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Entrance Question
Which of the following is one reason that diamond
is classified as a mineral instead of a rock?
A) It comes in different
colors.
B) It has specific crystal
structure.
C) It is extremely hard to
scratch.
D) It can be created in
a lab.
There are TWO
new Learning
Targets today!
What do we already think/know?
Minerals
Rocks
Bill Nye: Rocks and Soil
http://www.youtube.com/watch?v=6Vh1Uwg1ESA
Entrance Question
A
B
Rock A has alternating bands of grain-like minerals.
Rock B is a collection of various crystals.
Classify each rock as igneous, sedimentary, or
metamorphic rock.
Explain your answers.
Rocks
Introduction to Rocks
A rock can be defined as a naturally formed solid
that consists of particles of one or more natural
substances such as mineral grains, glass, and
fragments of plant debris.
• By the term "naturally formed," geologists
exclude from this definition human-made solids
such as concrete.
• With the term "solid," most geologists also
exclude loose substances such as silt, clay, and
sand from their definition of a rock.
Introduction to Rocks
Most rocks consist of a mixture of more than
one substance, usually a variety of minerals and
organic substances.
• Coal typically contains fragments of ancient
plant debris, called macerals, mixed with
assorted mineral grains.
• Sometimes particles of a single mineral form
the bulk of a rock, as calcite does in limestone.
Introduction to Rocks
Rocks form the outer layer, or crust, of Earth.
Geologists have developed three basic
categories of rock, distinguished by the
processes that form them.
Igneous Rock
• Igneous rock forms when molten rock below
Earth's surface cools enough to solidify. The
crust of the primitive Earth is believed to have
once consisted entirely of igneous rock.
Igneous Rock
• As magma cools, the elements flowing within
it slow their random movement. Gradually,
they begin to arrange themselves into orderly
patterns. This process of crystallization forms
igneous rock.
Igneous Rock
• Most igneous rocks are hard and compact
with little or no visible layering.
• The type of igneous rock that forms from
these crystallized elements depends largely on
the speed at which magma cools.
Igneous Rock
Igneous Rock
• Igneous rocks may have the following
characteristics:
(1) crystals that seem to be fused together
(2) holes due to volcanic gases
OR
(3) glassy
Igneous Rock
• Common igneous rocks include: pumice,
granite, and obsidian
Sedimentary Rock
• Sedimentary rock consists of sediment—
particles of dissolved and weathered rock, as
well as the remains of decayed plants and
animals.
Sedimentary Rock
• Typically, sedimentary rock forms when such
particles collect in oceans, lake beds, and
other places, where they become cemented
together in layers over hundreds or thousands
of years.
Sedimentary Rock
• Most of the rock that is exposed on Earth's
surface is sedimentary. When cut or exposed,
most sedimentary rock has obvious layering.
Within these rock layers, one can find the
remains of past environments, from rock
fragments to fossils.
Sedimentary Rock
• Many sedimentary rocks are formed by a
combination of compaction and cementation.
– Compaction is the intense compression of
sediment grains by the weight of overlying
material.
Sedimentary Rock
– Cementation involves dissolved materials that fill
the open spaces between grains, and then solidify
to cement them together.
Sedimentary Rock
• Sedimentary rocks may have the following
characteristics:
(1) sediments (sand, pebbles, fossils, etc.) appear
to be glued together
OR
(2) sediments appear to be held together by
cement
Sedimentary Rock
• Common sedimentary rocks include:
sandstone, conglomerate, and limestone
Metamorphic Rock
• Metamorphic rock forms when pre-existing
rock sinks, without melting, deep into Earth,
where it is twisted and deformed.
• The term "metamorphic" means to "change
form." Metamorphic rock arises from the
transformation of pre-existing rock that has
sunk deep within Earth's crust. There the rock
likely encounters heat and pressure.
Metamorphic Rock
• Metamorphic rock is that it never actually
melts during its transformation.
• Metamorphism occurs when tectonic or
volcanic forces warp and bake surrounding
rock.
Metamorphic Rock
• Metamorphic rocks may have the following
characteristics: appear to have been
(1) twisted
(2) folded
OR
(3) swirled as though the rocks had
become bendable or altered.
Metamorphic Rock
• Common metamorphic rock include: shale,
slate, and gneiss
The Rock Cycle
The rock cycle organizes the processes that can
transform one type of rock into another.
• There is no beginning or end to this cycle.
Shortcuts are also common in nature.
The Rock Cycle
The Rock Cycle
Igneous, Metamorphic, or Sedimentary?
IGNEOUS (Diorite)
Igneous, Metamorphic, or Sedimentary?
METAMORPHIC (Gneiss)
Igneous, Metamorphic, or Sedimentary?
METAMORPHIC (Soapstone)
Igneous, Metamorphic, or Sedimentary?
SEDIMENTARY (Sandstone)
Igneous, Metamorphic, or Sedimentary?
IGNEOUS (Granite)
Igneous, Metamorphic, or Sedimentary?
IGNEOUS (Scoria)
Igneous, Metamorphic, or Sedimentary?
SEDIMENTARY (Limestone)
Igneous, Metamorphic, or Sedimentary?
SEDIMENTARY (Conglomerate)
Igneous, Metamorphic, or Sedimentary?
METAMORPHIC (Phyllite)
Igneous, Metamorphic, or Sedimentary?
I am a rock with
“vesicles,” which are a
result of trapped gas
within molten rock as it
solidifies.
IGNEOUS (Scoria)
Igneous, Metamorphic, or Sedimentary?
I am a rock that was
“baked” while near a
heat source such as a
magma chamber.
METAMORPHIC (Hornfels)
Igneous, Metamorphic, or Sedimentary?
I am formed from very
rapidly cooling molten
rock material. I cool so
rapidly that crystals do
not form.
IGNEOUS (Obsidian)
Igneous, Metamorphic, or Sedimentary?
I begin as limestone but
end up twisted and
turned along with other
rocks to become
something else.
METAMORPHIC (Marble)
Igneous, Metamorphic, or Sedimentary?
I am composed of large
angular fragments. The
spaces between the large
fragments are filled with a
mineral cement that binds
the rock together.
SEDIMENTARY (Breccia)
Entrance Question
Answer Options:
Compact/Cement
Cool
Heat/Pressure
Weather/Erode
Melt
A
B
C
D
I
A: Cool
_____________
B: Melt
_____________
C: Weather/Erode
_____________
D: Heat/Pressure
_____________
Compact/Cement
E: ______________
Weather/Erode
F: ______________
G: Weather/Erode
_____________
H: Heat/Pressure
_____________
Melt
I: ______________
G
E
F
H
Review
Directions: Match the key words/phrases with
the appropriate rock type.
A “molten rock”
B “transform”
____
____
C “weather and erode” ____
A “volcanic”
____
C “grains”
C “cement”
____
____
A. IGNEOUS ROCK B. METAMORPHIC ROCK
C. SEDIMENTARY ROCK
What rock type?
Sedimentary
Sedimentary
Igneous
Igneous
Rock Cycle Journey
Rock Cycle Journey
Grouping
Part One: Complete the journey with a partner of the same color.
Part Two: When finished with the journey, check your work with someone
from a different group.