Author Question: What sorts of geologic structures would an earth scientist expect to find forming in a convergent ... (Read 81 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?

The average older adult in the United States takes five prescription drugs per day. Half of these drugs contain a sedative. Alcohol should therefore be avoided by most senior citizens because of the dangerous interactions between alcohol and sedatives.

Did you know?

The term pharmacology is derived from the Greek words pharmakon("claim, medicine, poison, or remedy") and logos ("study").

Did you know?

The senior population grows every year. Seniors older than 65 years of age now comprise more than 13% of the total population. However, women outlive men. In the 85-and-over age group, there are only 45 men to every 100 women.

Did you know?

Nitroglycerin is used to alleviate various heart-related conditions, and it is also the chief component of dynamite (but mixed in a solid clay base to stabilize it).

Did you know?

Many people have small pouches in their colons that bulge outward through weak spots. Each pouch is called a diverticulum. About 10% of Americans older than age 40 years have diverticulosis, which, when the pouches become infected or inflamed, is called diverticulitis. The main cause of diverticular disease is a low-fiber diet.

For a complete list of videos, visit our video library