Rocks and the Rock Cycle
Three Types of Rocks
• Rocks are
classified by how
they form
– Igneous
– Sedimentary
– Metamorphic
– Rocks can change
from one type to
another over time
Schist
Rock Classification
• Rocks are
classified by:
–
–
–
–
How they form
Texture
Grain size
Mineral
composition
Conglomerate Sedimentary Rock
Igneous Rocks
• Igneous rock:
forms when molten
rock (magma) cools
and hardens
• Classified by:
– Where they form
– Crystal (grain) size
Basalt
Intrusive Igneous Rock
• Intrusive igneous:
cooling takes place
slowly beneath
Earth’s surface
granite
Extrusive Igneous Rock
• Extrusive igneous:
cooling takes place
rapidly on Earth’s
surface
Pumice
Sedimentary Rock
• Sedimentary rock:
forms from the
compaction and/or
cementation of
sediments
• This process is
called lithification
• Sediments are:
– Rock pieces
– Mineral grains
– Shell fragments
Limestone
How do sediments form?
weathering
• Sediments form
through the
processes of
weathering and
erosion of rocks
exposed at Earth’s
surface
erosion
Sedimentary Rock con’t….
• Sedimentary rock
can also form from
the chemical
depositing of
materials that were
once dissolved in
water
• When water
evaporates, minerals
are left behind and
form rock
gypsum
Metamorphic Rock
• Metamorphic rock:
forms when any
rock type is
changed into a
different kind of
rock
• Changes due to
great heat and/or
pressure
Gneiss
How does rock change?
• Rocks are heated,
squeezed, folded,
or chemically
changed by contact
with hot fluids
marble
The Rock Cycle
The Earth Recycles Rock
• The rock cycle is an
ongoing series of
processes inside Earth
and on the surface
• Slowly changes rocks
from one kind to
another
• Any type of rock can
change into another
type
How does this relate to
plate tectonics?
• Plate movement
drives the rock
cycle
– Subduction (1 plate
pushed under
another plate)
• Re-melts rock into
magma
– Mountain building
• Folding, faulting,
uplift
• Exposes rock at the
surface to be
weathered and
a. Cementation and compaction (lithification)
b. Heat and pressure
c. Weathering, transportation(erosion), and deposition
d. Cooling and solidification
e. Melting
Rocks/Rock Cycle Foldable
• Your foldable should include
the following:
1. Name of each rock type
2. How each rock type formed
3. A brief description of rock
type
4. At least 2 examples of each
rock type
5. Illustrate 1 example for
each rock type
Copy Me
Do Now – Tuesday March 11
In Textbook:
• Complete
• pg. 107 #1-8
Do Now – Thursday March 4
Rock
Texture
Composition
Comments
Limestone is composed of the mineral
Conglomer
ate
Coarse,
2mm
Rounded
pebbles
Rounded pebbles,
sand and clay can
easily be seen
Sandstone
Medium,
.0625 – 2 mm
Quartz, other
minerals and
rock fragments
Sand grains can be
seen; rough surfaces
Shale
Microscopic,
.004 - .06 mm
Clays, micas
Has muddy
appearance
Limestone
Coarse to fine
Calcite, shells
May contain fossils,
seashells; fizzes
when in hydrochloric
acid
Chert
Fine
Quartz
Is light-colored; also
called flint; once used
for arrowheads
Rock salt
Coarse to fine
Halite
Has salty taste;
table salt
A.
B.
C.
D.
quartz
calcite
halite
gypsum
Based on the information given about each of these
rocks, into which rock type would all these examples
be classified?
A.
B.
C.
D.
Igneous
Metamorphic
Sedimentary
Mineral
Moh's
Hardness Scale
Approximate Hardness of
Common Objects
Talc
1
Gypsum
2
Fingernail (2.5)
Calcite
3
Copper penny (3.5)
Fluorite
4
Iron nail (4.5)
Apatite
5
Glass (5.5)
Feldspar
6
Steel file (6.5)
Quartz
7
Streak plate (7.0)
Topaz
Topaz
8
Corundum
9
Gypsum
Diamond
10
Which statement is best
supported by the data
shown?
A. An iron nail contains
fluorite.
B. A streak plate is
composed quartz.
C. Topaz is harder than a
steel file.
D. Apatite is softer than a
copper penny.
Based on the
processes shown in
the diagram, which
type of rock is
formed at #1?
A.
B.
C.
D.
Sedimentary
Igneous
Metamorphic
Clastic
Because heat and
pressure are needed
to form #3, it must be
what type of rock?
A.
B.
C.
D.
Sedimentary
Igneous
Metamorphic
Clastic