Question

What is the primary means of melting that occurs at divergent boundaries, convergent boundaries, and within a plate (intraplate)?

1) Magma rising from the mantle
2) Subduction of oceanic crust
3) Heat from the Earth's core
4) Friction between tectonic plates

Answer 1

Magma at divergent boundaries is produced by decompression melting, at convergent boundaries by subduction and water release, and at intraplate settings by heat from mantle plumes.

Step-by-step explanation:

The primary means of melting at divergent, convergent, and intraplate boundaries involve different geological processes:

• Divergent boundaries: Melting is primarily caused by decompression melting, where the mantle experiences decreased pressure as tectonic plates pull apart, leading to magma formation.
• Convergent boundaries: The process of subduction happens when one tectonic plate moves under another. Water released from the subducting oceanic crust lowers the melting temperature of the overlying mantle, causing magma to be produced.
• Intraplate settings: Magma generation is typically the result of heat from mantle plumes, which are thought to be generated at the core-mantle boundary and can cause melting of lithospheric rock independent of plate boundaries.

These processes are fundamental in shaping the geology of Earth and are deeply intertwined with tectonic plate movements and the formation of various geological features.