Question 20.11

Why would you want to know the timing of high tide if you wanted to observe a wave-cut terrace?

Question 20.12

In a 100-year period, the southern tip of a long, narrow, north-south beach has become extended about 200 m to the south by natural processes. What shoreline processes could have caused this extension?

Question 20.13

After a period of calm along a section of the Gulf Coast of North America, a severe storm with high winds passes over the shore and up the Mississippi Valley. Describe the state of the surf zone before the storm, during it, and after the storm has passed. What would happen to inland rivers?

Question 20.14

What are the chief differences between the Atlantic and Pacific oceans with regard to topography, plate tectonics, volcanism, and other seafloor processes?

Question 20.15

How might plate tectonics account for the contrast between the broad continental shelf off the east coast of North America and the narrow, almost nonexistent shelf off the west coast?

Question 20.16

A major corporation hires you to determine whether New York City’s garbage can be dumped at sea within 100 km offshore. What kinds of places would you explore, and what would your concerns be?

Question 20.17

There is very little sediment on the floor of the central rift valley of the Mid-Atlantic Ridge. Why is this so?

Question 20.18

A plateau rising from the deep seafloor to within 2000 m of the surface is covered with foraminiferal ooze, whereas the deep seafloor below the plateau, about 5000 m deep, is covered with clay. How can you account for this difference?

Question 20.19

You are studying a sequence of sedimentary rocks and discover that the beds near the base are shallow marine sandstones and mudstones. Above these beds is an unconformity, overlying which are nonmarine sandstones. Above this group of beds is another unconformity, and overlying it are marine beds similar to those at the base. What could account for this sequence?