erosional landforms

Question 1

how does rock type affect erosion?

Answer 1

some rocks are more resistant to erosion than others. high resistance rocks include chalk and limestone, and they form headland. low resistance rock includes sandstone and clay, forming bays.

Question 2

define a ‘discordant coastline’:

Answer 2

where bands of different rock run perpendicular to the coastline.
- on the other hand, concordant coastlines occur when rock runs parallel to the coastline

Question 3

how do headlands and bays form?

Answer 3

• destructive waves erode the coast through abrasion.
• differential erosion occurs, where the soft rock erodes faster, creating bays.
• the hard rock erodes slower, and remains jutting out, creating headlands.

Question 4

how are cliffs formed?

Answer 4

• cliffs are formed through coastal erosion and weathering
• resistant rock forms steep cliffs
• soft rock erodes quicker, creating gently sloping cliffs

Question 5

how are wave cut platforms and wave cut notches formed?

Answer 5

• destructive waves erode the cliff through processes such as hydraulic action and abrasion.
• waves erode the cliff between the high and the low tide lines.
• over time, this erosion creates a wave cut notch.
• this notch gradually gets larger, and the cliff above is unsupported.
• waves wash away the debris of the collapse.
• mass movement occurs as a result of gravity and the cliff retreats.
• the wave cut platform is the uneroded section of the original cliff at the base. the process repeats, when destructive waves once again erode the cliff face, with a new notch forming.

Question 6

what is a wave cut platform?

Answer 6

a flat, gently sloping ledge of rock that extends out into the sea from the base of the cliff.

Question 7

how are caves formed?

Answer 7

• destructive waves erode headland over time, through processes such as hydraulic action, attrition, and abrasion.
• faults and joints in the resistant rock are more vulnerable to erosion, and hydraulic action and abrasion will widen these.
• eventually, abrasion and hydraulic action enlarge the cracks into a cave.

Question 8

how are arches formed?

Answer 8

• after a cave is formed, waves continue to erode it, making it deeper.
• caves on both sides of the headland eventually erode through the headland, creating an arch.
• this arch is enlarged by weathering at the top and erosion at the bottom.

Question 9

how are stacks formed?

Answer 9

• after enough erosion and weathering has occurred on the arch, the top becomes unsupported, and it suffers from weathering, eventually collapsing due to gravity.
• this leaves an isolated pillar of rock, called a stack.

Question 10

describe swanage bay, and its erosional and depositional landforms:

Answer 10

• discordant coastline
• bands of hard and soft rock, creating bays and headlands

Question 11

describe old harry rocks, and its erosional and depositional landforms:

Answer 11

• headland made of chalk (soft rock)
• this headland jutted out to sea, created the formation of old harry, a stack
• soon, it will collapse, and become a stump