Download Objectives: Define rocks Describe the rock cycle and some changes

2-1 F
Objectives:
Define rocks
Describe the rock cycle and
some changes that a rock could
undergo.
Rocks are a mixture of
minerals, glass, organic
matter, and other
natural materials.
+
+
feldspar
hornblende
+
mica
=
quartz
Granite
Rocks are changed by processes
such as:
a. weathering
b. erosion
c. compaction
d. cementation
e. melting &
cooling
f. heat & pressure
Three types of rock
1. Igneous rock
2. Metamorphic rock
3. Sedimentary rock
Many times transformations are interrupted.
This is an example of an igneous rock
interrupted before completely transforming
into a metamorphic rock.
Here is a map showing the United States
and part of Canada and Mexico. This map
shows what type of rock makes up the
surface of these regions
Three little rocks went to the doc.
The first said, “Doctor, please!
On the ocean floor, washed down from the shore,
I was squished and squashed and squeezed.”
“Hmmm…” said the doc. ‘That’s not a great
shock.
You were just becoming a sedimentary rock.”
The second said, “Doc, I was boiling hot,
Deep down inside the planet,
But then I was pushed, cooled off, and smushed,
And now I feel like granite.”
“Hmmm…” said the doc. “Don’t be a
worrywart,
You’ve turned into stone of the igneous
sort.
The third said, “Doc, I started as a rock,
Just like these other two,
I was under great stress, I’m a flattened mess,
What I am now, I haven’t a clue.”
“Hmmm…” said the doc. “Your condition’s well
known.
It’s obvious now you’re a metamorphic stone.”
“Thank you, Doc!” said each little rock,
Wearing a happy smile,
Then one by one,
they rolled out in the sun
And sat there in a pile.
2-2F
Objectives:
.
Recognize magma and lava as the
materials that cool to form igneous rocks.
•Contrast the formation of intrusive and
extrusive igneous rock.
•Contrast granitic and basaltic igneous
rocks.
Comes from molten material.
It can be intrusive or extrusive.
Molten rock under
Earth’s surface is
less dense & is
forced upward. If it
cools under the
surface it forms
intrusive igneous
rock. The slower the
cooling process, the
larger the crystal
grains.
Lacc
olith
Batholith
Forms when lava hardens on or
near Earth’s surface.
It cools quickly and produces fine
grained crystals.
(ex. Pumice, Obsidian)
obsidian
pumice
Classification of Igneous Rock
Basaltic rocks
Dark gray to black
D
e
n
Fine grained
s
e
Granitic
Granitic
igneous
rocks are
light
colored
and less
dense
than
basaltic
rocks.
Andesitic
Andesitic
rocks have
compositions
between
granitic and
basaltic.
Igneous rock is the most abundant
rock on Earth.
2-3F
Objectives:
Describe conditions that cause
metamorphic rocks to form.
Classify metamorphic rocks as
foliated or nonfoliated.
Rocks that have changed due
temperature and pressure. They
can be formed from igneous,
sedimentary, or other
metamorphic rocks.
Examples
Granite changes
to gneiss
Limestone changes
to marble
Shale changes
to slate
Classification
(according to texture)
Foliated texture – line up in
parallel bands
slate
gneiss
Non-foliated rocks –no bands occur
quartzite
marble
Objectives:
Explain how
sedimentary rocks
form from
sediments.
Classify
sedimentary rocks
as detritil, chemical,
or organic.
Summarize the rock
cycle.
75% of the rocks on
Earth’s surface are
sedimentary rock.
Sedimentary rocks
are formed when
sediments are
pressed and
cemented together,
or when minerals
form from
solutions.
Detrital Sedimentary Rocks are
made by broken fragments of
eroded rocks.
Detrital rocks are
formed by the
process of
compaction and
cementation
Compaction
layer upon layer of sediments
build up
Pressure from upper layer
pushes down
Sediment sticks together
Solid rock
Cementation
Large pebbles & sand
Water soaks through
Dissolves minerals in rock
Forms a natural cement
Chemical Sedimentary Rock
Chemical sedimentary rock are from
dissolved minerals in a solution.
Rock Salt
Limestone
Organic Sedimentary Rock
Rocks made up of once living
things are called organic
sedimentary rock. Animal
shells make up natural chalk.
Coal is made of decayed
swamp plants.