Passage I
Metamorphic rocks form when temperature and/or pressure cause changes in preexisting rock. Figure 1 shows the temperature and pressure conditions in which certain facies (categories of metamorphic rocks) are formed.
A rock’s metamorphic grade (a measure of the intensity of metamorphism) is classified on a scale of low (very similar to the original rock) to high (very different from the original rock). Table 1 lists the grades of Facies A–G from Figure 1. Figure 2 shows characteristic minerals that may be present in rocks of a given grade.
5. Hornfels is a metamorphic rock formed when magma (molten rock) heats sedimentary rocks on Earth’s surface. According to Figure 1, hornfels is most likely a member of which of the following facies?
Your Answer is
Correct Answer is A
Explanation
The stem of the question mentioned sedimentary rock on Earth's surface, so it should be the closest to the surface, corresponding to Facies A in figure 1