Download The Rock Cycle

The Rock Cycle
“Where do rocks come from?”
Rocks and Minerals
 Rocks are made of minerals.
 Examples of minerals are:
 Wakabayashilte, azurite, and galena.
Minerals change when:
They are heated
They are put under pressure
Heat and pressure comes from:
Earth’s inner workings (convection
current)
Outer Earth forces (gravity, climate)
Without constantly changing heat
and pressure
rocks would all be the same
geology would be very boring (no
earthquakes, volcanoes or tsunami)
Because Earth is constantly
changing:
Three major rock types:
Igneous
Metamorphic
Sedimentary
One type of rock changes to
another through:
 Heat
 Pressure
 Erosion and
deposition
This is called:
 THE ROCK CYCLE
Reminder:
Magma is molten (melted) rock
Igneous Rocks
Form when magma solidifies
Types of Igneous Rock
Extrusive: when magma comes to the
surface in a volcanic eruption
Types of Igneous Rock
 Intrusive: when magma cools and
solidifies slowly within the Earth
 (note: intrusive rocks are found on
the surface due to erosion, or
uplifting)
Igneous rocks change:
Through weathering (aka: erosion)
 Wind
 Water
 Ice
The sediment is…
deposited on the sea floor
water pressure compacts and cements
it
And becomes…
 Sedimentary Rocks
Over time:
More layers of sediment are deposited
Pressure grows greater
Heat grows greater
The sedimentary rock recrystalizes
(the minerals change again)
And becomes…
 Metamorphic Rock
The temperature…
 rises again
 pressure increases
And the Metamorphic rock…
Becomes magma.
And the cycle begins again.
The End
For Now…
Glossary Terms
 Igneous (adj.)
 Formed by the
solidification of
molten rock;
produced by
volcanic heat.
Glossary (continued)
 Metamorphic
(adj.)
 A rock that has
become more
compact and more
highly crystalline
due to pressure and
heat. A rock that
has been changed.
 These are both
examples of Gneiss
– a type of
metamorphic rock
Glossary (continued)
 Sedimentary (adj.)
 Material deposited by water, wind, or
glacier.