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Glite Dictionary
extrusive

extrusive

9.9
Rock that forms when lava from a volcano cools quickly on the ground, like basalt
  • adjective
  • /ɛkˈstruːsɪv/
  • Specialized
translation icon : extrusivo
  • The difference between intrusive and extrusive rocks lies in where they solidify.

Examples

  • Geologists classified the ash deposit as extrusive because it originated from a volcanic eruption.

  • Basalt is an extrusive igneous rock commonly formed from rapidly cooled lava flows.

  • Basalt is an example of an extrusive rock.

  • The extrusive nature of this rock makes it very smooth.

  • Basalt is an example of an extrusive rock formed when lava cools quickly at the Earth's surface.

  • The formation of extrusive rocks occurs during volcanic eruptions, leading to fine-grained textures.

  • Geologists study how extrusive rocks, like pumice, are formed from lava that cools rapidly in the open air.

Synonyms

volcanic
vsextrusive
  • Specialized
1 4.1

Rock formed when lava or ash from a volcano cools

is limited to rocks made when molten material reaches the surface and cools quickly
eruptive
vsextrusive
  • Specialized
7.9

Rock made when hot lava or ash cools

focuses on surface eruption producing fine grained igneous rocks

Antonyms

intrusive
  • Specialized
1 8.6

Rock formed when hot liquid rock pushes into other rocks

How Fine-Grained

glassy
9 3.9
extrusive
  • Specialized
9.9

Surface Forms

extrusive positive

Morphology

extrusive = extrude (transparent) = extrude + ive

Formed from the verb 'extrude' + the adjectival suffix '-ive'; the meaning 'produced by extrusion / pushed out' aligns with this derivation and is predictable for learners familiar with 'extrude'.

Etymology

Extrusive comes from the parts ex- 'out' and trudere 'to push', and is like the English verb extrude which means 'to push out'. So extrusive rocks are those 'pushed out' onto the Earth's surface as lava, which is why they cool quickly on the surface.