Certain conditions are required for fossilisation [1] to take place. These
are:
* rapid burial under sediments, freezing in ice, embedding in hardened
resin (amber)
* prevention of decomposition
* consolidation and compression
PART
FREQUENCY
EXAMPLES AND CONDITIONS
WHOLE ORGANISM
Rare
Mammoths in ice, insects in amber, sloths mummified in caves (dry).
SOFT PARTS
Rare
Anaerobic acid conditions, peat bogs;
Soft marine/terrestrial plants: imprints left as C layer or impression.
HARD PARTS
Numerous
Bones, teeth, shells: often unaltered and intact; buried under
sediments.
The skull of twenty-million-years-ago Ekaltadeta Ima, a carnivorous
kangaroo, found in the rich fossil trove in Riversleigh limestone, North
Queensland.
