Strata and rocks 2

Review!

Strata and Rocks

There are many

different kinds of

rocks.

How are they formed? How

old are they?

Where do they come from?

A stratum is a horizontal layer of

material (rocks) especially one of

several parallel layers arranged,

one on top of the other.

Remember Parallel

from our math

lessons?

In mountains and cliffs, You can see many

different types of rocks that create the strata,

layered on top of each other

This can tell us a story that is anywhere

from thousands to BILLIONS of years old.

In this picture, you can see the different

colours, created by different types of rocks.

One type of rock you see is called

sedimentary.

Sedimentary rock is a rock formed by the

stratification of sediment.

Sedimentary rock is a rock formed by the

stratification of sediment.

…What is stratification?

Sedimentary rock is a rock formed by the

stratification of sediment.

Stratification is the formation or deposition of

layers as seen in sedimentary rock.

Sedimentary rock is a rock formed by the

stratification of sediment.

Stratification is the formation or deposition of

layers as seen in sedimentary rock.

…what is sediment?

Sedimentary rock is a rock formed by the

stratification of sediment.

Stratification is the formation or deposition of

layers as seen in sedimentary rock.

Sediment is material that has been broken into

tiny particles by weathering or erosion.

Different forces will transport the particles.

Sedimentary rock is a rock formed by the

stratification of sediment.

Stratification is the formation or deposition of

layers as seen in sedimentary rock.

Sediment is material that has been broken into

tiny particles by weathering or erosion.

Different forces will transport the particles.

The particles can be organic or inorganic.

Sedimentary rock is a rock formed by the

stratification of sediment.

SO. Sedimentary rock is made when tiny

particles are carried and then dropped into a

layer of rock, called stratification.

Organic

Inorganic

Strata are always formed horizontally.

Why?

Strata are always formed horizontally.

Because of gravity.

Gravity keeps everything

leveled across the surface,

by pushing everything

down.

But Sometimes, you see

something like this…

This is not horizontal…

This shows that other, HUGE forces

change the position of the rocks…

Even mountains..

The movement inside the earth

will push the rocks upwards,

over, upside down, break them

in half, bend them and twist

them until a whole unique story

has been made.

Strata can become:

Inclined, Vertical, Curved or Broken

Which one is which?

Inclined, Vertical, Curved or Broken

Ok, Next…

There are different

names for different

kinds of rocks.

Here are some

examples.

Pelite

Pelite

Conglomerate

Conglomerate

Sandstone

Sandstone

Shale

Shale

Limestone

Limestone

Let’s review:

Which rock is this?

Let’s review:

Which rock is this?

Pelite

Let’s review:

Which rock is this?

Let’s review:

Which rock is this?

Limestone

Let’s review:

Which rock is this?

Let’s review:

Which rock is this?

Sandstone

Let’s review:

Which rock is this?

Let’s review:

Which rock is this?

Shale

Let’s review:

Which rock is this?

Let’s review:

Which rock is this?

Conglomerate

Ok great. Now

let’s answer the

questions on

page 42.

There are three groups of rocks that are made on earth,

in space and in the universe.

These are called:

Igneous

Sedimentary

Metamorphic

Once you understand these, it will be easy to find out the

story of any rocks.

Igneous - Igneous means ‘born of

fire’.

Can anybody guess where igneous

rocks come from?

Sedimentary - We already

studied this, so where

would we find these

rocks?

Metamorphic - This word means

‘changing’.

To change a rock, you need a LOT of

heat and a LOT of pressure, and of

course, time.

Where would these

be?

Here are some examples of the rocks

Sedimentary

Here are some examples of the rocks

Igneous

Here are some examples of the rocks

Metamorphic

?

?

Here are some examples of the rocks

Igneous

So:

Igneous rocks are made from the liquid, molten

lava from deep inside the earth.

Sedimentary rocks are made from lots of tiny

sediments that lay on top of each other from

deposition.

Metamorphic rocks are made when rocks are

pushed and heated together so much, that they

change into something else.

This metamorphic rock looks like a

sedimentary rock!

Why?

This metamorphic rock looks like a

sedimentary rock!

Why?

If a sedimentary rock

is pushed and

heated, the

materials and

minerals will change,

but the pattern will

stay the same.

So if you want to learn about the history

of the earth, you just need to remember:

Igneous – Fire rocks

Sedimentary – Layered rocks

Metamorphic – Changed rocks