Eduqas GCSE Geology · 2.1

The Rock Cycle

50 revision questions with answers for 2.1 The Rock Cycle in Eduqas GCSE Geology (spec C480QS). Practise with flashcards, a topic quiz, a random quiz across the course, 5 crosswords, Five Degrees, Associations, or read every question and answer below.

All 50 questions and answers

Question 1
What is the rock cycle?
Answer:
A model linking igneous, sedimentary and metamorphic rocks through processes operating over geological time.
Question 2
Does the rock cycle have a single starting point?
Answer:
No. It is a network of possible transformations rather than one fixed sequence.
Question 3
How does magma become igneous rock?
Answer:
It cools and crystallises.
Question 4
How does exposed rock become sediment?
Answer:
Weathering breaks it down and erosion removes and transports the resulting material.
Question 5
How does loose sediment become sedimentary rock?
Answer:
Burial, compaction and cementation lithify the sediment.
Question 6
How can a sedimentary rock become metamorphic?
Answer:
Burial or contact with hot magma increases temperature and/or pressure, causing recrystallisation.
Question 7
How can a metamorphic rock contribute to magma?
Answer:
If sufficiently heated and partially or completely melted, it can produce melt.
Question 8
How can magma eventually become sedimentary rock?
Answer:
Magma crystallises; the rock is exposed, weathered and eroded; sediment is deposited and lithified.
Question 9
Can an igneous rock become metamorphic without first becoming sedimentary?
Answer:
Yes. Increased heat and/or pressure can metamorphose the igneous rock directly.
Question 10
Can a metamorphic rock be weathered to form sediment?
Answer:
Yes, after exposure at or near the surface.
Question 11
Can a sedimentary rock produce sediment that forms another sedimentary rock?
Answer:
Yes. It can be uplifted, weathered, eroded, deposited and lithified again.
Question 12
Why is uplift important to parts of the rock cycle?
Answer:
It can bring buried rocks towards the surface, exposing them to weathering and erosion.
Question 13
What is burial in a sedimentary setting?
Answer:
Accumulation of later sediment over earlier material, increasing pressure and potentially temperature.
Question 14
How can plate tectonics drive the rock cycle?
Answer:
Plate motion causes uplift, burial, deformation and melting, linking surface and internal processes.
Question 15
What energy source drives weathering and erosion by the water cycle?
Answer:
Solar energy drives evaporation and climate, while gravity moves water and sediment downhill.
Question 16
What energy source helps drive deep-Earth processes?
Answer:
Heat from Earth's interior, including heat released by radioactive decay.
Question 17
Granite weathers into sand. Which two rock-cycle stages are involved first?
Answer:
Weathering breaks down granite; erosion and transport move the resulting sediment.
Question 18
Sand is buried and cemented. What rock can form?
Answer:
Sandstone.
Question 19
Shale is buried and metamorphosed. Name a possible product.
Answer:
Slate.
Question 20
Limestone is heated beside an intrusion. Name a possible product.
Answer:
Marble.
Question 21
Quartz sandstone is recrystallised. Name a possible product.
Answer:
Metaquartzite.
Question 22
Basalt lava cools at the surface. Which rock-cycle process forms the basalt?
Answer:
Cooling and crystallisation of lava.
Question 23
What process must occur before magma can form from solid rock?
Answer:
Melting, commonly partial melting.
Question 24
Is melting required for contact metamorphism of limestone to marble?
Answer:
No. The limestone recrystallises in the solid state.
Question 25
A conglomerate contains rounded granite pebbles. What does this show?
Answer:
Granite existed, was exposed, weathered and transported before the conglomerate was deposited.
Question 26
A granite intrusion cuts shale and bakes it. Which event is younger?
Answer:
The granite intrusion is younger than the shale it cuts and heats.
Question 27
How can a volcanic ash layer become part of a sedimentary sequence?
Answer:
Ash is deposited, buried and preserved as a layer among other sediments.
Question 28
What happens to transported sediment when river energy decreases?
Answer:
Some particles settle and are deposited, with coarse material generally settling before finer material.
Question 29
Can a single rock undergo more than one transformation?
Answer:
Yes. It can experience several episodes of burial, deformation, uplift and erosion.
Question 30
What does a cross-cutting vein tell you about a host rock?
Answer:
The host rock formed before the fracture and mineral vein that cut it.
Question 31
What is gradualism in geology?
Answer:
The idea that some geological changes accumulate over long periods through relatively slow processes.
Question 32
What is catastrophism in geology?
Answer:
The recognition that sudden high-impact events can cause substantial geological change in a short time.
Question 33
Give a geological example of a catastrophic event.
Answer:
A major meteorite impact or explosive eruption.
Question 34
Give an example of a generally gradual geological process.
Answer:
The long-term erosion of a landscape by a river.
Question 35
Are catastrophism and gradualism mutually exclusive in Earth's history?
Answer:
No. Both rapid events and slow processes contribute to the geological record.
Question 36
Why can a thick sedimentary sequence represent millions of years?
Answer:
Individual beds accumulate over long intervals, often with gaps between deposition events.
Question 37
A 10 m sedimentary layer accumulates at 1 mm per year. Estimate the time.
Answer:
10 m = 10,000 mm; at 1 mm per year it takes about 10,000 years, assuming a constant rate.
Question 38
A lava flow cools at the surface while a large pluton cools underground. Which generally cools faster?
Answer:
The surface lava flow, because it loses heat more rapidly.
Question 39
Why can one rock record both slow and rapid events?
Answer:
Its formation may take a long time, while later faulting or impact can occur quickly.
Question 40
A river removes an average 0.2 mm of rock each year. Estimate removal in 1,000 years.
Answer:
0.2 x 1,000 = 200 mm, or 0.2 m, assuming a constant rate.
Question 41
How can an unconformity complicate a rock-cycle history?
Answer:
It indicates missing time caused by erosion or non-deposition between preserved rocks.
Question 42
Why is a diagram arrow from sediment to metamorphic rock incomplete without extra information?
Answer:
The sediment generally lithifies and is then subjected to sufficient heat and pressure to metamorphose.
Question 43
A student claims every rock must pass through the same stages. Why is this wrong?
Answer:
Rocks can follow different pathways; for example, igneous rock can metamorphose directly.
Question 44
A student says an impact and river erosion cannot both be important. Evaluate the claim.
Answer:
Both can be important: impacts cause abrupt change, while rivers can reshape landscapes gradually.
Question 45
What sequence links granite to a new granite through sedimentary and metamorphic stages?
Answer:
Weather and erode granite; deposit and lithify sediment; metamorphose the rock; melt and crystallise magma.
Question 46
Why does exposure at the surface increase weathering?
Answer:
Surface rocks interact with water, air and changing temperatures.
Question 47
Can the rock cycle run at exactly the same rate everywhere?
Answer:
No. Conditions such as climate, tectonic activity, burial depth and rock properties vary.
Question 48
How does erosion help reveal deeply formed rocks?
Answer:
It removes overlying material, eventually exposing rock that formed at depth.
Question 49
How can a change in energy drive deposition in a river?
Answer:
A slowing current loses capacity to transport some grains, so they settle.
Question 50
A borehole contains schist below a graded turbidite and laminated shale. Give evidence for different rates of change.
Answer:
Schist metamorphism was gradual; the turbidite records a rapid sediment flow; fine laminated shale accumulated more slowly.

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The Rock Cycle

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