Chapter 2 Rocks
Section 1
Lesson Objectives
Define rock
Describe how
rocks change
List rock
characteristics
that help to
identify it
Define rock
Keywords
Rock
Rock cycle
Igneous
Sedimentary
Metamorphic
Describe how rocks
change
List rock characteristics
that help to identify it
Define rock
Describe how rocks
change
List rock characteristics
that help to identify it
Keywords: rock, rock cycle
Rock
• Naturally occurring solid mixture made of minerals and
organic matter
Define rock
Describe how rocks
change
List rock characteristics
that help to identify it
Keywords: igneous, sedimentary, metamorphic
Rock type is determined by how it is formed
Three types of Rock
• Igneous- formed from magma
• Sedimentary- formed as a by-product of weathering,
erosion, decomposition
• Metamorphic- formed from changes in temperature
and/or pressure
Define rock
Describe how rocks
change
List rock characteristics
that help to identify it
Keywords: Rock cycle
Rock Cycle
• The continual process by which new rock forms from old rock
• Rock cycle animation
http://www.classzone.com/books/earth_science/terc/content/investigations/es0602/es0602page02.cfm
Define rock
Describe how rocks
change
List rock characteristics
that help to identify it
Keywords: igneous
Ways to tell which rocks are which:
Igneous:
• Intrusive igneous rocks– large crystals cemented together.
– Crystallize below Earth's surface
– Slow cooling that occurs there allows large crystals to form.
• Extrusive igneous rocks
–
–
–
–
–
small crystals some are not visible
Smooth surface
May have air pockets
May look like glass
erupt onto the surface where they cool quickly
Define rock
Describe how rocks
change
List rock characteristics
that help to identify it
Keywords: sedimentary
Ways to tell which rocks are which:
Sedimentary:
• Clastic sedimentary rocks
– Fragments of rocks cemented together
– Can be course grained like “conglomerate” or fine grained like shale
• Chemical
– Liquid evaporates leaving cemented crystals behind
• Organic
– May contain fossils
Define rock
Describe how rocks
change
Keywords: metamorphic
Ways to tell which rocks are which:
Metamorphic:
• Foliated– Banded
– crystals seem to go in the same direction
• Non-foliated– No bands
– Can have a glittery appearance
List rock characteristics
that help to identify it
Type of Rock?
Igneous
(Intrusive) Notice the air bubbles
Type of Rock?
Igneous
(Extrusive) Notice the absence of visible crystals
Type of Rock?
Metamorphic
Notice the bands
Type of Rock?
Sedimentary
Notice the pebble-like crystals
Type of Rock?
Sedimentary
Notice the sand-like texture
Type of Rock?
Igneous
Notice the air bubbles
Type of Rock?
Igneous
Notice the separate crystals
Type of Rock?
Metamorphic
Notice the
Type of Rock?
Sedimentary
Notice the glass-like appearance
Type of Rock?
Metamorphic
Notice the glittery appearance
Section 2
Lesson Objectives
Describe three
ways that igneous
rocks form
Explain how
cooling speed
affects texture
Distinguish
between
intrusive and
extrusive
Describe three ways that
igneous rocks form
Keywords
Texture
Composition
Igneous
Extrusive
Intrusive
Explain how cooling speed
affects texture
Distinguish between
intrusive and extrusive
Describe three ways that
igneous rocks form
Explain how cooling speed
affects texture
Distinguish between
intrusive and extrusive
Keywords: texture, composition
Texture and composition give clues as to how rocks are formed, and
are used to classify rocks
• Composition – the type of material a rock contains
• Texture – the size, shape and arrangement of the
minerals/particles that make up a rock.
• Cooling rate affects texture:
• Rocks that cool faster have very small crystals, air pockets, and
can be glassy
• Rocks that cool slower have larger crystals
Describe three ways that
igneous rocks form
Explain how cooling speed
affects texture
Distinguish between
intrusive and extrusive
Keywords
Igneous Rocks2 types depending on how formed
Extrusive rocks- formed by cooling lava so
cools quickly
obsidian
Texture:
• glassy (obsidian)
• porous (pumice)
• fine-grained (basalt)
pumice
Intrusive rocks- formed by cooling
magma so cools slowly
Texture:
• coarse-grained (granite)
basalt
granite
Formation of Extrusive Igneous Rocks
Formation of Intrusive Igneous Rock
Section 3
Lesson Objectives
Describe the 5
agents of erosion
Describe,
deposition,
compaction and
cementation
Differentiate
between types of
sedimentary
rocks and how
they form
Describe the 5 agents of
erosion
Keywords
Erosion
Deposition
Compaction
Cementation
Wind
Gravity
Running water
Glaciers
Waves
Sedimentary
Clastic
Chemical
Organic
Describe, deposition,
compaction and
cementation
Differentiate between
types of sedimentary
rocks and how they form
Describe the 5 agents of
erosion
Describe, deposition,
compaction and
cementation
Differentiate between
types of sedimentary
rocks and how they form
Keywords: sedimentary
Sedimentary Rocks
• Formed from the erosion, deposition, compaction and
cementation of minerals and other materials
• Occurs at or near the earth’s surface
• Three types:
• Clastic
• Chemical
• Organic
Describe the 5 agents of
erosion
Describe, deposition,
compaction and
cementation
Differentiate between
types of sedimentary
rocks and how they form
Keywords: clastic, chemical, organic
• Clastic Rocks (rock fragments)
• Conglomerates (pebbles)
• Sandstones (sand)
• Shales (mud & clay)
• Chemical Rocks (evaporation)
• Ex: rock salt, limestone, geodes, gypsum
• Organic Rocks (once living)
• Ex: limestone(coral and shells), coal (plants)
Clastic Sedimentary Rock…
made from fragments of rocks cemented
together
Conglomerate
Shale
Sandstone
Chemical Sedimentary Rocks…
formed from dissolved minerals that have
crystallized out of solution
Gypsum rock
Limestone
Geode
Organic Sedimentary Rocks…
made from previously living organisms
Coal (plant mateiral)
Limestone (shell & coral)
Describe the 5 agents of
erosion
Describe, deposition,
compaction and
cementation
Differentiate between
types of sedimentary
rocks and how they form
Keywords
Five Agents of Erosion
•
•
•
•
•
Gravity (Mass wasting)
Wind
Running water
Glaciers
Waves
Describe the 5 agents of
erosion
Describe, deposition,
compaction and
cementation
Differentiate between
types of sedimentary
rocks and how they form
Keywords: gravity
Gravity (Mass Wasting)
Soil creep
Slumping
Describe the 5 agents of
erosion
Describe, deposition,
compaction and
cementation
Keywords: wind
Wind
Differentiate between
types of sedimentary
rocks and how they form
Describe the 5 agents of
erosion
Describe, deposition,
compaction and
cementation
Differentiate between
types of sedimentary
rocks and how they form
Keywords: running water
Niagara Falls
Yellowstone
Canyon & River
Describe the 5 agents of
erosion
Keywords: glaciers
Glaciers
Describe, deposition,
compaction and
cementation
Differentiate between
types of sedimentary
rocks and how they form
Describe the 5 agents of
erosion
Keywords: waves
Waves
Describe, deposition,
compaction and
cementation
Differentiate between
types of sedimentary
rocks and how they form
Describe the 5 agents of
erosion
Describe, deposition,
compaction and
cementation
Differentiate between
types of sedimentary
rocks and how they form
Keywords: deposition
Deposition Examples
Nile River Delta:
landform that forms at the mouth of
a river, where the river flows into
an ocean, sea, estuary, or lake
Lateral moraine:
parallel ridges of debris deposited
along the sides of a glacier
Describe the 5 agents of
erosion
Describe, deposition,
compaction and
cementation
Differentiate between
types of sedimentary
rocks and how they form
Keywords: compaction, cementation
Compaction and Cementation
Section 4
Lesson Objectives
Describe how
metamorphic
rocks are formed
Differentiate
between foliated
and non-foliated
rocks
Determine
whether rocks
will become
either foliated
or non-foliated
Describe how
metamorphic rocks are
formed
Keywords:
Metamorphic
Foliated
Non-foliated
Differentiate between
foliated and non-foliated
rocks
Determine whether rocks
will become either
foliated or non-foliated
Describe how
metamorphic rocks are
formed
Differentiate between
foliated and non-foliated
rocks
Determine whether rocks
will become either
foliated or non-foliated
Keywords: metamorphic
Metamorphic Rocks
• Formed by tremendous heat & pressure,
and chemical reactions inside the crust.
• Formed from all three rock types.
Describe how
metamorphic rocks are
formed
Differentiate between
foliated and non-foliated
rocks
Keywords: foliated
Foliated texture
Give examples of some
metamorphic rocks
Describe how
metamorphic rocks are
formed
Differentiate between
foliated and non-foliated
rocks
Differentiate between
types of sedimentary
rocks and how they form
Keywords: foliated
Types of Metamorphic Rock
Slate
• Foliated (bands or layers)
Ex: schist, slate, gneiss
Gneiss
Describe how
metamorphic rocks are
formed
Differentiate between
foliated and non-foliated
rocks
Determine whether rocks
will become either
foliated or non-foliated
Keywords: non-foliated
Types of Metamorphic Rock continued
• Non-Foliated (no bands or layers)
Ex: marble and quartzite
Describe how
metamorphic rocks are
formed
Differentiate between
foliated and non-foliated
rocks
Determine whether rocks
will become either
foliated or non-foliated
Keywords: non-foliated
Pressure determines if metamorphic rocks will be
foliated or non-foliated
• If there is unequal pressure, rocks will be foliated
• If there is equal pressure, rocks will be nonfoliated
Closure:
1. In igneous rocks how is cooling rate and
crystal size related?
2. Which rock type would you have the best
chance of finding a fossil? Why?