Mountain chain

A mountain chain is a row of high mountain summits, a linear sequence of interconnected or related mountains, or a contiguous ridge of mountains within a larger mountain range. The term is also used for elongated fold mountains made of several parallel chains, sometimes called chain mountains. In mountain ranges the term is common, whereas in hill ranges a sequence of hills is usually called a ridge or hill chain. Elongated mountain chains occur most often where fold mountains have been squeezed by lateral pressure, and in nappe belts, where a sheet of rock has been pushed over another rock mass. Horst ranges and fault block mountains rarely form parallel chains. The linear pattern follows the direction of the thrust forces and the fault zones between the individual chains, where crushed rock erodes easily and carves long longitudinal valleys. Harder rock forms continuous ridges that run roughly parallel, interrupted only by short transverse valleys, and erosion later cuts the crests into summit chains, cols and passes.