噴ふん出しゅつ岩がん

noun

extrusive rock; effusive rock

Geological term for igneous rock formed from lava that has erupted onto the surface. Contrasts with 深成岩 (plutonic rock).

See also: 火山岩

• 玄げん武ぶ岩がんは代だい表ひょう的てきな噴ふん出しゅつ岩がんの一ひとつです。

  Basalt is one of the typical extrusive rocks.

• この地ち域いきには噴ふん出しゅつ岩がんが広ひろく分ぶん布ぷしている。

  Extrusive rocks are widely distributed in this area.