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?
Responses
A meltingmelting
B erosionerosion
C crystallizationcrystallization
D tectonic burialtectonic burial
Question 2
What process is most likely occurring at point 9 in the diagram?
Responses
A melting of metamorphic rock into magmamelting of metamorphic rock into magma
B melting of sedimentary rock into magmamelting of sedimentary rock into magma
C crystallization of magma into igneous rockcrystallization of magma into igneous rock
D crystallization of magma into metamorphic rock crystallization of magma into metamorphic rock

Answer 1

1) B — erosion.
Reason: Rock 3 is igneous and the arrow to sediment (6) represents weathering/erosion that breaks down igneous rock into sediment.

2) A — melting of metamorphic rock into magma.
Reason: Rock 8 is metamorphic; the arrow to magma represents melting of metamorphic rock to produce magma.