University of Bristol
EARTH
SCIENCES

The Miracle of Minerals

Olenoids serratus, Middle Cambrian Burgess Shale, trilobite.

Preservation of tissues which decay rapidly (e.g. muscle)
requires replication in a stable mineral early enough
to prevent the loss of morphological detail.

Allison 1988

This is the process of mineralisation.

The process of mineralisation is the changing of organic material into an inorganic state. Decaying organic tissue is generally replaced by calcium carbonate and or calcium phosphate. The rate at which an organism decays determines which minerals replace which tissues. The most important factor is the decay, for without decay no mineralisation would occur. Experiments using sterile carcasses were found to generate no precipitation of minerals.

The most spectacular mineralisation occurs in anaerobic conditions. These experiments generated the production of apatite (a phosphatic mineral). Recent experiments by Briggs and Kear (1994) on decaying shrimps found that different minerals tended to replicate in specific areas of a carcass.

Idealised shrimp showing where the two different tyupes of mineralisation, crystal bundles and mineralised tissues commonly occur. Briggs and Kear 1994.

The results can be spectacular. In many cases exquisite details of muscle and fine tissues are visible to the eye. The use of an scanning electron microscope allows further detailed structures to be identified.

The mineralisation process is incredibly dynamic. All these alterations are being driven by the decay process within the carcass itself, by tiny microbrials that recycle the organic material and generate a process that allows us a view of a different world and time.

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