Question

Magma formation at convergent plate boundaries is caused by

1. frictional heating as the subducting plate rubs against the overlying plate
2. the evaporation of water in the subducting plate which produces steam that infuses rock in the overlying plate and lowers its melting temperature
3. the drop in pressure experienced by rising hot mantle rock
4. anomalously high concentrations of radioactive isotopes of uranium, thorium, and potassium that generate large amounts of heat
5. increased temperatures generated by compression of the two colliding plates

Answer 1

Magma formation at convergent plate boundaries is primarily due to the release of water from the subducting oceanic plate, which lowers the melting temperature of the overlying mantle, resulting in magma production through a process called flux melting.

Step-by-step explanation:

The formation of magma at convergent plate boundaries is primarily caused by the release of water from subducting oceanic plates, which lowers the melting temperature of the overlying mantle, leading to magma production. This process is known as flux melting and is directly related to the presence of hydrate minerals in the subducting plate that release water under high temperatures and pressures. It is the most accurate among the given reasons for magma formation in these settings.

The subduction process involves an oceanic tectonic plate sinking into the mantle beneath an overriding plate. As it descends, increasing pressure and temperature cause the hydrated minerals to release water, which lowers the melting temperature of the mantle above the subducting slab. This reduction in melting temperature allows the mantle material to melt and form magma, which can rise to create volcanic eruptions at the Earth's surface.