Which geologic process is occurring to cause this conversion?

metamorphism

Explanation:

Metamorphism is a geological process where a mineral is chemically replaced, undergoing metamorphosis, becoming another, brought about by solution or by magmatic gases.

Metamorphism of this type, in general, is restricted to the surroundings of an intrusive body, which supplies the fluids capable of causing the metamatisation of the enclosing rocks. The synonyms of the word metasomatism are metasomatosis and metasomatic process. The word metasomatosis can also be used as a name for specific varieties of metasomatism.

producers: apple trees, potatoes, carrots, grains, acorns, cabbage, grass, corn, lettuce

consumers: deer, mice, rabbits, chickens, squirrels, horses, worms, cows

predators: eagles, frogs, wolves, owls