Fossilization occurs rapidly when the conditions are right. The conditions necessary for lithification of soft tissue give clues to unlock the history of a fossil deposit. Experiments show that microbes are involved in the mineralization of soft tissue. By decaying flesh they affect the acidity of the environment and release ions necessary for its mineralization. Fossilization in apatite seems to require associated death and decay. In the Jurassic Oxford Clay Formation in England, apatite preserved the soft tissue of many squid-like animals, probably after a mass mortality event occurred in a zone of already high phosphate levels from decaying carcasses. Apatite has also preserved gelatinous embryonic cells that deteriorate in hours. The presence of these microscopic fossils in mud rock gives clues about the conditions in which the sediments were deposited and lithified. Broken shells and sand grains, found in shale that contain soft tissue fossilized in illite, have led some researchers to conclude that the creatures were buried quickly in pulses of a dense mud flow. Soft tissue fossilization points to unusual conditions, conditions that are what would be expected in the sudden, extensive destruction of life, as recorded in the Genesis account of the worldwide Flood.
