A beach is a landform alongside a body of water which consists of loose particles, such as sand, gravel, pebbles, cobbles, and boulders. Wave, tide and current action carries, deposits and reworks the beach materials. Over time these changes can become substantial leading to significant changes in the condition, size and location of the beach.
Sand, gravel, and rock sizes are classified according to the Wentworth scale (see image in cache notes). This scale defines the size of sand as being of diameter between 0.0625mm to 2mm. Material sizes larger than this are classified using size terms such as gravel 2mm to 4 mm, pebbles 4mm to 64 mm, cobbles 64mm to 256 mm and boulders >256 mm.
Examine the condition of the material on Hallet Cove beach and answer the following questions. Send your answers to the cache owner by email or message. You can log immediately, but you do need to follow up with answers in a timely manner.
- Describe condition of the beach? Is it mainly rocks, sand or a mixture?
- What is the common size of the rocks found on the beach? What is the classification or size term for this material?
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Ref: Wentworth, C. K. (1922). "A Scale of Grade and Class Terms for Clastic Sediments". The Journal of Geology. 30 (5): 377–392.