science landforms and plate boundaries

Question 1

When does an Island Arc form?

Answer 1

An Island Arc forms as volcanic eruptions create new land and
plates continue to move

Question 2

What is subduction?

Answer 2

It is when two plates collide and the dense plate slips beneath the plate that is less dense.

Question 3

Explain Continental Collision

Answer 3

Continents collide where subduction completely closes an
ocean. The buoyant continental crust lifts up a broad region
known as a collisional mountain range.

Question 4

Explain Continental Rift—Plate Rips Apart

Answer 4

As the plate stretches and thins, the underlying asthenosphere flows upward and expands like a hot-air balloon, lifting the region to higher elevations. The continental crust breaks along faults, forming long mountain ranges separated by rift valleys.

Answer 5

If divergence continues, the continental crust completely breaks apart and thinner oceanic
crust forms between the two continental blocks.
● The ocean basin sinks below sea level because the crust is thinner and more dense, and
therefore less buoyant.
● Continued plate divergence can completely rip a continent apart and open a new ocean
between the continental fragments.

Question 6

Explain Shear Zones

Answer 6

The broad zone of shearing at a transform plate
boundary includes masses of rock displaced tens to
hundreds of miles, shallow earthquakes, and a
landscape consisting of long ridges separated by
narrow valleys

Question 7

what are the steps of land formation at Hot Spots?

Answer 7

1. A spot of hot mantle material
   breaks through thin crust.
2. The plate continues to move over the
   hotspot with convection currents.
3. A chain of volcanic islands is created as
   lava flows build new crust.