How does mountain building relate to the growth of continents?
What will be an ideal response?
Answer: Continents grow through time by the collision and accretion of crustal fragments that cannot be subducted along convergent plate boundaries. The low-elevation regions of continents are areas of long-term tectonic stability, called cratons, where Precambrian metamorphic and plutonic rocks are present at or near the surface. Craton crust formed during mountain-building events between 1 and 4 billion years ago. These mountain-building events featured collisions of thick blocks of low-density, mostly igneous crust. North American crust is a collage of these crustal blocks. Although the Precambrian mountains were long ago eroded down and partly buried, the elevation of the continental interior of North America above sea level is a result of the crustal thickening that occurred during ancient periods of mountain building.
You might also like to view...
Nikita Khrushchev's campaign to open new lands to farming was called the _________ _________ ____________.
Fill in the blank(s) with the appropriate word(s).
The volcanic Emperor Seamount-Hawaiian Island chain resulted from a hot spot
a. True b. False
Active stratovolcanoes (or composite volcanoes) are most commonly found
a) along rift valleys (divergent boundaries) b) on hot spots c) along subduction zones d) along continent-continent collision zones e) in all of the geologic settings described above
Migmatite ____
A)is produced during the lower temperature range of metamorphism B)is a nonfoliated rock C)never occurs due to regional metamorphism D)always shows rotational metamorphism E)has both igneous and metamorphic characteristics