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class="firstHeading mw-first-heading"><span class="mw-page-title-main">Pyroclastic rock</span></h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. 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class="interlanguage-link interwiki-az mw-list-item"><a href="https://az.wikipedia.org/wiki/Piroklastik_s%C3%BCxur" title="Piroklastik süxur – Azerbaijani" lang="az" hreflang="az" data-title="Piroklastik süxur" data-language-autonym="Azərbaycanca" data-language-local-name="Azerbaijani" class="interlanguage-link-target"><span>Azərbaycanca</span></a></li><li class="interlanguage-link interwiki-br mw-list-item"><a href="https://br.wikipedia.org/wiki/Piroklastek" title="Piroklastek – Breton" lang="br" hreflang="br" data-title="Piroklastek" data-language-autonym="Brezhoneg" data-language-local-name="Breton" class="interlanguage-link-target"><span>Brezhoneg</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Roca_pirocl%C3%A0stica" title="Roca piroclàstica – Catalan" lang="ca" hreflang="ca" data-title="Roca piroclàstica" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-da badge-Q70893996 mw-list-item" title=""><a href="https://da.wikipedia.org/wiki/Pyroklastisk_bjergart" title="Pyroklastisk bjergart – Danish" lang="da" hreflang="da" data-title="Pyroklastisk bjergart" data-language-autonym="Dansk" data-language-local-name="Danish" class="interlanguage-link-target"><span>Dansk</span></a></li><li class="interlanguage-link interwiki-et mw-list-item"><a href="https://et.wikipedia.org/wiki/P%C3%BCroklastiline_kivim" title="Püroklastiline kivim – Estonian" lang="et" hreflang="et" data-title="Püroklastiline kivim" data-language-autonym="Eesti" data-language-local-name="Estonian" class="interlanguage-link-target"><span>Eesti</span></a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://el.wikipedia.org/wiki/%CE%A0%CF%85%CF%81%CE%BF%CE%BA%CE%BB%CE%B1%CF%83%CF%84%CE%B9%CE%BA%CF%8C_%CF%80%CE%AD%CF%84%CF%81%CF%89%CE%BC%CE%B1" title="Πυροκλαστικό πέτρωμα – Greek" lang="el" hreflang="el" data-title="Πυροκλαστικό πέτρωμα" data-language-autonym="Ελληνικά" data-language-local-name="Greek" class="interlanguage-link-target"><span>Ελληνικά</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Roca_pirocl%C3%A1stica" title="Roca piroclástica – Spanish" lang="es" hreflang="es" data-title="Roca piroclástica" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/Arroka_piroklastiko" title="Arroka piroklastiko – Basque" lang="eu" hreflang="eu" data-title="Arroka piroklastiko" data-language-autonym="Euskara" data-language-local-name="Basque" class="interlanguage-link-target"><span>Euskara</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D8%B3%D9%86%DA%AF_%D8%A2%D8%B0%D8%B1%D8%A2%D9%88%D8%A7%D8%B1%DB%8C" title="سنگ آذرآواری – Persian" lang="fa" hreflang="fa" data-title="سنگ آذرآواری" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Pyroclastite" title="Pyroclastite – French" lang="fr" hreflang="fr" data-title="Pyroclastite" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-ga mw-list-item"><a href="https://ga.wikipedia.org/wiki/Carraig_phireaclastach" title="Carraig phireaclastach – Irish" lang="ga" hreflang="ga" data-title="Carraig phireaclastach" data-language-autonym="Gaeilge" data-language-local-name="Irish" class="interlanguage-link-target"><span>Gaeilge</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%ED%99%94%EC%82%B0%EC%87%84%EC%84%A4%EC%95%94" title="화산쇄설암 – Korean" lang="ko" hreflang="ko" data-title="화산쇄설암" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A4%9C%E0%A5%8D%E0%A4%B5%E0%A4%B2%E0%A4%96%E0%A4%A3%E0%A5%8D%E0%A4%A1%E0%A4%BE%E0%A4%B6%E0%A5%8D%E0%A4%AE%E0%A4%BF_%E0%A4%AA%E0%A4%A6%E0%A4%BE%E0%A4%B0%E0%A5%8D%E0%A4%A5" title="ज्वलखण्डाश्मि पदार्थ – Hindi" lang="hi" hreflang="hi" data-title="ज्वलखण्डाश्मि पदार्थ" data-language-autonym="हिन्दी" data-language-local-name="Hindi" class="interlanguage-link-target"><span>हिन्दी</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Piroklastik" title="Piroklastik – Indonesian" lang="id" hreflang="id" data-title="Piroklastik" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%A1%D7%9C%D7%A2_%D7%A4%D7%99%D7%A8%D7%95%D7%A7%D7%9C%D7%A1%D7%98%D7%99" title="סלע פירוקלסטי – Hebrew" lang="he" hreflang="he" data-title="סלע פירוקלסטי" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-jv mw-list-item"><a href="https://jv.wikipedia.org/wiki/Piroklastik" title="Piroklastik – Javanese" lang="jv" hreflang="jv" data-title="Piroklastik" data-language-autonym="Jawa" data-language-local-name="Javanese" class="interlanguage-link-target"><span>Jawa</span></a></li><li class="interlanguage-link interwiki-mk mw-list-item"><a href="https://mk.wikipedia.org/wiki/%D0%9F%D0%B8%D1%80%D0%BE%D0%BA%D0%BE%D0%BD%D0%B3%D0%BB%D0%BE%D0%BC%D0%B5%D1%80%D0%B0%D1%82" title="Пироконгломерат – Macedonian" lang="mk" hreflang="mk" data-title="Пироконгломерат" data-language-autonym="Македонски" data-language-local-name="Macedonian" class="interlanguage-link-target"><span>Македонски</span></a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/Piroklastik" title="Piroklastik – Malay" lang="ms" hreflang="ms" data-title="Piroklastik" data-language-autonym="Bahasa Melayu" data-language-local-name="Malay" class="interlanguage-link-target"><span>Bahasa Melayu</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Pyroclastisch_gesteente" title="Pyroclastisch gesteente – Dutch" lang="nl" hreflang="nl" data-title="Pyroclastisch gesteente" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E7%81%AB%E5%B1%B1%E7%A0%95%E5%B1%91%E5%B2%A9" title="火山砕屑岩 – Japanese" lang="ja" hreflang="ja" data-title="火山砕屑岩" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-nn mw-list-item"><a href="https://nn.wikipedia.org/wiki/Pyroklastisk_bergart" title="Pyroklastisk bergart – Norwegian Nynorsk" lang="nn" hreflang="nn" data-title="Pyroklastisk bergart" data-language-autonym="Norsk nynorsk" data-language-local-name="Norwegian Nynorsk" class="interlanguage-link-target"><span>Norsk nynorsk</span></a></li><li class="interlanguage-link interwiki-nds mw-list-item"><a href="https://nds.wikipedia.org/wiki/Pyroklastisch_Steen" title="Pyroklastisch Steen – Low German" lang="nds" hreflang="nds" data-title="Pyroklastisch Steen" data-language-autonym="Plattdüütsch" data-language-local-name="Low German" class="interlanguage-link-target"><span>Plattdüütsch</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Ska%C5%82y_piroklastyczne" title="Skały piroklastyczne – Polish" lang="pl" hreflang="pl" data-title="Skały piroklastyczne" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Rocha_pirocl%C3%A1stica" title="Rocha piroclástica – Portuguese" lang="pt" hreflang="pt" data-title="Rocha piroclástica" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%9F%D0%B8%D1%80%D0%BE%D0%BA%D0%BB%D0%B0%D1%81%D1%82%D0%B8%D1%87%D0%B5%D1%81%D0%BA%D0%B8%D0%B5_%D0%B3%D0%BE%D1%80%D0%BD%D1%8B%D0%B5_%D0%BF%D0%BE%D1%80%D0%BE%D0%B4%D1%8B" title="Пирокластические горные породы – Russian" lang="ru" hreflang="ru" data-title="Пирокластические горные породы" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-sl mw-list-item"><a href="https://sl.wikipedia.org/wiki/Piroklasti%C4%8Dne_sedimentne_kamnine" title="Piroklastične sedimentne kamnine – Slovenian" lang="sl" hreflang="sl" data-title="Piroklastične sedimentne kamnine" data-language-autonym="Slovenščina" data-language-local-name="Slovenian" class="interlanguage-link-target"><span>Slovenščina</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/Piroklastik_kaya%C3%A7" title="Piroklastik kayaç – Turkish" lang="tr" hreflang="tr" data-title="Piroklastik kayaç" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%9F%D1%96%D1%80%D0%BE%D0%BA%D0%BB%D0%B0%D1%81%D1%82%D0%B8%D1%87%D0%BD%D1%96_%D0%BF%D0%BE%D1%80%D0%BE%D0%B4%D0%B8" title="Пірокластичні породи – Ukrainian" lang="uk" hreflang="uk" data-title="Пірокластичні породи" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/%C4%90%C3%A1_m%E1%BA%A1t_v%E1%BB%A5n_n%C3%BAi_l%E1%BB%ADa" title="Đá mạt vụn núi lửa – Vietnamese" lang="vi" hreflang="vi" data-title="Đá mạt vụn núi lửa" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E7%81%AB%E5%B1%B1%E7%A2%8E%E5%B1%91%E5%B2%A9" title="火山碎屑岩 – Chinese" lang="zh" hreflang="zh" data-title="火山碎屑岩" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target"><span>中文</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q512121#sitelinks-wikipedia" title="Edit interlanguage links" class="wbc-editpage">Edit links</a></span></div> </div> </div> </div> </header> <div class="vector-page-toolbar"> <div class="vector-page-toolbar-container"> <div id="left-navigation"> <nav aria-label="Namespaces"> <div id="p-associated-pages" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-associated-pages" > <div class="vector-menu-content"> <ul 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print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">For other uses, see <a href="/wiki/Pyroclastic_(disambiguation)" class="mw-redirect mw-disambig" title="Pyroclastic (disambiguation)">Pyroclastic (disambiguation)</a>.</div><figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Pyroclastic_Flow_St._Helens.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/8/84/Pyroclastic_Flow_St._Helens.jpg/300px-Pyroclastic_Flow_St._Helens.jpg" decoding="async" width="300" height="205" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/8/84/Pyroclastic_Flow_St._Helens.jpg/450px-Pyroclastic_Flow_St._Helens.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/8/84/Pyroclastic_Flow_St._Helens.jpg 2x" data-file-width="600" data-file-height="410" /></a><figcaption><a href="/wiki/United_States_Geological_Survey" title="United States Geological Survey">USGS</a> scientist examines <a href="/wiki/Pumice" title="Pumice">pumice</a> blocks at the edge of a pyroclastic flow from <a href="/wiki/Mount_St._Helens" title="Mount St. Helens">Mount St. Helens</a></figcaption></figure> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:BishopTuff.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/6/69/BishopTuff.jpg/220px-BishopTuff.jpg" decoding="async" width="220" height="165" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/69/BishopTuff.jpg/330px-BishopTuff.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/69/BishopTuff.jpg/440px-BishopTuff.jpg 2x" data-file-width="3648" data-file-height="2736" /></a><figcaption>Rocks from the <a href="/wiki/Bishop_Tuff" title="Bishop Tuff">Bishop Tuff</a>, uncompressed with <a href="/wiki/Pumice" title="Pumice">pumice</a> on left; compressed with <a href="/wiki/Fiamme" title="Fiamme">fiamme</a> on right.</figcaption></figure> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><span><video id="mwe_player_0" poster="//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Volcanic_Stone_2D.ogv/220px--Volcanic_Stone_2D.ogv.jpg" controls="" preload="none" data-mw-tmh="" class="mw-file-element" width="220" height="183" data-durationhint="13" data-mwtitle="Volcanic_Stone_2D.ogv" data-mwprovider="wikimediacommons" resource="/wiki/File:Volcanic_Stone_2D.ogv"><source src="//upload.wikimedia.org/wikipedia/commons/transcoded/a/aa/Volcanic_Stone_2D.ogv/Volcanic_Stone_2D.ogv.480p.vp9.webm" type="video/webm; codecs="vp9, opus"" data-transcodekey="480p.vp9.webm" data-width="578" data-height="480" /><source src="//upload.wikimedia.org/wikipedia/commons/transcoded/a/aa/Volcanic_Stone_2D.ogv/Volcanic_Stone_2D.ogv.720p.vp9.webm" type="video/webm; codecs="vp9, opus"" data-transcodekey="720p.vp9.webm" data-width="868" data-height="720" /><source src="//upload.wikimedia.org/wikipedia/commons/a/aa/Volcanic_Stone_2D.ogv" type="video/ogg; codecs="theora"" data-width="1215" data-height="1008" /><source src="//upload.wikimedia.org/wikipedia/commons/transcoded/a/aa/Volcanic_Stone_2D.ogv/Volcanic_Stone_2D.ogv.240p.vp9.webm" type="video/webm; codecs="vp9, opus"" data-transcodekey="240p.vp9.webm" data-width="290" data-height="240" /><source src="//upload.wikimedia.org/wikipedia/commons/transcoded/a/aa/Volcanic_Stone_2D.ogv/Volcanic_Stone_2D.ogv.360p.webm" type="video/webm; codecs="vp8, vorbis"" data-transcodekey="360p.webm" data-width="434" data-height="360" /><source src="//upload.wikimedia.org/wikipedia/commons/transcoded/a/aa/Volcanic_Stone_2D.ogv/Volcanic_Stone_2D.ogv.360p.vp9.webm" type="video/webm; codecs="vp9, opus"" data-transcodekey="360p.vp9.webm" data-width="434" data-height="360" /></video></span><figcaption>Flight through a <a href="/wiki/Computed_tomography" class="mw-redirect" title="Computed tomography">μCT</a>-image stack of a <a href="/wiki/Lapilli" title="Lapilli">lapillus</a> of the volcano <a href="/wiki/Katla_volcano" class="mw-redirect" title="Katla volcano">Katla</a> in <a href="/wiki/Iceland" title="Iceland">Iceland</a>. Find spot: Beach near <a href="/wiki/Vik,_Sogn" title="Vik, Sogn">Vik</a> at the end of road 215. Acquisition done using "CT Alpha" by "Procon X-Ray GmbH", Garbsen, Germany. Resolution 11,2μm/<a href="/wiki/Voxel" title="Voxel">Voxel</a>, width approx. 24 mm.</figcaption></figure> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><span><video id="mwe_player_1" poster="//upload.wikimedia.org/wikipedia/commons/thumb/0/07/Volcanic_Stone_3D.ogv/220px--Volcanic_Stone_3D.ogv.jpg" controls="" preload="none" data-mw-tmh="" class="mw-file-element" width="220" height="124" data-durationhint="31" data-mwtitle="Volcanic_Stone_3D.ogv" data-mwprovider="wikimediacommons" resource="/wiki/File:Volcanic_Stone_3D.ogv"><source src="//upload.wikimedia.org/wikipedia/commons/transcoded/0/07/Volcanic_Stone_3D.ogv/Volcanic_Stone_3D.ogv.480p.vp9.webm" type="video/webm; codecs="vp9, opus"" data-transcodekey="480p.vp9.webm" data-width="854" data-height="480" /><source src="//upload.wikimedia.org/wikipedia/commons/0/07/Volcanic_Stone_3D.ogv" type="video/ogg; codecs="theora"" data-width="1024" data-height="576" /><source src="//upload.wikimedia.org/wikipedia/commons/transcoded/0/07/Volcanic_Stone_3D.ogv/Volcanic_Stone_3D.ogv.240p.vp9.webm" type="video/webm; codecs="vp9, opus"" data-transcodekey="240p.vp9.webm" data-width="426" data-height="240" /><source src="//upload.wikimedia.org/wikipedia/commons/transcoded/0/07/Volcanic_Stone_3D.ogv/Volcanic_Stone_3D.ogv.360p.webm" type="video/webm; codecs="vp8, vorbis"" data-transcodekey="360p.webm" data-width="640" data-height="360" /><source src="//upload.wikimedia.org/wikipedia/commons/transcoded/0/07/Volcanic_Stone_3D.ogv/Volcanic_Stone_3D.ogv.360p.vp9.webm" type="video/webm; codecs="vp9, opus"" data-transcodekey="360p.vp9.webm" data-width="640" data-height="360" /></video></span><figcaption>3D-Rendering of the above image stack, in parts transparent. Heavy particles in red.</figcaption></figure> <p><b>Pyroclastic rocks</b> are <a href="/wiki/Clastic_rock" title="Clastic rock">clastic rocks</a> composed of rock fragments produced and ejected by explosive volcanic eruptions. The individual rock fragments are known as <b>pyroclasts</b>. Pyroclastic rocks are a type of <a href="/wiki/Volcaniclastic" class="mw-redirect" title="Volcaniclastic">volcaniclastic</a> deposit, which are deposits made predominantly of volcanic particles.<sup id="cite_ref-fisher-1961_1-0" class="reference"><a href="#cite_note-fisher-1961-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-fisher-schminke-1984-89_2-0" class="reference"><a href="#cite_note-fisher-schminke-1984-89-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> 'Phreatic' pyroclastic deposits are a variety of pyroclastic rock that forms from volcanic steam explosions and they are entirely made of accidental clasts. 'Phreatomagmatic' pyroclastic deposits are formed from explosive interaction of <a href="/wiki/Magma" title="Magma">magma</a> with <a href="/wiki/Groundwater" title="Groundwater">groundwater</a>.<sup id="cite_ref-FOOTNOTEFisher19611409_3-0" class="reference"><a href="#cite_note-FOOTNOTEFisher19611409-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> The word <i>pyroclastic</i> is derived from the Greek <span title="Greek-language text"><span lang="el">πῦρ</span></span>, meaning fire; and <span title="Greek-language text"><span lang="el">κλαστός</span></span>, meaning broken.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (November 2024)">citation needed</span></a></i>]</sup> </p><p>Unconsolidated accumulations of pyroclasts are described as <a href="/wiki/Tephra" title="Tephra">tephra</a>. Tephra may become <a href="/wiki/Lithified" class="mw-redirect" title="Lithified">lithified</a> to a pyroclastic rock by cementation or chemical reactions as the result of the passage of hot gases (<a href="/wiki/Fumarolic" class="mw-redirect" title="Fumarolic">fumarolic</a> alteration) or groundwater (e.g. <a href="/wiki/Hydrothermal_alteration" class="mw-redirect" title="Hydrothermal alteration">hydrothermal alteration</a> and <a href="/wiki/Diagenesis" title="Diagenesis">diagenesis</a>) and burial, or, if it is emplaced at temperatures so hot that the soft glassy pyroclasts stick together at point contacts, and deform: this is known as <a href="/wiki/Welding_(geology)" class="mw-redirect" title="Welding (geology)">welding</a>.<sup id="cite_ref-schmincke-2003-138_4-0" class="reference"><a href="#cite_note-schmincke-2003-138-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> </p><p>One of the most spectacular types of pyroclastic deposit is an <a href="/wiki/Ignimbrite" title="Ignimbrite">ignimbrite</a>, which is the deposit of a ground-hugging pumiceous pyroclastic density current (a rapidly flowing hot suspension of pyroclasts in gas). Ignimbrites may be loose deposits or solid rock, and they can bury entire landscapes. An individual ignimbrite can exceed 1000 km<sup>3</sup> in volume, can cover 20,000 km<sup>2</sup> of land, and may exceed 1 km in thickness, for example where it is ponded within a volcanic caldera. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Classification">Classification</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Pyroclastic_rock&action=edit&section=1" title="Edit section: Classification"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Pyroclasts include juvenile pyroclasts derived from chilled magma, mixed with accidental pyroclasts, which are fragments of <a href="/wiki/Country_rock_(geology)" title="Country rock (geology)">country rock</a>. Pyroclasts of different sizes are classified (from smallest to largest) as <a href="/wiki/Volcanic_ash" title="Volcanic ash">volcanic ash</a>, <a href="/wiki/Lapilli" title="Lapilli">lapilli</a>, or <a href="/wiki/Volcanic_block" title="Volcanic block">volcanic blocks</a> (or, if they exhibit evidence of having been hot and molten during emplacement, <a href="/wiki/Volcanic_bomb" title="Volcanic bomb">volcanic bombs</a>). All are considered to be pyroclastic because they were formed (fragmented) by volcanic explosivity, for example during explosive decompression, shear, thermal <a href="/wiki/Decrepitation" title="Decrepitation">decrepitation</a>, or by attrition and abrasion in a volcanic conduit, volcanic jet, or pyroclastic density current.<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> </p> <table class="wikitable"> <tbody><tr> <th>Clast size</th> <th>Pyroclast</th> <th>Mainly unconsolidated (tephra)</th> <th>Mainly consolidated: pyroclastic rock </th></tr> <tr> <td>> 64 mm</td> <td>block (angular)<br />bomb (if fluidal-shaped)</td> <td>blocks; agglomerate</td> <td>pyroclastic breccia; agglomerate </td></tr> <tr> <td>< 64 mm</td> <td>lapillus</td> <td>lapilli</td> <td>lapillistone (<a href="/wiki/Lapilli_tuff" class="mw-redirect" title="Lapilli tuff">lapilli tuff</a> is where lapilli are supported within a matrix of tuff) </td></tr> <tr> <td>< 2 mm</td> <td>coarse ash</td> <td>coarse ash</td> <td>coarse <a href="/wiki/Tuff" title="Tuff">tuff</a> </td></tr> <tr> <td>< 0.063 mm</td> <td>fine ash</td> <td>fine ash</td> <td>fine tuff </td></tr></tbody></table> <p>Pyroclasts are transported in two main ways: in atmospheric eruption plumes, from which pyroclasts settle to form topography-draping <a href="/wiki/Pyroclastic_fall" title="Pyroclastic fall">pyroclastic fall</a> layers, and by pyroclastic density currents (PDCs) (including <a href="/wiki/Pyroclastic_flow" title="Pyroclastic flow">pyroclastic flows</a> and <a href="/wiki/Pyroclastic_surge" title="Pyroclastic surge">pyroclastic surges</a>),<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> from which pyroclasts are deposited as pyroclastic density current deposits, which tend to thicken and coarsen in valleys, and thin and fine over topographic highs. </p><p>During <a href="/wiki/Plinian_eruption" title="Plinian eruption">Plinian eruptions</a>, <a href="/wiki/Pumice" title="Pumice">pumice</a> and <a href="/wiki/Volcanic_ash" title="Volcanic ash">ash</a> are formed when foaming <a href="/wiki/Silicic" title="Silicic">silicic</a> <a href="/wiki/Magma" title="Magma">magma</a> is fragmented in the volcanic conduit, because of rapid shear driven by decompression and the growth of microscopic bubbles. The pyroclasts are then entrained with hot gases to form a supersonic jet that exits the volcano, admixes and heats cold atmospheric air to form a vigorously buoyant <a href="/wiki/Eruption_column" title="Eruption column">eruption column</a> that rises several kilometers into the stratosphere and cause <a href="/wiki/Volcanic_ash_and_aviation_safety" title="Volcanic ash and aviation safety">aviation hazards</a>.<sup id="cite_ref-FOOTNOTESchmincke2003155–176_7-0" class="reference"><a href="#cite_note-FOOTNOTESchmincke2003155–176-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> Particles fall from atmospheric eruption plumes and accumulate as layers on the ground, which are described as fallout deposits.<sup id="cite_ref-FOOTNOTEFisherSchmincke19848_8-0" class="reference"><a href="#cite_note-FOOTNOTEFisherSchmincke19848-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> </p><p>Pyroclastic density currents arise when the mixture of hot pyroclasts and gases is denser than the atmosphere and so, instead of rising buoyantly, it spreads out across the landscape. They are one of the greatest hazards at a volcano, and may be either 'fully dilute' (dilute, turbulent ash clouds, right down to their lower levels) or 'granular fluid based' (the lower levels of which comprise a concentrated dispersion of interacting pyroclasts and partly trapped gas).<sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> The former type are sometimes called <i>pyroclastic surges</i> (even though they may be sustained rather than "surging") and lower parts of the latter are sometimes termed <i>pyroclastic flows</i> (these, also, can be sustained and quasi steady or surging). As they travel, pyroclastic density currents deposit particles on the ground, and they entrain cold atmospheric air, which is then heated and thermally expands.<sup id="cite_ref-FOOTNOTESchmincke2003177–208_10-0" class="reference"><a href="#cite_note-FOOTNOTESchmincke2003177–208-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> Where the density current becomes sufficiently dilute to loft, it rises into the atmosphere as a 'phoenix plume'<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> (or 'co-PDC plume').<sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> These phoenix plumes typically deposit thin ashfall layers that may contain little pellets of aggregated fine ash.<sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> </p><p>Hawaiian eruptions such as those at <a href="/wiki/K%C4%ABlauea" title="Kīlauea">Kīlauea</a> produce an upward-directed jet of hot droplets and clots of magma suspended in gas; this is called a <a href="/wiki/Lava_fountain" class="mw-redirect" title="Lava fountain">lava fountain</a><sup id="cite_ref-macdonald-etal-2983_14-0" class="reference"><a href="#cite_note-macdonald-etal-2983-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> or 'fire-fountain'.<sup id="cite_ref-allaby-2013_15-0" class="reference"><a href="#cite_note-allaby-2013-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> If sufficiently hot and liquid when they land, the hot droplets and clots of magma may agglutinate to form 'spatter' ('agglutinate'), or fully coalesce to form a clastogenic <a href="/wiki/Lava_flow" class="mw-redirect" title="Lava flow">lava flow</a>.<sup id="cite_ref-macdonald-etal-2983_14-1" class="reference"><a href="#cite_note-macdonald-etal-2983-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-allaby-2013_15-1" class="reference"><a href="#cite_note-allaby-2013-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Pyroclastic_rock&action=edit&section=2" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Silicon_dioxide" title="Silicon dioxide">Silicon dioxide</a></li> <li><a href="/wiki/Hyaloclastite" title="Hyaloclastite">Hyaloclastite</a> – Volcaniclastic accumulation or breccia</li> <li><a href="/wiki/Peperite" title="Peperite">Peperite</a> – Sedimentary rock that contains fragments of younger igneous material</li> <li><a href="/wiki/Scoria" title="Scoria">Scoria</a> – Dark vesicular volcanic rock</li></ul> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Pyroclastic_rock&action=edit&section=3" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap mw-references-columns"><ol class="references"> <li id="cite_note-fisher-1961-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-fisher-1961_1-0">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite id="CITEREFFisher1961" class="citation journal cs1">Fisher, Richard V. (1961). "Proposed classification of volcaniclastic sediments and rocks". <i>Geological Society of America Bulletin</i>. <b>72</b> (9): 1409. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1961GSAB...72.1409F">1961GSAB...72.1409F</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1130%2F0016-7606%281961%2972%5B1409%3APCOVSA%5D2.0.CO%3B2">10.1130/0016-7606(1961)72[1409:PCOVSA]2.0.CO;2</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Geological+Society+of+America+Bulletin&rft.atitle=Proposed+classification+of+volcaniclastic+sediments+and+rocks&rft.volume=72&rft.issue=9&rft.pages=1409&rft.date=1961&rft_id=info%3Adoi%2F10.1130%2F0016-7606%281961%2972%5B1409%3APCOVSA%5D2.0.CO%3B2&rft_id=info%3Abibcode%2F1961GSAB...72.1409F&rft.aulast=Fisher&rft.aufirst=Richard+V.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APyroclastic+rock" class="Z3988"></span></span> </li> <li id="cite_note-fisher-schminke-1984-89-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-fisher-schminke-1984-89_2-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFFisherSchmincke1984" class="citation book cs1">Fisher, Richard V.; Schmincke, H.-U. (1984). <i>Pyroclastic rocks</i>. Berlin: Springer-Verlag. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/3540127569" title="Special:BookSources/3540127569"><bdi>3540127569</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Pyroclastic+rocks&rft.place=Berlin&rft.pub=Springer-Verlag&rft.date=1984&rft.isbn=3540127569&rft.aulast=Fisher&rft.aufirst=Richard+V.&rft.au=Schmincke%2C+H.-U.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APyroclastic+rock" class="Z3988"></span></span> </li> <li id="cite_note-FOOTNOTEFisher19611409-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-FOOTNOTEFisher19611409_3-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFFisher1961">Fisher 1961</a>, p. 1409.</span> </li> <li id="cite_note-schmincke-2003-138-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-schmincke-2003-138_4-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFSchmincke2003" class="citation book cs1">Schmincke, Hans-Ulrich (2003). <i>Volcanism</i>. Berlin: Springer. p. 138. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9783540436508" title="Special:BookSources/9783540436508"><bdi>9783540436508</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Volcanism&rft.place=Berlin&rft.pages=138&rft.pub=Springer&rft.date=2003&rft.isbn=9783540436508&rft.aulast=Schmincke&rft.aufirst=Hans-Ulrich&rfr_id=info%3Asid%2Fen.wikipedia.org%3APyroclastic+rock" class="Z3988"></span></span> </li> <li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text">Heiken, G. and Wohletz, K., 1985 <i>Volcanic Ash</i>, University of California Press;, pp. 246.</span> </li> <li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFPhilpottsAgue2009" class="citation book cs1">Philpotts, Anthony R.; Ague, Jay J. (2009). <i>Principles of igneous and metamorphic petrology</i> (2nd ed.). Cambridge, UK: Cambridge University Press. p. 73. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9780521880060" title="Special:BookSources/9780521880060"><bdi>9780521880060</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Principles+of+igneous+and+metamorphic+petrology&rft.place=Cambridge%2C+UK&rft.pages=73&rft.edition=2nd&rft.pub=Cambridge+University+Press&rft.date=2009&rft.isbn=9780521880060&rft.aulast=Philpotts&rft.aufirst=Anthony+R.&rft.au=Ague%2C+Jay+J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APyroclastic+rock" class="Z3988"></span></span> </li> <li id="cite_note-FOOTNOTESchmincke2003155–176-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-FOOTNOTESchmincke2003155–176_7-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFSchmincke2003">Schmincke 2003</a>, pp. 155–176.</span> </li> <li id="cite_note-FOOTNOTEFisherSchmincke19848-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-FOOTNOTEFisherSchmincke19848_8-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFFisherSchmincke1984">Fisher & Schmincke 1984</a>, p. 8.</span> </li> <li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFBreardLube2017" class="citation journal cs1">Breard, Eric C.P.; Lube, Gert (January 2017). "Inside pyroclastic density currents – uncovering the enigmatic flow structure and transport behaviour in large-scale experiments". <i>Earth and Planetary Science Letters</i>. <b>458</b>: <span class="nowrap">22–</span>36. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2017E&PSL.458...22B">2017E&PSL.458...22B</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.epsl.2016.10.016">10.1016/j.epsl.2016.10.016</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Earth+and+Planetary+Science+Letters&rft.atitle=Inside+pyroclastic+density+currents+%E2%80%93+uncovering+the+enigmatic+flow+structure+and+transport+behaviour+in+large-scale+experiments&rft.volume=458&rft.pages=%3Cspan+class%3D%22nowrap%22%3E22-%3C%2Fspan%3E36&rft.date=2017-01&rft_id=info%3Adoi%2F10.1016%2Fj.epsl.2016.10.016&rft_id=info%3Abibcode%2F2017E%26PSL.458...22B&rft.aulast=Breard&rft.aufirst=Eric+C.P.&rft.au=Lube%2C+Gert&rfr_id=info%3Asid%2Fen.wikipedia.org%3APyroclastic+rock" class="Z3988"></span></span> </li> <li id="cite_note-FOOTNOTESchmincke2003177–208-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-FOOTNOTESchmincke2003177–208_10-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFSchmincke2003">Schmincke 2003</a>, pp. 177–208.</span> </li> <li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFSulpizioDellino2008" class="citation journal cs1">Sulpizio, Roberto; Dellino, Pierfrancesco (2008). 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Honolulu: University of Hawaii Press. pp. 6, 9, <span class="nowrap">96–</span>97. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0824808320" title="Special:BookSources/0824808320"><bdi>0824808320</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Volcanoes+in+the+sea+%3A+the+geology+of+Hawaii&rft.place=Honolulu&rft.pages=6%2C+9%2C+%3Cspan+class%3D%22nowrap%22%3E96-%3C%2Fspan%3E97&rft.edition=2nd&rft.pub=University+of+Hawaii+Press&rft.date=1983&rft.isbn=0824808320&rft.aulast=Macdonald&rft.aufirst=Gordon+A.&rft.au=Abbott%2C+Agatin+T.&rft.au=Peterson%2C+Frank+L.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APyroclastic+rock" class="Z3988"></span></span> </li> <li id="cite_note-allaby-2013-15"><span class="mw-cite-backlink">^ <a href="#cite_ref-allaby-2013_15-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-allaby-2013_15-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFAllaby2013" class="citation book cs1">Allaby, Michael, ed. (2013). "Fire-fountain". <i>A dictionary of geology and earth sciences</i> (Fourth ed.). Oxford University Press. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9780199653065" title="Special:BookSources/9780199653065"><bdi>9780199653065</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Fire-fountain&rft.btitle=A+dictionary+of+geology+and+earth+sciences&rft.edition=Fourth&rft.pub=Oxford+University+Press&rft.date=2013&rft.isbn=9780199653065&rfr_id=info%3Asid%2Fen.wikipedia.org%3APyroclastic+rock" class="Z3988"></span></span> </li> </ol></div></div> <style data-mw-deduplicate="TemplateStyles:r1239549316">.mw-parser-output .refbegin{margin-bottom:0.5em}.mw-parser-output .refbegin-hanging-indents>ul{margin-left:0}.mw-parser-output .refbegin-hanging-indents>ul>li{margin-left:0;padding-left:3.2em;text-indent:-3.2em}.mw-parser-output .refbegin-hanging-indents ul,.mw-parser-output .refbegin-hanging-indents ul li{list-style:none}@media(max-width:720px){.mw-parser-output .refbegin-hanging-indents>ul>li{padding-left:1.6em;text-indent:-1.6em}}.mw-parser-output .refbegin-columns{margin-top:0.3em}.mw-parser-output .refbegin-columns ul{margin-top:0}.mw-parser-output .refbegin-columns li{page-break-inside:avoid;break-inside:avoid-column}@media screen{.mw-parser-output .refbegin{font-size:90%}}</style><div class="refbegin" style=""> <div class="mw-heading mw-heading2"><h2 id="Other_reading">Other reading</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Pyroclastic_rock&action=edit&section=4" title="Edit section: Other reading"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1235681985">.mw-parser-output .side-box{margin:4px 0;box-sizing:border-box;border:1px solid #aaa;font-size:88%;line-height:1.25em;background-color:var(--background-color-interactive-subtle,#f8f9fa);display:flow-root}.mw-parser-output .side-box-abovebelow,.mw-parser-output .side-box-text{padding:0.25em 0.9em}.mw-parser-output .side-box-image{padding:2px 0 2px 0.9em;text-align:center}.mw-parser-output .side-box-imageright{padding:2px 0.9em 2px 0;text-align:center}@media(min-width:500px){.mw-parser-output .side-box-flex{display:flex;align-items:center}.mw-parser-output .side-box-text{flex:1;min-width:0}}@media(min-width:720px){.mw-parser-output .side-box{width:238px}.mw-parser-output .side-box-right{clear:right;float:right;margin-left:1em}.mw-parser-output .side-box-left{margin-right:1em}}</style><style data-mw-deduplicate="TemplateStyles:r1237033735">@media print{body.ns-0 .mw-parser-output .sistersitebox{display:none!important}}@media screen{html.skin-theme-clientpref-night .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}</style><div class="side-box side-box-right plainlinks sistersitebox"><style data-mw-deduplicate="TemplateStyles:r1126788409">.mw-parser-output .plainlist ol,.mw-parser-output .plainlist ul{line-height:inherit;list-style:none;margin:0;padding:0}.mw-parser-output .plainlist ol li,.mw-parser-output .plainlist ul li{margin-bottom:0}</style> <div class="side-box-flex"> <div class="side-box-image"><span class="noviewer" typeof="mw:File"><a href="/wiki/File:Commons-logo.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/40px-Commons-logo.svg.png" decoding="async" width="30" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/60px-Commons-logo.svg.png 1.5x" data-file-width="1024" data-file-height="1376" /></a></span></div> <div class="side-box-text plainlist">Wikimedia Commons has media related to <span style="font-weight: bold; font-style: italic;"><a href="https://commons.wikimedia.org/wiki/Category:Pyroclastic_rocks" class="extiw" title="commons:Category:Pyroclastic rocks">Pyroclastic rocks</a></span>.</div></div> </div> <ul><li>Blatt, Harvey and Robert J. Tracy (1996) <i>Petrology: Igneous, Sedimentary, and Metamorphic</i>, W.H.W. Freeman & Company; 2nd ed., pp. 26–29; <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-7167-2438-3" title="Special:BookSources/0-7167-2438-3">0-7167-2438-3</a></li> <li>Branney, M.J., Brown, R.J. and Calder, E. (2020) Pyroclastic Rocks. In: Elias, S. and Alderton D. (eds) Encyclopedia of Geology. 2nd Edition. Elsevier. <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9780081029084" title="Special:BookSources/9780081029084">9780081029084</a></li></ul> </div> <div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol dl,.mw-parser-output .hlist ol ol,.mw-parser-output .hlist ol ul,.mw-parser-output .hlist ul dl,.mw-parser-output .hlist ul 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