Why are the names intrusive and extrusive appropriate for two types of igneous rocks?
why are the names intrusive and extrusive appropriate for the two types of igneous rock? magma pushes into earlier rocks and cools to from intrusive igneous rocks. extrusive means “to put out”. lava is pushed out onto earths surface, where it cools to form extrusive igneous rocks.
Are intrusive and extrusive rocks are types of igneous rocks?
The two main categories of igneous rocks are extrusive and intrusive. Extrusive rocks are formed on the surface of the Earth from lava, which is magma that has emerged from underground. Intrusive rocks are formed from magma that cools and solidifies within the crust of the planet.
Why are some igneous rocks called intrusive?
Crystallization. Igneous rocks form when molten material cools and hardens. Igneous rocks are called intrusive or plutonic when they cool and solidify beneath the surface. Because they form within the Earth, cooling occurs slowly.
How are intrusive and extrusive igneous rocks classified?
Igneous rocks may be simply classified according to their chemical/mineral composition as felsic, intermediate, mafic, and ultramafic, and by texture or grain size: intrusive rocks are course grained (all crystals are visible to the naked eye) while extrusive rocks may be fine-grained (microscopic crystals) or glass ( …
How do intrusive and extrusive igneous rocks differ from each other quizlet?
The difference between intrusive and extrusive igneous is that, intrusive rock is one that forms when magma cools within Earth. Extrusive igneous rock is one that, forms when lava cools on Earths surface.
Why are intrusive rocks coarse grained and extrusive rocks fine grained?
Because extrusive rocks cool quickly, they only have time to form very small crystals such as basalt or none at all. On the other hand, intrusive rocks grow larger crystals because they take longer to cool. Extrusive rocks are usually fine-grained or glassy while intrusive rocks are coarse-grained.
Why do extrusive rocks are smoother or has glassy surface than intrusive rocks?
If lava cools extremely quickly, and has very little water dissolved in it, it may freeze into glass, with no minerals (glass by definition is not a mineral, because it does not have a crystal lattice). Such a rock is said to have a glassy texture. Like lava flow rocks, these are also extrusive igneous rocks.
What are Extrusive rocks and intrusive rocks quizlet?
Extrusive rocks form from volcanic eruptions above or at the Earth’s surface, and intrusive rocks cool and harden under the Earth’s surface.