A tombolo is a coastal depositional landform that connects an offshore island to the mainland. Arrange the following stages in the progressive development of a tombolo in the correct sequential order, from first to last.
- 1Ocean waves refract around an offshore island, dissipating their energy and creating a sheltered, low-energy marine zone behind it.
- 2Longshore drift moves littoral sand and shingle along the mainland coastline into the sheltered zone of quiet water.
- 3Accumulating beach sediment builds outward from the mainland coast as a narrow sand spit extending across the water gap.
- 4The advancing ridge of sediment reaches and attaches directly to the offshore island, forming a continuous land bridge.
Answer
The correct order of tombolo formation begins with wave refraction creating a sheltered low-energy zone behind an island, followed by longshore drift depositing sediment in the calm area, the outward growth of a spit from the mainland, and finally the attachment of the sediment ridge to the island.
The formation of a tombolo begins when incoming sea waves refract around an offshore island, dissipating their energy and creating a sheltered, low-energy zone behind the island. Longshore drift then transports sand and shingle along the coastline into this calm area. As sediment accumulates, it extends outward from the mainland as a spit until it eventually spans the gap and connects to the island, forming a tombolo.
Step-by-Step Solution
Key Concept
Tombolo Formation via Wave Refraction and Longshore Drift