2.2 - Piece of Cake (Causeway Coast)

Question 1

What two factors complicate the order of resistance to erosion?

Answer 1

• Age of the rock

- Permeability

Question 2

How does age of the rock affect erosion?

Answer 2

• Older limestones have been compressed over time and have accumulated over millions of years, making them significantly more resistant to erosion and weathering.
• Recently released volcanic lava flows and tephra deposits are typically weaker, and so are more vulnerable to erosion.

Question 3

How does permeability affect erosion?

Answer 3

• Groundwater flow can weaken rocks by exploiting joint structures.
• Permeability of rock can allow high pore water pressures to be created within cliffs, reducing stability.

Question 4

Sandstone, limestone and shale are examples of what rock?

Answer 4

Sedimentary

Question 5

List 3 examples of igneous rocks.

Answer 5

• Granite
• Basalt
• Dolerite

Question 6

Describe the erosion rate of metamorphic rock and justify this.

Answer 6

• Slow rate of erosion:
• Crystalline metamorphic rock is resistant to erosion due to its inherent structure.
• However, these crystals are orientated in one direction, which produces weaknesses.

Question 7

Describe the rate of erosion for igneous rock and explain why it is so.

Answer 7

• Very slow:
• As crystalline rock, the interlocking crystals make for strong and resistant rocks.
• With few joints, there are limited weaknesses for erosion to exploit.

Question 8

Describe the erosion rate of sedimentary rock and provide relevant support.

Answer 8

• Moderate to fast:
• Sedimentary rock is clastic, comprised of mud, sand and organic matter. Weak substances such as these are more vulnerable to erosion than more resistant rock such as metamorphic and igneous.
• Rock with many fractures (e.g. shale) are weaker due to the greater number of points of exploit.

Question 9

Give examples of sedimentary, metamorphic and igneous rock in Northern Ireland.

Answer 9

Igneous - Basalt
Sedimentary - Sandstone
Metamorphic - Schist

Question 10

Explain how igneous rocks are formed (hint: basalt).

Answer 10

• They form as molten rock, which cools and solidifies.

- The rapid rate of magma cooling makes the crystals unseen by the naked eye.

Question 11

Explain how sedimentary rocks are formed (hint: sandstone).

Answer 11

• Typically composed of particles / pieces of other rock that has been eroded.
• These accumulate as layers over time.
• Sandstone is comprised of grains of mkst commonly quartz, bound by minerals.

Question 12

Explain how metamorphic rocks are formed (hint: schist).

Answer 12

• They are subject to intense heat and/or pressure.