Strata and rocks 1

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Strata and Rocks

What is a rock?

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Strata and Rocks

This, of course!

But it’s never that simple. There are many different kinds of rocks.

How are they formed? How old are they? Where do they come from?

A stratum is something that can tell us a very, very, very long and interesting answer to the rock’s stories.

A stratum is a horizontal layer of material (rocks) especially one of several parallellayers 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.

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.

But I wouldn’t want to listen to it before bed…

Strata can become:

Inclined, Vertical, Curved or Broken

Which one is which?

Inclined, Vertical, Curved or Broken

Let’s go to page 38 and answer the questions, then move to the

questions on page 40.

So, how was this formed?

These are the White cliffs of Dover

These are different. These are actually made from tiny little sea creatures called coccoliths

When they die, their white bones become the sediment of the cliffs!

Over millions and millions of years, those bones are collected and the cliff gets bigger and bigger, until you have this.

Because this is done by animals, there is no significant strata.

You can tell a story all over the world using Strata.

One day in 1883, there was a mountain called Krakatoa. But this was not an ordinary mountain.

This was a volcano.

Krakatoa was a big, powerful volcano, stronger than all his friends. But she got bored easily, so

she often decided to erupt. She exploded. And on the special day in 1883, her explosion was one of

the biggest, EVER.

You can tell a story all over the world using Strata.

One day in 1883, there was a mountain called Krakatoa. But this was not an ordinary mountain.

This was a volcano.

Krakatoa was a big, powerful volcano, stronger than all his friends. But she got bored easily, so

she often decided to erupt. She exploded. And on the special day in 1883, her explosion was one of

the biggest, EVER.

You can tell a story all over the world using Strata.

The eruption in 1883 was so big, and so loud that she destroyed 65% of the island she was living in!

She cause huge tsunamis and killed over 36,000 people.

The noise was so loud, people could hear it up to 4,800km away! People could record the

shockwaves from anywhere on the planet Earth.

You can tell a story all over the world using Strata.

Here is Krakatoa now.

When a volcano erupts, it throws thousands, millions of tonnes of dust and rock into the air, molten rock down the mountain and on the land and makes the sky dark.

This dust and sediment will eventually drop from the sky onto the rocks and create a stratum

That’s a lot of dust…

When Krakatoa erupted, the next year was darker, colder, and people called it ‘the year without summer’ because everywhere in the world had less sunshine and heat, the crops died and everyone had a difficult time.

When this happens ALL OVER THE WORLD, you can see the same stratum in Africa, Antarctica, Europe and Asia… everywhere. If you see the same stratum, thousands of miles away, it can tell you a story in great detail!

THE END