SES2 Plate Tectonics

What causes seafloor spreading to occur?

• Old crust is destroyed at divergent boundaries.

• New crust forms at divergent boundaries, pushing old crust outwards.

• Old crust pushes new crust towards divergent boundaries.

• New crust forms as plates move over hotspots.

Answer explanation

Seafloor spreading occurs at divergent boundaries where new crust forms as magma rises and solidifies, pushing older crust outward. This process continuously creates new oceanic crust.

Which of the following boundaries is a divergent boundary?

• The boundary between the Nazca Plate and the Pacific Plate

• The boundary between the South American Plate and the Nazca Plate

Answer explanation

The boundary between the Nazca Plate and the Pacific Plate is a divergent boundary where tectonic plates move apart, allowing magma to rise and create new crust. The other option describes a convergent boundary.

Tags

NGSS.MS-ESS2-3

When a divergent boundary happens under continental crust, it's called a:

• Rift Valley

• Block Mountain

• Folded Mountain

• Mid-Ocean Ridge

Answer explanation

A divergent boundary under continental crust creates a rift valley, where the land is pulled apart, leading to the formation of a low area. This is distinct from other geological features like block or folded mountains.

Tags

NGSS.MS-ESS2-2

When a divergent boundary occurs underneath the ocean, it's called a:

• Rift Valley

• Ocean Ridge

• Subduction Zone

• Fault Block Mountain

Answer explanation

A divergent boundary under the ocean creates new oceanic crust, forming an Ocean Ridge. This is where tectonic plates move apart, unlike a Rift Valley, which occurs on land, or a Subduction Zone, where one plate goes under another.

Tags

NGSS.MS-ESS2-3

NGSS.MS-ESS2-2

Tectonic Plate movement is caused by ______________.

• the rotation of the Earth

• ocean tides

• convection currents in the mantle

• the moon's gravity

Answer explanation

Tectonic plate movement is primarily driven by convection currents in the mantle. These currents are caused by the heat from the Earth's core, which creates a flow that moves the plates on the surface.

Tags

NGSS.MS-ESS2-1

In which type of boundary do the plates move away from each other?

• convergent

• normal

• divergent

• transform

Answer explanation

The correct answer is 'divergent' because at divergent boundaries, tectonic plates move away from each other, leading to the formation of new crust as magma rises to the surface.

The Great Rift Valley in Africa and the Mid-Ocean Ridge were all created by this boundary

• Divergent

• Convergent

• Reform

• Transform

Answer explanation

The Great Rift Valley and the Mid-Ocean Ridge are formed at divergent boundaries, where tectonic plates move apart, allowing magma to rise and create new crust.

Tags

NGSS.MS-ESS2-3

Which processes occur at divergent boundaries? Check all that apply.

• Volcanic eruptions

• Earthquakes

• Sea floor spreading

• Rifting

Answer explanation

At divergent boundaries, tectonic plates move apart, leading to volcanic eruptions, earthquakes, sea floor spreading, and rifting. All these processes are interconnected and occur as the crust is pulled apart.

Tags

NGSS.HS-ESS1-5

NGSS.HS-ESS2-1

Divergent Boundaries

• Create new crust

• Destroy crust

• Neither create or destroy

Answer explanation

Divergent boundaries occur where tectonic plates move apart, allowing magma to rise and solidify, thus creating new crust. This process contrasts with convergent boundaries, which destroy crust.

Tags

NGSS.MS-ESS2-3

Why did the oceanic plate subduct?

• Less dense

• More dense

• Heavier

• Thinner

Answer explanation

The oceanic plate subducts because it is more dense than the continental plate. This density difference causes the heavier oceanic plate to sink into the mantle at convergent boundaries.