{"id":2319,"date":"2026-09-24T22:58:53","date_gmt":"2026-09-24T20:58:53","guid":{"rendered":"https:\/\/www.geoleg.cat\/?page_id=2319"},"modified":"2026-09-24T23:51:38","modified_gmt":"2026-09-24T21:51:38","slug":"calculadora-de-composicio-de-roques-ignies","status":"publish","type":"page","link":"https:\/\/www.geoleg.cat\/index.php\/que-oferim\/recursos-didactics\/recursos-geologia\/calculadora-de-composicio-de-roques-ignies\/","title":{"rendered":"Calculadora de composici\u00f3 de roques \u00edgnies"},"content":{"rendered":"\t\t\t<section class=\"gqapf-app\" data-gqapf id=\"gqapf-1\">\n\t\t\t\t<header class=\"gqapf-header\">\n\t\t\t\t\t<div class=\"gqapf-brand-row\">\n\t\t\t\t\t\t<a class=\"gqapf-brand\" href=\"https:\/\/www.geoleg.cat\/\" target=\"_blank\" rel=\"noopener noreferrer\"><img decoding=\"async\" data-src=\"https:\/\/www.geoleg.cat\/wp-content\/plugins\/geoleg-calculadora-streckeisen\/assets\/img\/geoleg-logo.png\" alt=\"Ge\u00f2leg.cat\" src=\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\" class=\"lazyload\" style=\"--smush-placeholder-width: 600px; --smush-placeholder-aspect-ratio: 600\/128;\"><\/a>\n\t\t\t\t\t\t<span class=\"gqapf-brand-separator\" aria-hidden=\"true\"><\/span>\n\t\t\t\t\t\t<a class=\"gqapf-brand\" href=\"https:\/\/geologia365.com\/\" target=\"_blank\" rel=\"noopener noreferrer\"><img decoding=\"async\" data-src=\"https:\/\/www.geoleg.cat\/wp-content\/plugins\/geoleg-calculadora-streckeisen\/assets\/img\/geologia365-logo.jpg\" alt=\"Geologia365.com\" src=\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\" class=\"lazyload\" style=\"--smush-placeholder-width: 1400px; --smush-placeholder-aspect-ratio: 1400\/373;\"><\/a>\n\t\t\t\t\t\t<button type=\"button\" class=\"gqapf-text-size\" data-size title=\"Augmenta la lletra\" aria-label=\"Augmenta la mida de la lletra\">A+<\/button>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<p class=\"gqapf-kicker\">Laboratori virtual \u00b7 Petrologia \u00edgnia<\/p>\n\t\t\t\t\t<h2>Calculadora de roques \u00edgnies segons la composici\u00f3<\/h2>\n\t\t\t\t\t<p>Introdueix la proporci\u00f3 dels minerals i situa la mostra dins del diagrama QAPF.<\/p>\n\t\t\t\t\t<div class=\"gqapf-tags\"><span>Roques plut\u00f2niques i volc\u00e0niques<\/span><span>Composici\u00f3 modal<\/span><span>Resultat dins del diagrama<\/span><\/div>\n\t\t\t\t<\/header>\n\t\t\t\t<div class=\"gqapf-intro\"><strong>Com funciona?<\/strong> Introdueix el percentatge de cada component en la roca sencera: Q (quars), A (feldspat alcal\u00ed), P (plagi\u00f2clasi), F (feldespatoides) i M (altres minerals, principalment m\u00e0fics). La suma ha de ser 100 %. QAPF \u00e9s el nom del diagrama format pels quatre primers components: l\u2019eina retira M i normalitza Q\u2013A\u2013P o F\u2013A\u2013P per situar el punt.<\/div>\n\t\t\t\t<form class=\"gqapf-form\" data-form novalidate>\n\t\t\t\t\t<div class=\"gqapf-heading\"><span class=\"gqapf-step\">1<\/span><h3>Tipus de roca<\/h3><\/div>\n\t\t\t\t\t<fieldset class=\"gqapf-mode\"><legend class=\"gqapf-sr\">Tria un diagrama<\/legend>\n\t\t\t\t\t\t<label><input type=\"radio\" name=\"gqapf-1-mode\" value=\"plutonic\" data-mode checked><span>Plut\u00f2nica (gra gruixut)<\/span><\/label>\n\t\t\t\t\t\t<label><input type=\"radio\" name=\"gqapf-1-mode\" value=\"volcanic\" data-mode><span>Volc\u00e0nica (gra fi)<\/span><\/label>\n\t\t\t\t\t<\/fieldset>\n\t\t\t\t\t<div class=\"gqapf-divider\"><\/div>\n\t\t\t\t\t<div class=\"gqapf-heading gqapf-heading-actions\"><span class=\"gqapf-step\">2<\/span><h3>Composici\u00f3 de la roca sencera<\/h3><button type=\"button\" class=\"gqapf-random\" data-random>Fes-ho aleatori<\/button><\/div>\n\t\t\t\t\t<p class=\"gqapf-help\">Q i F no poden coexistir en el QAPF. M inclou els minerals que no s\u00f3n Q, A, P ni F; si M arriba al 90 %, cal classificar la roca com a ultram\u00e0fica amb un altre diagrama.<\/p>\n\t\t\t\t\t<div class=\"gqapf-inputs\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"gqapf-input-card\"><label for=\"gqapf-1-q\"><b>Q<\/b> Quars<\/label><div class=\"gqapf-unit\"><input id=\"gqapf-1-q\" data-part=\"q\" type=\"number\" min=\"0\" max=\"100\" step=\"0.1\" inputmode=\"decimal\" value=\"25\"><span>%<\/span><\/div><\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"gqapf-input-card\"><label for=\"gqapf-1-a\"><b>A<\/b> Feldspat alcal\u00ed<\/label><div class=\"gqapf-unit\"><input id=\"gqapf-1-a\" data-part=\"a\" type=\"number\" min=\"0\" max=\"100\" step=\"0.1\" inputmode=\"decimal\" value=\"55\"><span>%<\/span><\/div><\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"gqapf-input-card\"><label for=\"gqapf-1-p\"><b>P<\/b> Plagi\u00f2clasi<\/label><div class=\"gqapf-unit\"><input id=\"gqapf-1-p\" data-part=\"p\" type=\"number\" min=\"0\" max=\"100\" step=\"0.1\" inputmode=\"decimal\" value=\"20\"><span>%<\/span><\/div><\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"gqapf-input-card\"><label for=\"gqapf-1-f\"><b>F<\/b> Feldespatoides<\/label><div class=\"gqapf-unit\"><input id=\"gqapf-1-f\" data-part=\"f\" type=\"number\" min=\"0\" max=\"100\" step=\"0.1\" inputmode=\"decimal\" value=\"0\"><span>%<\/span><\/div><\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"gqapf-input-card\"><label for=\"gqapf-1-m\"><b>M<\/b> Altres minerals<\/label><div class=\"gqapf-unit\"><input id=\"gqapf-1-m\" data-part=\"m\" type=\"number\" min=\"0\" max=\"100\" step=\"0.1\" inputmode=\"decimal\" value=\"0\"><span>%<\/span><\/div><\/div>\n\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<div class=\"gqapf-total\" data-total>La suma \u00e9s 100 %.<\/div>\n\t\t\t\t\t<details class=\"gqapf-advanced\"><summary>Dades opcionals per precisar el nom<\/summary><p class=\"gqapf-advanced-intro\">Aquests valors ajuden a escollir entre dos noms quan el punt QAPF cau en un camp compartit. Deixa\u2019ls en blanc si no tens les dades: no formen part de la suma Q + A + P + F + M.<\/p><div class=\"gqapf-advanced-content\">\n\t\t\t\t\t\t<div class=\"gqapf-input-card\"><label for=\"gqapf-1-an\">Composici\u00f3 de la plagi\u00f2clasi (An)<\/label><div class=\"gqapf-unit\"><input id=\"gqapf-1-an\" data-extra=\"an\" type=\"number\" min=\"0\" max=\"100\" step=\"0.1\" inputmode=\"decimal\" placeholder=\"Si es coneix\"><span>% An<\/span><\/div><small><strong>Qu\u00e8 \u00e9s An?<\/strong> \u00c9s el percentatge del component anortita dins la plagi\u00f2clasi, mesurat en aquest mineral; no \u00e9s la quantitat de plagi\u00f2clasi de tota la roca. En certs camps plut\u00f2nics, ajuda a triar entre diorita i gabre (o els seus equivalents monzo i fo\u00eddics).<\/small><\/div>\n\t\t\t\t\t\t<div class=\"gqapf-input-card\"><label for=\"gqapf-1-silica\">Di\u00f2xid de silici (SiO\u2082)<\/label><div class=\"gqapf-unit\"><input id=\"gqapf-1-silica\" data-extra=\"silica\" type=\"number\" min=\"0\" max=\"100\" step=\"0.1\" inputmode=\"decimal\" placeholder=\"Si es coneix\"><span>% massa<\/span><\/div><small><strong>Qu\u00e8 \u00e9s SiO\u2082?<\/strong> \u00c9s la proporci\u00f3 en massa de s\u00edlice obtinguda d\u2019una an\u00e0lisi qu\u00edmica de la roca sencera, diferent del percentatge de quars (Q). En els camps volc\u00e0nics 9\u201310, ajuda a distingir basalt d\u2019andesita al voltant del 52 %.<\/small><\/div>\n\t\t\t\t\t\t<div class=\"gqapf-input-card\"><label for=\"gqapf-1-ol\">Olivina normativa (norma CIPW)<\/label><div class=\"gqapf-unit\"><input id=\"gqapf-1-ol\" data-extra=\"olNorm\" type=\"number\" min=\"0\" max=\"100\" step=\"0.1\" inputmode=\"decimal\" placeholder=\"Si es coneix\"><span>%<\/span><\/div><small><strong>Qu\u00e8 \u00e9s CIPW?<\/strong> \u00c9s un m\u00e8tode que calcula minerals te\u00f2rics a partir de l\u2019an\u00e0lisi qu\u00edmica. L\u2019olivina normativa \u00e9s calculada, no l\u2019olivina observada al microscopi: el llindar del 10 % ajuda a distingir basanita de tefrita.<\/small><\/div>\n\t\t\t\t\t<\/div><\/details>\n\t\t\t\t\t<div class=\"gqapf-buttons\"><button class=\"gqapf-calculate\" type=\"submit\">Classifica la roca<\/button><button class=\"gqapf-clear\" data-clear type=\"button\">Esborra els valors<\/button><\/div>\n\t\t\t\t\t<p class=\"gqapf-feedback\" data-feedback role=\"status\" aria-live=\"polite\">Introdueix una composici\u00f3 i prem \u00abClassifica la roca\u00bb.<\/p>\n\t\t\t\t<\/form>\n\t\t\t\t<div class=\"gqapf-output\" data-output hidden>\n\t\t\t\t\t<div class=\"gqapf-result-overview\">\n\t\t\t\t\t\t<div class=\"gqapf-result\"><p>Nom segons el camp QAPF<\/p><h3 data-rock-name><\/h3><p data-field-name><\/p><div data-notes><\/div><\/div>\n\t\t\t\t\t\t<div class=\"gqapf-composition\"><h3>Composici\u00f3 analitzada<\/h3><div data-whole><\/div><h4>Components QAPF normalitzats (sense els altres minerals M)<\/h4><div data-normalized><\/div><p data-ratio><\/p><p class=\"gqapf-help\">Els primers percentatges s\u00f3n de la roca sencera. Els segons exclouen M i sumen 100 %.<\/p><\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<div class=\"gqapf-plot\"><h3>Punt al diagrama de Streckeisen<\/h3><div class=\"gqapf-plot-layout\"><div class=\"gqapf-plot-side\"><svg data-diagram viewBox=\"0 0 800 700\" role=\"img\" aria-label=\"Diagrama QAPF amb els n\u00fameros dels camps i la posici\u00f3 de la mostra\"><\/svg><div class=\"gqapf-play\"><strong>Juga amb el diagrama<\/strong><p>Clica qualsevol punt del rombe i veur\u00e0s una altra roca a l\u2019instant. Es mant\u00e9 el percentatge d\u2019altres minerals (M).<\/p><button type=\"button\" data-play>Prova un punt aleatori al rombe<\/button><\/div><\/div><div class=\"gqapf-legend\"><h4>Correspond\u00e8ncia dels camps<\/h4><p><strong data-legend-mode><\/strong> \u00b7 Clica una casella per provar la composici\u00f3 d\u2019aquell camp.<\/p><p class=\"gqapf-legend-key\">* = amb quars \u00b7 \u2019 = amb pocs feldespatoides<\/p><div data-legend><\/div><\/div><\/div><\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<details class=\"gqapf-sources\"><summary>Fonts i l\u00edmits d\u2019aplicaci\u00f3<\/summary><div><p>Classificaci\u00f3 segons el <a href=\"https:\/\/nora.nerc.ac.uk\/id\/eprint\/3223\/1\/RR99006.pdf\" target=\"_blank\" rel=\"noopener noreferrer\">British Geological Survey, RR\/99\/06<\/a>: figura 11 (plut\u00f2niques) i figura 19 (volc\u00e0niques), basades en Streckeisen. En roques volc\u00e0niques v\u00edtries o de mineralogia no quantificable s\u2019utilitza habitualment el TAS. Les roques especials, alterades o pirocl\u00e0stiques requereixen altres criteris.<\/p><\/div><\/details>\n\t\t\t\t<footer class=\"gqapf-footer\"><div class=\"gqapf-counter\"><strong data-count>72<\/strong> c\u00e0lculs efectuats<\/div><div class=\"gqapf-footer-brand\"><img decoding=\"async\" data-src=\"https:\/\/www.geoleg.cat\/wp-content\/plugins\/geoleg-calculadora-streckeisen\/assets\/img\/geologia365-logo.jpg\" alt=\"Geologia365.com\" src=\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\" class=\"lazyload\" style=\"--smush-placeholder-width: 1400px; --smush-placeholder-aspect-ratio: 1400\/373;\"><span>Amb el suport de Geologia365.com<\/span><\/div><p>Eina creada per Ge\u00f2leg.cat \u00b7 Classificaci\u00f3 orientativa: una petrografia acurada pot ser necess\u00e0ria per al nom definitiu.<\/p><\/footer>\n\t\t\t<\/section>\n\t\t\t\n<h1 dir=\"auto\" data-section-id=\"1q9ezcd\" data-start=\"375\" data-end=\"426\">Calculadora de roques \u00edgnies segons la composici\u00f3<\/h1>\n<h2 dir=\"auto\" data-section-id=\"1uvqnjx\" data-start=\"428\" data-end=\"469\">Com es pot posar nom a una roca \u00edgnia?<\/h2>\n<p dir=\"auto\" data-start=\"471\" data-end=\"852\">Un granit i una riolita poden tenir una composici\u00f3 mineral semblant i, tanmateix, rebre noms diferents. Per classificar-los cal saber si estudiem una roca plut\u00f2nica o volc\u00e0nica i quins minerals la formen. Aquesta calculadora permet explorar-ho amb els dos diagrames de Streckeisen o QAPF: introdueixes la composici\u00f3, veus on cau la mostra i obtens el nom del camp corresponent.<\/p>\n<p dir=\"auto\" data-start=\"854\" data-end=\"1015\">L\u2019eina treballa amb proporcions modals, \u00e9s a dir, el percentatge en volum que ocupa cada grup de minerals dins la roca.<\/p>\n<h2 dir=\"auto\" data-section-id=\"zrwcsi\" data-start=\"1017\" data-end=\"1051\">Qu\u00e8 signifiquen Q, A, P, F i M?<\/h2>\n<ul data-start=\"1053\" data-end=\"1266\">\n<li data-section-id=\"160egcp\" data-start=\"1053\" data-end=\"1068\"><strong data-start=\"1055\" data-end=\"1061\">Q:<\/strong> quars.<\/li>\n<li data-section-id=\"1tgbwqw\" data-start=\"1069\" data-end=\"1111\"><strong data-start=\"1071\" data-end=\"1077\">A:<\/strong> feldspats alcalins, com l\u2019ortosa.<\/li>\n<li data-section-id=\"1u3qzhm\" data-start=\"1112\" data-end=\"1134\"><strong data-start=\"1114\" data-end=\"1120\">P:<\/strong> plagi\u00f2clasis.<\/li>\n<li data-section-id=\"1b4oul0\" data-start=\"1135\" data-end=\"1176\"><strong data-start=\"1137\" data-end=\"1143\">F:<\/strong> feldespatoides, com la nefelina.<\/li>\n<li data-section-id=\"1krxx9p\" data-start=\"1177\" data-end=\"1266\"><strong data-start=\"1179\" data-end=\"1185\">M:<\/strong> els altres minerals, entre els quals hi ha miques, amf\u00edbols, piroxens i olivina.<\/li>\n<\/ul>\n<p dir=\"auto\" data-start=\"1268\" data-end=\"1581\">Els cinc percentatges han de sumar 100 % de la roca sencera. El rombe t\u00e9 dos triangles: el superior \u00e9s Q\u2013A\u2013P i l\u2019inferior, F\u2013A\u2013P. Q i F no es combinen en una mateixa classificaci\u00f3 QAPF. La llegenda al costat del dibuix relaciona cada n\u00famero amb el nom de la roca.<\/p>\n<h2 dir=\"auto\" data-section-id=\"5tqy1f\" data-start=\"1583\" data-end=\"1630\">Per qu\u00e8 es retira M abans de situar el punt?<\/h2>\n<p dir=\"auto\" data-start=\"1632\" data-end=\"1861\">El diagrama compara Q, A, P i F. Per situar-hi la mostra, la calculadora aparta M i recalcula els altres percentatges perqu\u00e8 sumin 100 %. Per exemple, <strong data-start=\"1783\" data-end=\"1822\">Q normalitzat = 100 \u00d7 Q \/ (100 \u2212 M)<\/strong>. El mateix c\u00e0lcul s\u2019aplica a A, P i F.<\/p>\n<div class=\"group TyagGW_tableContainer TyagGW_tableContainerWithTableOfContents\" dir=\"auto\">\n<div class=\"TyagGW_tableWrapper flex flex-col-reverse w-fit\" tabindex=\"-1\">\n<table class=\"w-fit min-w-(--thread-content-width)\" dir=\"auto\" data-start=\"1863\" data-end=\"2121\">\n<thead data-start=\"1863\" data-end=\"1915\">\n<tr data-start=\"1863\" data-end=\"1915\">\n<th class=\"last:pe-10\" data-start=\"1863\" data-end=\"1875\" data-col-size=\"sm\">Component<\/th>\n<th class=\"last:pe-10\" data-start=\"1875\" data-end=\"1898\" data-col-size=\"sm\">% de la roca sencera<\/th>\n<th class=\"last:pe-10\" data-start=\"1898\" data-end=\"1915\" data-col-size=\"sm\">% al diagrama<\/th>\n<\/tr>\n<\/thead>\n<tbody data-start=\"1932\" data-end=\"2121\">\n<tr data-start=\"1932\" data-end=\"1961\">\n<td data-start=\"1932\" data-end=\"1944\" data-col-size=\"sm\">Q \u00b7 Quars<\/td>\n<td data-start=\"1944\" data-end=\"1951\" data-col-size=\"sm\">28 %<\/td>\n<td data-start=\"1951\" data-end=\"1961\" data-col-size=\"sm\">30,4 %<\/td>\n<\/tr>\n<tr data-start=\"1962\" data-end=\"2001\">\n<td data-start=\"1962\" data-end=\"1984\" data-col-size=\"sm\">A \u00b7 Feldspat alcal\u00ed<\/td>\n<td data-start=\"1984\" data-end=\"1991\" data-col-size=\"sm\">40 %<\/td>\n<td data-start=\"1991\" data-end=\"2001\" data-col-size=\"sm\">43,5 %<\/td>\n<\/tr>\n<tr data-start=\"2002\" data-end=\"2037\">\n<td data-start=\"2002\" data-end=\"2020\" data-col-size=\"sm\">P \u00b7 Plagi\u00f2clasi<\/td>\n<td data-start=\"2020\" data-end=\"2027\" data-col-size=\"sm\">24 %<\/td>\n<td data-start=\"2027\" data-end=\"2037\" data-col-size=\"sm\">26,1 %<\/td>\n<\/tr>\n<tr data-start=\"2038\" data-end=\"2072\">\n<td data-start=\"2038\" data-end=\"2059\" data-col-size=\"sm\">F \u00b7 Feldespatoides<\/td>\n<td data-start=\"2059\" data-end=\"2065\" data-col-size=\"sm\">0 %<\/td>\n<td data-start=\"2065\" data-end=\"2072\" data-col-size=\"sm\">0 %<\/td>\n<\/tr>\n<tr data-start=\"2073\" data-end=\"2121\">\n<td data-start=\"2073\" data-end=\"2095\" data-col-size=\"sm\">M \u00b7 Altres minerals<\/td>\n<td data-start=\"2095\" data-end=\"2101\" data-col-size=\"sm\">8 %<\/td>\n<td data-start=\"2101\" data-end=\"2121\" data-col-size=\"sm\">No es representa<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<p dir=\"auto\" data-start=\"2123\" data-end=\"2484\"><em data-start=\"2123\" data-end=\"2185\">Exemple hipot\u00e8tic (dades hipot\u00e8tiques).<\/em> Si seleccionem roca plut\u00f2nica, el punt cau al camp 3b: monzogranit. La relaci\u00f3 P\/(A + P) \u00e9s del 37,5 %. Si seleccionem roca volc\u00e0nica amb la mateixa composici\u00f3 modal, el diagrama retorna riolita. Aix\u00f2 mostra per qu\u00e8 tamb\u00e9 hem de con\u00e8ixer el tipus de roca que estem classificant.<\/p>\n<h2 dir=\"auto\" data-section-id=\"1kv620r\" data-start=\"2486\" data-end=\"2520\">Com faig servir la calculadora?<\/h2>\n<ol data-start=\"2522\" data-end=\"2853\">\n<li data-section-id=\"1xphbjg\" data-start=\"2522\" data-end=\"2560\">Tria plut\u00f2nica o volc\u00e0nica.<\/li>\n<li data-section-id=\"97bkhk\" data-start=\"2561\" data-end=\"2655\">Introdueix Q, A, P, F i M com a percentatges de la roca sencera i comprova que sumin 100 %.<\/li>\n<li data-section-id=\"1gq4t3o\" data-start=\"2656\" data-end=\"2762\">Prem \u00abClassifica la roca\u00bb per veure el nom, el camp, el punt al rombe i la composici\u00f3 normalitzada.<\/li>\n<li data-section-id=\"1lwsseq\" data-start=\"2763\" data-end=\"2853\">Clica altres punts del rombe o fes servir \u00abFes-ho aleatori\u00bb per comparar resultats.<\/li>\n<\/ol>\n<p dir=\"auto\" data-start=\"2855\" data-end=\"3127\">Una prova interessant per a l\u2019aula \u00e9s variar M mantenint la mateixa proporci\u00f3 entre Q, A i P. El punt es mantindr\u00e0 pr\u00e0cticament al mateix lloc despr\u00e9s de normalitzar les dades. En alguns camps, per\u00f2, M encara pot ajudar a precisar el nom final, com passa amb l\u2019anortosita.<\/p>\n<h2 dir=\"auto\" data-section-id=\"n58ral\" data-start=\"3129\" data-end=\"3170\">Per qu\u00e8 de vegades apareixen dos noms?<\/h2>\n<p dir=\"auto\" data-start=\"3172\" data-end=\"3295\">La posici\u00f3 al QAPF no sempre permet escollir un nom \u00fanic. Si coneixes aquestes dades, pots afegir-les a l\u2019apartat opcional:<\/p>\n<ul data-start=\"3297\" data-end=\"3839\">\n<li data-section-id=\"16n1ddd\" data-start=\"3297\" data-end=\"3477\"><strong data-start=\"3299\" data-end=\"3324\">An de la plagi\u00f2clasi:<\/strong> indica el component anortita <em data-start=\"3354\" data-end=\"3377\">dins d\u2019aquest mineral<\/em>. No \u00e9s el percentatge de plagi\u00f2clasi de la roca. Pot ajudar a distingir monzodiorita de monzogabre.<\/li>\n<li data-section-id=\"him7xt\" data-start=\"3478\" data-end=\"3662\"><strong data-start=\"3480\" data-end=\"3508\">SiO\u2082 de la roca sencera:<\/strong> \u00e9s una dada qu\u00edmica expressada en percentatge en massa. No \u00e9s el percentatge de quars; ajuda a distingir basalt d\u2019andesita en alguns camps volc\u00e0nics.<\/li>\n<li data-section-id=\"1s12qb6\" data-start=\"3663\" data-end=\"3839\"><strong data-start=\"3665\" data-end=\"3692\">Olivina normativa CIPW:<\/strong> \u00e9s un percentatge <em data-start=\"3711\" data-end=\"3721\">calculat<\/em> a partir de la composici\u00f3 qu\u00edmica, no la quantitat d\u2019olivina observada. Pot ajudar a diferenciar basanita de tefrita.<\/li>\n<\/ul>\n<p dir=\"auto\" data-start=\"3841\" data-end=\"4050\">Per exemple, Q = 0 %, A = 10 %, P = 50 %, F = 0 % i M = 40 % dona \u00abbasalt o andesita\u00bb. Si afegim SiO\u2082 = 49 % en massa, la calculadora retorna \u00abbasalt\u00bb (dades inventades per il\u00b7lustrar el funcionament).<\/p>\n<h2 dir=\"auto\" data-section-id=\"e5ol9w\" data-start=\"4052\" data-end=\"4082\">Quan no \u00e9s adequat el QAPF?<\/h2>\n<p dir=\"auto\" data-start=\"4084\" data-end=\"4524\">Cal disposar d\u2019una estimaci\u00f3 mineral\u00f2gica prou fiable. Si una roca volc\u00e0nica \u00e9s v\u00edtria o t\u00e9 cristalls massa petits per determinar-ne les proporcions, es pot utilitzar la classificaci\u00f3 qu\u00edmica TAS quan hi ha una an\u00e0lisi adequada. Per a les roques amb M igual o superior al 90 % calen els diagrames d\u2019ultram\u00e0fiques; les roques pirocl\u00e0stiques o molt alterades tamb\u00e9 poden requerir altres criteris.<\/p>\n<p dir=\"auto\" data-start=\"4526\" data-end=\"4781\">El resultat orienta la identificaci\u00f3, per\u00f2 dep\u00e8n de la qualitat de la mostra i de la mesura. Si el punt cau just sobre una l\u00ednia divis\u00f2ria, una petita difer\u00e8ncia pot canviar el nom. Per a una mostra real, conv\u00e9 contrastar-lo amb l\u2019observaci\u00f3 petrogr\u00e0fica.<\/p>\n<p dir=\"auto\" data-start=\"4783\" data-end=\"4994\" data-is-last-node=\"\" data-is-only-node=\"\"><strong data-start=\"4783\" data-end=\"4792\">Font:<\/strong> <a class=\"decorated-link\" href=\"https:\/\/nora.nerc.ac.uk\/id\/eprint\/3223\/1\/RR99006.pdf?utm_source=chatgpt.com\" target=\"_new\" rel=\"noopener\" data-start=\"4793\" data-end=\"4951\">Gillespie i Styles (1999), <em data-start=\"4821\" data-end=\"4896\">BGS Rock Classification Scheme, Volume 1: Classification of igneous rocks<\/em><\/a>, especialment les figures 11, 12, 19 i 21.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Calculadora de roques \u00edgnies segons la composici\u00f3 Com es pot posar nom a una roca \u00edgnia? Un granit i una riolita poden tenir una composici\u00f3 mineral semblant i, tanmateix, rebre [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":0,"parent":1204,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_monsterinsights_skip_tracking":false,"footnotes":""},"wf_page_folders":[],"class_list":["post-2319","page","type-page","status-publish","hentry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v28.5 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Calculadora de composici\u00f3 de roques \u00edgnies - Formaci\u00f3 i Divulgaci\u00f3 en Geologia #Geoturisme<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.geoleg.cat\/index.php\/que-oferim\/recursos-didactics\/recursos-geologia\/calculadora-de-composicio-de-roques-ignies\/\" \/>\n<meta property=\"og:locale\" content=\"ca_ES\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Calculadora de composici\u00f3 de roques \u00edgnies - Formaci\u00f3 i Divulgaci\u00f3 en Geologia #Geoturisme\" \/>\n<meta property=\"og:description\" content=\"Calculadora de roques \u00edgnies segons la composici\u00f3 Com es pot posar nom a una roca \u00edgnia? 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