Download rocks - Warren County Schools

ROCKS
What is a rock?
What is a rock?
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Made of entirely one mineral or several minerals.
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Could contain organic matter (composed of living
material, usually carbon based).
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The chemical make-up of the rock may vary from
one sample to another.
Types of Rocks
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What are the three classes of rocks?
Types of Rocks
What are the three classes of rocks?
1. Igneous Rocks
2. Sedimentary Rocks
3. Metamorphic Rocks
Igneous Rocks
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Name comes from the Latin word “ignis” meaning from fire.
Formed when super hot magma or lava cools.
There are seven different classes based on chemical
composition of the igneous rock.
Types of Igneous Rocks
Extrusive Igneous Rocks:

Formed from lava that
quickly solidifies at the
cooler surface.
Produces fine-grained
rocks.
Ex. basalt and rhyolite
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david-amador.com
geology.com
Types of Igneous Rocks
Intrusive Igneous Rocks:
 Trapped magma under the
crust solidifies slowly.
 Intrusive rocks are composed
of larger crystals because
form slower.
 Larger crystals give these
rocks a rougher texture
Ex. granite

Mount Rushmore is carved
from granite in the Black
Hills of South Dakota.
Mount Rushmore is carved from granite in the Black
Hills of South Dakota.
Igneous Rock

The most common
known igneous rock is
granite.

It is composed almost
entirely of feldspar and
quartz
Igneous Rocks: Mafic vs. Felsic
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Mafic : chemically
composed of iron and
magnesium, and smaller
amounts of quartz.

Felsic: chemically
composed of potassium,
feldspar, and large
amounts of quartz.
csmres.jmu.edu
Bell Ringer: Rocks

What is the difference between intrusive and
extrusive igneous rocks?

T or F: Intrusive igneous rocks are composed
of larger crystals then extrusive igneous rocks.

Would mafic or felsic magma be magnetic?
Explain your answer.
Igneous Rock Formations
Extrusive Igneous Structues:
 volcanoes
Intrusive Igenous Structures:
 batholiths
 laccoliths
 sills
 dikes
indiana.edu
Sedimentary Rocks
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All sedimentary rocks are made of materials called
sediments deposited by natural and chemical processes.
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Sediments become cemented or compacted together
over time forming a solid rock
Types of Sediments
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Tiny grains of sand
Broken pieces of rock along the bottom of a
stream
Fragments of seashells
Layers of mud
Organic matter (plant and animal remains)
Sediments and Sedimentary Rocks
Gravity, water, or wind carries them to a destination.
 Sediments deposit in layers over time. (strata= layers)
 Loosely deposited sediments eventually form a solid rock by:
1.Compaction: sediments squeezed together by
gravity/pressure.
2. Cementation: sediments glued together by minerals
deposited by water.
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Sedimentary Rock
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The most common
sedimentary rock is
limestone.
Develops from living
remains (shells, mollusks)
Coal is another example of
a sedimentary rock derived
from organic remains.
Sedimentary Rock
Ripple marks formed in the
sand by wind
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Often preserve some characteristics from which they
were formed.
Ripple marks formed in the sand will appear in the rock
formed from the sand deposits.
Sedimentary Rocks
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The source of most fossil
remains.
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The age of a rock can be
determined by studying the
fossils within it.(Radiometric
Dating)

Identify when prehistoric
organisms and vegetation thrived
and became extinct.
Fossilized Leaves
Sedimentary Rocks
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The diverse colors within the
sedimentary layers (strata)
gives scientists an idea of their
chemical make-up.
The red and pink bands in the
Grand Canyon exhibit the
iron found in the sediment.
Sedimentary Rocks: Location
 Sedimentary
rocks cover almost all of
the ocean floor and about threefourths of Earth's surface land area.
Metamorphic Rock
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Metamorphism: change in the chemical make-up of rocks
Heat, pressure, and hot fluids cause rocks to change into
other rocks.
Where would this most likely occur?
Metamorphic Rock
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Heat, pressure, and hot fluids cause rocks to change
into other rocks.
Where would this most likely occur? within the Earth
at subduction zones
Metamorphic Rock
Formed from compression of
Tectonic plates
The geologic processes that created the North Cascades
changed the original rock into metamorphic rock.
Types of Metamorphic Rock

Slate is a common form
that is easily split into
slabs
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Gneiss (pronounced
“nice”) contains light and
dark bands
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Granite is also a
common type
The Rock Cycle
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Almost all of the rocks that compose the Earth’s
crust today are made of the same stuff as the
rocks that dinosaurs and other ancient life forms
walked, crawled, or swam over. While the
stuff(matter) that rocks are made of has
changed, the rocks themselves, have not. Over
time rocks are recycled into other rocks.
The Rock Cycle
The Rock Cycle