Petrology | Igneous, Sedimentary & Metamorphic

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class="md-content"> <div class="md-article-container template-desktop"> <div class="infinite-scroll-container article last"> <article class="article-content container-lg qa-content px-0 pt-0 pb-40 py-lg-20 content " data-topic-id="454469"> <div class="grid gx-0"> <div class="col-auto"> <div class="topic-left-rail md-article-drawer position-relative d-flex border-right-sm border-left-sm open"> <div class="drawer d-flex flex-column open"> <div class="left-rail-section-content"> <div class="topic-left-rail-header text-truncate bg-gray-50 position-relative text-right d-flex align-items-center"> <div class="tlr-title px-20 py-15 text-left"> <em class="material-icons text-gray-400 d-lg-none" data-icon="toc"></em> <a class="font-serif font-weight-bold text-black link-blue" href="https://www.britannica.com/science/petrology">petrology</a> </div> <button aria-label="Close" class="js-sections-close-button btn-link btn-sm btn d-lg-none position-absolute top-0 p-10 right-0" > <em class="material-icons font-26" data-icon="close"></em> </button> </div> <div class="section-content pl-10 pr-20 pl-sm-50 pr-sm-60 pl-lg-5 pr-lg-10 pt-10 pt-lg-0 bg-gray-50 clear-catfish-ad"> <div class="toc mb-20"> <div class="font-serif font-14 font-weight-bold mx-15 mb-15 mt-20"> Table of Contents </div> <span class="toc-extra-link selected link-gray-900 mt-15"> Introduction </span> <a class="toc-extra-link link-gray-900" href="https://www.britannica.com/science/petrology/additional-info">References & Edit History</a> <a class="toc-extra-link link-gray-900" href="/facts/petrology">Related Topics</a> </div> <div class="mb-30 tlr-discover"> <div class="text-gray-900 p-5 font-serif font-14 font-weight-bold mx-10 mb-10"> Discover </div> <div class="imagelink-with-image-on-the-side card card-horizontal tlr-img-with-side-link ml-15 link-gray-900 mb-10" > <div class="position-relative card-media" style="flex: 0;"> <a class="ilf-image position-relative" href="/list/10-famous-artworks-by-leonardo-da-vinci"> <img loading="lazy" src="https://cdn.britannica.com/06/200006-131-ABB681CF/Leonardo-da-Vinci-Italian-Renaissance-Florence-Engraving-1500.jpg?w=200&h=200&c=crop" alt="Leonardo da Vinci (1452-1519), Italian Renaissance painter from Florence. 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Head of Tollund Man. Died at about age 30-40, Dated to about 280 BCE early Iron Age. Found Bjaeldskovdal bog Denmark in 1950 near Elling Woman. Most well preserved bog body to date. Human remains mummified in natural peat bogs. mummy, embalm" width="200" height="200" /> </a> </div> <div class="card-body ilf-content"> <a class="font-weight-semi-bold d-block mb-5 font-16 ilf-title" href="/list/9-noteworthy-bog-bodies-and-what-they-tell-us" >9 Noteworthy Bog Bodies (And What They Tell Us)</a> </div> </div> <div class="imagelink-with-image-on-the-side card card-horizontal tlr-img-with-side-link ml-15 link-gray-900 mb-10" > <div class="position-relative card-media" style="flex: 0;"> <a class="ilf-image position-relative" href="/story/whats-the-difference-between-buffalo-and-bison"> <img loading="lazy" src="https://cdn.britannica.com/04/187404-131-2839AF60/bison-American-buffalo-plains-prairie.jpg?w=200&h=200&c=crop" alt="American bison (Bison bison) also known as buffalo or plains buffalo on the prairie, western U.S." width="200" height="200" /> </a> </div> <div class="card-body ilf-content"> <a class="font-weight-semi-bold d-block mb-5 font-16 ilf-title" href="/story/whats-the-difference-between-buffalo-and-bison" >What鈥檚 the Difference Between Bison and Buffalo?</a> </div> </div> <div class="imagelink-with-image-on-the-side card card-horizontal tlr-img-with-side-link ml-15 link-gray-900 mb-10" > <div class="position-relative card-media" style="flex: 0;"> <a class="ilf-image position-relative" href="/list/10-best-sports-rivalries-of-all-time"> <img loading="lazy" src="https://cdn.britannica.com/53/189653-131-A7E9422A/Kevin-Garnett-shooting-Ronny-Turiaf-Boston-Celtics-2008.jpg?w=200&h=200&c=crop" alt="NBA Lakers Celtics Finals Kevin Garnett shooting." width="200" height="200" /> </a> </div> <div class="card-body ilf-content"> <a class="font-weight-semi-bold d-block mb-5 font-16 ilf-title" href="/list/10-best-sports-rivalries-of-all-time" >10 Great Sports Rivalries</a> </div> </div> </div> </div> </div> </div> <button class="drawerToggle btn position-sticky border btn-xs btn-white btn-circle rounded-sm d-none d-lg-flex " type="button" 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Bowen</a></dd> <dd><a href="/biography/Victor-Moritz-Goldschmidt" topicid="237916">Victor Moritz Goldschmidt</a></dd> <dd><a href="/biography/Ferdinand-Zirkel" topicid="657585">Ferdinand Zirkel</a></dd> <dd><a href="/biography/Auguste-Michel-Levy" topicid="379954">Auguste Michel-L茅vy</a></dd> <dd><a href="/biography/Karl-Heinrich-Ferdinand-Rosenbusch" topicid="509912">Karl Heinrich Ferdinand Rosenbusch</a></dd> </dl> <button class="js-more-btn d-none btn btn-unstyled font-12 bg-gray-50" aria-label="Toggle more/less fact data"> <em class="js-content link-blue">(Show more)</em> </button> </div> </div> <div class=""> <div class="js-fact mb-10 line-clamp clamp-3"> <dl> <dt>Related Topics: </dt> <dd><a href="/science/sedimentary-petrology" topicid="532227">sedimentary petrology</a></dd> <dd><a href="/science/petrography" topicid="454249">petrography</a></dd> <dd><a href="/science/petrogenesis" topicid="663182">petrogenesis</a></dd> <dd><a href="/science/metamorphic-petrology" topicid="377774">metamorphic petrology</a></dd> <dd><a href="/science/experimental-petrology" topicid="198454">experimental petrology</a></dd> </dl> <button class="js-more-btn d-none btn btn-unstyled font-12 bg-gray-50" aria-label="Toggle more/less fact data"> <em class="js-content link-blue">(Show more)</em> </button> </div> <div class="text-center"> <a class="btn btn-sm btn-link p-0" href="/facts/petrology"> See all related content </a> </div> </div> </div> </div><span class="marker before-article"></span><section data-level="1" id="ref1"><span class="marker PREMOD1 mod-inline"></span><p class="topic-paragraph"><strong><span id="ref273975"></span>petrology</strong>, scientific study of rocks that deals with their <a class="md-dictionary-link md-dictionary-tt-off mw" data-term="composition" href="https://www.merriam-webster.com/dictionary/composition" data-type="MW">composition</a>, texture, and structure; their occurrence and distribution; and their origin in relation to physicochemical conditions and geologic processes. It is concerned with all three major types of rocks鈥攊gneous, metamorphic, and sedimentary. Petrology includes the subdisciplines of <span id="ref273976"></span>experimental petrology and <span id="ref273977"></span><a href="https://www.britannica.com/science/petrography" class="md-crosslink ">petrography</a>. Experimental petrology involves the laboratory synthesis of rocks for the purpose of <a class="md-dictionary-link md-dictionary-tt-off mw" data-term="ascertaining" href="https://www.merriam-webster.com/dictionary/ascertaining" data-type="MW">ascertaining</a> the physical and chemical conditions under which <a href="https://www.britannica.com/science/rock-geology" class="md-crosslink autoxref " data-show-preview="true">rock</a> formation occurs. Petrography is the study of rocks in thin section by means of a <span id="ref273978"></span><a href="https://www.britannica.com/technology/petrographic-microscope" class="md-crosslink ">petrographic microscope</a> (<em>i.e.,</em> an instrument that employs polarized light that vibrates in a single plane). Petrography is primarily concerned with the systematic classification and precise description of rocks.</p><div class="one-good-fact-module"> </div><span class="marker MOD1 mod-inline"></span><span class="marker PREMOD2 mod-inline"></span><p class="topic-paragraph">Petrology relies heavily on the principles and methods of <a href="https://www.britannica.com/science/mineralogy" class="md-crosslink autoxref " data-show-preview="true">mineralogy</a> because most rocks consist of minerals and are formed under the same conditions. Also essential to petrological research is the careful mapping and sampling of rock units, which provide <a class="md-dictionary-link md-dictionary-tt-off eb" data-term="data" href="https://www.britannica.com/dictionary/data" data-type="EB">data</a> on regional gradations of rock types and on associations unavailable by other means. </p><span class="marker MOD2 mod-inline"></span></section> <span class="marker end-of-content"></span><span class="marker after-article"></span></div> <div id="chatbot-root"></div> </div> </div> </div> <div class="ai-dialog-placeholder"></div> </div> </div> <aside class="col-md-da-320"></aside> </div> </div> </div> </div> </article></div> </div></div> </div> </main> <div id="md-footer"></div> <noscript><iframe src="//www.googletagmanager.com/ns.html?id=GTM-5W6NC8" height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript> <script type="text/javascript" id="_informizely_script_tag"> var IzWidget = IzWidget || {}; (function (d) { var scriptElement = d.createElement('script'); scriptElement.type = 'text/javascript'; scriptElement.async = true; scriptElement.src = "https://insitez.blob.core.windows.net/site/f780f33e-a610-4ac2-af81-3eb184037547.js"; var node = d.getElementById('_informizely_script_tag'); node.parentNode.insertBefore(scriptElement, node); } )(document); </script>  <script> window.ap3c = window.ap3c || {}; var ap3c = window.ap3c; ap3c.cmd = ap3c.cmd || []; ap3c.cmd.push(function() { ap3c.init('ZO4siT4cLwnykPnzZWJtd3Byb2Q', 'https://engage.email.britannica.com/'); ap3c.track({v: 0}); }); ap3c.activity = function(act) { ap3c.act = (ap3c.act || []); ap3c.act.push(act); }; var s, t; s = document.createElement('script'); s.type = 'text/javascript'; s.src = "https://engage.email.britannica.com/app.js"; t = document.getElementsByTagName('script')[0]; t.parentNode.insertBefore(s, t); </script> <script class="marketing-page-info" type="application/json"> {"pageType":"Topic","templateName":"DESKTOP","pageNumber":1,"pagesTotal":1,"pageId":454469,"pageLength":167,"initialLoad":true,"lastPageOfScroll":false} </script> <script class="marketing-content-info" type="application/json"> [] </script> <script src="https://cdn.britannica.com/mendel-resources/3-130/js/libs/jquery-3.5.0.min.js?v=3.130.14"></script> <script type="text/javascript" data-type="Init Mendel Code Splitting"> (function() { $.ajax({ dataType: 'script', cache: true, url: 'https://cdn.britannica.com/mendel-resources/3-130/dist/topic-page.js?v=3.130.14' }); })(); </script> <script class="analytics-metadata" type="application/json"> {"leg":"C","adLeg":"C","userType":"ANONYMOUS","pageType":"Topic","pageSubtype":null,"articleTemplateType":"SMALL","gisted":false,"pageNumber":1,"hasSummarizeButton":false,"hasAskButton":false} </script> <script type="text/javascript"> EBStat={accountId:-1,hostnameOverride:'webstats.eb.com',domain:'www.britannica.com', json:''}; </script> <script type="text/javascript"> ( function() { $.ajax( { dataType: 'script', cache: true, url: '//www.britannica.com/webstats/mendelstats.js?v=1' } ) .done( function() { try {writeStat(null,EBStat);} catch(err){} } ); })(); </script> <div id="bc-fixed-dialogue"></div> </body> </html>

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Petrology | Igneous, Sedimentary & Metamorphic | Britannica