Module 2: Plate Tectonics Practice Quiz

Subduction zones are areas where new seafloor is created.

False

The Hawai'ian Islands were formed within the last 2 million years above a hot spot that is now inactive.

False

The asthenosphere is cooler than the lithosphere.

False

Transform faults are never found at mid-ocean ridges.

False

If two oceanic plates collide and one is older and cooler (and therefore, denser) than the other, what will happen?

A deep trench will form.

A cross section of Earth reveals a layered structure that has different thicknesses and densities. How do geologists know this?

from observing the transit times through Earth of seismic waves generated by earthquakes

Which statement with regards to hot spots is true?

Hot spots are relatively stationary features.

The Hawai'ian Islands formed as they pass over a hot spot in the middle of the ____.

Pacific Plate

Earlier then 200 million years ago, the continents were joined into one supercontinent called ____.

Pangaea

Alfred Wegener was a polar explorer who suggested that at one time, Earth's landmasses were joined into a supercontinent called Pangaea.

True

Density is a measure of relative heaviness and is defined as mass per unit volume.

True

One piece of evidence that suggests the existence of Pangaea is the apparent fit of continents across North and South Atlantic.

True

The oceanic crust is primarily made of basalt.

True

There are three types of plate convergences: continent-continent, ocean-continent, and ocean-ocean convergent plate boundaries.

True

The hot, partially melted, slowly flowing layer of Earth is called the ____.

asthenosphere

New crust is being generated ____.

at divergent plate boundaries

Geologists believe that a new ocean basin is forming ____.

at the East African Rift Valley

The Himalayan Mountains were formed as a result of ____.

continent-continent convergence

A "mystery" in our understanding of plate tectonics has been, until recently, the nature of the power source capable of moving the plates and the continents embedded within them. Recent evidence indicates the power source to be ____.

convection currents within Earth's mantle moving the plates

The rigid outer layer of Earth that comprises the continental crust, oceanic crust, and the uppermost mantle is called the ____.

lithosphere

One cubic meter of which of these would weigh the most?

mantle

The ____ accounts for 83 percent of Earth's volume.

mantle

The youngest seafloor rocks are found ____.

near the rift valleys of mid-ocean ridges

Japan is located along the "Pacific Ring of Fire" and experiences many earthquakes. The majority of the earthquakes around Japan occur ____.

only on the east side of the island where the Pacific plate subducts

What are the primary elements in Earth's continental crust?

oxygen, silicon, and aluminum

The magnetic striping of the seafloor is considered evidence of seafloor spreading and ____.

periodic reversals in the polarity of Earth's magnetic field

Some plateaus, ocean ridges, ancient island arcs, and parts of continental crust are too buoyant to be subducted. These are, instead, squeezed and sheared onto the face of a continent, forming ____.

terranes

A boundary in which crustal plates slide laterally past one another is called a ____.

transform fault

California's San Andreas fault is which type of plate boundary?

transform plate boundary

Scientists believe the breakup of Pangaea occurred about ____.

200 million years ago

About how many kilometers (miles) is it from the center of Earth to the outer edge of the outer core?

6,370 kilometers (3,980 miles)

The largest known mantle plume is located beneath ____.

Africa

Convection within the inner core facilitates continental drift.

False

As early as the 1700s, scientists and observers noticed a remarkable coincidence of shape of the Atlantic coasts of Africa and ____.

South America

What is the primary reason for the inside of Earth being hot?

The decay of radioactive elements is creating heat in Earth's inner layers.

Why was Alfred Wegener's idea of continental drift dismissed?

The evidence at the time seemed to suggest a solid mantle that did not allow drifting of continents to be possible.

Which statement is true with regard to subduction zones?

They are zones where old seafloor descends into the crust and mantle.

Roughly how fast do most lithospheric plates move?

about 5 centimeters per year

Buoyancy is the ability of an object to float in a fluid by ____.

displacing a volume of water equal in weight to its own weight

The mid-ocean ridges are ____.

divergent plate boundaries