Author Question: Explain why the mountains of the Western Cordillera of North America exhibit high elevations but do ... (Read 45 times)

go.lag · **on:** Jul 16, 2018

Explain why the mountains of the Western Cordillera of North America exhibit high elevations but do not have deep crustal roots.

What will be an ideal response?

Question 2

Continents tend to have the oldest rocks in the center with younger rocks flanking the center. Explain this observation, with reference to cratons and exotic terranes.

What will be an ideal response?

onowka · **Reply #1 on:** Jul 16, 2018

Answer to Question 1

The region is underlain with low-density buoyant mantle.

Answer to Question 2

Precambrian rock masses (cratons) are preserved, yet usually highly metamorphosed. These rocks were emplaced in the middle to lower crust during mountain building, then exposed and later buried under sedimentary rocks. Bands of younger rock formed by accretion of material that was too light (i.e., crust) to subduct. Many are volcanic arcs and are referred to as exotic terranes.