Question

What size is the crystal in an extrusive igneous rock?

3. Although all intrusive igneous rocks form in the same location, there are still different methods
of formation.
A. What are three methods of intrusive igneous rock formation? (3 points)
B. What happens during each method to form intrusive igneous rocks? (3 points)

Answer 1

A. Three methods of intrusive igneous rock formation are:

Solidification of Magma

Fractional Crystallization

Assimilation

B. The following happens during each method to form intrusive igneous rocks:

Solidification of Magma: In this method, magma cools and solidifies underground. As the magma cools, crystals form, and the minerals in the magma become more concentrated. Over time, the magma solidifies into a pluton or a body of intrusive igneous rock.

Fractional Crystallization: In this method, minerals in the magma crystallize at different temperatures. As the magma cools, minerals that crystallize at higher temperatures settle out first, leaving a residual magma that is enriched in minerals that crystallize at lower temperatures. This process continues until all the minerals have crystallized, forming a body of intrusive igneous rock.

Assimilation: In this method, magma from a magma chamber intrudes into and melts surrounding rocks. As the magma moves through the rocks, it assimilates some of the rock material, which then becomes part of the magma. The assimilated material can cause changes in the composition of the magma, which can lead to the formation of a different type of intrusive igneous rock.

Step-by-step explanation: