Question #14f13

1 Answer
Jul 26, 2017

convection currents observed in liquids are a cycle. The hot liquid rises in the middle turns outwards drops on the sides and returns to the middle to rise again.

Explanation:

No one has observed the convection cycle in the mantle. It is extrapolated from the observed convection cycles in liquids.

There is evidence that the heat from a convection cycle in the mantle rises at divergent boundaries like the Mid Atlantic Ridge. There is also evidence that the subduction zones at the convergent boundaries between an ocean crust and a continental crust are places where the heat drops/

Based on the observed convection cycles in liquids and the evidence of heat movement in the mantle the theorized convection currents in the mantle are described as cycles.