What are the two ways that magma can be generated?

What are the two ways that magma can be generated?

In this case, water overlying the subducting seafloor would lower the melting temperature of the mantle, generating magma that rises to the surface. Magma leaves the confines of the upper mantle and crust in two major ways: as an intrusion or as an extrusion. An intrusion can form features such as dikes and xenoliths.

What effect does heat have on the mantle?

The lower mantle is heated directly by conduction from the core. In conduction, heat is transferred as atoms collide. In the process of conduction, heat flows from warmer objects to cooler objects. Hot lower mantle material rises upward (Figure below).

Why does the mantle rock cool down as it reaches the surface?

As the core heats the bottom layer of mantle material, particles move more rapidly, decreasing its density and causing it to rise. The rising material begins the convection current. When the warm material reaches the surface, it spreads horizontally. The material cools because it is no longer near the core.

What is the thickest layer of the mantle?

The mantle’s thickness is about 2900 km – so if you consider the Earth’s core as one big thing, then the core is the “thickest layer” (though has a bigger radius is probably a better way of saying it) – but the idea of a separate outer and inner core is generally accepted.

What temperature is the upper mantle?

Temperature and pressure The highest temperature of the upper mantle is 900 °C (1,650 °F) Although the high temperature far exceeds the melting points of the mantle rocks at the surface the mantle is almost exclusively solid.

What makes the rock more fluid in the mantle?

Convection currents happen inside the mantle and are caused by the continuous circular motion of rocks in the lithosphere being pushed down by hot molasses liquid from the asthenosphere. The rocks then melt and float up as molasses liquid because it is less dense and the rocks float down because it is more dense.