epigenesis

The term "epigenesis" has two primary meanings. In biology, it refers to the theory that an organism develops from an egg or spore through a series of processes where undifferentiated cell masses develop into specialized organs and systems. This contrasts with the older theory of preformation.1

In geology, "epigenesis" describes changes in a rock's mineral character due to external influences. This is distinct from "diagenesis," which encompasses all the processes that alter sediment after deposition but before it becomes rock, occurring at relatively low temperatures and pressures. "Epigenetic" in a geological context refers to structures or deposits formed after the surrounding rock has already been laid down.1234