Ho ho, far away we go
To a land that’s far across the sea
Bing bong, sound the sailing gong
For now we’re leaving for Adventure Island
A sand island is an island that is largely made of sand. The world's largest sand island is Fraser Island. Other examples of large sand islands are Moreton, North Stradbroke and Bribie islands, which also lie off the east coast of Australia. Other well known sand islands surround Cape Cod, including Martha's Vineyard and Nantucket. Sea water currents transport eroded deposits along the shoreline through a process known as longshore drift.
Longshore drift affects numerous sediment sizes in different ways depending on the sediment size. Sand is largely affected by the oscillatory force of breaking waves, the motion of sediment due to the impact of breaking waves and bed shear from long-shore current. Shingle beaches are much steeper than sandy ones, plunging breakers are more likely to form, causing the majority of long shore transport to occur in the swash zone, due to a lack of an extended surf zone.
Diagram demonstrating longshore drift
1=beach
2=sea
3=longshore current direction
4=incoming waves
5=swash
6=backwash
Adventure Island in the kingdom of Diddley-Dum-Diddley is populated with strange inhabitants and lot of birds. To answer the tasks for this earthcache you need visit the island and send your answers to the cache owner by message or email. To show you have visited this earthcache location you will need also include a picture of yourself or your GPSr with the view across the channel.
Flower Potts asks - Is the island beach formed from sand or shingle?
Captain Crook asks - What is the common size of the sediment on the beach?
Miser Meanie asks - Estimate how much sediment is moved on this island beach by each tide cycle? You will need to work out the length and width of the beach. Assume the movement of sand is 5mm deep.