Download Rock Cycle - SweeneyScientists

CH 3
ROCKS
ROCK!
NEED TO KNOW
1. The three groups of rocks are classified by ____.
2. In Figure 3-1, what type of rock should occur in the part of the rock cycle
labeled B?
3. In Figure 3-1, what process or processes would be occurring in the part of
the rock cycle labeled E?
4.In Figure 3-1, what type of rock should occur in the part of the rock cycle
labeled F?
5. A rock that forms when magma hardens beneath Earth’s surface is called an ____.
6. The more time an igneous rock has to cool, the __________ the crystal size.
7. Which of the following represents the correct order of the processes
involved in sedimentary rock formation?
8. Fossils are only found in ____.
9. A conglomerate is a rock that forms as a result of ____.
10. All of the energy that drives Earth’s rock cycle comes from ____.
The Rock Cycle
‹ Rocks are any solid mass of mineral or
mineral-like matter occurring naturally
as part of our planet.
‹ Types of Rocks
1. Igneous rock is formed by the crystallization
of molten magma.
2. Sedimentary rock is formed from the
weathered products of preexisting rocks that
have been transported, deposited, compacted,
and cemented.
3. Metamorphic rock is formed by the alteration
of pre-existing rock deep within Earth (but still
in the solid state) by heat, pressure, and/or
chemically active fluids.
Rock
Cycle
Interactions among Earth’s water, air, land, and living
things can cause rocks to change from one type of rock
to the other.
The Rock Cycle
‹ Shows the interrelationships among the three
rock types (igneous, sedimentary, and
metamorphic)
‹ Magma is molten material that forms deep
beneath the Earth’s surface.
‹ Lava is magma that reaches the surface.
‹ Weathering is a process in
which rocks are broken down by
water, air, and living things.
‹ Sediment is weathered pieces of
Earth elements.
The Rock Cycle
Energy That Drives the Rock Cycle
‹ Processes driven by heat from the Earth’s
interior are responsible for forming both
igneous rock and metamorphic rock.
‹ Weathering and the movement of weathered
materials are external processes powered by
energy from the sun.
‹ External processes
produce sedimentary rocks.
Igneous Rock
• Igneous rock forms deep within Earth’s interior
or at Earth’s surface from fiery volcanic
eruptions.
3.2 Igneous Rocks
‹ Igneous rocks can be classified based
on their composition and texture.
1. Texture
• Coarse-grained texture is caused by slow
cooling resulting in larger crystals.
• Fine-grained texture is caused by rapid
cooling resulting in smaller, interconnected
mineral grains.
• Porphyritic texture is caused by different rates
of cooling resulting in varied sized minerals.
• Glassy texture is caused by very rapid cooling.
Igneous Rocks
2. Composition
• Granitic composition rocks are made mostly
of light-colored quartz and feldspar.
• Basaltic composition rocks are made mostly
of dark-colored silicate minerals and
plagioclase feldspar.
• Andesitic composition rocks are between
granitic light-color minerals and basaltic
composition dark-colored minerals.
• Ultramafic composition rocks are made mostly
from iron and magnesium-rich minerals.
Igneous Rock
• Intrusive: Forms under or “inside” Earth’s surface. Cools slowly.
(MAGMA)
• Extrusive: Forms above or “externally from Earth’s surface.
Cools quickly.
(LAVA)
Extrusive Igneous
• When lava hardens and cools quickly.
FINE GRAIN
Extrusive Igneous
• Small grains----fast cooling.
Some extrusive rocks cool off so quickly that no
crystals have time to form. This makes the rock
very smooth like a piece of glass. This can
happen when a volcano erupts into the ocean
Intrusive Igneous
• When magma hardens and cools slowly.
CORSE GRAIN
granite
feldspar
Igneous Rock
• Glassy texture: superfast cooling.
• Porphyritic texture: fast + slow cooling= different
size crystals. Gas bubbles get caught inside the rock
itself.
Igneous Rocks
Composition
• Granitic: Light colored rocks, continental crust.
• Basaltic: Dark colored rocks, oceanic crust.
Sedimentary Rock
• Sedimentary rocks form when existing rock begin to
break down.
• Weathering, erosion and deposition are the processes
that form these rocks
Do you
notice the
layers?
What does
each layer
represent?
Sedimentary Rock
• Deposition: When an agent of erosion—water, wind,
ice, or gravity—looses energy, it drops the sediment.
Water is the
number 1
erosional
agent on
Earth.
Sedimentary Rock
Compaction is a process that squeezes or compacts
sediment.
Cementation takes place when dissolved minerals are
deposited in the tiny spaces among the sediments.
Sedimentary Rocks
Clastic: Made from
weathered bits of rocks
and minerals.
Chemical: forms when
dissolved minerals
precipitate from water
solutions.
Sedimentary Rocks
• Some sedimentary rock can be chemically formed.
• This is when dissolved minerals precipitate from water
solutions and leave behind a solid.
Think of
letting a
glass of
salt water
dry up.
What is
left?
Limestone Rock
Fossils in Sedimentary Rock
•
ALL Fossils are found in sedimentary rock!
•
Fossils can be used to help answer many questions about the rocks
that contain them.
Sedimentary rocks
have clues in them to
reveal how they
formed. They also can
tell you what Earth’s
conditions were like at
the time of their
formation.
What would ripple marks on a sedimentary rock
suggest?
Metamorphic Rock
• “Morph” means to change.
•
Most “metamorphisim” (changing) occurs at high temperatures and
pressures inside the surface of Earth
• HEAT + PRESSURE
Metamorphic Rock
• Contact Metamorphism: Hot magma moves
onto rock. (small changes)
• Regional Metamorphism: Large scale
deformation. (large changes---mountain building)
Metamorphic Rock
• Foliated: when minerals re-crystallize under
extreme conditions. BANDS
• Non-Foliated: Usually one mineral.
SPECKS