UNIT 2:
ROCKS,
SOIL & MASS
MOVEMENTS
CONCEPT MAPPING
• A concept map is a diagram
showing the relationships
among concepts.
▫ graphical tool for
organizing and representing
knowledge
▫ Concepts are represented as
boxes or circles
▫ Connected with labeled
arrows in a branching
structure.
CONCEPT MAP #1: Forces & Motion
Igneous, sedimentary, and metamorphic
rocks are interconnected by a set of
processes called the rock cycle. A common
path through the rock cycle is for igneous
rock to be weathered, transported and
deposited to eventually become
sedimentary rock. Then this sedimentary
rock is subjected to high temperatures &
pressures that turn it into metamorphic
rock. Eventually the metamorphic rock
becomes new igneous rock.
CONCEPT MAP #2: Matter & Energy
There are many factors that affect the
appearance of a rock. For igneous rocks,
these factors include the composition and
the rate of cooling. For sedimentary rocks,
these include the types of sediment
compacted (clastic, chemical, biological).
For metamorphic rocks, these include the
amounts of heat, pressure, and hot fluids
the rocks are exposed to.
What do you already know?
• What is a rock?
• What are the three major types of rocks?
• What energy processes destroy and make new
rocks?
Mineral
Naturally occurring
inorganic solid with
a definite crystalline
structure and
specific chemical
composition
Rock
• Naturally
occurring solid
made of one or
more minerals
• Rocks are
classified based
on the way they
form.
Three Major
Types of
Rocks
1. IGNEOUS =
formed when
liquid magma
cools and
hardens
▫ From the Latin
ignis meaning
born of fire
Three Major
Types of
Rocks
2. SEDIMENATRY =
formed from the
sediments of
other rocks
already present or
very near earth’s
surface
Three Major
Types of
Rocks
3. METAMORPHIC =
formed under
high pressure and
heat for long
periods of time
 The heat and pressure
cause the rock to change
into new rock.
 Metamorphosism =
change of form
COMPACTION &
CEMENTATION
SEDIMENT
ERODE &
WEATHER
ERODE &
WEATHER
HEAT &
PRESSURE
MELT
ERODE &
WEATHER
HEAT &
PRESSURE
IGNEOUS
ROCK
THE
SEDIMENTARY
ROCK
ROCK
CYCLE
METAMORPHIC
ROCK
MELT
COOL &
HARDEN
MELT
MAGMA
IGNEOUS ROCK
• Always begins as magma deep in the earth.
The magma cools and hardens into crystals
deep in the earth or nearer to the surface.
• Classified by where they form, texture, and
composition
Two Types of Igneous Rock
1. Intrusive =
formed deep
within the
Earth
• Examples:
batholith,
dike, sill,
stock,
laccolith
Two Types of Igneous Rock
2. Extrusive =
formed from
lava at Earth’s
Surface
▫ Examples:
volcanic
rock, pumice,
obsidian
Igneous Texture
• Depends on the size of the crystals
• Slower cooling = larger crystals
▫ Intrusive rocks cool more slowly,
creating larger crystals.
▫ Called “coarse-grained”
▫ Example: granite
Igneous Texture
QUESTION:
• Faster cooling = smaller crystals
WHICH
MORE
DENSE▫ Extrusive IS
rocks
cool more
quickly,
creating smaller or no crystals
BASALT
OR
GRANITE?
▫ Called “fine-grained”
BASALT IS MORE DENSE
the
floor is made
it while the
crust is made
▫ ocean
No crystals
=ofglassy
orcontinental
amorphous
mostly of Granite which is LESS DENSE!
▫ Examples:
obsidian
The
Land will “float”basalt,
on the ocean
floor at subduction zones!
Igneous Texture
• Porphyritic Texture: when magma cools
and harden under Earth’s surface, it can
cool at different rates, causing varying
crystal sizes. The result is called
porphyritic.
• Larger crystals
can even form on
smaller crystals
Igneous Textures
COARSE-GRAINED
PORPHYRITIC
FINE-GRAINED
GLASSY
Composition
• What is it made of? What color is it?
• Six mineral combinations:
Quartz
Feldspar
Pyroxene
Amphibole
Olivine
Mica
• The combinations of the minerals determine
the color of the rock.
Types of Marble
Examples of Igneous Rocks
1. Granite
2. Rhyolite
3. Gabbro
4. Basalt
5. Obsidian
6. Pumice
Metamorphic Rock
• Metamorphosis means change
▫ So, metamorphic rock is changed ingenous
or sedimentary rock
Agents of Metamorphism
• Heat: changed occur between 100oC and 2000C
• Pressure: Extreme pressures 12-16km below
Earth’s surface can change the crystalline
structure, altering the type of rock
• Reaction to solutions (ex: hydrothermal vents)
Types of Metamorphism
1. Contact Metamorphism=rocks are heated through
WHAT
TYPE
OF
METAMORPHISM
IS
direct
contact
with
magma
or lava.
THIS EXAMPLE? over a large
2. Regional Metamorphism=occurs
area.
a.
b.
Is the most common type of metamorphism
Widespread and intense heat and pressure deep in the earth cause changes in the
rock.
Classification of Metamorphic Rock
1. Foliated: Crystals are
arranged in bands or
layers
a.Cleavage occurs along
these bands
2. Unfoliated: do not have
bands of crystals
a.Do not cleave in layers
b.Most contain 1 mineral
(ex: marble is nonfoliated
rock made of calcite)
Examples of Metamorphic Rock
Parent rockoriginal rock before
metamorphism
takes place
1. Slate (Shale)
2. Gneiss (Schist,
granite)
3. Marble (Limestone)
4. Quartzite
(Sandstone)
5. Schist (Phyllite)
6. Anthracite
(Bituminous coal)
Sedimentary Rock
• Sediments: form from
the breakdown of
igneous, sedimentary,
or metamorphic rocks
at Earth’s surface
▫ Deposited in layers, and are
compacted & cemented
forming new rock.
▫ Can be reformed into
igneous rock by subduction
at deeps-sea trenches
(returned to the interior of
the earth)
Examples of Sedimentary Rocks
CLASTIC ROCKS
CONGLOMERATE
BRECCIA
SANDSTONE
SHALE
SILTSTONE
Gravel size
particles
Angular
particles
Sand sized
particles
Very fine
Very very
fine
Examples of Sedimentary Rocks
CHEMICAL
BIOCHEMICAL
Limestone & Gypsum
Coquina & Chalk
Precipitate from solution
Shells and skeletons of marine
organisms cemented together
Sedimentary Rock
• 75% of all rocks on Earth’s surface are
sedimentary
• Mainly made of mud, sand, and gravel
• Moved by wind and water. Faster wind or
water can carry larger particles.
Sedimentary Rocks
• Over millions of years mud, sand, grave,
bones, and shells settle to the sea floor as
sediments.
• They pile up in layers of meters thick.
White Cliffs of Dover, England
Sedimentary Rocks
• As sediments pile up,
the pressure becomes
greater.
▫ What happens to the
sediments?
 The pressure squeezes
the sediment together,
hardening it into rock.
• Results in rock layers
or strata. This is the
major characteristic of
sedimentary rocks!
Features of Sedimentary Rock
1. Strata= layering
of the rock when
there is a change
in the type of
sediments
deposited
2. Ripple Marks
3. Mud Cracks
4. Fossils= remains
of animals and
plants preserved
in the rock.
Examples of Sedimentary Rock
•
•
•
•
•
Conglomerate
Breccia
Sandstone
Limestone
Rock salt
IGNEOUS
METAMORPHIC
SEDIMENTARY
How it’s formed:
Examples:
Becoming Metamorphic:
Becoming Igneous:
Becoming Igneous:
Becoming Sedimentary:
Becoming Metamorphic:









How does it change
into other rock
types? Explain
Becoming Sedimentary:
thoroughly!!
At least 2 other
facts: