3.b Submergent coastal landscapes form as sea level rises.

Question 1

What are the 3 submergent landforms?

Answer 1

Rias, fjords, and shingle beaches.

Question 2

When were rias formed?

Answer 2

During the Flandrian Transgression.

Question 3

What is a ria?

Answer 3

Submerged river valleys.

Question 4

What are the low areas of a ria like?

Answer 4

The lowest part of the river’s course, and the floodplains alongside the river, may be completely drowned.

Question 5

What are the high areas of a ria like?

Answer 5

The higher land, forming the tops of the valley sides and the middle and upper part of the river’s course, remains exposed.

Question 6

What are rias underlain with?

Answer 6

They are underlain by alluvial deposits.

Question 7

What is the cross-section and centre of a ria like?

Answer 7

Its cross-section is shallow

The centre is deeper.

Question 8

What are rias influenced by?

Answer 8

They are influenced by tides (inter-tidal).

Submerged at high tides, sandbanks are exposed at low tides.

Question 9

What is the structure of a ria like?

Answer 9

V-shaped, with gently sloping sides.

Question 10

Give an example of a ria?

Answer 10

Salcombe and Padstow in Cornwall.

Question 11

When were fjords formed?

Answer 11

During the Flandrian Transgression.

Question 12

What is a fjord?

Answer 12

Submerged glacial valleys.

Question 13

What is the structure of a fjord like?

Answer 13

They have steep, almost cliff-like, valley sides.

U-shaped, harsh dropping sides.

Question 14

What is the water like in a fjord?

Answer 14

Water is uniformly deep, often reaching over 1000m.

Question 15

What do fjords contain? What causes these?

Answer 15

Contain thresholds.

These are caused by a thinner glacial layer producing reduced rates of erosion.

Question 16

What is a fjord threshold?

Answer 16

Shallow sections at the front of the fjord entrance.

Question 17

Give an example of a fjord.

Answer 17

Sogne Fjord in Norway.

(~200km long).

Question 18

What does wave action do to a rias valley sides?

Answer 18

Increase steepness, but this has limited significance.

Question 19

What does wave action do to a fjords valley sides?

Answer 19

Wave action (along with weathering) reduces steepness.

Question 20

There has been a 0.6m eustatic sea level rise in 100 years. What does this mean for the modification of rias and fjords?

Answer 20

There has been a 0.6m eustatic sea level rise in 100 years.

This means there are more storms, so consequently increased erosion.

Question 21

What is there always the potential for, during the modification of rias and fjords?

Answer 21

There is always the potential for mass movement.

Question 22

How does a shingle beach form?

Answer 22

Sediment accumulates on this surface, deposited by rivers, meltwater streams and low-energy waves.

As sea levels rose at the end of the last glacial period, wave action pushed these sediments onshore.

Question 23

In some places, what may form instead of a shingle beach? Give an example.

Answer 23

In some places, they beached at the bases of former cliff lines; elsewhere they may form tombolos and bars.

For example, the tombolo at Chesil Beach is thought to have formed in this way during the Flandrian Transgression. Sediment carried into the English Channel by meltwater during the Würm glacial accumulated in locations such as Lyme Bay.

Question 24

What do shingle beaches do? What are they composed of?

Answer 24

Shingle beaches remove and/ or bring sediment.

They are composed of unconsolidated material, and are especially vulnerable to modification.

Question 25

What has the tombolo at Chesil Beach been affected by?

Answer 25

Significantly affected by present day longshore drift processes and is likely to continue to be so in the future.

Recent storms have seen waves over-topping the beach.

Question 26

What happened to Chesil beach in 2009? Is this common?

Answer 26

In 2009, 1 metre-sized pieces of shelly clay were eroded from in front of the beach and washed up onto it at West Bexington in a winter storm.

With higher sea levels and more frequent storm events this sort of sediment accumulation will become common.