Classifying Rocks
Igneous Rocks
Sedimentary Rocks
Metamorphic Rocks
The Rock Cycle
100
This is the name for the tiny pieces of minerals and other materials that make up rocks.
What is "grains"?
100
Besides texture and mineral composition, how are igneous rocks classified?
By their origin.
100
Many limestone deposits were formed from the remains of small, tropical animals called ______________, which live in colonies and from hard skeletons.
Corals!
100
What two forces must be present to turn a rock into a metamorphic rock.
Heat and pressure
100
______________ is a series of precesses on Earth's surface and in the crust and mantle that slowly change rocks from one kind to another.
The rock cycle
200
What are the three ways that rocks are classified? Hint: what do geologists look at when classifying rocks?
color, texture, mineral composition
200
When looking at an igneous rock's origin, it can be either ___________ or __________.
Intrusive or extrusive.
200
When examining sedimentary rock that has built up in layers over time, where would you expect to find the oldest layer? Why?
On the bottom. This layer formed first, then more sediment was deposited over it.
200
How are metamorphic rocks classified?
Metamorphic rocks are classified by the arrangement of their grains.
200
What builds, destroys, and changes rocks in the crust?
Forces deep inside the Earth and at Earth's surface.
300
In general, how do a rock's minerals affect its color?
Light colored minerals make a rock lighter colored than dark colored minerals.
300
Describe how the two categories of igneous rocks form?
Intrusive = magma cools inside the earth Extrusive = lava cools outside the earth
300
What are the four steps in the process of forming a sedimentary rock? In order, please.
erosion, deposition, compaction, cementation
300
Can any rock become a metamorphic rock? Why or why not?
Yes, any rock can be a metamorphic rock as long as it experiences heat and pressure which changes its mineral composition.
300
A rock is melted in the mantle, then flows out through a volcano, where it cools. What kind of rock has been formed? Be specific!
Extrusive igneous rock
400
When talking about a rock's grains, what are the three factors geologists look at?
Size, shape, and pattern
400
What mineral is found in many types of rocks, but especially in igneous rocks?
Silica
400
How is a clastic rock different than an organic rock?
A clastic rock is made of pieces of smaller rocks, an organic rock is made from the remains of living things.
400
Explain the process that forms a metamorphic rock? What happens and where?
A rock gets pushed deep beneath the Earth's surface, close to the mantle. There it experiences heat and pressure that change the rock's mineral composition.
400
A sedimentary rock undergoes heat and pressure until it changes into a new type of rock. Then that rock is worn down over time. What processes have happened to that rock?
It changed into a metamorphic rock and was eroded.
500
How would a rock with no visible grain compare to a rock with fine grain? What is the difference between them?
Fine grain still has visible grain pieces, no visible grain you can't tell the pieces apart.
500
Would you expect a fine-grained igneous rock to be extrusive or intrusive? Why?
Extrusive, fine-grain means it has small crystals and cooled quickly
500
Many places on earth have limestone formed from coral reefs but are no where near the ocean. What does the stone tell you about the environment of that place earlier on in its history?
That place was a warm, shallow ocean where coral could live.
500
What is the difference between a foliated and nonfoliated rock? Give two differences.
A foliated rock has its grains arranged in layers. This rock can break apart easily. Nonfoliated rocks have their grains arranged randomly and do not break apart easily.
500
A metamorphic rock gets worn down by wind and rain, its particles get moved to a new location and form a new layer of rock. Then that rock gets pushed below the crust and melts. What changes did the rock undergo?
Erosion (weathering), deposition, sedimentation, rock melted into magma.
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