Author Question: How was the style of plate tectonics different in the Archean than it is today? When did the present ... (Read 34 times)

vinney12

  • Hero Member
  • *****
  • Posts: 586

How was the style of plate tectonics different in the Archean than it is today? When did the present
  style of plate tectonics begin? What will be an ideal response?



Question 2

What is the origin of greenstone belts? What will be an ideal response?



Jossy

  • Sr. Member
  • ****
  • Posts: 336
Answer to Question 1

Earth in the Archean was much hotter than it is today because Earth's radiogenic heat production was
much higher; in other words, many radiogenic isotopes have decayed to stable daughters and no longer
give off heat. With more heat available, seafloor spreading and plate movements took place more
rapidly. The current plate tectonics style began by the Paleoproterozoic.



Answer to Question 2

Greenstone belts developed in back-arc marginal basins that open and then close. When the basin
opens, volcanism and sedimentation take place, and then the basin closes during a period of
compression. During closure, the rocks are intruded by plutons and metamorphosed, and the
greenstone belt is folded into a syncline and also faulted.




Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
 

Did you know?

Asthma cases in Americans are about 75% higher today than they were in 1980.

Did you know?

Carbamazepine can interfere with the results of home pregnancy tests. If you are taking carbamazepine, do not try to test for pregnancy at home.

Did you know?

During the twentieth century, a variant of the metric system was used in Russia and France in which the base unit of mass was the tonne. Instead of kilograms, this system used millitonnes (mt).

Did you know?

As many as 20% of Americans have been infected by the fungus known as Histoplasmosis. While most people are asymptomatic or only have slight symptoms, infection can progress to a rapid and potentially fatal superinfection.

Did you know?

Serum cholesterol testing in adults is recommended every 1 to 5 years. People with diabetes and a family history of high cholesterol should be tested even more frequently.

For a complete list of videos, visit our video library