Download Rocks and the Rock Cycle

 There are THREE large classifications of rocks:
 Igneous
 Metamorphic
 Sedimentary
 Each type of rock is formed differently and can CHANGE from
one type to another over time
 The way rocks are formed determines how we classify them
Forms when molten rock (magma or lava)
cools and hardens
If cooling is SLOW beneath the surface—
igneous rock is INTRUSIVE
If cooling is RAPID above the surface—
igneous rock is EXTRUSIVE
Forms when rocks are changed into different kinds
of rocks by great HEAT and/or PRESSURE
They are heated, squeezed, folded, or chemically
changed by contact with hot fluids and/or tectonic
forces
When heat and pressure reach the rock’s melting
point, it melts into magma
Forms from the COMPACTION and/or CEMENTATION
of rock pieces, mineral grains, or shell fragments called
sediments
Sediments are formed through the processes of
weathering and erosion of rocks exposed at Earth’s
surface
Sedimentary rocks can also form from the chemical
depositing of materials that were once dissolved in
water
Rocks are used for building and construction based on
their properties
Heat and pressure results in metamorphic changes in
minerals that, in turn, result in a rock being reclassified
as a metamorphic rock
As heat and pressure increase, one type of metamorphic
rock will transform into another type
When slow cooling magma is ejected before it has
completely cools, the resulting igneous rock will have a
mixture of macroscopic and microscopic mineral
crystals (porphyritic texture: both intrusive and
extrusive features)
The rock cycle is an ongoing process
The rock cycle is an example of how Earth
recycles itself
Please draw the diagram on the next slide!