Rock Your World SG

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Contents

Unit map

Part 1:

Activity 1.1

Activity 1.2

Activity 1.3

Activity 1.4

Summary

Part 2:

Activity 2.1

Activity 2.2

Activity 2.3

Activity 2.4

Activity 2.5

Activity 2.6

Activity 2.7

Summary

Part 3:

Activity 3.1

Activity 3.2

Summary

Rocks – part of the Earth System

Every rock tells a story

The deep Earth

Cycling rocks

It’s all in the crust

Lesson Outcomes Checklist Part 1

2

3-9

4

5

7

8

9

Minerals – ingredients in the rock recipe 10-23

Rock or mineral?

Diagnostic properties

Testing minerals

Rock identification

Mining our everyday minerals

Careers in mineral exploration

Money for rocks

Lesson Outcomes Checklist Part 2

11

12

15

19

20

21

22

23

Rocks from the earth’s furnace – igneous rocks

Big and small crystals

Erupting and intruding

Lesson Outcomes Checklist Part 3

24-29

25

27

29

Part 4:

Activity 4.1

Activity 4.2

Activity 4.3

Activity 4.4

Activity 4.5

Summary

Part 5:

Activity 5.1

Activity 5.2

Activity 5.3

Summary

Part 6:

Activity 6.1

Activity 6.2

Activity 6.3

Activity 6.4

Activity 6.5

Activity 6.6

Activity 6.7

Summary

Part Summaries

Grain by grain – sedimentary rocks

Breaking rocks

Which sediments where?

Sticking things together

Grains and rocks

Making rocks from body parts

Lesson Outcomes Checklist Part 4

Shearing, baking and burying – metamorphic rocks

These rocks are so hot!

Regional metamorphosis

A tortured history

Lesson Outcomes Checklist Part 5

The rock cycle

Rocks into rocks

On the level

How do fossils form?

Is this the same as that?

Relative geological time

How long does it take?

Forming landforms

Lesson Outcomes Checklist Part 6

Glossary

30-39

31

33

34

35

37

39

40-47

41

43

45

47

48-62

49

52

54

55

56

58

61

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63

69

Icon Meaning

Digital interactive Hands-on inquiry Classroom activity Notebooking Discussion

11

Part 1 Rocks – part of the Earth System Part 2 Minerals – ingredients in the rock recipe Part 3 Rocks from the Earth’s furnace – igneous rocks Part 4 Grain by grain – sedimentary rocks Part 5 Shearing, baking and burying – metamorphic rocks Part 6 The rock cycle

2

Part 1: Rocks – part of the Earth System

Activity 1.1 Every rock tells a story

Activity 1.2 The deep Earth

Activity 1.3 Cycling rocks

Activity 1.4 It’s all in the crust

1 Rock Your World Part 1 3

Activity type

Activity

1.1

Every rock tells a story

ROCKS HELP US:

• understand how the landscapes around us were formed • know where it is safe to build and to farm • find valuable minerals.

?

What stories could a rock tell?

We often see rocks lying around, but how did they get there? Where did they come from?

They seem to have been there forever, but even rocks change. It just takes a very long time.

Some have experienced violent events in the past. Others have formed beneath warm, shallow seas.

A geologist knows their stories.

A field geologist reading the story in the rocks.

This is Connie Conglomerate. Click here to hear her and her friends' interesting stories.

Rock Your World Part 1 Rocks – part of the Earth System 4

Activity type

Activity

1.2

The deep Earth

What's on the ?

It is very difficult to see into the Earth because it is somewhere very difficult for us to go. Mining takes humans deep beneath the Earth’s surface but how deep can they really go?

Several types of mines can be found around the world. Vertical shaft mines hold the record for being the deepest mines in the world. The deepest mine is the Mponeng gold mine in South Africa at 4 km. (The centre of the Earth is 6400 km deep.) Many problems arise when digging so deep into the Earth.

HEAT:

At 5 km the temperature reaches 70ºC and therefore massive cooling equipment is needed to allow workers to survive at such depths.

WEIGHT:

At 3.5 km the pressure of rocks above you is 9,500 tonnes per square metre, or about 920 times normal atmospheric pressure. When rock is removed through mining this pressure triples in the surrounding rock. This effect coupled with the cooling of the rock causes a phenomenon known as rock bursts, which accounts for many of the 250 deaths in South African mines every year.

The

LITHOSPHERE

lies below? is a thin crust of rock that surfaces the Earth, but what

?

How deep can we dig?

The characters in the book "Journey To The Center Of The Earth", the 1864 science fiction novel by Jules Verne, look up inside a cavern. Does this picture seem realistic? Could we really make a journey to the Earth’s centre?

Rock Your World Part 1 Rocks – part of the Earth System 5

Activity 1.2 The deep Earth Continued

?

What lies beneath the surface?

Lava flowing out of Mt Etna is red hot and flows like a gooey liquid. It comes from deep underground. It provides clues about what conditions are like deep beneath the Earth’s surface.

An erupting volcano in Hawaii produces a long river of lava.

UNDERLYING MAGMA CHAMBER Click on the link to explore some imaginary and real trips deep below Earth’s surface.

Rock Your World Part 1 Rocks – part of the Earth System 6

Activity type

Activity

1.3

Cycling rocks

?

What are the different types of rocks? Where do rocks come from?

ROCKS ARE MADE FROM:

other, broken down rocks melted rock.

Mt Everest is the highest mountain on Earth. It is part of the Himalayas, the most massive mountain range. It is made of rock, but how did it form?

The island of Hawaii has one of the most active volcanoes on Earth: Kilauea. It is a place where new rocks are being made.

The cliffs at the entrance to Sydney Harbour look like solid layers of sand. How did they form?

Click here to learn how rocks are made and break down.

Rock Your World Part 1 Rocks – part of the Earth System 7

Activity

1.4

It’s all in the crust

Describing rocks What to use:

Each GROUP will require:

• collection of rocks including common examples of the 3 rock groups • dissecting microscope • camera (if available) • internet access.

Each STUDENT will require:

• Notebook.

What to do:

Step 1

You have been given some examples of three types of rocks, which have been labelled. Your task is to examine the rock.

Step 2

In your

Notebook

write a brief description of each rock. Click here to learn more about the lithosphere.

Activity type DOWNLOAD e-NOTEBOOK ?

What is the lithosphere?

The lithosphere is the part of the Earth that is made up of rock and soil.

THERE ARE 3 COMMON ROCK TYPES.

These are sedimentary, igneous and metamorphic rocks.

Sedimentary Sandstone Igneous Granite Metamorphic Marble Rock Your World Part 1 Rocks – part of the Earth System 8

Rocks are more than just small features that are found occasionally lying on the ground. They are the fundamental part of the crust on which we live. There are different types of rock, which form under different conditions and have different geological histories. The Earth consists of several distinct layers, including the crust , mantle , outer core , and inner core . A combination of very high temperatures and pressures produce conditions in the mantle and core that are quite different to those found at the Earth’s surface. As the surface is approached the pressure and temperature drops until you reach the crust where the rock is relatively cool and solid.

Although most rocks appear to be endlessly durable they have a life story. Rocks are broken down and rebuilt over very long periods of time .

All rocks on Earth can be broadly categorised into three groups; sedimentary , igneous and metamorphic . These groups of rocks have different characteristics that relate to the manner in which they are formed.

1 DOWNLOAD LESSON OUTCOMES CHECKLIST Rock Your World Part 1 Rocks – part of the Earth System 9

Part 2: Minerals – ingredients in the rock recipe

Activity 2.1 Rock or mineral?

Activity 2.2 Diagnostic properties

Activity 2.3 Testing minerals

Activity 2.4 Rock identification

Activity 2.5 Mining our everyday minerals

Activity 2.6 Careers in mineral exploration

Activity 2.7 Money for rocks

2 Rock Your World Part 2 10

Activity

2.1

Rock or mineral?

Activity type DOWNLOAD e-NOTEBOOK

Comparing rocks and minerals What to use:

Each GROUP will require:

• samples of granite, sandstone, and calcite • dissecting microscope.

Each STUDENT will require:

• Notebook.

?

What is the difference between rocks and minerals?

What to do:

Step 1

Run your finger over the surface of the sandstone. What does it feel like?

Step 2

In pairs, take turns looking at the two rock samples (the granite and sandstone) under the microscope. When you look closely at these rocks, what do you notice about their structure?

Step 3

Look at the mineral sample (calcite) under the microscope. How does it compare to the rock samples?

Granite Marble Sandstone

ROCKS AND MINERALS ARE ALL AROUND US.

Calcite Gold Quartz

Click here to discover some differences between rocks and minerals.

Rock Your World Part 2 Minerals – ingredients in the rock recipe 11

Activity

2.2

Diagnostic properties

WHAT IS WHAT?

We tell OBJECTS apart in our everyday lives.

How do we do this?

?

How do we identify different objects?

CLEVER MARKETING

When you go to the grocery store you see shelves full of breakfast cereal.

If you already know which brand of cereal you are looking for, how do you locate it on the shelf?

What to do:

Write your answers in your

Notebook

.

How do we remember which ones are hot?

Activity type DOWNLOAD e-NOTEBOOK

We use

DIAGNOSTIC PROPERTIES

of objects to keep ourselves safe.

Marketing organisations spend a lot of time putting their clients' products in distinctive packaging. This allows customers to target their product on a shelf.

We use

DIAGNOSTIC PROPERTIES

of objects to find things we are looking for.

Rock Your World Part 2 Minerals – ingredients in the rock recipe 12

Activity 2.2 Diagnostic properties Continued

?

How can we tell these minerals apart?

Quartz Potassium feldspar Muscovite Biotite Calcite Hornblende Rock Your World Part 2 Minerals – ingredients in the rock recipe 13

Activity 2.2 Diagnostic properties Continued What to use:

• specimens of common rock forming minerals (e.g. quartz, potassium feldspar, muscovite, biotite, calcite, hornblende) or selected images of these minerals in the online collection

Rocks and Minerals • Notebook

• internet access.

What to do:

Step 1

In groups of 3-4, compare the six minerals provided. What diagnostic properties of minerals could we use to tell them apart? Record at least five of these in your

Notebook.

Step 2

In your

Notebook

make a table with a description of each of these six minerals.

Discussion:

How would you explain the term "diagnostic property" to one of your friends?

Mineral Diagnostic properties of minerals Colour Quartz Potassium feldspar Muscovite White Biotite Calcite Hornblende

Quartz Potassium feldspar Muscovite Biotite Calcite Hornblende Rock Your World Part 2 Minerals – ingredients in the rock recipe 14

Activity

2.3

Testing minerals

Activity type DOWNLOAD e-NOTEBOOK

DIAGNOSTIC TESTS FOR MINERALS

Geologists use the following diagnostic tests to help identify minerals.

HARDNESS

Mohs scale of hardness was created in 1812 by the geologist Friedrich Mohs. It describes how hard it is to scratch a mineral. Gypsum (2) is harder than talc (1). Gypsum can scratch talc but talc cannot scratch gypsum.

Some common tests that can be used to test hardness are included in the following table.

Mineral Talc Gypsum Mohs Hardness Scale Hardness 1 2 Calcite Fluorite Apatite 5 Potassium feldspar 6 3 4 Quartz Topaz Corundum Diamond 7 8 9 10 Common tests Fingernail (2.5) will scratch it Glass or paper clip (5.5) will scratch it Will scratch glass Diamond (10) will scratch all

CLEAVAGE

Does the mineral split in patterns with a particular shape? This usually reveals the shape of the crystals it is made from. Do not break the crystals you are examining. Try to work out the cleavage by observing the crystal intact.

Cubic

When a mineral breaks in three directions and the cleavage planes form right angles (90° to each other). Results in pieces in the shape of a cube.

Octahedral

When a mineral breaks in the form of a diamond, resulting in 8 nearly equal faces.

Rhombohedral

When a mineral breaks in three directions and the cleavage planes form angles that are other than 90°. The shape formed is called a rhombohedron.

Pinacoidal

breaks in one direction, leaving a single flat surface (cleavage plane). When a mineral breaks into very thin sheets, like mica minerals, the pinacoidal cleavage is called micaceous.

When a mineral

STREAK

What colour is the powder if you scratch the crystal on a hard, rough surface? Often a rough ceramic tile is used for this test.

Rock Your World Part 2 Minerals – ingredients in the rock recipe 15

Activity 2.3 Testing minerals Continued

DIAGNOSTIC TESTS FOR MINERALS

Geologists use the following diagnostic tests to help identify minerals.

COLOUR

What colour is the mineral. The same mineral can come in a few different colours, making this a difficult test to apply sometimes.

LUSTRE

How does the light shine off the mineral? The descriptions used for this characteristic include: • vitreous (or glassy) • dull • waxy • metallic • silky • pearly.

Can you think of any other terms that might fit the minerals you are observing?

Pyrite has a metallic lustre Fluorite has a vitreous lustre Kyanite has a pearly lustre Kaolinite has a dull lustre Rock Your World Part 2 Minerals – ingredients in the rock recipe 16

Activity 2.3 Testing minerals Continued Testing quartz and biotite What to use:

• biotite • quartz • streak plate • glass slide, steel paper clip

• Science by Doing Notebook.

What to do:

Step 1

Copy the results table into your

Notebook

or download the

e-Notebook

.

Step 2

In small groups conduct diagnostic tests on biotite and quartz and record your results in the table.

Quartz Biotite

?

Can you perform mineral tests?

Mineral Hardness 1 to 10 Mineral hardness is described on the Mohs scale, ranging from 1 to 10.

Cleavage Does it split in particular ways, revealing the shape of its crystals?

Streak What colour is its powder if it is scratched on a rough, hard surface?

Colour What colour/ colours is it?

Lustre How does it shine in the light?

Step 3

Now obtain a copy of

Activity sheet 2.3 Testing minerals

results compare?

. Check your results for quartz and biotite against the entries in the table on the Activity sheet. How did your

Rock Your World Part 2 Minerals – ingredients in the rock recipe 17

Activity 2.3 Testing minerals Continued

?

Can you identify the unknown minerals?

A new geologist dropped a box of labeled minerals when she was out in the field. After picking them up, she discovered she had two unlabeled specimens.

Can you help her identify the unknown minerals using their diagnostic properties? Testing unknown minerals What to use:

• unknown mineral A • unknown mineral B • mineral study kit • streak plate • glass slide, steel paper clip

• Science by Doing Notebook • Activity sheet 2.3 Testing minerals.

What to do:

Step 1

The unknown minerals are rock forming minerals listed in the table on

Activity sheet 2.3

. Working in small groups, test each of the unknown minerals and complete the rows in the table.

Step 2

Explore the other minerals in the mineral study kit. Test them and compare your results with the table in

Activity sheet 2.3.

Discussion:

Take turns to report back to the class on each of the mystery minerals. Explain the properties you used to ‘fingerprint’ the mineral.

Rock Your World Part 2 Minerals – ingredients in the rock recipe 18

Activity

2.4

Rock identification

A ug i t e

ANDESITE

The igneous rock Andesite is comprised of the minerals plagioclase feldspar, augite and hornblende.

?

If you know what minerals are in a rock, can you then identify the rock?

Activity type Pl a gio cl a s e f e lds pa r Hor n b l ende

Click here to identify three rocks from their mineral makeup.

Rock Your World Part 2 Minerals – ingredients in the rock recipe 19

Activity

2.5

Mining our everyday minerals

MINERAL EXTRACTION

An ore is a natural deposit of rocks or minerals from which we can extract elements (e.g. iron or aluminium) profitably. We typically extract or mine ores from the ground using an open pit excavation (a big hole) or by excavating underground (a big tunnel).

Mining an ore depends on:

• the shape of the ore deposit • how deep it is • safety and environmental considerations, and • how expensive it is to get the ore out of the ground.

Kalgoorlie Superpit 12m @ 0.38g/t Au 15m @ 0.30g/t Au 204m 10m @ 1.1g/t Au 56m @ 0.46g/t Au 191m

?

How do we get minerals out of the ground for our own use?

5m @ 1.58g/t Au 3m @ 0.73g/t Au 1m @1.47g/t Au 2m @ 4.00g/t Au 20m @0.86/t Au 2.15m @ 6.29g/t Au incl 1m @ 12.06g/t Au 0.47m @ 30.98g/t Au 6m @ 6.57g/t Au incl 0.21m @ 1.28g/t Au 8.68m @ 1.28g/t Au 180m 11m @ 0.32g/t Au

Activity type

Regolith Basalt Fesic Volcanics Granite 121.57m @ 0.98g/t Au Visible Gold in Quartz Vein 2.08m @ 5.72g/t Au 0.21m @ 3.42g/t Au Click here to find out more about mining and minerals.

East Kalgoolie Gold Mine Cross Section 546m 14.66m @ 0.15g/t Au

20 Rock Your World Part 2 Minerals – ingredients in the rock recipe

Activity

2.6

Careers in mineral exploration

A ROCKY CAREER

Finding mineral deposits that are worth mining, takes a team of scientists from different fields of science...

Activity type

Click here to find out about their work.

Rock Your World Part 2 Minerals – ingredients in the rock recipe 21

Activity type

Activity

2.7

Money for rocks

?

What are Australia’s most valuable rocks?

Diamonds are very valuable.

THE "WELCOME STRANGER"

NUGGET

The "Welcome Stranger" is a famous 72 kg gold nugget discovered in 1869 by John Deason and Richard Oates under 3 cm of soil under a stringybark tree. In today’s prices the nugget was worth $2.8 million.

A very dull looking rock. Iron ore – banded iron formation.

Looks like gold, sometimes called ‘fools’ gold’. Actually a mineral called chalcopyrite. It contains copper.

15cm

Click here to learn more about Australia’s mineral wealth.

Rock Your World Part 2 Minerals – ingredients in the rock recipe 22

Minerals are not rocks. Minerals are the pure substances , or chemicals, that rocks are made from. Most rocks contain a mixture of several minerals, as individual crystals and grains.

We identify objects and separate them from others using diagnostic properties . Geologists use diagnostic tests to help identify minerals. The hardness test is a measure from 1 (soft like talc) to 10 (hard like diamond). Cleavage describes how the mineral splits (cubic, octahedral, etc.). Streak is the colour when the mineral is scratched across a white tile. Colour is the colour of the mineral and lustre is how light shines off the mineral.

Each rock type is always comprised of the same rock forming minerals. Identification of these minerals can be used to identify the rock. Minerals are typically the raw materials that many of our material items (e.g. cars, telephones) are made of, or the energy supplies (e.g. coal, oil) that we use to make them operate.

The scientists that find the minerals we need for our technological society include: Geophysicists – study the physics of the Earth (gravitational, magnetic, electrical, and seismic properties).

Geochemists – study the chemistry of rocks, soils and water bodies.

Geologists – collect rock and soil samples to test for minerals.

Minerals that seem to be most valuable, such as gold and diamonds, do not actually account for the majority of Australia’s export income. Iron ore and coal are our main export earners .

2 DOWNLOAD LESSON OUTCOMES CHECKLIST Rock Your World Part 2 Minerals – ingredients in the rock recipe 23

Part 3: Rocks from the Earth’s furnace - igneous rocks

Activity 3.1 Big and small crystals

Activity 3.2 Erupting and intruding

3 Rock Your World Part 3 24

Activity

3.1

Big and small crystals

?

Why do some rocks have bigger crystals than others?

Comparing crystal size What to use:

Each GROUP will require:

• sample of molten phenyl salicylate (in hot water bath) • 2 glass slides • dissecting microscope or compound microscope at low power • pipette • paper towel.

GOGGLES GLOVES LAB COAT SHOES

What to do:

Step 1

Cool a slide in the fridge. Wrap a slide in a paper towel and warm it in your hands.

Step 2

Place a few small seed crystals on the centre of each slide.

Step 3

Using the pipette, add a drop of molten phenyl salicylate over the seed crystals on each slide.

!

WARNING: AVOID CONTACT WITH SKIN AND EYES.

drop of phenyl salicylate

Step 4

Inspect the two slides using the microscope on the lowest power. You may be able to watch the crystals growing.

Step 5

Record your observations in your

Notebook.

Discussion:

1. Was there a difference in the growth and final size of the crystals on the two slides?

2. How does this experiment model the formation of crystals in igneous rocks?

3. Could you design an experiment to produce even bigger or smaller crystals?

Activity type DOWNLOAD e-NOTEBOOK The size of crystals in a rock tells us about how and where they were made.

Rock Your World Part 3 Rocks from the earth’s furnace – igneous rocks 25

Silicate Tetrahedron

Si Si Na+ Si Si Si Si Si Na+ Si Si Si Na+ Si

Si0² in it’s crystalline form, quartz Activity 3.1 Big and small crystals Continued Silicate Tetrahedron

As magma cools it forms into crystals. Did you know that the chemical structure of the crystals in rocks is very similar to the structure in glass?

IT IS BASED ON THE ELEMENTS SILICON (SI) AND OXYGEN (O).

Si Si Si Si Si Si Si Si0² in its crystalline form, quartz

Si0² in it’s glass form

Silicate Tetrahedron Si Na+ Si Si Si Na+ Si Si Si Si Si Si Si Na+ Si0² in its glass form

Si0² in it’s crystalline form, quartz

Quartz is a true crystal, but glass is not. What do you notice that is different about the structure of quartz and glass?

What to do:

Make a brief note in your

Notebook

.

Rock Your World Part 3 Rocks from the earth’s furnace – igneous rocks Si Si Si Si Si Si 26

Si0² in it’s glass form

Si

Activity

3.2

Erupting and intruding

IGNEOUS ROCKS

form when molten rock called magma cools. Let’s see how geologists sort out which ones are which.

Molten rock cooling deep underground Activity type DOWNLOAD e-NOTEBOOK Karlu Karlu or Devils Marbles are located 105 km south of Tennant Creek in the Northern Territory.

These boulders cooled slowly, deep beneath the surface of the Earth.

How did they get to the surface?

Cools slowly Large crystals

Molten rock might solidify deep beneath the Earth’s surface.

These form

PLUTONIC

rocks. They are also called

INTRUSIVE

rocks. ?

Why?

A piece of granite Notice the large crystals in the magnified image.

Karlu Karlu or Devils Marbles

Rock Your World Part 3 Rocks from the earth’s furnace – igneous rocks 27

Activity 3.2 Erupting and intruding Continued

?

A volcano erupts on Hawaii forming new basalts. These are no longer formed on mainland Australia. Why?

Notice the small crystals in the magnified image.

Molten rock, or lava, flows from volcanoes and solidifies on the surface.

These form

VOLCANIC

rocks.

They are also called

EXTRUSIVE

rocks.

?

Why?

Comparing intrusive and extrusive rocks

A piece of basalt

What to do:

Observe the samples of igneous rock provided by your teacher. Examine the rocks with a hand lens or dissecting microscope. What differences do you observe between the granite and basalt samples? Make a note of these in your

Notebook.

IGNEOUS CRYSTAL FORMATION COOLS QUICKLY ABOVE THE SURFACE COOLS SLOWLY BELOW THE SURFACE

The lava on the volcano Cools quickly Small crystals

SMALL CRYSTALS EG BASALT BIG CRYSTALS EG GRANITE Click here to test your understanding of volcanic and plutonic rocks

Rock Your World Part 3 Rocks from the earth’s furnace – igneous rocks 28

Plutonic igneous rocks form when molten rock called magma is intruded below the Earth surface . The magma cools slowly because it is insulated by the enclosing rock, and there is time for large crystals to grow forming a coarse-grained rock. An example of a plutonic igneous rock is granite .

Volcanic igneous rocks form when molten rock called l ava is erupted at the Earth surface . The lava cools rapidly because there is a large temperature contrast between the lava and the air. This quenched rock forms very small crystals resulting in a fine-grained rock. An example of a volcanic igneous rock is basalt .

3 DOWNLOAD LESSON OUTCOMES CHECKLIST Rock Your World Part 3 Rocks from the earth’s furnace – igneous rocks 29

Part 4: Grain by grain - sedimentary rocks

Activity 4.1 Breaking rocks

Activity 4.2 Which sediments where?

Activity 4.3 Sticking things together

Activity 4.4 Grains and rocks

Activity 4.5 Making rocks from body parts

4 Rock Your World Part 4 30

Activity

4.1

Breaking rocks

Part 1: Physical weathering What to use:

Each GROUP will require:

• 9 sugar cubes • medium glass jar and lid for shaking the cubes • 2 beakers • warm and cold water

• Science by Doing

Notebook

• access to electronic balance.

Step 2

Place the cubes in the jar and shake 20 times. Then weigh the whole cubes again.

Step 3

Repeat this step four more times. Record the weights of the remaining whole cubes and a photo or sketch each time in your data table.

What to do: Discussion:

Part 1: Physical weathering Step 1

Weigh 5 sugar cubes and record this in your

Notebook.

Take a photo or draw a simple sketch of the cubes showing their overall shape and appearance.

1. What changes did you observe in the cubes?

2. How were the changes affected by the number of shakes?

3. Look up the word abrasion and explain how it is relevant to this experiment.

Shaking trial 0 shakes 20 shakes 40 shakes 60 shakes 80 shakes 100 shakes Drawing/photo of 5 cubes Mass of 5 cubes (g)

?

How do rocks break down?

Activity type DOWNLOAD e-NOTEBOOK Rock Your World Part 4 Grain by grain – sedimentary rocks 31

Activity 4.1 Breaking rocks Continued Part 2: Chemical weathering What to do:

Part 2: Chemical weathering Step 1

Using only 4 sugar cubes design an experiment to test the difference in how quickly the cubes dissolve in water when: a) The surface area of the sugar is increased by crushing.

b) The temperature of the water is increased.

Discussion:

Chemical weathering occurs mostly through the action of water. Sometimes the water contains small amounts of dissolved chemicals such as carbon dioxide.

In your

Notebook

record how the chemical weathering (dissolving) of the sugar cubes was affected by surface area and temperature.

Click here to see a video on weathering and erosion.

Rock Your World Part 4 Grain by grain – sedimentary rocks 32

?

What are sediments? Where do they come from? Where are they deposited in our landscapes?

Activity type

Activity

4.2

Which sediments where?

When rocks weather at the Earth’s surface they break down to form sediments.

These sediments can be formed, transported and deposited in many different places. These places are Sediments formed in different places have different shapes, sizes and compositions.

SEDIMENTARY ENVIRONMENTS

Sand dunes River Glacier Beach Coral reef

These places are called

SEDIMENTARY ENVIRONMENTS

Salt lake River estuary Deep marine

Click here to look at sedimentary environments and their sediments in more detail.

Rock Your World Part 4 Grain by grain – sedimentary rocks 33

Activity

4.3

Sticking things together

Making sedimentary rocks What to use:

Each GROUP will require:

• a selection of gravels, sands and silt • a selection of possible binders including - PVA glue - lime - silica (silicon dioxide) - gypsum - commercial cement - plaster of paris • small beaker (200 ml) • plastic cups with holes in the bottom, and spoons.

Each STUDENT will require:

• Notebook

• camera (if available).

What to do:

Part 1 Step 1

Your task is to design an experiment to determine which binding material produces the most durable rock.

Step 2

Put 1-2 cm of sand or gravel in a beaker and mix with some binding material and a small amount of water. You may choose which binder to use, or which combination of binders to use.

Step 3

Pour the mixture into a cup and press down. Any free water will be squeezed out of the hole at the bottom.

Step 4

Repeat this process with sediments of different sizes, until you have a range of ‘rocks’ using different binders. Leave aside to set.

Part 2

Design a test that gives you measurements that you could use to compare the hardness of your different rocks. How can the results be presented in a table and also displayed in a graph? Record your results in your

Notebook

.

Discussion:

Compare your results with other groups in the class and write a conclusion for your experiment.

?

How do rocks stick together?

Activity type DOWNLOAD e-NOTEBOOK Rock Your World Part 4 Grain by grain – sedimentary rocks 34

Activity

4.4

Grains and rocks

When sediments pile on top of each other, and water with minerals in solution pass through, they become compacted and cemented together. This turns them from sediments into sedimentary rocks.

Activity type DOWNLOAD e-NOTEBOOK The grains in a sedimentary rock are called

CLASTS

So, rocks that are made up of compacted and cemented rock fragments are called:

CLASTIC SEDIMENTARY ROCKS

Sediments are described using 5 features:

Composition

What are the clasts made of?

Grain size

A piece of calcareous sandstone How big are the clasts in the rock?

Sorting

Are the clasts all the same size or different sizes?

?

How are common sedimentary rocks like mudstones, sandstones and conglomerates formed?

Rounding Shape

Do the clasts have smooth surfaces or rough surfaces?

Are the clasts round like a ball or long and thin, smooth or angular?

Rock Your World Part 4 Grain by grain – sedimentary rocks 35

Activity 4.4 Grains and rocks Continued Characterising sedimentary rocks What to use:

Each GROUP will require:

• specimens of sandstone, mudstone and conglomerate • specimens of beach sand, dried mud or silt, pebbles • dissecting microscope and hand lens.

Each STUDENT will require:

• internet access

• Activity sheet 4.4 Grain size comparator

• scissors

• Notebook.

Step 2

Examine the beach sand using the hand lens and the dissecting microscope. Use the descriptions provided in the table below to help you complete your observations table for the beach sand specimen.

Step 5

Examine the mudstone in the same way. How easy was it to characterize the clasts in mudstone?

Step 6

Repeat these steps using the piece of conglomerate. You may like to

Clast characteristics

Composition Grain size Sorting Rounding Sphericity What are the clasts (grains) made of?

How big are the clasts (grains) in the rock?

Are the clasts all the same size or different sizes?

Are the clasts smooth or rough?

Do the clasts have blocky, flat or elongated shapes?

What to do:

Your task is to characterise the grains, or clasts, that make up three different sedimentary rocks; sandstone, mudstone and conglomerate. Each of these rocks is called a clastic sedimentary rock, because they are all made of grains or fragments that are glued together.

Step 1

Cut out the

Grain Size Comparator

provided in

Activity Sheet 4.4

so that you can use it to analyse each specimen.

Observations table

Sediment or rock Composition Grain size Sorting Rounding Sphericity Beach sand Sandstone Mud or silt Mudstone

Step 3

Examine the piece of sandstone in the same way and fill in its line in the table. How did the clasts in the sandstone compare with the beach sand?

Step 4

Examine the sample of mud or silt using the hand lens and the dissecting microscope. Fill in its line in the table. examine the 3D conglomerate sample in the online collection

Rocks and Minerals

Click on the link above and use the tools provided to observe it from all angles and measure its clasts.

.

Discussion:

Look at the clasts making up each of the three rocks. Can you determine which sedimentary environment produced each rock? You might like to revisit

Activity 4.2 Which sediments where?

complete the table below.

and watch the videos at the link below. Then

Rock

Mudstone Sandstone Conglomerate

Sedimentary environment

Click here to watch videos about sedimentary rocks and complete a Click-and Drag exercise.

Rock Your World Part 4 Grain by grain – sedimentary rocks 36

Activity type

Activity

4.5

Making rocks from body parts

Activity 1: Testing for calcium carbonate

?

What rocks are formed when dead plants or animals accumulate?

DOWNLOAD e-NOTEBOOK The southern region of South Australia is famous for vineyards and wine production.

This region is known as the limestone coast.

Spencer Gulf

South Australia

Wine Region Gulf St Vincent

BAROSSA VALLEY EDEN VALLEY

Adelaide

40 million years ago the whole region was beneath a shallow sea. Gradually shells and other marine animals collected on the ocean floor. As they were buried they formed into sediments; and finally into a sedimentary rock called

LIMESTONE

.

J ust like the shells and corals they are made from, limestone is made of a chemical called

CALCIUM CARBONATE (CaCO

this activity.

3

)

.

Calcium carbonate is quite reactive, as you will notice in This means that the individual grains often disintegrate and are no longer visible in the final rock.

McLAREN VALE If dead plants and animals are buried in the sedimentary pile, leaves and branches, shells and bones are commonly preserved as fossils, and sometimes even the soft parts are preserved if they are buried fast enough.

A piece of limestone

What to use:

Each GROUP will require:

• limestone, egg shells, small amount of calcium carbonate, sea shells, some sand, sandstone • dissecting microscope, hand lens • dropper bottle of dilute HCl.

Each STUDENT will require:

• Notebook.

What to do:

Step 1

Test each sample you have with a few drops of HCl. Record your observations in your

Notebook.

Step 2

Now observe the piece of limestone under the microscope. Can you observe individual grains?

Discussion:

All the samples that fizzed contained calcium carbonate. Which samples did not?

Rock Your World Part 4 Grain by grain – sedimentary rocks 37

Activity 4.5 Making rocks from body parts? Continued

COAL, OIL AND GAS

300 million years ago in what is now Eastern Australia the climate was warm and wet. The swampy land was covered with great forests of ancient trees. They shed their leaves into the mud and over time the dead plant material compacted in deep layers.

At first it become a mushy black material called

PEAT

.

Eventually it turned into

COAL

.

peat coal

Coal is one of Australia’s biggest export items. The world mostly uses coal to make electricity in enormous power stations. According to the World Coal Association there are over 2300 coal-fired power stations worldwide. Approximately 620 of these power stations are in China. Many countries are gradually reducing the number of these power stations.

Activity 2: Burning coal

AFTER BEFORE

NEW S

What to use:

Each GROUP will require:

• a small piece of coal • a crucible (without lid) • Bunsen burner, tripod, clay triangle • dissecting microscope, hand lens.

Each STUDENT will require:

• Notebook.

What to do:

Step 1

Examine the piece of coal under the microscope. Describe its appearance.

Step 2

Crush a small quantity into the crucible and heat with the Bunsen. Observe its reaction.

Click here to explore some Australian rocks that have been made from body parts.

Rock Your World Part 4 Grain by grain – sedimentary rocks 38

Rocks can be broken down through a combination of chemical and physical processes . These processes are referred to as weathering .

Sediments created through the processes of weathering can be moved from one place to another by a variety of physical agents, including water, glaciers and wind. This process is called erosion .

Different parts of the landscape are characterised by different sediments because the processes taking place there contribute specific sediment types. High parts of mountain ranges typically have poorly sorted, angular, coarse sediments that have formed locally. River mouths typically have well-sorted, rounded, fine sediments that have been transported a long distance from the original site of formation.

Sediments solidify into sedimentary rock in a process called that typically involves compaction and cementation of sediment particles together. The more compacted and the better cemented (dependent on cement type) the sedimentary rock, the more resistant this rock is to subsequent weathering and erosion.

The grains in rocks are called clasts . Any sedimentary rock that is comprised of grains cemented together is called a clastic rock . The grains in different rocks are characterized by the nature of the sediments from which the rocks are formed. These, in turn, are characterized by how the sediments were formed in the first place, and what they have experienced since.

Biogenic rocks are formed from sediments of accumulated body parts . Key examples are coal formed from plant matter and limestone formed from animal remains .

4 DOWNLOAD LESSON OUTCOMES CHECKLIST Rock Your World Part 4 Grain by grain – sedimentary rocks 39

Part 5: Shearing, baking and burying – metamorphic rocks

Activity 5.1 These rocks are so hot!

Activity 5.2 Regional metamorphosis

Activity 5.3 A tortured history

5 Rock Your World Part 5 40

Activity

5.1

These rocks are so hot!

Activity type DOWNLOAD e-NOTEBOOK In this activity you will compare the properties of clay that has been exposed to different conditions.

?

What happens when rocks are heated?

What to use:

Each GROUP will require:

• potter’s clay • access to a clay firing oven, or • a crucible with lid, pipe clay triangle, tripod, Bunsen burner and matches.

Each STUDENT will require:

• Notebook.

What to do:

Part 1: Drying clay bricks Step 1

Take some of the damp clay and shape it into four identical, small bricks. The size of the bricks will depend on where you are going to ‘fire’ it: in an oven or in the crucible.

Step 2

Place your four bricks on a shelf in the lab to dry for a few days.

Part 2: Firing a brick Step 3

When dry heat two of the bricks in the hot oven or in the crucible. If using the crucible you will need to place the brick inside the crucible, cover it with a lid, position it on the pipe clay triangle and light the Bunsen. Heat your brick for at least 15 minutes. Heat it longer if using an oven.

Step 4:

Once the bricks have been heated sufficiently, allow them to cool to room temperature.

Part 3: Comparing bricks Step 5:

Design some tests to assess the ‘rockiness’ of your bricks. What characteristics do rocks have? How do they react to water or to pressure? Are they hard or soft?

Discussion:

1. In your

Notebook

describe how the properties of your rock changed in response to high heat.

2. How does this relate to the formation of some metamorphic rocks?

Rock Your World Part 5 Shearing, baking and burying – metamorphic rocks 41

Activity 5.1 These rocks are so hot! Continued

METAMORPHOSE

– to change form or appearance

?

Contact metamorphism

Pressure Magma Pressure What happens when hot magma intrudes into cooler surrounding rocks?

When hot magma intrudes into cooler rocks it bakes them in a narrow zone around the intrusion.

In this zone minerals change their structure. They might melt and recrystallise.

Hot magma is typically intruded at temperatures between 700°C and 1200°C. Let's find out what this can do to the rock around the intrusion?

MUDSTONE MIGHT CHANGE TO HORNFELS

This process is similar to

BAKING BRICKS

The

CONTACT METAMORPHIC

rock is typically denser, harder and more brittle than the original (parent) rock.

Click here to see how baked clay forms bricks and tiles, and how this relates to the formation of metamorphic rocks.

Rock Your World Part 5 Shearing, baking and burying – metamorphic rocks 42

Activity

5.2

Regional metamorphosis

Sometimes many layers are formed, one on top of the other. This process can go on for thousands or even millions of years, forming sediments many kilometres thick. The rocks lower down experience extremely high pressures and temperatures. Occasionally these rock layers are tipped onto their side, providing an indication of how thick the original sediments were.

N Scotland has some spectacular scenery, but its geology is remarkable for displaying a metamorphic gradient.

?

What happens when rocks are progressively buried because other rocks are layered on top of them?

Activity type DOWNLOAD e-NOTEBOOK Moine Thrust t Inverness Buchen Zones Aberdeen Gr eat Glen Faul t Area investigated by Barrow

Scale, km 50 Youngest rocks buried less deep Moiniam Oldest rocks buried the deepest Simplified map of the Scottish Highlands showing the main metamorphic Precambrian units which decrease in age from northwest to southeast (from Turner, 1968)

In north Scotland, layers of buried sediment have been tipped on their side.

Today, if we travel from east to west, we see rocks that have been buried deeper and deeper in the metamorphic pile.

This gives us an idea of how incredibly deep some of these sediments were buried. Refer to a map of Scotland to estimate how deep these sediments were when they were originally horizontal.

43 Rock Your World Part 5 Shearing, baking and burying – metamorphic rocks

Activity 5.2 Regional metamorphosis Continued

MARBLE

is a metamorphic rock that has experienced both immense heat and pressure. It is formed from the parent rock, limestone.

A piece of marble Are the new rocks made from the same chemicals?

What to use:

Each GROUP will require:

• samples of limestone and marble • dilute hydrochoric (0.5M) acid in a dropper bottle.

Each STUDENT will require:

• Notebook.

What to do:

Use the acid test you have conducted before to test whether marble has a similar chemical composition to its parent rock; limestone.

Discussion:

In your

Notebook

the acid test.

describe whether marble responded in the same way to What can you conclude from this?

?

Click here to learn how a sediment became a famous sculpture through the process of metamorphosis.

Rock Your World Part 5 Shearing, baking and burying – metamorphic rocks 44

Activity type

Activity

5.3

A tortured history

?

What does extreme heat and pressure do to rocks?

Most metamorphic rocks have experienced high temperatures and pressures.

This might simply be because they have been buried very deep within the Earth’s crust, where it is very hot.

This process can occur on enormous scales, producing metamorphic formations that are tens of kilometres deep.

Eventually geological processes, such as weathering and erosion, expose these rocks at the surface once again.

METAMORPHIC ROCKS

often look very different to their parent rock.

MUDSTONE

changes to

SLATE

Enormous layers of rock might be buried many kilometres below the surface, and be changed by heat and pressure.

LIMESTONE

changes to

MARBLE SANDSTONE

changes to

QUARTZITE

The metamorphic rock is typically harder and more brittle than the original (parent) rock. It might appear foliated (consisting of thin sheets) – e.g. slate, gneiss, schist, or non-foliated – e.g. marble, quartzite, hornfels.

Rock Your World Part 5 Shearing, baking and burying – metamorphic rocks 45

Activity 5.3 A tortured history Continued

?

If shale (or mudstone) is metamorphosed under different pressures or temperatures, will it make different metamorphic rocks?

Shale Low Grade

Increasing temperature

Slate Hornfels Schist Increas ing metam orphic grade Blueschist Gneiss Migmatite High Grade

All of these different rocks started as mudstone (shale) a sedimentary rock, but they end up as different metamorphic rocks because they experience different conditions of heat and pressure.

A metamorphic rock forms when any rock is exposed to very high temperatures or pressures, or both.

The type of rock formed depends on the combination of pressure and temperature.

Where do rocks experience these?

What is the difference between a metamorphic rock and an igneous rock?

Click here to explore how the rocks change the deeper they are buried.

Rock Your World Part 5 Shearing, baking and burying – metamorphic rocks 46

Different metamorphic rocks can form under a range of different conditions of heat and pressure .

Contact metamorphism (increased temperature alone) occurs when hot magma is intruded nearby and it bakes shale into hornfels .

Regional or burial metamorphism occurs when sediments are buried deep underground and subjected to increased temperature and pressure . Shale progressively changes into slate, schist and gneiss . Sandstone changes into quartzite . Limestone changes into marble .

The metamorphic rock is typically harder and more brittle than the original (parent) rock. It might appear foliated (consisting of thin sheets) – e.g. slate, gneiss, schist, or non-foliated – e.g. marble, quartzite, hornfels.

5 DOWNLOAD LESSON OUTCOMES CHECKLIST Rock Your World Part 5 Shearing, baking and burying – metamorphic rocks 47

Part 6: The rock cycle

Activity 6.1 Rocks into rocks

Activity 6.2 On the level

Activity 6.3 How do fossils form?

Activity 6.4 Is this the same as that?

Activity 6.5 Relative geological time

Activity 6.6 How long does it take?

Activity 6.7 Forming landforms

6

Activity

6.1

Rocks into rocks

Activity type DOWNLOAD e-NOTEBOOK

The

ROCK CYCLE

shows how

SEDIMENTARY, IGNEOUS

rocks and minerals so far!

and

METAMORPHIC

rock processes are related to each other. It allows us to integrate all of the ideas we have learned about

?

Where do rocks come from and where do they go?

Rock Your World Part 6 The rock cycle 49

Activity 6.1 Rocks into rocks Continued Rocks and minerals are continuously formed and broken down as part of the Rock Cycle. Let’s re-visit some of these processes.

SEDIMENTARY PROCESSES

• sediments accumulate • sediments undergo compaction and cementation to form rock

IGNEOUS PROCESSES

• molten rock called magma cools slowly underground to form plutonic rocks with large crystals • molten rock called lava erupts on Earth’s surface to form volcanic rocks with small crystals

METAMORPHIC PROCESSES

• rocks subjected to high heat and/or pressure change in texture to have a foliated (layered) appearance (e.g. slate, gneiss, schist) or a non-foliated appearance (e.g. marble, quartzite, hornfels)

Click here to test your knowledge of the Rock Cycle.

Rock Your World Part 6 The rock cycle 50

Activity 6.1 Rocks into rocks Continued Modelling the rock cycle

In this activity you will compare the properties of wax crayon that has been exposed to different conditions.

What to use:

Each GROUP will require:

• wax crayons in 3 contrasting colours • sharp knife or grater (or pencil sharpener – see below) • aluminium foil (or metal cupcake cases) • very hot water • rolling pin or heavy book • candle • iced water • kitchen paper.

What to do:

Step 1

Grate or chop the crayons into small pieces, keeping the colours separate.

Step 2

Sprinkle a layer of each colour crayon into a small piece of tin foil.

Step 3

Fold up the foil and press down on it with great pressure. You might want to slip it into your shoe and walk on it for ten minutes. Open the foil and observe any changes.

Step 4

Re-wrap your squished crayon (sedimentary rock) and heat it by dunking it in very hot water for a few moments, then squish it some more. You could also use other metamorphic crayon-rocks or igneous crayon-rocks to make your metamorphic rock.

Step 5

Re-wrap your heated, squished “metamorphic rock”. This time dunk it in the very hot water for long enough for the crayon to melt completely. Alternatively, briefly hold your foil packet in a candle flame which will melt your crayon more quickly.

Discussion

In your

Notebook

answer the following questions.

1. How was weathering and erosion modelled in this activity?

2. Which part of the activity modelled the laying down of sediments, and then the pressure that creates sedimentary rocks?

3. How did the model represent the heat and pressure that creates metamorphic rocks?

4. How was the formation of igneous rocks modelled in this activity?

Rock Your World Part 6 The rock cycle 51

Activity

6.2

On the level

Activity 1: Making sediments What to use:

Each GROUP will require:

• 1.25 litre PET bottle with lid • pebbles about 10mm in size • granules about 4mm in size • sand about 1mm in size.

Each STUDENT will require:

• Notebook.

How do we figure out which sediment was deposited first and which ones were deposited later?

SEDIMENTARY ROCKS

Sediments settle out in layers. This might be happening in an ocean, a shallow sea or river system.

What to do:

Step 1

Fill 1.25 litre PET bottle half full with water.

Step 2

Add a handful of one of the sediments to your bottle.

Step 3

Add a handful of a different sediment to your bottle.

Step 4

Add a handful of the third sediment to your bottle.

Step 5

Add further handfuls of different sediments to your bottle. Make a note of any things you notice during the settling process in your

Notebook

. Include a drawing or photo of your sediments.

Discussion:

1. Which is the oldest sediment (first deposited) in your bottle?

2. Did each of the sediments settle out evenly in your bottle?

Activity type DOWNLOAD e-NOTEBOOK

Law 1: The oldest sediments are on the bottom

Sedimentary layers are deposited in a time sequence, with oldest on the bottom and youngest on the top.

Law 2: The sediments are deposited horizontally

If undisturbed the layers settle out horizontally. 52 Rock Your World Part 6 The rock cycle

Activity 6.2 On the level Continued Activity 2: Graded bedding What to do:

Step 1

Fill 1.25 litre PET bottle half full with water.

Step 2

Mix some pebbles, granules and sand together. Add a handful of the mixed sediment to your bottle.

Step 3

Let the sediment settle. Then add a second handful of mixed sediment to your bottle.

Step 4

Add a few more handfuls of mixed sediment, waiting each time for the sediment to settle.

Step 5

Include a drawing or photo in your

Notebook

of your sediments.

Discussion:

1. The pattern produced in this experiment was different to the one produced in Activity 1. How was it different?

2. How might a pattern like this one be produced in real life, for example in a shallow sea with a large river flowing into it?

GRADED BEDDING

occurs when sediments settle out with heavy particles at the bottom and finer particles towards the top. Sometimes multiple beds can settle out in a series of separate storm events.

Graded Bedding Fine Coarse Rock Your World Part 6 The rock cycle 53

Activity type

Activity

6.3

How do fossils form?

A

FOSSIL

is the trace or remains of an organism that lived long ago, most commonly preserved in sedimentary rock. Fossils are found in successive beds until they become extinct.

?

What are fossils and how do they form?

Some fossils are small and seem insignificant.

Some fossils are large and spectacular

FOSSILS ARE USEFUL TO SCIENTISTS IN TWO WAYS.

They tell us about what life was like in prehistoric times.

They also help geologists identify different rock layers, or stata. By identifying specific fossils, they can match up rock types and strata in different parts of the world.

Click here to explore how fossils form.

Rock Your World Part 6 The rock cycle 54

Activity

6.4

Is this the same as that?

Can we use fossils to figure out which sediments were deposited first and which ones were deposited later?

?

Activity type DOWNLOAD e-NOTEBOOK

Sandstone cliffs near Sydney Rock layers above the platform near Depot Beach, NSW.

Cliffs containing layers of sandstone can be found all down the south coast of NSW, from Sydney to Ulladulla. Many of the layers look the same, but how could we tell if they belonged to the same formation?

Often geologists identify layers of sedimentary rock by the fossils they contain.

The study of rock layers is called

STRATIGRAPHY

.

In the early 19th century geologists noticed that rock layers in different parts of the world could be correlated and matched because they contained the same fossils. This was at a time when they didn’t fully understand what fossils were. They used the pattern of fossils in different rock strata to identify their relative ages. Relative dating tells scientists if a rock layer is “older” or “younger” than another. This would also mean that fossils found in the deepest layer of rocks in an area would represent the oldest forms of life in that particular rock formation.

What to do:

Learn how fossils are used to map the stratigraphy of different sedimentary rock beds by completing the tasks in

Activity sheet 6.4 Stratigraphy

and your

e-Notebook

.

Rock Your World Part 6 The rock cycle 55

Activity type

Activity

6.5

Relative geological time

A LONG STORY IN THE ROCKS

Many things happen to rock beds once they are laid down, making it difficult to interpret their history.

But in some places the beds remain lying as they first did. One of the most spectacular examples in the world is the Grand Canyon, in Colorado, USA

270 million years 275 million years The Grand Canyon, in the USA, is one of the world’s most famous tourist destinations. The layer cake structure makes the major ideas about sedimentary rocks easy to see. 340 million years These rock layers lie as they were first formed. They are horizontal.

The oldest layers are at the bottom.

The fossils found in the different layers tell the story of evolution over a period of 100 million years.

The layers you see here are around 1km thick. On average, how much sediment was deposited per year. You may be surprised at the answer.

Rock Your World Part 6 The rock cycle 56

Activity 6.5 Relative geological time Continued

Using our understanding of how sedimentary rocks are laid down, and by studying the fossils they contain, geologists have been able to devise a geological time scale. This is used to identify and sequence any rock strata that are discovered. This is known as the relative geological time scale.

Once the sequence was understood, scientists used radiometric dating to put dates to the different periods represented. Radiometric dating uses the decay of radioactive elements in the rocks to determine their age.

Click here to explore the Grand Canyon and journey back in time.

GEOLOGIC TIME SCALE:

650 MILLION YEARS AGO TO THE PRESENT Era 0 1.8

Period

Quaternary Neogene Paleogene

Events Evolution of humans Mammals diversify 50 100 150 200 250 300 350 400 450 500

Cretaceous Jurassic Triassic Permian Carboniferous Devonian Silurian Ordoviciar Cambrain

Extinction of dinosaurs First primates First flowering plants First birds Dinosaurs diversify First mammals First dinosaurs Major extinctions Reptiles diversify First Reptiles Scale Trees Seed Ferns First amphinians Jawed fishes diversify First vascular land plants Sudden diversification of metazoan families First fishes First chordates 550 600 First skeletal elements First soft-bodied metazoans First animal traces 650

Rock Your World Part 6 The rock cycle 57

Activity

6.6

How long does it take?

THESE GEOLOGICAL PROCESSES TAKE A LONG, LONG, LONG TIME…

GEOLOGICAL TIME

IS MEASURED IN THOUSANDS OR MILLIONS OF YEARS.

Weathering Erosion Solidification Metamorphism Melting Compaction & cementation Activity type DOWNLOAD e-NOTEBOOK Rock Your World Part 6 The rock cycle 58

Activity 6.6 How long does it take? Continued Rock Cycle Game What to use:

Each STUDENT will require:

• Science by Doing

Notebook

.

Each GROUP will require

: • Rock Cycle Game

instructions and dice • scissors • sticky tape.

What to do:

Step 1

Set up five stations around the room labelled: • Magma station • Sediment station • Igneous rock station • Metamorphic rock station • Sedimentary rock station

Step 2

In small groups, cut out, fold and sticky tape the five dice. Put the completed dice at their respective stations.

Step 3

Download the

e-Notebook

or draw up a table like this one in your

Notebook

to record the 10 rolls of the dice. What happened?

1 Dice roll 2 3 Time (yrs) 200,000 400,000 600,000

Step 4

Individually, choose the station you would like to begin with. Roll the die to determine if you stay at that station or move to a different station. Write your result into your log. Each roll of the die is equivalent to 200,000 years.

Step 5

After 10 rolls of the dice you have experienced 2 million years of the geological rock cycle.

Step 6

Draw a rock cycle diagram in your

Notebook

and show the pathway your rock took. Compare your rock’s history with other students in your group.

Discussion:

1. In what ways did the rock histories differ?

2. In which part of the rock cycle did your rock spend the most time?

3. Which part/s of the rock cycle did your rock miss?

Rock Your World Part 6 The rock cycle 59

Activity 6.6 How long does it take? Continued

The International Commission on Stratigraphy provides the most up-to date version of the Geological Time Scale for use worldwide.

The ‘Period’ term (e.g. Jurassic – like in Jurassic Park) is most widely used by geologists.

?

How has the Earth changed over Geological Time?

Numerical Age (Ma)

0.781 1.80

7.246 11.63 13.82

DEFINITION:

Some

periods

are divided into

epochs

.

The period of geological time in which a single type of rock system is formed .

is the basic unit Two or more

periods

comprise a geological

era

.

Two or more eras form an eon , the largest division of geologic time.

Stage/Age Series/Epoch

Pleistocene Pliocene Micocene

System/Period

Quaternary

Erathem/Era Eonothem/Eon

Neogene Cenozoic 37.8 41.2

Eocene Paleogene Phanerozoic Upper Cretaceous Mesozoic Lower Click here to see the whole geological time scale and find out how geology helps us.

Rock Your World Part 6 The rock cycle 60

Activity

6.7

Forming landforms

?

How do these processes produce the landforms we see around us?

Once upon a time the Australian continent had mighty mountain ranges. Today the Australian landscapes show the signs of millions of years of erosion.

Activity type

THREE DISTINCTIVE AUSTRALIAN LANDFORMS.

Where are they, and which is which?

Beds of limestone formed from layers of broken down coral reefs. These were worn away by the ocean waves over millions of years.

Great beds of sandstone have been worn away by dry, desert winds, exposing dramatic features surrounded by sandy desert.

A high mountain range was worn down by glaciers as they slowly ground their way down to the sea, leaving valleys behind.

Click here and match these landforms with the processes that made them.

Rock Your World Part 6 The rock cycle 61

The Rock Cycle describes the slow, continual recycling of rocks and sediments in the lithosphere. It shows how sediments can be formed into sedimentary rocks, then possibly metamorphic rock, magma and then igneous rock or any combination of the processes.

Sediments accumulate in horizontal layers with the oldest sediment on the bottom and the youngest layer on the top. Graded bedding occurs when sediments settle out with heavy particles at the bottom and finer particles towards the top within the one layer. This typically occurs during a storm event when sediments of all sizes are transported and deposited.

A fossil is the trace or remains of an organism that lived long ago, most commonly preserved in sedimentary rock. Fossils are found in successive layers until that organism became extinct. Fossils are useful to us because: • They tell us about what life was like in prehistoric times • They help us identify different rock layers and match up with rock layers in different parts of the world.

The study of rock layers is called stratigraphy . Rock layers in different parts of the world can be correlated and matched because they contain the same fossils. This relative dating tells scientists if a rock layer is older or younger than another. Using our understanding of how sedimentary rocks are laid down, and by studying the fossils they contain, geologists have been able to devise a relative geological time scale . This divides time up into periods, eras, eons and epochs . Scientists have calculated the actual ages of rock layers using radiometric dating which uses the decay of radioactive elements in the rocks to determine their age.

Australia has many iconic landforms (e.g. Uluru, Snowy Mountains, 12 Apostles), each of which has been influenced by geological processes like weathering , erosion or deposition .

6 DOWNLOAD LESSON OUTCOMES CHECKLIST Rock Your World Part 6 The rock cycle 62

Rocks are more than just small features that are found occasionally lying on the ground. They are the fundamental part of the crust on which we live. There are different types of rock, which form under different conditions and have different geological histories. The Earth consists of several distinct layers, including the crust , mantle , outer core , and inner core . A combination of very high temperatures and pressures produce conditions in the mantle and core that are quite different to those found at the Earth’s surface. As the surface is approached the pressure and temperature drops until you reach the crust where the rock is relatively cool and solid.

Although most rocks appear to be endlessly durable they have a life story. Rocks are broken down and rebuilt over very long periods of time .

All rocks on Earth can be broadly categorised into three groups; sedimentary , igneous and metamorphic . These groups of rocks have different characteristics that relate to the manner in which they are formed.

1 Rock Your World Part 1 Rocks – part of the Earth System 63

Minerals are not rocks. Minerals are the pure substances , or chemicals, that rocks are made from. Most rocks contain a mixture of several minerals, as individual crystals and grains.

We identify objects and separate them from others using diagnostic properties . Geologists use diagnostic tests to help identify minerals. The hardness test is a measure from 1 (soft like talc) to 10 (hard like diamond). Cleavage describes how the mineral splits (cubic, octahedral, etc.). Streak is the colour when the mineral is scratched across a white tile. Colour is the colour of the mineral and lustre is how light shines off the mineral.

Each rock type is always comprised of the same rock forming minerals. Identification of these minerals can be used to identify the rock. Minerals are typically the raw materials that many of our material items (e.g. cars, telephones) are made of, or the energy supplies (e.g. coal, oil) that we use to make them operate.

The scientists that find the minerals we need for our technological society include: Geophysicists – study the physics of the Earth (gravitational, magnetic, electrical, and seismic properties).

Geochemists – study the chemistry of rocks, soils and water bodies.

Geologists – collect rock and soil samples to test for minerals.

Minerals that seem to be most valuable, such as gold and diamonds, do not actually account for the majority of Australia’s export income. Iron ore and coal are our main export earners .

2 Rock Your World Part 2 Minerals – ingredients in the rock recipe 64

Plutonic igneous rocks form when molten rock called magma is intruded below the Earth surface . The magma cools slowly because it is insulated by the enclosing rock, and there is time for large crystals to grow forming a coarse-grained rock. An example of a plutonic igneous rock is granite .

Volcanic igneous rocks form when molten rock called l ava is erupted at the Earth surface . The lava cools rapidly because there is a large temperature contrast between the lava and the air. This quenched rock forms very small crystals resulting in a fine-grained rock. An example of a volcanic igneous rock is basalt .

3 Rock Your World Part 3 Rocks from the earth’s furnace – igneous rocks 65

Rocks can be broken down through a combination of chemical and physical processes . These processes are referred to as weathering .

Sediments created through the processes of weathering can be moved from one place to another by a variety of physical agents, including water, glaciers and wind. This process is called erosion .

Different parts of the landscape are characterised by different sediments because the processes taking place there contribute specific sediment types. High parts of mountain ranges typically have poorly sorted, angular, coarse sediments that have formed locally. River mouths typically have well-sorted, rounded, fine sediments that have been transported a long distance from the original site of formation.

Sediments solidify into sedimentary rock in a process called that typically involves compaction and cementation of sediment particles together. The more compacted and the better cemented (dependent on cement type) the sedimentary rock, the more resistant this rock is to subsequent weathering and erosion.

The grains in rocks are called clasts . Any sedimentary rock that is comprised of grains cemented together is called a clastic rock . The grains in different rocks are characterized by the nature of the sediments from which the rocks are formed. These, in turn, are characterized by how the sediments were formed in the first place, and what they have experienced since.

Biogenic rocks are formed from sediments of accumulated body parts . Key examples are coal formed from plant matter and limestone formed from animal remains .

4 Rock Your World Part 4 Grain by grain – sedimentary rocks 66

Different metamorphic rocks can form under a range of different conditions of heat and pressure .

Contact metamorphism (increased temperature alone) occurs when hot magma is intruded nearby and it bakes shale into hornfels .

Regional or burial metamorphism occurs when sediments are buried deep underground and subjected to increased temperature and pressure . Shale progressively changes into slate, schist and gneiss . Sandstone changes into quartzite . Limestone changes into marble .

The metamorphic rock is typically harder and more brittle than the original (parent) rock. It might appear foliated (consisting of thin sheets) – e.g. slate, gneiss, schist, or non-foliated – e.g. marble, quartzite, hornfels.

5 Rock Your World Part 5 Shearing, baking and burying – metamorphic rocks 67

The Rock Cycle describes the slow, continual recycling of rocks and sediments in the lithosphere. It shows how sediments can be formed into sedimentary rocks, then possibly metamorphic rock, magma and then igneous rock or any combination of the processes.

Sediments accumulate in horizontal layers with the oldest sediment on the bottom and the youngest layer on the top. Graded bedding occurs when sediments settle out with heavy particles at the bottom and finer particles towards the top within the one layer. This typically occurs during a storm event when sediments of all sizes are transported and deposited.

A fossil is the trace or remains of an organism that lived long ago, most commonly preserved in sedimentary rock. Fossils are found in successive layers until that organism became extinct. Fossils are useful to us because: • They tell us about what life was like in prehistoric times • They help us identify different rock layers and match up with rock layers in different parts of the world.

The study of rock layers is called stratigraphy . Rock layers in different parts of the world can be correlated and matched because they contain the same fossils. This relative dating tells scientists if a rock layer is older or younger than another. Using our understanding of how sedimentary rocks are laid down, and by studying the fossils they contain, geologists have been able to devise a relative geological time scale . This divides time up into periods, eras, eons and epochs . Scientists have calculated the actual ages of rock layers using radiometric dating which uses the decay of radioactive elements in the rocks to determine their age.

Australian has many iconic landforms (e.g. Uluru, Snowy Mountains, 12 Apostles), each of which has been influenced by geological processes like weathering , erosion or deposition .

6 Rock Your World Part 6 The rock cycle 68

Glossary

Term

Basalt Biogenic Calcite Calcium carbonate Cement Cementation Clastic Clasts Cleavage Coal Compaction Concrete Conglomerate Contact metamorphism Core Crust Crystalline Deposition Diagnostic property Eon Epoch Era Erosion Extrusive Foliated Fossil Fracture

Description

An igneous rock derived from molten lava that has flowed out onto the surface of the Earth.

A rock or mineral formed from any dead organisms.

Crystal of calcium carbonate.

A compound found in minerals such as calcite and rocks such as limestone and marble.

A substance that solidifies and hardens used in building. Made from limestone.

The gluing together of rock particles (clasts) by the precipitation of mineral matter in the pore spaces.

A type of rock made from grains, or clasts, cemented together.

The grains found in sedimentary rocks.

The typical shape of the crystals of a mineral when it is broken.

A mineral, consisting mostly of carbon, formed from partially decomposed plants 100s of millions of years ago.

The process by which a sediment is squeezed together by the weight of overlying sediments.

An aggregrate of pebbles bonded together by cement.

A sedimentary rock derived from a mix of fine sediments, pebbles and boulders.

Metamorphism (change) caused by intrusion of hot magma.

The central layer of the Earth, mostly comprised of iron and nickel.

The surface layer of the Earth, comprised of rock.

Formed from crystals of a pure substance.

Wind, ice and water transport eroded sediment to a distant location where it is deposited.

A property used to identify a particular type of rock or mineral.

Two or more eras form an eon. It is the largest unit of geological time.

A division of geological time that is a subdivision of a period.

A span of geological time marked by a beginning and an end. E.g. Cenozoic era 66 million years ago to present day.

The movement of sediments from one place to another through agents such as wind and water.

Extrusive rock is also called volcanic rock. It is rock formed from quickly cooling lava that has erupted at the Earth's surface.

Consisting of thin sheets.

The remains, or impression, of dead organisms preserved in a layer of sedimentary rock.

The shape and texture of the surface of a crystal when it is fractured.

Rock Your World Glossary 69

Glossary

Term

Geochemist Geologist Geophysicist Glass Graded sediment Grain comparator Hardness scale Hematite Hornfels Igneous Intrusive Lava Limestone Lithosphere Lustre Magma Magnetism Mantle Melting Metamorphic Mineral Moh's scale of hardness Mudstone Onion skin weathering Ore Palaeontologist

Description

A scientist who studies the chemistry of rocks, minerals or mining.

A scientist who studies the solid and liquid matter that constitutes the Earth as well as the processes that shape it.

A scientist who studies physical processes and structure of the Earth's crust, often related to mining.

A material produced from Silicon dioxide, which is molded into particular shapes rather than forming pure crystals.

A sediment where different sized particles have settled out separately in distinct layers.

A device for analysing the size and shape of grains found in sediments or a sedimentary rock.

A scale, from 1 to 10, used to describe the hardness of different minerals. Diamond has a hardness of 10 and talc has a hardness of 1.

A mineral composed of one form of iron oxide. Conducts electricity and is sometimes magnetic.

A metamorphic rock formed by the contact between a mudstone or shale and a hot igneous intrusion.

A rock derived from molten rock.

Intrusive rock is also called plutonic rock. It is rock that forms from slowly cooled magma at depth.

Molten rock that erupts on Earth's surface.

A type of sedimentary rock formed from broken down shelled marine organisms or coral.

The rigid outer part of the Earth consisting of the crust and upper mantle.

The way that light interacts with the surface of a rock or mineral, giving it a certain appearance.

Molten rock formed below the Earth's surface.

One of the forces of nature that can act through a vacuum and at a distance.

The largest layer of the Earth lying below the crust, comprised of very hot rock.

When rock is heated and it turns to magma.

A type of rock that has been subjected to high temperature and/or pressure.

A naturally occurring chemical compound, usually crystalline in form.

Friedrich Moh created a scale of hardness describing numerically the hardness of minerals from soft (1) to hard (10).

A type of sedimentary rock formed from fine, silty sediments.

Occurs in regions which experience big differences between day and night temperatures. Rocks expand and contract and the outer layers flake off creating rounded rocks called tors.

A naturally occurring solid material from which a metal or valuable mineral can be extracted profitably.

A scientist who studies fossils.

Rock Your World Glossary 70

Glossary

Term

Parent rock Peat Period Plutonic Quartz Radioactivity Radiometric dating Regional metamorphism Regolith Relative dating Rock Rock cycle Sandstone Sediment Sedimentary Seismic Solidification Steel Stratigraphy Streak Tor Trilobite Volcanic Vulcanologist Weathering

Description

The original rock that a metamorphic rock, or a sediment, may have formed from.

Deposits of partially decayed plant material, usually forming in wet, boggy environments.

Geological time unit given to a specific stratigraphic sequence of rock. E.g. Carboniferous period (359 - 299 mya) was a time of low sea levels when much algae,zooplankton and plant life was transformed into coal, oil and natural gas.

The solidification of rock from magma at considerable depth underground.

A hard, glassy mineral, composed mainly of silicon dioxide.

Particles and rays that come from some unstable atoms.

Determining the age of rocks or minerals using the decay of radioactive elements they contain.

Metamorphism (change) caused by increased heat and pressure due to burial.

The layer of loose material including dust, soil and broken rock, that covers the solid bedrock below.

The science of determining the relative order of past events; i.e. which rock layer is older than which.

The basic building block of the Earth's crust and mantle. Usually a collection of minerals joined together in some way.

A model that explains the processes involved in the breaking down and creation of different types of rocks.

A rock derived from deposits of sand.

Layers of broken down rock and soil.

A rock made from sediments.

Referring to vibrations in the Earth's crust, often associated with earthquakes.

When molten rock cools to form rock.

A form of iron hardened by the addition of carbon.

A branch of geology that studies rock layers, how they form and can be dated.

The colour of the powder of a mineral that has been scraped across a rough, hard surface.

Rounded boulder.

Ancient hard-shelled arthropod (invertebrate with an exosketeton) that lived on the sea-floor 520 million years ago.

Formed from magma (actually lava) erupted from a volcano.

A scientist who studies volcanoes.

The wearing down of rocks and minerals through physical or chemical processes.

Rock Your World Glossary 71

Project Management

Executive Director: Professor Denis Goodrum, FACE (Australian Academy of Science) Director of Curriculum Development: Jef Byrne Web and Digital Co-ordinator: Dr Jen Liu Education Specialist: Dr Jim Woolnough Administrative Coordinator: Katie Ryan Administrative Officer: Kathy Hamilton

Authors

This resource was originally written in 2015 by: Dr Leah Moore, Dr Jim Woolnough and Jef Byrne.

This resource was revised in 2017 by: Jef Byrne.

Science by Doing

would like to thank Spinks and Suns for the design and development of this resource.

Funding Acknowledgement

Science by Doing

is supported by the Australian Government.

Disclaimer

The views expressed herein do not necessarily represent the views of the Australian Government, Department of Education or Education Services Australia. These materials are intended for education and training only. Every effort is made to ensure the accuracy of the information presented in these materials. We do not assume liability for the accuracy or completeness of the information contained within.

The Australian Academy of Science accepts no responsibility for any loss or damage whatsoever suffered as a result of direct or indirect use or application of any of these training materials.

© Australian Academy of Science, 2017.

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