Download Class PowerPoint on Rock Cycle, Fossils, and Fossil

& Minerals
Rocks,Rocks
Fossils,
Fossil Fuels
Sedimentary Rock Formation
www.energyinst.org.uk/education/glossary/
•
Sediments (broken pieces of rock) are
deposited in an area (often under water)
and pile up over time.
•
These small pieces of rock form
sedimentary layers and more pressure is
put on the lower (oldest) layers as the
amount of sediment on top of them
increases.
•
This pile up of sediments compacts the
lower layers of sediment forcing the
water out from between the rocks.
•
Cementation happens as dissolved
minerals become deposited in the
spaces between the sediments. These
minerals act as glue or cement to bind
the sediments together.
Fossil Formation
•
Fossils form when an organism dies and is covered quickly by sediment.
•
•
An example would be a sand storm moving in quickly and covering the organism.
Organisms that live in the sedimentary layer or on the sea floor become fossils more often.
•
Once covered with sediment the organism is compacted along with the sediment and as
sedimentary rock forms, it may leave an impression fossil on the rock.
•
The remains of the organism decay, but minerals may fill this space and create a 3-D fossil
Fossils Provide Information
•
Fossils provide evidence that can help us understand the conditions of
that specific location/ region at a given past time.
•
For instance, we could find out that an area that is currently a desert
was once covered by water.
•
Fish fossils on a mountain tell us the mountain was once under water.
•
Fossils will be found in sedimentary rocks only!!!
•
Remember, the older fossils are in the lower rock layers and younger
fossils are in the higher rock layers.
So how is a mineral different
from a rock?
• All minerals must:
– Occur naturally in
nature
– Inorganic solid
– Crystal structure
– Definite chemical
composition
• Rocks are a mixture of
minerals and other
organic matter
http://nature.ca/museum/press/2006/pr06-02-07_minstucson_e.cfm
Fossil Fuel Formation
• Fossil Fuels begin forming as sedimentary
rock forms, but it takes HEAT,
PRESSURE, and TIME (lots of time)!
• Because it takes so long to form, fossil
fuels are considered nonrenewable
resources.
Fossil Fuel Formation
If dead plant matter, or
Peat, is trapped in the
sediment layers it will be
compacted along with the
sediment. As the layers
are pushed down heat
from the earth along with
pressure from the
sediments will harden it
into COAL.
• Click to see video
of how Coal was
formed
Fossil Fuel Formation
If dead animal matter,
mainly microscopic sea
organisms, is trapped in
the sediment layers it is
compacted, and heated
over time to form OIL.
Natural Gas may also
form in areas where oil
is located.
Animation of Oil and
Natural Gas Formation
Origin of rocks
• Metamorphic rocks
are formed from other
rocks that have been
pushed deep into the
earth’s crust
• Pressure from the
earth above and heat
from the mantle below
cause them to change
shape, color, grain and
crystal structure
http://www.classzone.com/books/earth_science/terc/content/visualizations/es0607/es06
07page01.cfm?chapter_no=visualization
Origin of rocks
• Igneous rocks are
formed from the
cooling of magma or
lava
– Lava is magma that
reaches the earth’s
surface
www.outreach.canterbury.ac.nz/.../igneous.jpg
Rock cycle
Click title to go to a great rock cycle website!
http://www.classzone.com/books/earth_science/terc/content/investigati
ons/es0602/es0602page02.cfm