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
玄武岩は代表的な噴出岩の一つです。
Basalt is one of the typical extrusive rocks.
Extrusive rocks are widely distributed in this area.