Pyritisation
of fossil woodPyritisation
of fossil woodFossil remains provide the only direct evidence of the nature of prevailing ecology during the geological past. They are therefore of importance for understanding the evolutionary history of life on earth. Organic material is susceptible to decay but with appropriate conditions can become fossilised. Mineralisation by pyrite is known to preserve animal remains and is one of the most important modes of plant preservation. However, the factors that determine in which tissues and what settings pyritisation occurs are poorly understood, particularly within the plant realm. To date, most research on pyritised plant material has centred on optical reflected light microscopy of polished surfaces and scanning electron microscopy of fractures surfaces of the anatomy of fossil specimens. We have begun to investigate the pyritisation processes of fossil wood vis SEM EBSD anaysis, which reveals in detail the cellular structure of the wood prior to fossilisation (see examples below).
Associated workers:
Click on the thumbnails below to go to the full sized image.
 1.
FSE image of cell structures in a pyritised fossil twig. |
 2.
FSE detail of cell structure. |
 3.
FSE image showing the central pith (lower left) and outer tracheids in a
pyritised conifer axis. |
 4.
Automated EBSD image of the upper right part of Fig. 3. Note the coarser
crystal 'cell' structure of the pith compared with the tracheids. |
 5.
EBSP 'band contrast image' of Fig. 4; note now the appearance of an apparent
cellular structure , incorporating angular fragments and framboids (?),
particularly within the pith region, undetected in all previous images.
|
 6.
Equivalent 'EBSP 'pattern quality' image of Fig. 4. |
