The Western Cordillera has three sections. They are:
The Eastern Mountains are made up of two mountain ranges. These two mountain ranges are the Rocky Mountains and the Columbia Mountains.
These mountain ranges are separated by a long valley called 'The Rocky Mountain Trench', which was created by erosion along a zone of faults.
The Rockies (Rocky Mountains) are the youngest mountains in Canada (See 'physical features of the western cordillera' for a picture of the Rockies). They are also made up of mainly sedimentary rock, and were created by faulting and folding.
The Columbia Mountains are made up of mainly sedimentary rock and some metamorphic rock that is beneath the surface in layers. These mountains are not as tall as the Rockies because they are older and erosion has started to happen. They are also made by faulting and folding, just like the Rocky Mountains.
The Interior Plateaus were made by volcanic activity and are made of igneous and sedimentary rock. They contain very valuable metals like zinc, copper, and even gold. Also, the Interior Plateaus are in the center/middle of the Western Cordillera.
The Coast Mountains were created from the Pacific Plate going underneath the North American Plate, and the pressure from this happening caused magma to rise into the Earth's crust. When it cooled, it then formed the Coast Mountains. The Coast Mountains are made of metamorphic and igneous rock.
The Coast Mountains have a deep trough running through the middle, just like the Eastern Mountains, splitting them into two ranges. These two ranges are the Island Mountain Range, which is on offshore islands; and the Coast Mountain Range, which is on the mainland.
The Pacific Ocean fills the trough that divides the Island and Coast mountain ranges.