Do intrusive igneous rocks form quickly or slowly?

Answer 1

Fast and slow are relative terms. If a heated igneous rock takes 3 hours to cool, is that fast or slow?

During their formation, however, magma can solidify very slowly or very quickly. Rocks that have cooled quickly from magma are referred to as extrusive igneous rocks, such as obsidian and scoria. Rocks that have formed from slow cooling magma are called intrusive igneous rocks, such as granite and gabbro. The difference between the two types is in their grain size. Slow cooling magma produces large grained rock, and fast cooling magma produces fine-grained rock.

Answer 2

Igneous rocks are formed with or without crystals. The matter of crystals are whether it is extrusive or intrusive. When igneous rocks are extrusive, they usually cool rapidly, causing little or no crystals to form. When igneous rocks are intrusive, they tend to cool slowly,forming more crystals.

Extrusive-Outside the volcano

Intrusive-Inside the volcano

Answer 3

Extrusive rock is igneous rock formed from lava that erupted onto Earth's surface, then the magma cools quickly.

Source: Interactive Science Florida Course 2

Answer 4

Thermal metamorphic rocks cool relatively fast, regional metamorphic rocks cool slowly.

Answer 5

Yes, as magma intrusions stay inside the earth, when they cool down, they have to give their warmth to the earth, and this goes relatively slow (as compared to air or water).

Answer 6

Slowly, (relatively to extrusive). This is because there is more heat underground, therefore the magma has more time to cool and crystallize.

Answer 7

Sedimentary rocks do not cool, they are deposited at surface temperatures and then in anything warm as they are buried.

Answer 8

It cools slowly

Answer 9

It cools quickly