The Bitter Springs preservational mode is the preservation of microorganisms in silica, in shallow Precambrian waters.^[1]

Contents 1 Taphonomic processes 2 Occurrence 3 Constraints 4 References

[edit] Taphonomic processes

Silica is emplaced around the organisms very rapidly, before their cells can even collapse; the strong silica is able to withstand great pressures and preserves three dimensional detail even after metamorphosis.^[1] Microbial mats, as they decayed, acted as nucleii for silica precipitation.^[1]

[edit] Occurrence

The preservational mode is only present in the Precambrian, and is restricted to shallow or tidal waters.^[1] After this point, organisms such as sponges extracted silica from the oceans in order to construct tests (skeletons), with the result that the surface oceans no longer became supersaturated with respect to silica when evaporation condensed the mineral.^[1]

[edit] Constraints

Because microbial mats and shallow, supersaturated seas were necessary for the formation of this form of deposit, larger eukaryotic organisms could not survive in the regions in which these deposits were formed; hence the record is mainly restricted to bacteria.^[1]

[edit] References

v • d • e Modes of preservation in the Cambrian Exceptional Phosphate Orsten type · Doushantuo type Silica Bitter Springs type Carbonaceous film Burgess Shale type Pyrite Beecher's Trilobite Bed type Casts and moulds Ediacaran type Legged trilobite fossil Conventional Shelly Small shelly fossils · Conventional fossils Organic Acritarchs · Organic-walled microfossils Traces Microbialites · Trace fossils

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