Barrier Islands

Question 1

What are the features of a barrier island?

Answer 1

• Run parallel to the land behind, may be attached or not
• have a lagoon on the landward side of the island
• consist of sandy sediment

Question 2

What Tidal conditions can they form in? Why?

Answer 2

Micro or meso-tidal conditions.

Macro tidal conditions have too great an energy and do not allow the deposition of sandy sediment.

Question 3

Where can B islands form?

Answer 3

• where there is a good sediment supply
• where there is a gently sloping continental shelf
• where there is sufficient wave energy and onshore winds
• rising sea levels
• meso/micro tidal

Question 4

What is the importance of B islands?

Answer 4

used for expensive real estate, provide protection for the mainland behind, from storms.

Question 5

How do waves and onshore winds form B islands?

Answer 5

long shore drifts cause sandbars to form, which eventually become sub-aerial. waves cause the over topping of the island and move sediment towards the back of the island. here the sand accumulates and may be stabilised by colonising vegetation, later leading to higher plant species colonisation.

Question 6

Why are rivers important?

Answer 6

rivers provide sediment, more rivers = more sediment, the more sediment the more b islands.