Rocks and Rock Cycle Practice Test

Name:

Date:

Part A: Earth’s Structure and Rock Processes

Learning intention: I can describe key rock-cycle processes and timescales, and explain how the properties of rocks reflect their formation and influence their use. AC9S8U04

Conditions: 80 minutes, individual work, no open books. Total: 42 marks.

Score: ______ / 42 Percentage: ______ %

1. Earth’s four layers: Match each description to the correct layer. Then write the four layer names in order from the outside to the centre. (8 marks)

A. Solid and partly melted rock; the thickest layer.

B. Solid rock, about 5–70 km thick, and thickest beneath continents.

C. Liquid iron and nickel; its movement helps produce Earth’s magnetic field.

D. Solid iron and nickel under extreme pressure and temperatures above 6000 °C.

Crust

Mantle

Outer core

Inner core

Write the layers from outside to centre: 1. ____________________ 2. ____________________ 3. ____________________ 4. ____________________

2. A pressure graph shows 125 GPa at 2000 km depth and 145 GPa at 2200 km depth. Estimate the pressure at 2100 km. (1 mark)

3. Describe how temperature and pressure change as depth below Earth’s surface increases. (2 marks)

4. Name the three main types of rock. (3 marks)

a. ______________________________ b. ______________________________ c. ______________________________

5. A landslide carries rocks and soil down a steep hillside. What rock-cycle process does this mainly represent? (1 mark)

6. Deep underground, heat causes solid rock to melt. (2 marks)

a. Select the correct statement about the melted material. (1 mark)

It is called magma while it remains underground.

It is called sediment because it is made of small pieces.

It is always a solid mineral.

b. What type of rock can form when this melted material cools and crystallises? (1 mark)

7. Lava cools quickly on Earth’s surface after a volcanic eruption. Name the process and the type of rock formed. (2 marks)

Part B: The Rock Cycle and Rock Identification

8. Draw and label a rock cycle. Include all of the following: weathering and erosion, sediment, compaction and cementation, magma, cooling and crystallisation, melting, sedimentary rock, igneous rock and metamorphic rock. Use arrows to show possible changes. (9 marks)

9. The rock cycle is not a one-way process. Explain what this means and give two examples of possible changes between rocks or materials. (3 marks)

10. A volcanic mudflow called a lahar leaves a layer of mud and rock. Sedimentary layers are later deposited on top of it. Explain why the lahar is older than the sedimentary layers above it. (2 marks)

Practical Rock Identification

Your teacher will provide three numbered rock samples. Carefully observe each sample. Record features such as colour, grain size, crystals, layers, holes, hardness or fossils. Identify the rock type and name if you know it. Give other examples of that rock type.

11. Sample 1 (3 marks)

Observations:

Rock type and name: __________________________________________

Other example(s) of this rock type: ______________________________

12. Sample 2 (3 marks)

Observations:

Rock type and name: __________________________________________

Other example(s) of this rock type: ______________________________

13. Sample 3 (3 marks)

Observations:

Rock type and name: __________________________________________

Other example(s) of this rock type: ______________________________

Teacher-Only Answer Guide

1. Earth’s layers: A = mantle, B = crust, C = outer core, D = inner core. Outside to centre: crust, mantle, outer core, inner core. Award 1 mark for each correct match and 1 mark for each correctly ordered layer.

2. Approximately 135 GPa.

3. Both temperature and pressure increase as depth increases. Award 1 mark for each trend.

4. Sedimentary, igneous and metamorphic.

5. Weathering and erosion, or erosion and deposition if suitably explained. Accept mass movement as a related process.

6. a. It is called magma while underground. b. Igneous rock.

7. Cooling and crystallisation; igneous rock. Accept extrusive igneous rock.

8. Award up to 9 marks: correct inclusion and connection of weathering and erosion, sediment, compaction and cementation, sedimentary rock, melting, magma, cooling and crystallisation, igneous rock and metamorphic rock. Arrows should show that more than one pathway is possible.

9. The cycle has several possible pathways rather than one fixed sequence. Examples include sedimentary rock weathering into sediment, igneous rock changing into metamorphic rock through heat and pressure, or any rock melting to form magma.

10. The principle of superposition states that, in undisturbed layers, lower layers were deposited before layers above them. Therefore, the lahar layer formed first.

11–13. Award 1 mark for useful observations, 1 mark for a suitable rock type and name where possible, and 1 mark for accurate examples of that rock type. Accept scientifically justified alternatives based on the samples provided.

Total: 42 marks.