Exam 13: The Ocean Floor

Sediments derived primarily from the products of weathering on the continents are called ________.

Which one of the following is not part of the continental margin?

echo sounder Doppler radar sidescan sonar radar altimeters

When organisms living in seawater grow shells,the ratio between the isotopes of oxygen (18O/16O)trapped in their shell is dependent on the sea temperature.Why might geologists collect these sea shells from deep-sea sediments that are Pleistocene in age and measure their oxygen isotope ratios?

The continental rise lies at the bottom of the continental slope.

If Yellowstone were on the ocean floor,it would produce ________.

The lowest point on earth is in the ________ Ocean.

Multibeam provides the best modern technique for obtaining seafloor bathymetry,so why hasn't it been used for the entire ocean?

The most extensive mountain range on Earth extends for about 65,000 kilometers on the ocean floor and is known as the ________.

The best modern technique for obtaining high resolution bathymetry of the seafloor is ________.

A geologist is studying sediments on land that were originally deep sea sediments.She finds the minerals zircon and garnet in the sediments,which could only come from a continental region.These sediments must be ________.

Why isn't manganese mined on the seabed when there are abundant manganese nodules in some parts of the ocean floor?

Much of the Gulf of Mexico is underlain by large thicknesses of salt that formed in a small ocean basin like the red sea,as the north Atlantic spreading began in Mesozoic time.This salt is a good example of ________.

rift valley subduction volcanic island arc trench

Manganese nodules do not accumulate below 4500 meters depth because the manganese minerals are highly soluble in seawater below that depth.

In the present day,what is the most valuable non-living commodity obtained from sea floor?

Deep sea trenches are important features for plate tectonic studies because ________.

The principal technique for finding ocean depth today is ________.

Sailors in the 16th-18th century dreaded "rounding the horn" because of strong winds and heavy seas.Cape Horn is about latitude 55°S at the tip of South America.These sailors considered this a passage from the Atlantic to Pacific oceans,but this ocean is now often called ________.

The most important economic resource in the ocean today is ________.