Phosphatization

[4][6] The structures that are most famously preserved in phosphate in the Burgess Shale are the midgut glands of Leanchoilia,[7] perhaps on account of their central position and plausibly a low pH.

Phosphatization can be microbially mediated, especially in decay-resistant groups such as arthropods; or substrate-dominated, where phosphate-rich tissue leads the mineralization process (as in fish).

The phosphatic microfossils of the Doushantuo Formation, a fossil-rich lagerstätte of the Ediacaran period, about 590–565 Ma (megaannua; million years ago), display some of the most spectacular cellular-level preservation known from the geologic record.

The fossils include what may be metazoan blastulas, possibly animal embryos at an early stage in cell division.

The Doushantuo Formation presents a classic example of phosphatic fossilization:[excessive quote] A refinement to viewing the internal structure of fossilized embryos uses specialized microscopic three-dimensional X-ray computed tomography, a kind of micro CAT scan.