Author Question: What sorts of geologic structures would an earth scientist expect to find forming in a convergent ... (Read 76 times)

cnetterville

  • Hero Member
  • *****
  • Posts: 547
What sorts of geologic structures would an earth scientist expect to find forming in a convergent plate boundary? Draw a cross section to help explain your answer.
 
  What will be an ideal response?

Question 2

How do terranes relate the growth of continental crust over geologic time? What region of North America illustrates this process well?
 
  What will be an ideal response?



Pamela.irrgang@yahoo.com

  • Sr. Member
  • ****
  • Posts: 323
Answer to Question 1

Answer: You would expect structures that form under compression. Reverse (and thrust) faults would be forming at relatively shallow depths, where rocks are deforming in a brittle fashion. Folding of the rocks into anticlines and synclines would also be likely. I'd expect some variation on this diagram:

Answer to Question 2

Answer: Terranes are relatively small crustal fragments (microcontinents, volcanic island arcs, or oceanic plateaus). Terranes may be accreted to continents when subduction brings them to a trench, but they usually do not subduct due to their relatively low density. The terranes are peeled off the subducted slab and thrust onto the leading edge of the continent. Thus, they add bulk (mass, volume) to the edge of the continent. The western Cordillera is composed of many accreted terranes that originated mostly far to the south. Tectonic motions slathered them on to the edge of North America, and so their deformed, metamorphosed bulk piles up on the continent's leading edge like smashed bugs on the windshield of a fast-moving car.



Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question


 

Did you know?

Autoimmune diseases occur when the immune system destroys its own healthy tissues. When this occurs, white blood cells cannot distinguish between pathogens and normal cells.

Did you know?

Each year in the United States, there are approximately six million pregnancies. This means that at any one time, about 4% of women in the United States are pregnant.

Did you know?

There are approximately 3 million unintended pregnancies in the United States each year.

Did you know?

Multiple sclerosis is a condition wherein the body's nervous system is weakened by an autoimmune reaction that attacks the myelin sheaths of neurons.

Did you know?

Asthma occurs in one in 11 children and in one in 12 adults. African Americans and Latinos have a higher risk for developing asthma than other groups.

For a complete list of videos, visit our video library