Author Question: Describe the plate tectonic theory. What will be an ideal ... (Read 71 times)

scienceeasy · **on:** Jul 29, 2018

Describe the plate tectonic theory.

What will be an ideal response?

Question 2

Why is it that the most ancient rocks are found on the continents, and not on the ocean floor?

What will be an ideal response?

asdfasdf · **Reply #1 on:** Jul 29, 2018

Answer to Question 1

Answer: The lithosphere is broken up into about a dozen rigid moving plates that move in response to convection cycles within the planet's interior. Two types of boundaries between these platesdivergent and convergentare the sites where crust is formed (seafloor spreading) and destroyed (subduction zones). At transform boundaries, plates slide horizontally past each other.

Answer to Question 2

Answer: The ocean floors are sites of crustal formation. New crust generated at a spreading center, pushes older crust away. In general, continental crust does not get subducted because of its low density. Older oceanic crust has been subducted, while older continental crust has not.