Mountains and Plates 11.3

Front

Which of the following best describes the Plate Tectonics Theory?

Back

The theory that Earth's outer shell is divided into several plates that glide over the mantle.

Answer explanation

The correct choice describes the Plate Tectonics Theory, which states that Earth's outer shell consists of several plates that move over the mantle, explaining geological phenomena like earthquakes and volcanic activity.

Front

Type of plate boundary where two tectonic plates move away from each other.

Back

Divergent boundary

Answer explanation

A divergent boundary occurs when two tectonic plates move away from each other, leading to the formation of new crust. This is in contrast to convergent boundaries where plates collide, and transform boundaries where they slide past each other.

Front

How are mountain ranges like the Himalayas formed?

Back

By the collision and convergence of continental plates.

Answer explanation

Mountain ranges like the Himalayas are formed by the collision and convergence of continental plates. This tectonic activity causes the Earth's crust to buckle and fold, creating towering peaks.

Front

What is an accretionary wedge, and how does it form?

Back

A mass of sediment and rock scraped off a descending plate and piled up at a convergent boundary.

Answer explanation

An accretionary wedge forms at a convergent boundary where an oceanic plate descends beneath another plate. Sediment and rock are scraped off the descending plate and accumulate, creating the wedge shape.

Front

What is a primary cause of earthquakes?

Back

The sudden release of energy due to the movement of tectonic plates.

Answer explanation

The primary cause of earthquakes is the sudden release of energy due to the movement of tectonic plates. This movement creates stress along faults, leading to seismic activity.

Front

What is a terrane, and how does it relate to plate tectonics?

Back

A fragment of crustal material formed on, or broken off from, one tectonic plate and accreted to another.

Answer explanation

A terrane is a fragment of crustal material that forms on one tectonic plate and can be broken off and accreted to another plate. This process is significant in plate tectonics as it contributes to the formation of mountain ranges and geological diversity.

Front

Which type of plate boundary is most commonly associated with volcanic activity?

Back

Convergent boundary

Answer explanation

Volcanic activity is most commonly associated with convergent boundaries, where one tectonic plate is forced under another, leading to melting and magma formation. This process often results in volcanic eruptions.

Front

How do divergent plate boundaries contribute to the formation of new oceanic crust?

Back

By the upwelling of magma from the mantle, creating new crust as plates move apart.

Answer explanation

Divergent plate boundaries allow tectonic plates to move apart, enabling magma from the mantle to rise and solidify, thus forming new oceanic crust. This process is essential for the continuous renewal of the ocean floor.

Front

What is the primary effect of an earthquake on the Earth's surface?

Back

The shaking and displacement of the ground.

Answer explanation

The primary effect of an earthquake is the shaking and displacement of the ground, which occurs due to the sudden release of energy in the Earth's crust. This movement can cause significant damage to structures and landscapes.

Front

Explain the role of subduction zones in the formation of volcanic mountain ranges.

Back

Subduction zones cause the melting of the subducting plate, leading to magma formation and volcanic activity.

Answer explanation

Subduction zones occur where one tectonic plate is forced under another, causing the subducting plate to melt. This melting generates magma, which can rise to the surface and result in volcanic activity, forming volcanic mountain ranges.