Exam 6: The Active Earth: Plate Tectonics

The Hawaiian Island chain was formed over a(n) ____________________.

The circulation of the mantle is driven by which of the following?

The ____________________ theory states that the lithosphere is a shell of hard, strong rock that floats on the hot, plastic asthenosphere.

The reason that the mantle below the asthenosphere is stronger than the mantle above it is because the increasing pressure overcomes the effect of rising temperature.

A geologist would expect this phenomena to occur when one plate slips past another. _____________

Explain how a hot-spot forms and how they differ from mantle plumes.

The Antarctic Circumpolar Current isolated Antarctica over the South Pole because of ___________ ___________ that occurred between 38 and 28 million years ago.

The seafloor spreading hypothesis was put forth after oceanographers detected changes in the magnetic polarity of newly formed oceanic crust near the Mid-Atlantic Ridge.

If you were studying guyots in the Pacific Ocean, which would be the oldest of the chain?

If a geologist studied the San Andreas Fault, she or he would be examining what specific type of plate boundary? ____________________

A geologist who studies the uppermost mantle and overlying crust would be researching which specific segment of the lithosphere? ________________

Explain why the mantle contains plastic and weak rock in the asthenosphere yet stronger rock at the bottom of the mantle near the outer core.

If you were a geologist, you would expect what to form inland near subduction zones due to the movement of mantle through the lithosphere.

There have been three supercontinents in geologic past. Which supercontinent would contain fossil evidence since it formed during the Paleozoic Era?    ____________________

When two continental plates converge, they form ____.

The interior of lithospheric plates are normally tectonically active with occurrences of earthquakes and volcanoes because these areas represent major plate boundaries.

__________ have occurred on average every 500,000 years during the past 65 million years of Earth's history.

If you were a geologist studying Harry Hess during World War II, which specific discovery would you have made after mapping the depth of the ocean floor? _________________

Explain the two possible mechanisms that Wegener proposed to explain how continents drift.

Where two plates carrying oceanic crust converge __________________.