Examine the figure and consider a rock under the conditions shown by the black dot labeled "Start here." What would you have to do to that rock in order to cause it to begin melting?

Question

Quizplus · Accepted Answer

According to the figure, the rock is currently located in the solid region of the diagram (left of the solidus line). In order for the rock to begin melting, it would need to cross the solidus line and enter the two-phase region where both solid and liquid may exist together. This could be achieved by increasing the rock's temperature (moving it to the right in the diagram), decreasing its pressure (moving it upward), or adding water (which could decrease its melting temperature and/or change its composition). Therefore, any of these options could help the rock to start melting.

Examine the Figure and Consider a Rock Under the Conditions