Question 2.1

Using Figure 2.7, trace the boundaries of the South American Plate on a sheet of paper and identify segments that are divergent, convergent, and transform-fault boundaries. Approximately what fraction of the plate area is occupied by the South American continent? Is the fraction of the South American Plate occupied by oceanic crust increasing or decreasing over time? Explain your answer using the principles of plate tectonics.

Question 2.2

In Figure 2.7, identify an example of a transform-fault boundary that (a) connects a divergent plate boundary with a convergent plate boundary and one that (b) connects a convergent plate boundary with another convergent plate boundary.

Question 2.3

Using the isochron map in Figure 2.15, estimate how long ago the continents of Australia and Antarctica were separated by seafloor spreading. Did this happen before or after South America separated from Africa?

Question 2.4

Name three mountain belts formed by continental collisions that are occurring now or have occurred in the past.

Question 2.5

Most active volcanoes are located on or near plate boundaries. Give an example of a volcano that is not on a plate boundary and describe a hypothesis consistent with plate tectonics that can explain its presence there.