New answers tagged

3

Where one part of a plate continues almost horizontally while an adjacent section is driven down into the mantle, wouldn't that cause a violent fracture of the plate, and if not, why not? In case of the Nazca plate probably not because that is still warm and partly ductile (see the linked work in the other thread). Also, these cracks and deformations ...


1

The forces of a magnetic field on materials that are not ferromagnetic and not electric conductors are negligible compared to pressure, tension, and buoyancy. It is likely safe to ignore them for the upper mantle. However, the lower mantle is a semiconductor with a significant thermal gradient, which induces electrical gradient via thermoelectricity. This ...


13

As you said, the Andean belt is divided into four segments, usually called the northern, central, southern, and austral volcanic zones (NVZ, CVZ, SVZ and AVZ, respectively; your map lacks the AVZ). This has been interpreted as a difference in the angle of subduction. Under the active zones, the subducting plate (called "slab") sinks into the mantle, ...


5

So, this is the setting. A relatively young plate plate is subducted under the south American continent. The subducting oceanic plate contains water that is squeezed out under pressure and starts to rise. Water (fluids) generally lower the melting point, so hot asthenosphere above the colder subducting plate partially melts, the magma, being more mobile, ...


-1

When an oceanic plate is subducted below a continental plate, it dives into the mantle, taking water with it and producing frictional heat which melts some of the rock (rock with a high water content melts more easily). This produces plumes of magma beneath the continental plate margins. As the magma is lighter than the mantle material, it rises until it ...


Top 50 recent answers are included