Plate Tectonics and Earth's Interior

The diagram represents a model of Earth’s surface and internal structure. Letters A, B, C, and D represent four different layers. Some depths below Earth’s surface are shown. Which Earth layer is inferred to be composed of solid nickel and iron?

• A

• B

• C

• D

In which area of Earth’s interior is the pressure most likely to be 1.2 million atmospheres?

• Asthenosphere
• Stiffer Mantle
• Inner Core
• Outer Core

At which depth below Earth’s surface is the interface between Earth’s outer core and stiffer mantle located?

• 700 km
• 2900 km
• 2000 km
• 5100 km

Scientists have classified Earth’s interior into the known layers based primarily on evidence gained by studying

• deep drill cores
• volcanic eruptions
• gravity measurements
• earthquake seismic waves

According to the Earth Science Reference Tables, as the depth within the Earth's interior increases, the

• density, temperature, and pressure increase
• density, temperature, and pressure decrease
• density and temperature increase, but pressure decreases
• density increases, but temperature and pressure decrease

Compared to oceanic crust, continental crust is generally

• older and thinner
• older and thicker
• younger and thinner
• younger and thicker

When two tectonic plates collide, oceanic crust usually subducts beneath continental crust because oceanic crust is primarliy composed of igneous rock that has

• low density and is mafic
• low density and is felsic
• high density and is mafic
• high density and is felsic

The cross-section shows the direction of movement of an oceanic plate over a mantle hot spot, resulting in the formation of a chain of volcanoes labeled A, B, C, and D. The geologic age of volcano C is shown. What are the most likely geologic ages of volcanoes B and D?

• B is 5 million years old and D is 12 million years old

• B is 12 million years old and D is 6 million years old

• B is 9 million years old and D is 9 million years old

• B is 10 million years old and D is 4 million years old

The movement of tectonic plates is inferred by many scientists to be driven by

• tidal motions in the hydrosphere
• density differences in the troposphere
• convection currents in the asthenosphere
• solidification in the lithosphere

Which features are commonly formed at the plate boundaries where continental crust converges with oceanic crust?

• large volcanic mountain ranges parallel to the coast at the center of the continents
• A deep ocean trench and a continental volcanic mountain range near the coast
• An underwater volcanic mountain range and rift valley on the ocean ridge near the coast
• Long chains of mid-ocean volcanic islands perpendicular to the coast