Author Question: How was the style of plate tectonics different in the Archean than it is today? When did the present ... (Read 57 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?

You should not take more than 1,000 mg of vitamin E per day. Doses above this amount increase the risk of bleeding problems that can lead to a stroke.

Did you know?

Most fungi that pathogenically affect humans live in soil. If a person is not healthy, has an open wound, or is immunocompromised, a fungal infection can be very aggressive.

Did you know?

According to the American College of Allergy, Asthma & Immunology, more than 50 million Americans have some kind of food allergy. Food allergies affect between 4 and 6% of children, and 4% of adults, according to the CDC. The most common food allergies include shellfish, peanuts, walnuts, fish, eggs, milk, and soy.

Did you know?

Calcitonin is a naturally occurring hormone. In women who are at least 5 years beyond menopause, it slows bone loss and increases spinal bone density.

Did you know?

According to research, pregnant women tend to eat more if carrying a baby boy. Male fetuses may secrete a chemical that stimulates their mothers to step up her energy intake.

For a complete list of videos, visit our video library