Mountain chains are linear features characterized by components that can be recognized in the interiors of all continents (roots of ancient chains with little topography less than 3.3 billion years old). And along many continental margins (young chains and island arcs with majestic topography) as products of plate tectonics processes. Their thickened crust contains components recognizable in both ancient and modern chains: deformed continental margins with characteristic structure; continental or oceanic components; cores of deeply rocks buried subjected to very high temperatures and pressures producing recrystallization. And molten rocks that either crystallize deep in the crust or reach the surface as volcanic rocks; large faults, some with hundreds of km displacement, which trend parallel to and occasionally cross the linear chain. And features inherited from previous continental margins that make each unique and separable from other chains formed by one or more collisional plate tectonic events (orogenies). Yet all contain characteristics that also make them similar and formed by the same process.