Igneous activity

Japanese: 火成作用 - かせいさよう（英語表記）igneous activity

It refers to the entire process of magma's life, including its generation deep underground, its ascent, intrusion, eruption, and solidification. Igneous activity is broadly divided into volcanic activity and plutonic activity. Volcanic activity is centered on the eruption of magma that occurs in relation to tectonic and geological conditions such as stable continental regions, oceanic regions, and orogenic belts, and is the subject of research on volcanic belts, oceanic crust, volcanoes and volcanic rocks, hydrothermal deposits, and hot springs. Plutonic activity is a process related to the formation of plutonic rocks, hybrid rocks, granitization, and metamorphic rocks under specific tectonic and geological conditions such as orogenic belts, and is also related to the formation of continental crust and the growth of continental cores. On continents, part of the plutonic activity reaches the surface and becomes volcanic activity, but on the ocean floor, volcanic activity is the main activity, so the two may be two igneous activities with quite different characteristics.

Source: Encyclopaedia Britannica Concise Encyclopedia About Encyclopaedia Britannica Concise Encyclopedia Information

Japanese:

地下深部におけるマグマの発生，マグマの上昇，貫入，噴出および固結など，マグマの一生にまつわる全過程をいう。火成作用は火山作用と深成作用に大別される。火山作用は安定大陸地域，海洋地域，造山帯などの構造地質的条件に関連して起るマグマの噴出を中心とし，火山帯，大洋底地殻，火山および火山岩，熱水鉱床，温泉などの研究対象となる。深成作用は造山帯という特定の構造地質的条件下での深成岩，混成岩，花崗岩化作用，変成岩の形成などに関連する作用で，大陸地殻の形成や大陸核の成長なども関連する。大陸では深成作用の一部が地表に達して火山作用となるが，大洋底では火山作用が主であるから，両者は相当性格の異なる2つの火成作用かもしれない。

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