The preservational mode of the
Doushantuo formation involves very early
phosphatisation on a cellular level - with cells being replaced by phosphate before they degrade.
Occurrence
The mode of preservation is typically found in shallow, high energy waters, as lenses of phosphate in carbonate rocks.
[ Its occurrence is assisted by high concentrations of ]phosphate
In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid .
The phosphate or orthophosphate ion is derived from phospho ...
, which are presumably led to precipitate around the degradation products of cells and cell walls.[
]
What is preserved
Cells are preserved at a cellular level, with arguments that sub-cellular structures may even represent cell nuclei.
Bias
Although the preservational window is open pretty continually from about through most of the Cambrian
The Cambrian Period ( ; sometimes symbolized C with bar, Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million ...
, it tends to preserve microscopic things, such as embryo
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...
s and bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...
.[
]
References
Doushantuo-type microfossils from latest Ediacaran phosphorites of northern Mongolia
Doushantuo embryos preserved inside diapause egg cysts
Three‐Dimensional Phosphatic Preservation Of Giant Acritarchs From The Terminal Proterozoic Doushantuo Formation In Guizhou And Hubei Provinces, South China
Cambrian fossil record
Fossilization
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