What is the difference between the formation of intrusive and extrusive igneous rocks?

Answer 1

It is a matter of time. Crystallization processes can occur more easily when the rock is kept at a certain temperature during a long time. Because of that, well-formed and well crystallized minerals will appear in intrusive igneous rocks (such as granitoids). On the opposite, when a rock spreads rapidly over the Earth's surface, the temperature decreases rapidly, keeping the minerals from forming. A homogeneous paste will form, without any (or few) minerals in it. It is the case for volcanics rock.

Answer 2

Extrusive rocks are... extruded... onto the surface as the lava that we all think of. It cools fairly quickly, into rocks with fairly small crystals (might need a magnifying lens to see them). The exact chemistry of the parent magma will determine the type of rock. Oceanic volcanoes are generally basaltic (mafic or ultramafic), continental are generally granitic (felsic or intermediate). They're put down in "relatively thin" layers

Intrusive rocks cool for thousands of years beneath the surface in huge plutons or batholyths. This allows them to grow very large crystals (easily seen by the unaided eye). These intrusive rocks are almost always granitic-type rock.

My sources are:

from my science teacher who worked at the science museum

yahooanswer.com

ask.com

wikipedia the free encyclopedia

I hope this information helped. Good luck!

Answer 3

Extrusive rocks are... extruded... onto the surface as the lava that we all think of. It cools fairly quickly, into rocks with fairly small crystals (might need a magnifying lens to see them). The exact chemistry of the parent magma will determine the type of rock. Oceanic volcanoes are generally basaltic (mafic or ultramafic), continental are generally granitic (felsic or intermediate). They're put down in "relatively thin" layers

Intrusive rocks cool for thousands of years beneath the surface in huge plutons or batholyths. This allows them to grow very large crystals (easily seen by the unaided eye). These intrusive rocks are almost always granitic-type rock.

My sources are:

from my science teacher who worked at the science museum

yahooanswer.com

ask.com

wikipedia the free encyclopedia

I hope this information helped. Good luck!

Answer 4

intrusive:below ground

extrusive:at the surface

Answer 5

When melted rock cools on Earth's surface, it is called Extrusive

When rocks cool below Earth's surface, it is called Intrusive

Answer 6

Intrusive igneous rocks cool beneath the crustal surface. Extrusive cool above the surface - pillow lavas cool below the sea but above the crust.

Answer 7

Extrusive igneous rock is found outside the Earth's crust. Intrusive, however, is found underneath the Earths crust