(8.ESS2.4) Mechanisms for Plate Motion

8.ESS2.4 Review
Mechanisms for Plate Motion

Vocabulary

Mantle Convection - he very slow creeping motion of Earth's solid silicate mantle as convection currents carry heat from the interior to the planet's surface. The Earth's surface lithosphere rides atop the asthenosphere and the two form the components of the upper mantle

Slab Pull - a geophysical mechanism whereby the cooling and subsequent densifying of a subducting tectonic plate produces a downward force along the rest of the plate

Ridge Push - the result of gravitational forces acting on the young, raised oceanic lithosphere around mid-ocean ridges, causing it to slide down

Seafloor Spreading - the formation of new areas of oceanic crust, which occurs through the upwelling of magma at mid-ocean ridges and its subsequent outward movement on either side
Density - an objects mass in a given amount of space
Energy - the ability to do work

Multiple Choice

What's happening at A?

• Rock is being heated up by the core and moving toward the surface.

• Rock is being cooled down and moving toward the surface.

• Crust is being melted and sinking into the mantle.

• Slab pull is going to pull the plate along.

Multiple Choice

What's happening at B?

• A trench is being formed by a convergent boundary.

• Mantle material is cooling down and forming new crust at the mid-ocean ridge.

• Plates are being separated by mantle convection, leaving a gap between the plates.

• Rock is cooling down causing it to sink back into the mantle.

Multiple Choice

What's happening at C?

• The tectonic plate is being pushed along by the convection current underneath.

• Sunlight is heating up the crust, causing it to move around.

• Plates are being separated by mantle convection, leaving a gap between the plates.

• Rock is cooling down causing it to sink back into the mantle.

A: the core is heating up mantle material causing it to rise
B: new crust is being formed as mantle material reaches the surface and cools
C: the tectonic plate is being moved because of convection currents underneath and seafloor spreading that pushes the older crust away
D: crust is sinking back into the mantle at a convergent boundary
E: cooler rock from the surface is sinking back toward the lower parts of the mantle next to the core.

Multiple Choice

What causes mantle material to rise?

• Heat causes materials to become less dense and move toward the surface.

• Heat causes things to be more dense and move toward the surface.

• Cool temperature cause things to be less dense and move toward the surface.

• Cool temperature cause things to be more dense and move toward the surface.

Multiple Choice

Where does the energy come from to cause the tectonic plates to move?

• The heat from the sun warms up the crust

• The radioactive elements in the core release energy as they decay

• Energy from earth's motion through space causes the tectonic plates to shift

• The use of fossil fuels and the movement of heavy machinery causes the tectonic plates to move