Question

Which of the following is a characteristic of continental rifts?

1) Some magmas are felsic and intermediate
2) Heat from hot mafic magma can melt continental crust
3) Solid asthenosphere undergoes decompression melting

Answer 1

The following a characteristic of continental rifts is 3) Solid asthenosphere undergoes decompression melting

Step-by-step explanation:

This means that as the plates pull apart, the pressure on the asthenosphere decreases, causing it to melt and form magma. This magma is usually basaltic in composition, which is a type of mafic magma. The statement that best fits this characteristic is option 3) Solid asthenosphere undergoes decompression melting.

For example, the East African Rift System is a continental rift zone where the African continent is slowly breaking apart. As the plates separate, the solid asthenosphere beneath the continent experiences a decrease in pressure, leading to decompression melting. This results in the formation of basaltic magma, which erupts to the surface as lava and forms new crust. Therefore the correct answer is 3) Solid asthenosphere undergoes decompression melting