How do igneous rocks form?(1 point)
Responses
from the evaporation of water
from the evaporation of water
from the modification of existing rock
from the modification of existing rock
from the cementing of sediments
from the cementing of sediments
from the cooling of magma
Igneous rocks form from the cooling of magma. To understand how igneous rocks form, it is important to understand the process of magma cooling.
Magma is a molten mixture of minerals and gases that exists beneath the Earth's surface. It is formed through the melting of existing rocks under high temperatures and pressures.
When magma rises to the surface, it is exposed to the cooler environment, causing it to lose heat. As the heat is lost, the magma solidifies and crystallizes, forming igneous rocks. The rate at which the magma cools determines the texture of the resulting rock.
If the magma cools slowly beneath the Earth's surface, the resulting rocks are called intrusive or plutonic igneous rocks. These rocks have larger crystals because the slow cooling allows for the growth of mineral crystals. Examples of intrusive igneous rocks include granite and gabbro.
On the other hand, if the magma cools rapidly on the Earth's surface, the resulting rocks are called extrusive or volcanic igneous rocks. These rocks have smaller crystals or may even be glassy because the rapid cooling does not allow enough time for large crystals to form. Examples of extrusive igneous rocks include basalt and obsidian.
Therefore, to answer the question, igneous rocks form from the cooling of magma.