The relief

Theories about the formation and modification of the relief

• Catastrophism: this theory says that the relief has been created by sudden, short and violent events.

  Georges Cuvier

• Uniformitarianism: this theory says that the relief has been formed by geological processes that have been active since the formation of the Earth. 

Charles Lyell

Both theories are correct because some relief has been created by a violent and sudden event, but other has been formed little by little by a slow geological process.

Factors that shape the relief

• External geological agents:

• Climate: set of all the external agents that characterize a particular area (temperature, precipitation, humidity...).

• Lithology: part of geology that studies the rocks (grain size, particle size, chemical and physical characteristics, composition, texture, type of transport, mineralogical composition, spatial distribution, cementitious material...).

• Rock's structure
  

• Living organisms 

• Water, ice

• Wind 

• Gases