Deep inside the Earth
the temperature is very hot. It is so hot that it melts rock.
The melted rock is called magma. When
a volcano erupts the magma pours out. When magma comes out of the
volcano it is called lava. Once it
cools it becomes igneous
This mountain is made of
cooled magma. It used to be a volcano, but after many
years of weathering and erosion the outer part of the volcano
wore away and all that is left is the cooled magma that was
inside the volcano. What kind of rock is this?
4. How is
sedimentary rock formed?
You know that rocks break down
through weathering. The broken rocks turn into sediment.
Sediment is cemented into
sedimentary rocks. Sedimentary rocks
are made at the surface of the Earth, not deep underground like
metamorphic rock. Because sedimentary rock is made from layers of
sediment, this is the kind of rock in which you
find dinosaur fossils. Look closely at these sedimentary
rocks. Can you see shells imbedded in the rock?
Can you see the layers in the
sedimentary rock below?
5. How is
metamorphic rock formed?
The weight of the
ground presses down on rocks that are deep under the surface.
Metamorphic rocks are made when underground rocks are pressed and
heated. They are not hot enough to melt and turn into magma, but
they are heated enough to change them from sedimentary to metamorphic.
Look at the lines in
this rock. They are bent and wavy. You can see how pressure
and heat have changed the layers of sedimentary rock into a metamorphic
6. What is a rock cycle?
Rocks are slowly
changing. A rock can start as a piece of sediment, become a
sedimentary rock, as it is pushed deeper into the Earth it can change
into a metamorphic rock. Then it can melt, become magma that is
shot to the surface through a volcano and cool to become an igneous
rock. It can go through this change over and over and over, that
is why it's called a cycle. Here is a picture of how it works.
1. Which type of rock forms in layers?
igneous sedimentary metamorphic
2. What's the main difference between lava and magma?
temperature when formed location type of rock
Once a rock has changed to a metamorphic rock, which
of these can it later become?
a sedimentary, igneous, or another metamorphic rock only another metamorphic rock an igneous or a similar metamorphic rock
fossils not usually found in metamorphic rock?
no organisms were alive when metamorphic rock formed Metamorphic rock is formed
from processes that destroy fossils Metamorphic
rock is too hard to break open to find fossils