On the basis of mode of origin, mountains are classified as
- Original or Tectonic mountains
- Circum-erosional or Relict or Residual mountains
Original or Tectonic mountains are formed as a result of tectonic forces.The tectonic mountains may be categorized into:
- Fold mountains (the Himalayas, the Rockies, the Andes)
- Block mountains (Vosges mountains in France, the Black Forest in Germany, Vindhya and Satpura in India)
- Volcanic mountains (Cascade Range in the USA, Mount Kenya, Mount Kilimanjaro, Mount Fujiyama).
Residual landform, also called Relict Landform, landform that was produced as the remains of an ancient landscape, escaping burial or destruction to remain as part of the present landscape. Residual landforms are often the result of changed climatic conditions, but they may be due to volcanism or to crustal uplift and downwarping.
Circum-erosional or Relict or Residual mountains (Aravallis in India, Urals in Russia) are the remnants of old fold mountains derived as a result of denudation (strip of covering).
Residual mountains may also evolve from plateaus which have been dissected by rivers into hills and valleys.
Examples of dissected plateaux, where the down-cutting streams have eroded the uplands into mountains of denudation, are the Highlands of Scotland, Scandinavia and the Deccan Plateau.