Author Question: Where does the sand at a beach come from? What will be an ideal ... (Read 16 times)

FButt · **on:** Jul 16, 2018

Where does the sand at a beach come from?

What will be an ideal response?

Question 2

What factors can cause shoreline shape and position to change over time?

What will be an ideal response?

rnehls · **Reply #1 on:** Jul 16, 2018

Answer to Question 1

Most of the sand on beaches is delivered to the ocean from land by rivers and then moved along the shoreline by longshore currents. In some cases the sand may also be eroded from nearby shoreline outcrops or scoured from the seafloor by incoming waves.

Answer to Question 2

Coastal erosion causes shorelines to retreat in the landward direction, whereas sediment deposition moves shorelines in the seaward direction.
Rise or fall in sea level (caused by changes to ocean basin shape or the volume of water in the ocean) cause shorelines to shift.
Tectonic uplift or subsidence cause changes in shoreline shape and position.