Hi i'm remmy and i have already watched 4 ocean documentaries today.
Did you know the pacific plate is moving about as fast as a human fingernail is growing?
You can basically say goodbye to some very old rocks, vanishing in the mariana trench, everytime you clip your nails!!!
@remmy partial melt from that rock is being thrown back on the crust again in Japan, and Philipines, Mafic Basaltic rock sinks, and the lighter minerals melt to make a much more felsic magma which erupts to the surface as Rhyolitic, or Andesitic lava, but most of that ocean crust becomes part of the mantle which despite being hot enough to melt most rock, is kept mostly solid by pressure (most falsely believe it is molten which is likely due to convection, but solids convect too)
@remmy wooah