What important physical and chemical process occurs to subducted seafloor as it reaches a depth of 100 kilometres depth in the upper mantle?
A)It experiences nearly a doubling in its density as the subducted basalt recrystallizes to peridotite.
B)The subducted seafloor entirely melts generating a line of explosive volcanoes.
C)Heat from the surrounding mantle drives off water and other volatiles from the slab, which escape upwards, lowering the melting point of the overlying asthenospheric mantle.
D)The cooling of the ocean crust from the cold, deep ocean water of the trenches causes the subducted crust to freeze the mantle, cracking and freezing it to generate the largest earthquakes.

Question

Quizplus · Accepted Answer

As subducted seafloor reaches depths of around 100 kilometres in the upper mantle, the heat from the surrounding mantle causes water and other volatiles trapped in the slab to escape upwards. These volatiles lower the melting point of the overlying asthenospheric mantle, leading to the generation of magma that can fuel volcanic activity. This process is known as flux melting and is responsible for the formation of many volcanic arcs associated with subduction zones.

What Important Physical and Chemical Process Occurs to Subducted Seafloor