Question

the rock cycle describes the transitions through geologic time among the three main rock types: sedimentary, metamorphic, and igneous. as the diagram illustrates, each of the types of rocks is altered or destroyed when it is forced out of its equilibrium conditions. the three types of rocks are identified on the diagram as: igneous (3), sedimentary (6), and metamorphic (8). given this information, which process is most likely occurring at 4? a melting b erosion c crystallization d tectonic burial what process is most likely occurring at point 9 in the diagram? a melting of metamorphic rock into magma b melting of sedimentary rock into magma c crystallization of magma into igneous rock d crystallization of magma into metamorphic rock

Explanation:

1. For the first question about point 4: Point 4 shows a transition from igneous rock (3) to sedimentary rock (6). Erosion breaks down rocks into sediments which then form sedimentary rocks. Melting would turn rock into magma, crystallization forms igneous rock from magma, and tectonic burial is related to the formation of metamorphic rock from burial - related pressure and heat.
2. For the second question about point 9: Point 9 shows a transition from metamorphic rock (8) to magma (1). The process is the melting of metamorphic rock into magma. Crystallization turns magma into igneous rock, and sedimentary rock is not involved in this transition at point 9.

Answer:

1. B. erosion
2. A. melting of metamorphic rock into magma