QUESTION 3 Chapter 3.1.2. Box 3.1. What is hydration-induced melting? O a, when a water-rich comet impacts a planetary surface, causing the impacted rocks to melt. b. when hot rocks come in contact with warm water at mid-ocean ridges, causing instant melting. When the liquid outer core heats up the base of the mantle sufficiently to cause melting. dWhen water-rich or gas-rich fluids are added to the mantle, reducing the melting temperature. QUESTION 4 Chapter 3.1.2. Box 3.1. Which type of melting causes volcanoes to occur at subduction zones? O a Decompression melting Increased temperature melting OCHydration-induced melting Od. All of the above

The rocks of oceanic crust are created by spending a huge amount of time in a water-rich environment. During the subduction process, the plates at greater depth are comprised of rocks that contain water in them. As this water reaches the mantle, the conditions of pressure and temperature forces these hydrated rocks to remove the water from them. This water then mixes up with the mantle and thereby reduces the melting point of the mantle rocks. This results in the formation of magma. These magma being lighter eventually rises upward that eventually leads to the formation of the volcanoes. This process of melting is known as the hydration-induced melting.

Thus, the hydration-induced melting process is responsible for the formation of volcanoes on the overriding plates.

Hence, the correct answers are mentioned above.