During mantle convection, heat from the earth's core causes material in the mantle to expand and move upward. What happens when it reaches the top?

1 Answer
Oct 29, 2017

Mid Ocean ridges are formed pushing the curst apart forming new ocean crust, Also hot spots are formed causing volcanos and volcanic islands.

Explanation:

The mid Atlantic ridge is one place where the magma is thought to rise due to convection currents in the mantle. Undersea volcanos and vents are formed where the magma comes to the top of the crust. Iceland is a place where the volcanos reach the surface. It is stunning to see the places in Iceland where the crust is splitting apart as the upwelling magma pushes the European plate away from the North American plate.

Examples of hotspot are the Hawaii islands and Yellowstone Caldera
As the crust is pushed over the hotspot volcanic islands are formed.
Kauai being the oldest island formed by the hotspot and the Big Island of Hawaii the youngest. The Yellowstone Caldera is the cone left over from a volcanic eruption. The hotspot under the Caldera causes the famous geysers and hot springs in Yellowstone National Park.

The upwelling magma causes ballistic volcanos found in mid ocean ridges and hotspots like Yellowstone.