The Rock Cycle
1
Classifying Rocks
Three questions to keep in mind when
classifying rocks:
1. Did the rock form on Earth’s surface or
deep underground?
2. Did the rock form quickly or slowly?
3. Were the particles carried by wind,
water, or ice?
2
3
4
Sedimentary
› Forms when particles of
preexisting rock are
transported by water, wind, or
gravity and accumulate to form
layers called sediment on
Earth’s solid surface.
› Created from the deposition of
sediments in layers over time
› Can observe grains
5
Shale
6
Sandstone
7
Conglomerate
8
Creation of Sediments
Weathering - Breakdown of parent rock by
water, air, and living things
Erosion - Running water, flowing ice, wind,
and gravity move pieces of rock from one
place to another.
9
Deposition - Particles of rock settle out of
air and water and accumulate as sediment
on Earth’s surface
Compaction and Cementation - The process
by which sediment is squeezed and glued
into a rock
10
Igneous
› Created from the
cooling and
solidification of
magma or lava
› Magma
› Rock below
surface
› Lava
› Rock above
surface
11
Melting and Solidifying
Often results in the formation
of igneous rock.
Underground = Intrusive
Above Ground = Extrusive
12
Obsidian and Pumice
13
Metamorphic Rock
› Existing rock is
subjected to very
high heat and
pressure
› Forms when rock
is buried deep
underground
14
Gneiss
15
Marble
16
Schist
17
Changing Form
Metamorphism - When rock is buried it is
exposed to pressure and heat, it causes the
atoms and molecules in the solid rock to
rearrange, forming new crystals, new
minerals, and new textures
18
The Rock Cycle - The process that transforms one
type of rock into another
19