Answer:
dynamothermal metamorphism can break down the structures of their constituent minerals, but the minerals are unstable in that metamorphic environment.
Explanation:
The above option is the logical answer to the question
What happens to the older crust during seafloor spreading?
Answer:
Oceanic crust slowly moves away from mid-ocean ridges and sites of seafloor spreading. As it moves, it becomes cooler, more dense, and more thick. Eventually, older oceanic crust encounters a tectonic boundary with continental crust. In some cases, oceanic crust encounters an active plate margin
Explanation: