Convection Currents and Plate Tectonics

As the plates move apart, the decrease in overlying _______________ causes parts of the mantle to melt, forming magma.

Magma rises through the weak areas in the crust to the Earth's surface and fills the gaps caused by spreading plates, forming _______________ volcanoes.

The decrease in overlying pressure causes parts of the underlying mantle to melt, forming _______________.

As the subducting plate sinks into the mantle, the high-pressure forces water out of its _______________ crust.

Water lowers the melting point of the overlying mantle, causing it to melt, form _______________.

Heat from the earth's ______ causes the mantle material to become less dense

The rising and sinking of the mantle material forms ______ currents

The ______ oceanic crust sinks deeper into the mantle under its own weight, pulling the rest of the plate with it

The age of rocks ______ to the centre of the mid oceanic ridge are the youngest

When earth's ______ reverses, the rocks record the reversals