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IGNEOUS
Now, what is an igneous rock?
Igneous rocks are rocks that are formed from lava or magma as it cools.
Igneous means “fire”. About 64.7% of the Earth’s crust consists of igneous rock.
Magma – is molten rock that is found underground. These rocks cool down over a long period of time.
Lava – is molten rock that is found above ground after a volcanic eruption. Because the lava is exposed to air it cools more rapidly.
Types of Igneous Rocks
Basalt
Crystals
Granite
Gypsum
Pumice
Quartz
SEDIMENTARY
Next we have sedimentary rocks.
Sedimentary rocks are rocks that are formed from compacted sediments or what was once a pre-existing rock that has been broken down.
Sediments are tiny bits and pieces of broken down rocks, minerals and shells.
Types of Sedimentary Rocks
Coal
Dolomite
Flint
Limestone
Shale
Siltstone
Travertine
METAMORPHIC
Metamorphic rocks are rocks that are a combination of igneous rocks and sedimentary rocks.
Metamorphic means “change.” In geology, when one rock breaks down and combines with materials from another rock (i.e., sediments of another rock) and then over a period of time between temperatures and weathering, the two or more different rocks solidify and become a new rock, the new rock is a “changed” rock from the original or it is a metamorphic rock. In a volcanic eruption, as the lava flows it pulls within it other smaller rocks and sediments and when these harden, the end result is a series of metamorphic rocks.
Types of Metamorphic Rocks
Marble
Quartzite
Slate
Soapstone
Finally, did you know that the study of rocks is known as petrology? And a person who studies rocks is known as a
petrologist. Petrology is a subfield of geology.
Did you find learning about rocks was easy? Well then, let’s see what you have learned so far by answering the following ten questions to see how many you can get right!
1 .
About 64.7% of the Earth’s crust consists of ________.
Sedimentary rock
Gypsum
Igneous rock
Metamorphic rock
2 .
The study of rocks is known as _______.
petrology
geology
archeology
earth science
3 .
These are rocks that are made up of tiny bits and pieces of broken down rocks, minerals and shells.
Igneous rocks
Basalt rocks
Metamorphic rocks
Sedimentary rocks
4 .
This is molten rock that is found above ground after a volcanic eruption.
Metamorphic
Lava
Magma
Granite
5 .
In a volcanic eruption, as the lava flows it pulls within it other smaller rocks and when these harden, the end result is a series of ___________.
sedimentary rocks
metamorphic rocks
marble rocks
igneous rocks
6 .
This is molten rock that is found underground.
7 .
________ means “change.”
Aggregate
Metamorphic
Sediment
Petrology
9 .
This is a collection of materials that are combined together to make one whole object.
Aggregate
Sediment
Lava
Magma
10 .
Which of the following is NOT an example of an igneous rock.
Shale
Granite
Quartz
Crystal