Marine Transportation Flashcards
What is traction?
Large stones and boulders are rolled and slid along the seabed and beach by moving sea water.
This happens in high energy environments.
What is saltation ?
Small stones bounce or leapfrog across the beach.
High energy conditions
What is suspension?
Very small particles of sand and silt are carried along by moving water.
What is solution?
Dissolved materials are transported within the mass of moving water.
Longshore drift occurs when what happens ?
When waves approach the shore at an angle and material is pushed up the beach by the swash in the same direction as the wave approach.
What happens as the water runs back down the beach?
The backwash drags material down the steepest gradient, which is generally perpendicularly back down the beach, where it is picked up by the following incoming wave.
What happens over a period of time ?
Sediment moves in a zigzag movement across the coast. If the material is carried some distance it will become smaller, more rounded and better sorted.
Obstacles such as groynes and piers interfere with what?
This drift and accumulation of sediment occurs on the windward side of the gyrones, leading to entrapment of beach material.
Deposition also does what?
Deposition of this material also take place in the sheltered locations, such as the head of a bay and where the coastline changes direction abruptly.
Here spits tend to develop.
