3.3 Depositional Landforms

Question 1

Keychain for spit formation

Answer 1

• Sand/shingle beach LSD extending beyond a turn in coastline
• At the turn, LSD loses energy = deposition
• River currents determine length of spit

Question 2

How is a tombolo formed?

Answer 2

• Is a sand/shingle bar that attaches coastline to offshore island
• Wave refraction around offshore island = area of calm water + deposition between island and coast

Question 3

How is a barrier beach/bar formed?

Answer 3

• Sand/shingle beach connecting 2 areas of land with shallow water lagoon behind it
• Forms when spit grows so long that it extends across a bay, closing it off

Question 4

How is a hooked/recurved spit formed?

Answer 4

• Spit whose end is curved landward
• Seaward end of spit naturally curves landward but hook may be more pronounced by secondary currents (river) or secondary prevailing wind direction

Question 5

How is an offshore bar formed?

Answer 5

• Ridge of sand found offshore
• Initially formed by rip-tide currents following destructive waves