class="infobox mobile-collapse-element"><caption class="infobox-title">Shale</caption><tbody><tr><td colspan="2" class="infobox-subheader notheme" style="background-color: #cddeff"><b><a href="/en/Sedimentary" title="Sedimentary" class="mw-redirect wl">Sedimentary rock</a></b></td></tr><tr><td colspan="2" class="infobox-image"><span class="mw-default-size"><a href="/en/File:Chattanooga_Shale_(Upper_Devonian;_Burkesville_West_Rt._90_roadcut,_Kentucky,_USA)_25_(40541681100).jpg" class="mw-file-description image media-thumb" data-hash="File:Chattanooga_Shale_(Upper_Devonian;_Burkesville_West_Rt._90_roadcut,_Kentucky,_USA)_25_(40541681100).jpg"><img loading="lazy" src="//upload.wikimedia.org/wikipedia/commons/thumb/0/04/Chattanooga_Shale_%28Upper_Devonian%3B_Burkesville_West_Rt._90_roadcut%2C_Kentucky%2C_USA%29_25_%2840541681100%29.jpg/220px-Chattanooga_Shale_%28Upper_Devonian%3B_Burkesville_West_Rt._90_roadcut%2C_Kentucky%2C_USA%29_25_%2840541681100%29.jpg" decoding="async" data-file-width="3000" data-file-height="4000" data-file-type="bitmap" height="293" width="220" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/04/Chattanooga_Shale_%28Upper_Devonian%3B_Burkesville_West_Rt._90_roadcut%2C_Kentucky%2C_USA%29_25_%2840541681100%29.jpg/330px-Chattanooga_Shale_%28Upper_Devonian%3B_Burkesville_West_Rt._90_roadcut%2C_Kentucky%2C_USA%29_25_%2840541681100%29.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/04/Chattanooga_Shale_%28Upper_Devonian%3B_Burkesville_West_Rt._90_roadcut%2C_Kentucky%2C_USA%29_25_%2840541681100%29.jpg/440px-Chattanooga_Shale_%28Upper_Devonian%3B_Burkesville_West_Rt._90_roadcut%2C_Kentucky%2C_USA%29_25_%2840541681100%29.jpg 2x" alt="Chattanooga_Shale_%28Upper_Devonian%3B_Burkesville_West_Rt._90_roadcut%2C_Kentucky%2C_USA%29_25_%2840541681100%29.jpg"></a></span><div class="infobox-caption">Shale</div></td></tr><tr><th colspan="2" class="infobox-header notheme" style="background-color: #ededed">Composition</th></tr><tr><td colspan="2" class="infobox-full-data"><a href="/en/Clay_minerals" title="Clay minerals" class="mw-redirect wl">Clay minerals</a> and <a href="/en/Quartz" title="Quartz" class="wl">quartz</a></td></tr></tbody></table> <footer class='mobile-collapse-footer mobile-collapse-btn'><b>Close</b> <span class='arrow'>▲</span></footer></div><p>The term <i>shale</i> is sometimes applied more broadly, as essentially a synonym for <a href="/en/Mudrock" title="Mudrock" class="wl">mudrock</a>, rather than in the more narrow sense of clay-rich fissile mudrock.<span class="mw-ref reference" id="cite_ref-3"><a href="#cite_note-3" style="counter-reset: mw-Ref 3;"><span class="mw-reflink-text">[3]</span></a></span></p>



Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals 4) and tiny fragments of other minerals, especially quartz and calcite. The term shale is sometimes applied more broadly, as essentially a synonym for mudrock, rather than in the more narrow sense of clay-rich fissile mudrock. 