{"id":207345,"date":"2025-04-21T14:03:09","date_gmt":"2025-04-21T14:03:09","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=207345"},"modified":"2025-04-21T14:03:11","modified_gmt":"2025-04-21T14:03:11","slug":"coarsely-crystalline-igneous-textures-indicate-that-there-was-a-lot-of-gas-in-the-magma","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/04\/21\/coarsely-crystalline-igneous-textures-indicate-that-there-was-a-lot-of-gas-in-the-magma\/","title":{"rendered":"Coarsely crystalline igneous textures indicate that there was a lot of gas in the magma"},"content":{"rendered":"\n

Coarsely crystalline igneous textures indicate that there was a lot of gas in the magma. <\/p>\n\n\n\n

The rock cooled slowly. <\/p>\n\n\n\n

The rock broke apart as it flowed. <\/p>\n\n\n\n

The rock cooled quickly. <\/p>\n\n\n\n

The ash and pumice were hot and became compacted.<\/p>\n\n\n\n

The correct answer and explanation is :<\/strong><\/mark><\/p>\n\n\n\n

Correct Answer: The rock cooled slowly.<\/strong><\/p>\n\n\n\n

Explanation (300 words):<\/h3>\n\n\n\n

Igneous rocks form from the cooling and solidification of molten rock material called magma (below the surface) or lava (on the surface). The texture of an igneous rock\u2014meaning the size, shape, and arrangement of its crystals\u2014is a key clue to understanding how and where it formed.<\/p>\n\n\n\n

A coarsely crystalline<\/em> texture, also known as phaneritic<\/em>, means the rock contains large, easily visible crystals. This kind of texture typically forms when magma cools slowly<\/strong> deep beneath the Earth\u2019s surface. The slow cooling process allows individual mineral crystals enough time to grow large before the entire mass solidifies. Granite is a common example of a coarse-grained igneous rock.<\/p>\n\n\n\n

In contrast, when magma or lava cools rapidly, as it does at or near the surface, there is not enough time for large crystals to form. This results in a fine-grained (aphanitic<\/em>) or even glassy texture, as seen in rocks like basalt or obsidian.<\/p>\n\n\n\n

The presence of gas in the magma affects the formation of bubbles and vesicles, not the crystal size. Rocks that had a lot of gas often show a vesicular<\/em> texture (e.g., pumice or scoria), which is not the same as coarsely crystalline. Similarly, rocks that break apart while flowing (like volcanic breccias or lava flows with autobrecciation) exhibit fractured or fragmented textures, not large crystals. Ash and pumice that become compacted can form tuff<\/em>, which is a pyroclastic rock, again with a very different texture from coarse crystals.<\/p>\n\n\n\n

Therefore, a coarsely crystalline<\/strong> igneous texture is a strong indicator that the rock formed intrusively<\/strong>, where it cooled slowly<\/strong>, allowing crystals to grow large. This texture helps geologists deduce the history and environment of the rock’s formation deep within the Earth.<\/p>\n\n\n\n

<\/figure>\n","protected":false},"excerpt":{"rendered":"

Coarsely crystalline igneous textures indicate that there was a lot of gas in the magma. The rock cooled slowly. The rock broke apart as it flowed. The rock cooled quickly. The ash and pumice were hot and became compacted. The correct answer and explanation is : Correct Answer: The rock cooled slowly. Explanation (300 words): […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-207345","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/207345","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=207345"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/207345\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=207345"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=207345"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=207345"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}