Rocks and Earths atmosphere

1
Rocks and Earths atmosphere

• Chemistry revision

2
In this lesson you will re-visit
The three main types of rock The Rock
Cycle Dating rock strata Plate tectonics,
convection cells Evolution of the Earths
atmosphere
3
You need to be able to
Name the 3 types of rock and two examples of
each. Label a cross section of the Earth. Be able
to state how rocks can be dated by fossil
evidence and igneous intrusion. Describe the
theory of plate tectonics. Draw the simple
diagram of a destructive and constructive plate
margin. Be able to describe the stages involved
with Earths atmosphere evolution.
4
There are 3 types or rock

Can you name the 3 types from this diagram?
This is a link to other pupils work
5
Sedimentary rocks
Tend to be crumbly and sometimes contain fossils.
They are laid down in layers the particles of
rock eventually cementing together. They are laid
down by water and wind.
Here are two examples
Limestone
Sandstone
6
Igneous rocks
Igneous rocks are formed from molten rocks which
have cooled and solidified. Below the Earths
surface molten rock is called magma, on the
surface it is lava. This rock is hard and has
crystals. Crystal size depends on how quickly the
rock cooled. Here are two examples
What can you say about how they cooled?
Granite
Basalt
Granite
7
Metamorphic rocks
There are rocks formed by high temperature and
pressure on existing rocks. They are hard and may
contain banded crystals.
Here are some examples
This is gneiss
This is marble
8
Clues in the Rocks
The Rock Cycle rocks are continually being
broken down and reformed into new rocks.
Can you label the process arrows?
9
How to find out the history of rocks
Igneous rocks can give useful information about
the geological history of an area. This can be
used to date the age of the rocks. Look at this
diagram. Can you explain what is going on?
Sedimentary rocks laid down first
Igneous rock intruded later on so is YOUNGER.
10
Plate tectonics how the earth moves
Convection currents in the mantle move the rigid
crust plates.
11
Plate boundaries
12
These plates have two types of movement
A constructive boundary
A destructive boundary
13
The evolution of the Earths atmosphere
Phase 1 The Earth was molten and volcanic for
many millions of years. Any gases boiled
away. Loads of carbon dioxide, steam, ammonia and
methane were given out.
Phew, stinky or what!
14
Phase 2
Phase 2
Plants evolved they really liked the carbon
dioxide atmosphere.
Water vapour condensed and formed oceans. The
water also absorbed carbon dioxide.
Carbon dioxide got wrapped up in fossil fuels and
sedimentary rocks like limestone.
15
Phase 3
Because of plants, lots of oxygen built up in the
atmosphere it is so poisonous many organisms
died!
BUT, this allowed more complex organisms to
evolve..
Oxygen also created the OZONE layer, though
poisonous, stopped harmful UV killing us off!
16
So can you.
Describe how the 3 types of rock are formed and
give examples of each? Fill out a partially
completed Rock Cycle? Explain why some continents
have similar fossils and rock types but are far
apart? Draw simple diagrams of a constructive and
destructive plate boundary? Explain how the
Earths atmosphere has changed over millions of
years?