Science Focus Topic 7 Notes: Mountains | Print |
Mountain building takes many years.
Cordillera is Spanish for mountain range.

Mountain Formation and Distribution

- most mountains are large areas that have uplifted due to the movement (converging, diverging or sliding) or heating of tectonic plates, where the build up of heat and pressure can cause folding and faulting
- sedimentary rock under slow, gradual pressure can fold (bend like plastic because they are made soft by the heat) or break - and can be changed to metamorphic rock in the process
- the upward, or top part of folded rock is called
anticline, the bottom is called syncline
- rock that is too brittle to fold under heat and pressure, will break, called thrust faulting
- when older rock ends up on top of younger rock as a result of
thrust faulting, the result is the formation of fault block mountains
- movement of rock along a fault can be vertical or horizontal and can be traced by the location of the '
basement rock' on both sides of the fault (see Figure 5.68, p. 413)
- mountains can be formed by the convergence of continental and oceania plates (the Continental plate is lighter and rides over the Oceanic plate) a combination of processes creates
complex mountains

Ages of Mountains

- mountains that are jagged at the top are 'young' mountains, while those that are more rounded (due to erosion and weathering) are 'old' mountains


- subduction of the Juan de Fuca plate (off the west coast of North America) has caused folding, faulting and uplifting, as well as magma has created volcanoes.
- the Himalayas are the youngest mountain range with the highest mountains (and still growing)
- one of the oldest ranges is the
Laurentian Mountains, in Quebec (they are being worn down)

Wrap-up p. 417 (for review)