rivers and coasts

• Erosion - attrition


  rocks that bash together to become smooth/smaller

  
• Erosion - solution


  acids in the river water that slowly dissolves rocks

  
• Erosion - abrasion


  the sandpapering/scraping action of a rock as it scrapes across a surface and wears itself away (on river banks and cliffs)

  
• Erosion - hydraulic action

  the sheer force of water crashing against the coastline causing material to be dislodged and carried away

  
• Transportation - solution


  minerals dissolve in water and are carried along

  
• Transportation - suspension


  sediment is carried along in the flow of water

  
• Transportation - saltation


  pebbles that bounce along the sea/river bed

  
• Transportation - traction

  boulders that roll along a river/sea bed by the force of flowing water

  
• mechanical weathering

  When rocks break apart due to physical changes, such as the formation of ice or salt crystals e.g. freeze thaw

  
• chemical weathering


  when acids dissolve rocks, such as limestone

  
• biological weathering


  breakdown of rocks by living things (animals + plants)

  
• deposition

  when the sea or river loses energy, it drops the material it has been carrying. It will drop the heaviest materials first as they require the most energy.

  
• longshore drift


  the movement of material along a coast by waves which approach at an angle (prevailing wind) to the shore but recede directly away from it
• constructive waves


  swash > backwash

  therefore builds up the coast and forms beaches as it also carries materials
• destructive waves


  swash < backwash

  therefore erodes the coast as the backwash is stronger so it will take material with it.